Jets, filters, etc for altitude change

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Jets, filters, etc for altitude change

Post  despres on Mon Jul 01, 2013 10:47 pm

So in about a month, I am moving from the mountains of Colorado (7,000 feet of elevation) to the beaches of Baja California.

My 'new' 01 650R is uncorked, and has a White Brothers Exhaust. From what I read, I am expecting to put a 68s and 175 jet in there, with the needle on the third position. Some guides seem to indicate that a 172 main would be better - should I pick one of those up to bring with me, or just go with the 175?

The bike had a box of spare parts with it, including the stock air filter, a metal screen and two metal brackets that are all the same shape as the filter. The filter on the bike is the kind with a built in plastic frame. Am I supposed to cram all those metal pieces in with the stock filter? It looks as though I could get away with just the screen or one of the frames (and I've read that the screen prevents the filter from burning up in the event of a backfire).

Any other spare parts or pieces I should get to deal with the altitude change? I'm sure I can get parts there, but my wife works at a Honda dealer, so it's pretty easy to stock up before the move.
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Re: Jets, filters, etc for altitude change

Post  BuRP on Tue Jul 02, 2013 10:59 am

A foam filter without built-in support (like the newer UNI's may have) needs a mesh screen to support it, as without it it'll be sucked into the cavity. The screen also will act as a flame-stopper in case of backfire.
Of course 1 screen is enough, and there's more 'open' (more air) than std-screen versions so pick the one you like best.
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Re: Jets, filters, etc for altitude change

Post  despres on Tue Jul 02, 2013 8:36 pm

I am guessing the one that has 3 or 4 layers of actual metal screens is the stock one, that could block some flames. There is one that is sort of a grid, with some holes that you could pass a deck of cards through, and the third one has a bunch of holes that are probably 1-2mm. That one might flow better, but probably wouldn't stop a fire, right?

As much as I'd like to maximize performance, I will probably put the stock screen back in there for safety and ease of maintenance.

One thing that is strange: I just drained the carb and pulled the main jet out to see how it was jetted and it is a 155?!? Granted I live in Colorado and so does the guy I bought it from, but my house is under 7,000 feet, and I bet his was at 5,000 or so. I had expected a 170 or 172. I haven't had a chance to ride the thing much, other than just around my block, but now I am scared to until I pull the carburetor off and see what exactly is done. It does seem to run fairly normal, so my guess is that he's got the needle riding high to compensate for the small jet, and he just didn't run at WOT too often. When I pulled the spark plug out to adjust the valves the other day, it looked pretty normal to me.

Anybody have any thoughts why someone would have a 155 main jet in a 650 with a full white brothers exhaust? Any carburetor related issues that would trick it into wanting a lean jet like that, like a washer on the wrong side of the slide or something funky to look for? I know the 155 isn't right, but I am hesitant to put a jet 8 sizes larger in there without figuring out why it seems to have worked with such a small one.

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Re: Jets, filters, etc for altitude change

Post  BuRP on Wed Jul 03, 2013 12:52 pm

Check the rubber manifold between head & carb - large round hole or rectangular slot? If the latter either cut it out (it's a restriction) or buy the 'uncorked' one.
Then ride WO - which will be out of breath/oomph/juice, so you'll have to put the bigger/normal sized jet in.
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Re: Jets, filters, etc for altitude change

Post  babuja on Wed Jul 03, 2013 1:37 pm

Also use one of this pro-seal for better fitting...and some grease on the air filter box.

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Re: Jets, filters, etc for altitude change

Post  despres on Wed Jul 03, 2013 2:17 pm

BuRP - I haven't checked the fitting, but in the box of spare parts I got when i bought the bike, I have a complete cork, with the weird metal tubes that connect to the head, some sort of valve with hoses, a bunch of strange rubber pieces and the rubber seal with the rectangle that you speak of, so I am quite confident that it was replaced with a proper one.

I guess it is possible that a 155 was the stock jet sold in a corked 650R at high altitude dealers, and the last guy uncorked it, installed a new exhaust and air filter but didn't touch the carb. That box of spare parts has little baggies with screws and all sorts of other stuff that seems likely to get thrown away or lost, but no jets or needles, so that seems possible.

My difficulty is that I have no time to ride this thing between now and when I move, and most likely will not have time to do the jetting between now and then either, so I just want to get parts. I am moving from over 6500 feet of elevation to under 300 feet, so the jetting will be quite different anyway.

Most of my riding will be between 0 and 2,000 feet of elevation, and in temps ranging from 65-100 degrees. From what I have read, I should get a 68s pilot, the better needle, and I am thinking I should get a 172, 175 and 178 main jet to experiment with. Does that sound right? Would 170, 172, 175 make more sense?

I will have to look at my air box to see what you are showing me in that picture, is it a rubber seal around the screen? Where does one buy one of those? It will be dusty where I'm going!
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Re: Jets, filters, etc for altitude change

Post  BuRP on Wed Jul 03, 2013 2:32 pm

I'd get the jets you mention, always nice to be able to try&error a bit when you've got some unknowns, like your headers for instance(?)
Once moved chuck in the biggest (and set needle to 3rd!) and see if it runs well (WO!) and/or rich. then size down one and try again, then next the smallest one. Do this running on a stretch you know well-enough, preferably with a bit of a long (not steep!) incline - which will give you a good impression of how well it is jetted. I'd leave in the smallest jet it runs well with WO, as anything less-open will be fine then too.
Oh, 68S idler jet you must get too - and check if you've got the correct needle?


Babuja,
what"s that thing?? Never seen it, curious...
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Re: Jets, filters, etc for altitude change

Post  babuja on Wed Jul 03, 2013 4:28 pm

BuRP wrote:
Babuja,
what"s that thing?? Never seen it, curious...

It's a neoprene gasket for perfect filter to air box seal.

This is it:
http://www.pcracingusa.com/

For longer engine life i always keep in my bikes new/clean air filter (some times I carry a extra pre-oiled air filter if needed) and short interval oil mantainance (never more than 1000km, usually 500km).

Dust ruins engine very very fast.


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Re: Jets, filters, etc for altitude change

Post  despres on Thu Jul 04, 2013 12:03 am

Babuja, those look like a good idea, I might have to look into getting one.

BuRP (or anyone else with the knowledge) - My bike has a white brothers cannister, I am not sure if the headers are White Bros or not, but they some sort of Stainless Steel aftermarket headers either way. Like I said, I will be mostly at sea level up to about 2,000 feet, and probably mostly temperatures between 80 and 100 degrees f. My expectation is that I will end up running the 175, but would like to get +/-1 jet size to test it out.

Does buying a 172,175 and 178 main jet seem to make the most sense? From what I have read, I doubt I will need a 170 or a 180, but the internet has been wrong before.
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Re: Jets, filters, etc for altitude change

Post  babuja on Thu Jul 04, 2013 7:54 am

I'm at sea level and using 175 (humidity about 80%) a bit reach...
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Re: Jets, filters, etc for altitude change

Post  BuRP on Thu Jul 04, 2013 10:32 am

I'd get 170/2/5, enough to play with.
Your sidecover is opened not so?


Thanks C, but I can't find the correct one there - you contacted them maybe?
I'd like to get a few, I got the same dislike for leaking dust BRP smile 
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Re: Jets, filters, etc for altitude change

Post  babuja on Thu Jul 04, 2013 1:23 pm

BuRP wrote:
Thanks C, but I can't find the correct one there - you contacted them maybe?
I'd like to get a few, I got the same dislike for leaking dust BRP smile 

Find one of those for XR in ebay...i've done a search but couldn't find one at this moment.

Just configure ebay with those words to repply when one is available...or just contact PC Racing. nice 

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Re: Jets, filters, etc for altitude change

Post  despres on Thu Jul 04, 2013 3:03 pm

OK, I'll do a 170/2/5, thanks. My side cover is not opened up, I thought about it, but it seems like I will just be cleaning the air filter all the time if I do that, and will sacrifice some performance for reliability.

I just ordered one of those proseals from WWW.PowerSportsJunkie.com. It seems there are still a few of them out there.

I haven't looked around, but on a harley I used to have, I had an edelbrock carb and air cleaner that was exposed enough that the motor would drown when I got caught in rain storm. I bought this thing from Edelbrock that fit over the air filter, and was a mesh fine enough to keep water out but let air in. I wonder if one could cut out their side cover, then cover it with a mesh like that, it seems like it would probably breath better than fully covered, but filter dust a bit better than nothing at all. Anybody tried anything like that?
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Re: Jets, filters, etc for altitude change

Post  despres on Fri Jul 05, 2013 2:14 pm

OK, some final questions on this topic:

I pulled the (UNI) filter that was on the bike out yesterday, and the back of it was sort of melted, presumably from not running with the screen behind it, as we have discussed. I have the stock filter as well, but I like to have at least one spare. How much difference is there in flow, really, between different brands of foam filters? Will I get noticeable changes in performance (or Jetting needs) running the stock filter vs Moose vs Uni?

I would also assume that the better the air flow, the more fine dust will make its way through the filter, so is there a best compromise?
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Re: Jets, filters, etc for altitude change

Post  babuja on Fri Jul 05, 2013 4:00 pm

despres wrote: How much difference is there in flow, really, between different brands of foam filters?  Will I get noticeable changes in performance (or Jetting needs) running the stock filter vs Moose vs Uni?
 

Insignificant...just use a clean filter well oiled all the time and change it regularly.
No jetting change needed.
Also apply some grease on the air box to help to grab some residual dust.

despres wrote:
I would also assume that the better the air flow, the more fine dust will make its way through the filter, so is there a best compromise?  

It´s a XR dirt bike or a SM? If it's a dirt bike just use a good foam filter. If it's a SM you could use some high flow air filter like kN (http://www.knfilters.com/air_filter/honda_xr650r.aspx)...but never use it on dirt bike...otherwise you'll ruim your engine very veeeeeeeeeeeeeeery fast.

If your looking for extra performance consider HRC kit (piston, chain, cam, cam sprocket...) but it will reduce XR stock engine reliability.

If you need more power keep the XR ang get one of this Bump

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Re: Jets, filters, etc for altitude change

Post  despres on Fri Jul 05, 2013 6:47 pm

That is what I figured about the foam filters: there was a pretty big disparity in pricing on them, so I wanted to check.

I bought this bike specifically to ride in the deserts and beaches of Baja California, so no KN filters. I am moving down there in about 6 weeks, but I rode dirt bikes down there a few weeks ago, and it was DUSTY, so I am trying to make sure I have all the parts I need before I head down, it is a much different environment than Colorado.

I don't want to make any modifications at this point, I just sold an orange bike to buy a red one because I want something very reliable when I am down there.
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Re: Jets, filters, etc for altitude change

Post  despres on Fri Jul 05, 2013 10:16 pm

For what it is worth, I said the other day that I ordered one of those ProSeal rings from Powersport Junkie, I just got an email from them that they are out of stock and the manufacturer no longer makes those for the XR650R, so they might be tough to come across.

I might look around the local hardware stores and see if I can come up with something to perform a similar function.
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Re: Jets, filters, etc for altitude change

Post  babuja on Fri Jul 05, 2013 10:36 pm

babuja wrote:
Find one of those for XR in ebay...i've done a search but couldn't find one at this moment.

Just configure ebay with those words to repply when one is available...or just contact PC Racing. nice 


Soon or later one of this is going to ebay...if i knew I would have bought some extra units for you guys BRP smile 
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