Re: MA$TER_E's Project Beasty

Guest Tue Jun 10, 2014 12:46 am

MA$TER_E wrote:Don't take this the wrong way but ya know BuRP, some times you come off as a bit of a I know you probably don't intend to but you do. I really appreciate you sharing your jetting though and do value your feedback. You're jetting really surprises me and confirms that I'm most definitely on the right track as I've done most of this tuning by myself. My carb shipped "pre jetted for an XR" which was so lean that you could see my headers glowing from space after 30 seconds of idling. So I started tuning until it idled right then proceeded from there.

Big Gun Full Exhaust, Stage 1 Hotcam, Opened Air Box, ~2500 feet (762m)

MY CURRENT TM40 JETTING IS?
Nearly identical to yours! LOL, So I'm not just jetting the bike to ride unless you are!

Pilot = 27.5
Air Jet = 1.2
Needle = 9DJY1
Clip = 3rd
Needle Jet = Y-4
Main = 145

But putting the pumper rod in totally made my bike run HORRIBLE. EDDY! Confirm, this. My bike runs great. Awesome even. The rod turned my bike into a blubbering mess. Without the rod, there is a small bog at the bottom end but its way better than the OEM carb. It starts super easy, idles great and feels good throughout the RPM's. Maybe I didn't get the end of the accelerator stopped quite right? That one is a PITA to adjust with the 4.7G tank in the way.

But how can the pumper not have a single impact on your jetting? I have an idea as to how it wouldn't but you said it
BuRP wrote:does NOT affect the jetting at all. Zilch! Nada!
Then didn't provide any explanation at all as to why. You clearly have some good experience and knowledge about the carb. Please explain why this is.

Every bike is slightly different and what works on one might not work on another one , we have very similar bikes ( full Exhaust system , stg1 hot cams , ... ) but you are 2000 feet higher in altitude so going by the book you should have smaller or identical pj to mine ,,, so 27,5 seems too big plus you have issues when the AP is aplayed so this tells me - "too much fuel" going in , but i might be wrong Bananatool

Guest Tue Jun 10, 2014 12:54 am

Hey Frosty,

I live at ~300 feet. But ride between 2000 - 6000 feet usually in the lower stuff like 2500 on average.

I regret not buying my carb from the power barn or XR's only. I bought it off ebay for a good price then made up the difference jetting. Came to me with a 22.5 pilot.

Guest Tue Jun 10, 2014 12:59 am

I can confirm with the pumper rod in, the bike didn't want to idle and was very sloppy off idle. With the rod removed it ran just fine.

Guest Tue Jun 10, 2014 9:09 am

The pump activated (rod installed) CAN not affect the jetting! The squirter-jet sits way in front of the venturi hence is not sucked on therefore cannot deliver fuel, but besides that the pump itself acts like a checkvalve. So, whatever also happened (also, yes) I dunno, but the rod in will not affect the jetting.
It is of paramount importance though that the tank, petcock, fuel filter (!!), lines and carb are absolutely spotlessly clean. The tinyest speck of dirt will mess findings up, and yes, I had same: glowing redhot headers, not a too-small IJ but some dirt!
On the IJ, my mistake: is must be a 25! I remember I tried to get rid of overheating (during ultra slow technical riding) by overfueling but the diff is negligeable >> put a 25 in! And yes, keep the 1.2 AJ.

Neither Barnes (better) nor XRsOnly (worse) provide correctly jetted carbs, but then again this is also impossible to do. Some 'fiddling' is always needed if only for the rel. humidity (very dry here in SA) and temperatures (warmish to hot here), and of course altitude plays a role too.
Oh, 300ft is sea level - come now, a mere 100 meters is an anthill.

Guest Tue Jun 10, 2014 9:17 am

Oh, your 140 main is too big. If you've got a cotton-gauze filter (K&N or similar, for dirtriding a BAD idea!) plus an open sidepanel plus a staged cam plus ported head plus larger valves then maybe, but this would be for racing on tar on a SM only.
Calculate the surface-area (cross section) diff between the 140 & 145... that's a difference of 7% - rather big, my hunch is you're overfuelling by a lot. IF you need bigger-than-140 (cool, highish humidity, sealevel, opened panel etc) at all then a 142.5 would do, but as said I doubt it.

Guest Tue Jun 10, 2014 9:24 am

"Without the rod, there is a small bog at the bottom end but its way better than the OEM carb."

There you go, you've jetted it too rich!
Without the rod active it must bog more than the std carb, not 'way better than...'.

Guest Tue Jun 10, 2014 4:45 pm

But you said you're running a 27.5 pilot and 140 main just a second ago. Why is that jetting such a horrible setup to run all of the sudden?

Thing is I don't think it matters what I do. You are going to keep informing me that everything I (an idiot) do is wrong and you're always right (and smarter). Right? 3 posts in a row means you're pretty lit up and I struck a nerve with you.

Don't get mad BuRP. We're like BRP besties BRP smile

Now. What jetting are you running really?

Guest Tue Jun 10, 2014 7:33 pm

He runs 25 / 140 , wake up

Guest Tue Jun 10, 2014 9:39 pm

Mad Frosty wrote:He runs 25 / 140 ,

Hey Frosty! BRP smile

That's what I've gathered LOL. I'd agree tho that the 27.5 pilot may be a little rich. I'd like to drop one size and try a 25 pilot and see how the fuel screw tuning goes. But I really do think something is funky with my accelerator pump settings. Its totally possible that I buggered the setup and didn't realize it. We're going to be riding this Saturday. Maybe I'll take a second and drop in the 25 pilot and accelerator pump rod this week and test it out.

Then again I'm $700 bucks deep into a 450X rebuild right now so maybe I wont... beat head

MA$TER_E's Project Beasty - Page 3 20140606_191123

Guest Tue Jun 10, 2014 10:02 pm

You know if you ripped that starter off and all those gears that go with it I bet you would save at least two pounds Very Happy

Guest Tue Jun 10, 2014 10:56 pm

What size its your AP nozzle jet ? If too big ( like from the HD ) it can overfuel badly , try the smallest size you have .

Guest Wed Jun 11, 2014 12:46 am

Mad Frosty wrote:What size its your AP nozzle jet ? If too big ( like from the HD ) it can overfuel badly , try the smallest size you have .

I'm pretty sure its a 70. But honestly I never pulled it and looked.

http://www.jetsrus.com/individual_parts/007_167_su.html

Guest Wed Jun 11, 2014 2:38 pm

MA$TER_E wrote:But honestly I never pulled it and looked.

You should! I think (can't remember) it is held by an o-ring, and if this item is damaged fuel may leak past.
Also, you must aim the jet (no need to remove it for this though), it must hit the needle or better, just right of the needle - as the airflow will deflect/bend the jet towards it.

Frosty, nope, I run 12.5 / 90 - am afraid of horses you see BRP smile

Guest Wed Jun 11, 2014 2:43 pm

MA$TER_E wrote:Why is that jetting such a horrible setup to run all of the sudden?

It isn't, 27.5 runs fine, although the idling is more solid with the 25. Marginally less surging too, in all it's better. Plus the screw sits exactly there where it is supposed to be.

Guest Wed Jun 11, 2014 3:05 pm

MA$TER_E wrote:You are going to keep informing me that everything I (an idiot) do is wrong and you're always right (and smarter). Right?

Wrong, on too many points to mention.
This is a forum where people ask things.
I try to help and answer as best as I can.
If I'm wrong I apologize, if you don't like the advice pls read past it.

Guest Wed Jun 11, 2014 5:24 pm

BuRP wrote:If I'm wrong I apologize, if you don't like the advice pls read past it.

Totally.

Guest Wed Jun 11, 2014 9:16 pm

Burp i know what your problem is , you are rushing too much , not reading the posts properly or fully and then answearing quickly creating missunderstanding ,.......
Relax and slow down a little bit , life its too short so dont rush it Bump

Guest Thu Jun 12, 2014 2:41 am

Holy Cow! Buckle up everyone, this is about to get crazy.

The 27.5 pilot I said I was running? I'm not. That's when it was still really really lean. I'm actually running...

A 37.5

MA$TER_E's Project Beasty - Page 3 20140611_183636

MA$TER_E's Project Beasty - Page 3 20140611_183636

Guest Thu Jun 12, 2014 2:56 am

oh this is going to be good. Release the hounds!

Guest Thu Jun 12, 2014 11:49 am

Eddy, give me some of that popcorn too BRP smile

Guest Thu Jun 12, 2014 2:55 pm

Lololololo

Guest Thu Jun 12, 2014 3:32 pm

So I'm just going to create another thread in the air/fuel area to get this resolved. This is the wrong place for carb tuning conversations.

Guest Thu Jun 12, 2014 3:34 pm

Here's how to determine the IJ size.
Mark (tippex) the throttle's 15%-open mark.
Mount 'a' side IJ - and of course have the AP disabled (rod out).
Set the clip to 'mid' (needle type not important), turn up the slide-screw, start the bugger on a stand (ie bike vertical) and turn the slide-srew down until still too-high revs.
Let it get warm to hot, if the latter run a hosepipe over a radiator.
Turn the mixture-screw in & out until it rev's highest.
Reduce the revs with the slide-screw.
Repeat until a notch too-low idle-revs are obtained.
Ride the bike over a flat road with MAX 15% throttle, and modulate the throttle veerryy slowly.
Feel how it goes, 'too small' and 'too rich' are easy to spot ('unwilling' & 'very willing' or 'too forgiving').
If 'ok' then look down to the chain and see how the engine surges, in the 2 or 3 lower gears.
The jet which surges least is the correct size.

Problem with this carb is that there's an airjet (AJ) in the idling system too, so this adds to the number of combinations hence to the T&E time. I also tried various needles and took 2 days to determine the IJ & AJ : 25 & 1.2.
The 27.5 I put in later to see if this would help preventing overheating, and although I think it does a bit the diff is negligible... hence I put the 25 back (which idles a bit more close to perfect).

Remember this carb is a pumper, so jet such that it is prone to stumble when the throttle is opened - which, with the AP enabled, will disappear.
Use it, don't...

Guest Thu Jun 12, 2014 6:10 pm

BuRP wrote:Here's how to determine the IJ size.
Mark (tippex) the throttle's 15%-open mark.
Mount 'a' side IJ - and of course have the AP disabled (rod out).
Set the clip to 'mid' (needle type not important), turn up the slide-screw, start the bugger on a stand (ie bike vertical) and turn the slide-srew down until still too-high revs.
Let it get warm to hot, if the latter run a hosepipe over a radiator.
Turn the mixture-screw in & out until it rev's highest.
Reduce the revs with the slide-screw.
Repeat until a notch too-low idle-revs are obtained.
Ride the bike over a flat road with MAX 15% throttle, and modulate the throttle veerryy slowly.
Feel how it goes, 'too small' and 'too rich' are easy to spot ('unwilling' & 'very willing' or 'too forgiving').
If 'ok' then look down to the chain and see how the engine surges, in the 2 or 3 lower gears.
The jet which surges least is the correct size.

Problem with this carb is that there's an airjet (AJ) in the idling system too, so this adds to the number of combinations hence to the T&E time. I also tried various needles and took 2 days to determine the IJ & AJ : 25 & 1.2.
The 27.5 I put in later to see if this would help preventing overheating, and although I think it does a bit the diff is negligible... hence I put the 25 back (which idles a bit more close to perfect).

Remember this carb is a pumper, so jet such that it is prone to stumble when the throttle is opened - which, with the AP enabled, will disappear.
Use it, don't...

Thank you BuRP that info is very helpful. I just posted a new thread in the jetting section about my carb which your feedback here does help answer some of my questions there.
http://www.xr650rforum.com/t2093-another-tm40-jetting-thread#14147

Guest Sat Oct 10, 2015 7:00 am

ooeddym wrote:Are those tires off a Huffy?

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