another standard carb issue

Can anybody recommend me a good place to order some OEM carb parts from?

The place i was going to order from(http://parts.hondaofbournemouth.co.uk/) has put there prices up since i phoned them a few days ago for a quote.
i need a gasket set(top gasket is pretty much dead its been apart that much)
65 idle
172main
needle kit and a float valve

if this lot wont work then i think i am going to give up haha

Try www.johnoldfield.co.uk

R056rx wrote:Try www.johnoldfield.co.uk

just tried all the part numbers with no luck but i will give them a call in the morning cheers

Well parts are ordered, hondaofbournemouth dropped there prices down again for some reason and johnoldfield is closed today.
Don't know why they bumped up there prices for one day, maybe just trying there luck
fingers crossed these parts turn up fast and get the bike sorted so i can finally go get muddy

Andy i am sure that you dont need the 172 mj , you have the scorpion exhaust on your bike that is very free flowing ( loud ) so the 178 mj must be spot on for your altitude . I dont think that the jetting its the problem , because even if you run little bit rich the bike should still run , if the bike does not run at all there is some other problem .

Mad Frosty wrote:Andy i am sure that you dont need the  172 mj , you have the scorpion exhaust on your bike  that is very free flowing ( loud  )  so the 178 mj must be spot on for your altitude . I dont think that the jetting its the problem  , because even if you run little bit rich the bike should still run , if the bike does not run at all there is some other problem .

well the bike fires up and idles fine(at the current settings) but try's to die as soon as i roll off the throttle.
i got the 172 for the future, if i get it running right i might consider taking it over to France, i normally go over there once every year or so to the pyrenees on the bike, loads of offroading fun over there and i could get the xr transported over there for £100 if my butt cheeks weren't up for it.

North American European Direct sales U Australian D,DK,DM General export
Stator 55 Watt 74 watt 74 watt 74 watt
Headlight 34 Watt, Plastic 34/34, Glass 34/34, Glass 34/34, Glass
Blinkers No Optional * Yes Yes
Brake Light No Yes Yes Yes
Horn No No Yes Yes
Corked Yes No Dlr. Discretion** No
OTD Jetting 125/65s/2nd 175/65s/3rd 112/65s/3rd 175/65s/3rd
Tires Dunlop D739FAJ/K695 IRC TR8 D/S IRC TR8 D/S IRC TR8 D/S
Speedo 99mi Odo Yes Yes Yes
Gearing 14/48 14/48 15/41 14/48
Mirrors No One Yes Yes
Keylock No Yes Yes Yes
* Plugs, wiring, switches, and mounts are there, but no blinker assemblies included.
** Dealer MAY install the kit, giving you a box of the original "corking" parts.
#13A Q: How do California bikes differ from the other NA bikes? They are identical except for the addition of a smog pump. It is located on the RH radiator (thus the empty mounting tabs there for the rest of the world) and is easily removed. Just unbolt the pump, and block the holes where it's lines mount to the cylinder. You can homebrew this by cutting the lines 1/2" or so from the cylinder and crimping them up on themselves, screw self tapping screws covered with RTV silicone into them, or using a kit such as that offered by Applied Racing.

#14 Q: What is the recommended uncorked jetting? Altitude and choice of exhaust tip is going to make a difference here, but ballpark is a 170 to 175 main and a 68S pilot for below 1000'. The richer pilot is a must have to keep things cooler at low speeds. Also, throw in a B53E needle, Honda PN 16012-MBN-641. It comes as a set with a new seat and has a richer grind at the tip, allowing more fuel at the lower throttle ranges. This info comes direct from a Honda service bulletin. (The Wrench 2/00)

Here's a couple variations that pop up. Some run as high as a 180 jet with stronger midrange results than the 175. They are easy to change, so grab a few extras and fiddle. Just remember to change only ONE THING AT A TIME when doing carb adjustments. It makes trouble shooting easier. Also, some have had bad luck with the B53E needle, getting funky throttle results with it. I run the stocker with no problems and have not yet tried the HRC one. I will asap for a comparison here.

#14A Q: How do I properly adjust the pilot screw? First, a quick definition to clear up a common misconception I see. The BRP has a pilot screw that can also be called a fuel screw because it is located on the outlet side of the carb. That means that screwing it in meters less fuel to the pilot circuit, while screwing it out meters more fuel to the circuit. If the screw were on the inlet side of the carb, it would be called an air screw and do just the opposite. Screwing it in would supply less air, screwing it out would supply more. Someone please correct me if I'm wrong, or if you have a better, more understandable, definition.

Anyway, here's the adjustment procedure for a fuel screw per Gary, our local group Einstein on stuff like this:

Make sure your engine is fully warmed up and set the pilot screw to 1.5 turns out. Then with the 68s installed, turn the pilot screw clockwise until the idle slows. Then turn the pilot screw counterclockwise until the idle slows again. Make a mental note of how many turns you made in between the low idle points. Then turn the pilot screw half way between the low idle points to finish the adjustment. If you turn the adjuster counterclockwise and the idle doesn't drop down, then you need a larger pilot jet. If you turn the pilot screw clockwise and the idle doesn't drop down, then you need a smaller pilot jet. After adjusting your pilot circuit, re-adjust your idle speed if necessary.

#15 Q: What's so special about the "S" in a 68s pilot jet? The 68s has smaller holes than a standard pilot. It will change the flow characteristics and atomization of the fuel. You can run a regular jet in there if you want, but then you won't be on the same playing field as the rest of us, meaning that we can't help you!

#15A Q: What's all this talk about the ACV (Air Cutoff Valve)?
#15B Q: What is the "Copsey Mod"? I'm gonna kill two berms with one bike here. The ACV is located on the rh side of the carb, just above the float bowl. Its the round casting that looks more at home on a mockup of the Death Star than on a bike carb. Behind it is a rubber diaphram that, in conjunction with some vacuum, actuates a valve that supplies air to the pilot circuit.

I've heard a couple of different theories on the function of this contraption, here's the one that works for me.

On the diaphram there is a 1/4" long nipple that seats into a valve. The valve is normally open, providing air to the pilot circuit. The nipple holds the valve in this open position using force provided by a spring located between the cover and the diaphram.

Also under the cover is a vacuum port that comes from the outlet side of the carb. Here's the theory of operation. Remember the diaphram is usually, under spring pressure, holding the valve open, supplying air to the pilot circuit. BUT, the valve operates whenever you are decelerating. When the slide is down and engine rpms are up, the port under the cover supplies vacuum that pulls the diaphram and pin away from the valve, allowing it to close.

This, in turn, allows less airflow to the pilot circuit, leaning out the flow a bit. It's an emissions device to help get the BRP green stickered.

The drawback to this is the creation of some popping from the exhaust on decel that cannot always be jetted out. So, if you've tried different jets and screw positions and still can't get things quite right, you may want to look into the valve and it's activities a bit more.

There are three methods to disable the valve. Two are valve friendly, meaning cheap, one is not. This third mod applies a totally different theory into the operation of the valve. Instead of getting into depth and tying up space on the FAQ, there is some user info located here:

All of the following came from the Yahoo! XR650R group over a period of a couple years.

I have not, as of 03/11/04, tried the "Copsey Mod". I have run into the mod of cutting the nipple, and do not recommend it. The bike in mention had a surge at steady throttle that could not be jetted out. The diaphram is around 80 bucks US if it is cut, therefore try the "Copsey Mod" first if you feel you must.

The reason why I have not done any testing with the ACV is because I don't have to! I don't need more engine braking, and I have jetted out the decelleration pop that leads many onto this topic.

Eric

____________________________________________________________________________

From: Copsey Stephen-WCSC001
Date: Wed Jun 18, 2003 3:15 am
Subject: RE: Heavy Throttle When Decelerating

Had an off-list reply (thanks bwbxr650r) referring me to this:
--- http://chblock.com/xr650r/general/fuel.html


I'm posting to the list because I have a different opinion on how the carb
operates and would be interested to see what other folks think.

If you study the "air-cut-off" valve on the carb, and the ports to and from it,
I believe it works as follows:

Normal operation - small white valve held open by the "nipple" on the diaphragm.
Allows full air supply to the pilot jet and hence normal mixture.

Note that in the valve "open" position the centre of the diaphragm is sort of
"closed" - pushed inwards against the carb body, but rests on 3 raised lugs
allowing air to flow around/through it.

Decelerating - vacuum from front of carb sucks diaphragm outwards allowing valve
to shut. Cuts off air supply to pilot. Pilot circuit can only let through fuel
and hence richens mixture on over-run.

So, to disable the device, all you need to do is stop the diaphragm being sucked
outwards against the spring. Simple - cut a small piece of plastic hose the
right length that will fit inside the spring, forcing the centre of the
diaphragm to remain seated against the carb, and unable to move outwards.

Which is exactly how my DRZ-S coasting enrichener circuitry worked, and exactly
how I disabled it.....

No permanent modification needed and reversible in seconds.

Following on from the subject title, I took the carb off and concluded that the
throttle slide sticking is NOT the cause of the jerky throttle (but does cause
the heavy throttle on deceleration).

The slide still had a good coating of fuel from Sunday's ride, and pushing hard
against the slide from the choke side to simulate decelerating conditions, the
slide always moved very smoothly even when the twist-grip felt heavier than in
actual riding.

So carb mixture behaviour is the cause I believe.....

I have disabled my air cut off thing but didn't get a chance to test it last
night. The big question is whether the stock pilot will be rich enough to
prevent popping on the over-run. Hopefully find out this evening!

Steve
UK
___________________________________________________________________
From: "Steve C"
Date: Wed Jun 18, 2003 4:09 pm
Subject: Re: Heavy Throttle When Decelerating


Ah yes, the boy's a genius

With the air cut off valve disabled the bike is now much smoother
indeed!

OK, the snatchiness is not totally eliminated but significantly
improved, pretty well gone in 1st and 2nd gear and the bike feels
much easier to control at low revs off-road - just the job!

Absolutely no change to the bike's behaviour otherwise - fuel screw
still at 1 and 1/2 turns out, and no popping on over-run - bl**dy
hell, too good to be true

This should in theory save some fuel as well, OK not much

Someone else going to try this, which I shall completely immodestly
refer to as the "Copsey-mod"

Steve C
UK
_____________________________________________________________________
From: "wang_tiddly_pom"
Date: Thu Jun 19, 2003 6:00 am
Subject: Re: Heavy Throttle When Decelerating


Hi,
Does sound good. Surprised about the lack of popping on the overrun,
did your bike pop at all before?
So, can the Copsey-mod () be done without removing the carb
completely (looks like it can from the manual)? What did you use to
prevent the diaphragm from doing it's thing (what size/length tube)?
And where are the pictures?

Adam
___________________________________________________________________
From: Copsey Stephen-WCSC001
Date: Mon Jun 23, 2003 4:11 am
Subject: Air Cut-Off Valve Mod



Hey folks,

Have uploaded some pics of what you need to do to disable this device.

After a long ride yesterday I can say that the snatchiness is still there, its still annoying, but the mod has improved the general rideability by what I think is a significant amount. In particular the bike seems to be smoother and easier to control at low revs in tight going, BUT, the strong engine braking does make it harder work than a smaller engine bike, and there's not much you can do about that.

Also played with the Pilot Screw - this bike is VERY sensitive to adjustment! :

A) 1 and 3/4 turns out - smoother on-off- throttle but popping exhaust, and occasional stall when blipping throttle

B) 1 and 1/4 turns out - no exhaust popping but noticeably more jerky

C) 1 and 1/2 turns out - good compromise with occasional pops

This is with fully uncorked bike with the Honda "Competition" tip.

CONCLUSION:
----------------------
A) useful mod for no cost
B) doesn't eliminate snatch



Steve C
___________________________________________________________________
Hi Aaron. You gave me quite a giggle there. One of the members of the group
is Steve Copsey, not Chopsey. (is that right, Steve?). He showed the group
how to disable the air cutoff valve by putting a 5mm piece of piping into
the valve. There is another suggestion (beer induced memory loss here -
cant remember) which blocks off the small hole which activates the valve.

Please guys - help me if I am wrong here, (I fix computers, not
carburetors) - this valve cuts off the air to the idle circuit when
decelerating to minimize pollution.

This being said, it does not make sense to me. If you cut off the air while
decelerating, the fuel that is there will not burn (fire needs oxygen), and
the unburned mixture will go straight out of the exhaust into the atmosphere
and kill all sorts of life forms and destroy the ozone layer and burn all of
us in Oz and ZA into a frazzle. (Hope it burns our rugby team into some sort
of awake state...) which defeats the object of helping with pollution.

So what is the function of the air cutoff valve???????????

Geoff
____________________________________________________________________

THE OPPOSING OPINION: Odd that what works for one fellow, won't work for another. Stevens mod above does the EXACT OPPOSITE of what Craig mentions below, yet both have had good results.
____________________________________________________________________
From: chblock@y.com
Date: Mon Oct 8, 2001 8:52 am
Subject: Air Cutoff Valve


I have a completely opposite opinion on this issue from what is
stated in a previous post copied at the bottom.

I had been riding an XR600 for 10 years when I traded it in for a BRP
this year. The first time I rode it, I immediately noticed that the
engine did not decelerate quickly and found it to be highly
irritating. I had no idea why the engine behaved this way at the
time which prompted me to investigate. The first thing I examined
was the Air Cutoff Valve since my XR600 did not have this device and
I suspected that was its function.

The Air Cutoff Valve (ACV) is a diaphram driven device on the
carberator that injects bypass air into the carberator's slow circuit
when manifold vacuum is low. Low manifold vacuum occurs when the
throttle position is approximately greater than 1/4. This has the
effect of damping the rate at which the engine slows on throttle
shutdown. Disabling the ACV is only a matter of cutting the metal
tit off the diaphram and can be reversed by installing a new diaphram
which is not an expensive part.

After installing the Power-up Kit from Honda (new needle and needle
jet, 168 main, and carb boot), removing the airbox restrictions, and
installing a Pro-Circuit T-4 pipe, I have absolutely no jetting
problems with the ACV disabled and I'm much happier with the way the
engine decelerates. It did richen up the slow circuit air/fuel
mixture quite a bit and I adjusted the mixture screw using the "lean
drop" as outlined in the service manual. I think this person had
some other problem going on, but I would recommend buying another
diaphram to test it with just to be safe. In any case, I was a lot
happier with the way the engine ran afterwards and another benefit is
it makes the slow circuit richer so I don't need to change the pilot
jet.

____________________________________________________________________
From: Eric J Foster
Date: Fri Jul 20, 2001 1:26 pm
Subject: Air cutoff valve

If anybody ever tells you to modify the tip of the air cutoff valve
in the carb, tell them to go get bent. My local shop got there hands
on their first BRP to do the uncorking and put on a WB E series bike.
He logged on to a group somewhere and that is one of the mods they
suggested. It causes really bad jerking while cruising at an even
throttle, as if it were really lean.
The pipe he put on was a E series pro-meg, 12 disks and the end
plate. I run substantially stronger with the R series. We put my R on
his bike and dynoed it with like jetting, and my bike still ran 3hp
more. I'll attribute it to my brp being very well broken in. I don't
know what is on the other bike, but the stock tire is 1/2 worn.
Anyway, be wary of what "knowledgable" people tell you for mods, you
might get more than you bargained for.......
___________________________________________________________________
From: chblock@yo.com
Date: Sat Oct 13, 2001 4:25 am
Subject: Re: Air Cutoff Valve

It's not hard to find. There's a round cap on the side of the
carberator about the size of a quarter held down by three screws.
Removing that will uncover a diaphram and a spring. Watch out for
the little round o-ring on the side that seals the manifold vacuum
port. It's very small and easy to lose. The diaphram has a metal
center with a tit on it. Cut the tit off with a pair of wire cutters
and file it flat. Put it back together and the ACV is disabled.
___________________________________________________________________
From: "Geoff Nell"
Date: Thu Nov 13, 2003 2:31 pm
Subject: RE: Mikuni or Edelbrock



I have stock air box/air filter/screen/side cover. Exhaust is Honda, but
completely open. If I shine a torch down the exhaust, I see nothing except
the pipe that goes down to the header.

This setup is working pretty well. Very little popping, still a bit of a
jerk putting on the throttle after decelerating, does not stall after
decelerating, and I can blip the throttle with about 80% enthusiasm..

I found that if I disable the air cutoff valve, the carb is terrible. It
surges at constant throttle and confuses me plenty as to where to put the
fuel screw. With the ACV installed, there is no delay to idle and
compression braking is just fine, and the power is more constant.

I still do not understand the 68S with which I can turn the screw in to the
stop without stalling, and it runs best at least 2 turns out!! Way too rich
on the slow, way too lean on the main but it STOMPS and is quite rideable!!

I will probably NEVER understand jetting.

Confused but happy Geoff. Mikuni in the long term plan... Don't tell my
wife.
___________________________________________________________________

Here's another way to disable the ACV, similar to the "Copsey Mod".

______________________________________________________

From my research through the archives and interpolation, and messing around with the parts a little, it seems to me that the following method of plugging the air cut valve (ACV) will cover all the ambiguities and close off everything, effectively eliminating the ACV and making the carb more "YZ like".
Hope this saves some of the newbies research.
1.Remove ACV cover (left side of bike 2 screws)
2. Temporarily remove Diaphragm, Large spring, and O-ring.
3. Find a piece of gasket material same thickness as O-ring. I didn't have any and ended up using the rubber flap that comes with the WR's for wet riding conditions. Cut a circle (Doesn't have to be perfect) the size of the O-ring and use a press fit into the hole that the O-ring came out of. All you're doing is covering the hole.
4. Look at the diaphragm. On one side there is a brass colored pin. Normally that pin faces the bike and opens a tiny valve inside the carburator because the spring is pushing on the pin. You don't want this to happen so turn the diaphragm upside down so the pin faces AWAY from the bike.
Note this position because this is how you want to install it.
5. Put the spring in the cover and locate the diaphragm on top of the spring. Put everything back together with blue loctite. Some people say to remove the spring but there's no need to if you flip the diaphragm.
That should do it.

I'm not ABSOLUTELY certain about all this but am REASONABLY certain. I'm no bike expert either so take it or leave it.

I'm having excellent results using 68S/160.
ACV vacuum port blocked and 2.5 turns out on idle mixture
Rockers are adjusted slightly on the tight side.
Full FMF system, minimal popping on decal and bags of power.
Great idle performance, both cold and hot engine.

I use a 95 octane fuel, was running a 168 prior to the 160.

I think a lot of guys have massive main jets by the sounds of it. 165 is fine at an altitude between 800-1600m, might actually be a tad too rich. Mind, open side plus headers/pipe, it simply buggers off.... 175??? Way too big if you ask me

Have you checked the hoses attached to the carb, i am referring to the thin black vent/breather hoses. I had a blocked float bowl vent pipe on an xr500, same make of standard carb. but smaller of course, still the same principle.The bike ran like a total dog, push some wire or compressed air through the hoses, might be a blockage, you will end up with a vacuum inside the float bowl.

thanks AURORA i will be taking the carb off again later and i will give this a try, i had heard of it but i didnt know 100% what it entailed thank you for the info


Zoro hopefully the new jets/parts get it sorted but if not i think thats the way i will be going next, plus i ordered the 172main as a spare for going over to france with if i decide to early next year, i can always try it and see if it improves things at all by going down a size.


BuRP i know its seems like a big difference in jets sizes compared to america/Africa, i have mostly been using this site( http://www.xr650r.us/jetting/ ) and other peoples advice on the jets, i am just hoping these jets/parts get it sorted, its been a while since i had a good play in the mud

cheers beaver350, whilst i take the carb off in a little bit i will check them out and make sure all is ok


i was hoping for confirmation that my parts had been dispatched by today but no luck yet

Well i had one more last go at the carb and tried the copsey mod with a 5mm piece of pipe and what a difference it has made.
I set my carb up as follows:

copsey mod done
needle in 4th position from top
175 main
68s idle
and 1 and 1/2 turns out on the mixture.

It now idles brilliantly with no erratic idling and seems to be a lot smoother on the power with no hiccups on full throttle, but that was only from a short ride out so i will be testing it more tomorrow.

I did notice it now takes a few(2 or 3) more kicks to fire it up from cold with no choke on though but i could happily live with that and tomorrow i will try firing it up with the choke on to see if it helps at all.

i have tried these carb settings before and got no joy with them so the only thing i can put it down to is the ACV being disabled i didnt think it would make that much of a difference though.

once i have taking it for a little blast out tomorrow i will also check the spark plug and see how its looking, fingers crossed its all good

Let us know how it goes , I am going to darlington at 1.00 should be back about 4.00 if you want to come up here , i hope it all works

Right guys some more advice might be needed, after a longer ride yesterday it is running a lot better than before but it is still hesitating on the power only on full throttle, its still there but it has calmed down a lot

i also made a mistake when i listed my current carb setup, it has actually got in the 178 main jet in at the moment and not the 175.

my new parts have arrived today so i am going to fit the new gaskets,float valve and needle/needle jet in tonight but since it has the 68s/178m in at the moment what would be your opinion on the jets?

at the moment it has:
copsey mod
needle on 4th clip down
68s idle jet
178 main jet
1 1/2 turns out on the mixture screw

i also have 65s, 70s slow jets and 172, 175, 180 main jets

I know it might be a pain in the neck, but if you can, only change one thing at a time, then test ride, otherwise you're not going to know what mod causes what change.  

R056rx wrote:I know it might be a pain in the neck, but if you can, only change one thing at a time, then test ride, otherwise you're not going to know what mod causes what change.  

Yeah its what i have been trying to do for the most part, i know the top gasket is pretty much dead so i am hoping its just a case of maybe a bit of a vacuum leak from that

Also ensure that the rubber boot/ intake manifold has a complete seal around it, the one between cylinder and carb.
I usually use a smear of grease around the inside at both ends, also make sure the little nut on the intake manifold is also sealed. It is screwed into the aluminium on the cylinder just past where the rubber boot is clamped on (the US bikes have a hose tail here for vacuum). I removed it and covered mine with a drip of Loctite 577 hydraulic sealant because that's all I had and is plentiful.

I would run the 68S, 172 main, middle clip on the B53E needle and try 2.5 turns out on the mixture.
Ensure the emulsion tubes are clean and free of corrosion (this is important) and make sure the little brass piece that sits into the venturi around the needle is the right way around while you're in there.
Set your float height to 16mm and give the needle and seat a good clean but be gentle with them.

Blow some compressed air through every orifice and hose while you have it apart. Keep the ACV blocked like you have.
Don't lose the little white plastic washer on the throttle shaft either.
Replace the pozidrive screws with cap screws if you get the chance.
Drain the remaining fuel you have in the tank (use it for the mower), clean and re-fill your tank with known fresh, good qaulity fuel, preferably not Ethanol based crap.

That should keep you busy for a couple of hrs.

R056rx,

I like you from your comments, you give good advice which makes sense. Old hand perhaps?

well i have replaced the needle jet, needle, float valve, and top gasket.
i have also tried running the carb with this setup:

172 main
68s idle
3rd clip down
16mm float height checked again and still spot on
2.5 turns out on the mixture

once again it idled fine and ran ok but with more popping than before and again loss of power only on 3/4-4/4 throttle  , its really off putting coming out of a corner and loosing all power  

this is how the spark plug looked after a few miles


dead top gasket(replaced)


new parts(and some old)


so i am going to give Frostys idea a go and try to run  65s,178m 3rd clip down and see how that goes.

EDIT:

i have tried the 65s,173, 3rd clip @1.5 turns out on the mixture and the bike did not like it one bit,it was a struggle to get it fired up and the idle was very erratic but i did manage to dial that out slightly, the bike was also popping rolling off the throttle as if the ACV wasn't disabled on it and also surging at a steady throttle whilst also losing power

Have you used the choke before starting ? What is the difference when running the engine cold and warm ?, ( things get worse or better as the engine warms up ? ) Does the fuel run freely out of the fuell tank ?

Where did you get the 173 mj from ?

Mad Frosty wrote:Have you used the choke before starting ? What is the difference when running the engine cold and warm ?, ( things get worse or better as the engine warms up ? ) Does the fuel run freely out of the fuell tank ?

Where did you get the 173 mj from ?

i think the fuel has been getting to my head frosty i meant 172 main and after the edit i meant i have tried the 178(not 173) with the 65s

yes the fuel runs freely from the tank but i have not tried running the bike cold(force of habbit) i naturally let the bike warm up whilst i am getting my helmet and gear on

oh and i have checked the carb insulators and physically they look fine with no tears or splits and seem to make a good seal around the carb and i also checked little nut on the intake manifold which seems good, the sealing washer was in good condition too

When i had the oem carb installed in mine i was running the popular jetting -
68s pj , 175mj , b53 needle , ..... 17mm float level , all the usual . I never had any problems in higher revs , the bike started first kick and ran strong , the only issue i had was a irregular iddle  , annoying but not serious .The bike was running little bit rich ( going by the sparkplug ).
The point is that we are roughly at the same altitude, same climate , similar bikes   so if your bike does not run well at fully open throttle  even with new jets  the issue its 100% not the jetting , even if the jetting was slightly off the bike should still run alright .
What are your compression readings like ?

Mad Frosty wrote:When i had the oem carb installed in mine i was running the popular jetting -
68s pj , 175mj , b53 needle , ..... 17mm float level , all the usual . I never had any problems in higher revs , the bike started first kick and ran strong , the only issue i had was a irregular iddle  , annoying but not serious .The bike was running little bit rich ( going by the sparkplug ).
The point is that we are roughly at the same altitude, same climate , similar bikes   so if your bike does not run well at fully open throttle  even with new jets  the issue its 100% not the jetting , even if the jetting was slightly off the bike should still run alright .
What are your compression readings like ?

yeah i have been thinking that myself but i have seen a few others on here with the same problems as me and same symptoms as mine too and it has calmed down with bigger jets in thats the only reason i have kept going on the carb, if its electrical it could explain the dash going off now and then but thats witch craft to me haha.

i cant remember the exact reading but it was over 100 after a few kicks in idle, i have been thinking about a leakdown test maybe on the cards but i cant afford it for a while to tell the truth

What about valve adjustment, where is that at the moment?
You'd be surprised how much better/ smoother these things run with the valves adjusted correctly.

Be sure to disconnect the decomp cable from the lever prior to adjusting them and triple check the gaps by turning the engine 720 between checks.

Zoro wrote:What about valve adjustment, where is that at the moment?
You'd be surprised how much better/ smoother these things run with the valves adjusted correctly.

Be sure to disconnect the decomp cable from the lever prior to adjusting them and triple check the gaps by turning the engine 720 between checks.

Hi Zoro i just set the valves to the standard specs and checked them last week so the valves should be good.
altho i did not disconnect the decomp cable, i didnt think that would be necessary for checking/adjusting the valves?

i know its a long shot but would there be any way to tell if the crank has been changed to a stage1/2? as i know the valve specs would be different if that had been done by a previous owner