Do I need to rejet - paper to a Foam Air Filter
 

Do I need to rejet if I only change the stock paper air filter for a UNI Foam Air Filter "without" removing the snorkel, just switch Paper to Foam?
Thanks

Hi,

Normaly when changing the airfilter to a diferent type you don't need to re-jet. Only when changing to high-output filters like delo witch let much more air in.

Maarten

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- www.maartensworld.tmfweb.nl -

I can confirm this - you don't need to re-jet if you only swtich air filters.

If you take the snorkel out, you will need to re-jet.

It's my impresion that the XRL runs so lean you ought to rejet whatever you - and a foam filter will increase airflow and so lean it some more, right?
I'm about to rejet mine and do all the other derestrictions. I hope it runs as well as they say it will, because it runs like a dog as standard.

Chris S

Desert Riders Project
http://www.adventure-motorcycling.com/riders

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Author of Sahara Overland and the Adventure Motorcycling Handbook, among other things

http://www.sahara-overland.com

Yep, it'll get a tad bit more air flow with the foam filter, but mine didn't seem to run noticably leaner when I took my paper filter out.

It is lean off the showroom floor (in the US anyways) and most everyone's seems to backfire quite a bit when backing off the throttle.

You'll get a nice power increase after taking the snorkel out (the bike will hardly run if take it out without rejetting), taking out the exhaust baffle (I replaced mine with a Thumper racing Baffle, it's still rather quiet) going to richer jetting and drilling out the slide as per Baja Designs' instruction.

Don't get your hopes too high though - its performance still won't blow you away after these mods. A buddy of mine went to an FMF exhaust and got still a little more power.

I'm really no expert on this, but I think the powerplant may be limited by the low compression ratio it runs at - 8.3:1 is very low! But in the grand scheme of things, it makes plenty of power for me.

After 20,000 miles I haven't had a single problem with my bike that wasn't related to me crashing it or forgetting to loctite something http://www.horizonsunlimited.com/ubb/smile.gif

If I was going to invest a lot of money, I'd spend it on getting the forks stiffened up - that's the bike's biggest weak point IMO. The bike handled much better after I put stiffer springs in and had the forks re-valved, and soon I'll put a fork brace on it, as I've heard that they make a huge difference in handling - I would only imagine the effect is increased with heavier loads.

Cheers!
Wright

[This message has been edited by wbagwell (edited 30 May 2002).]

For the record Wright, what rating forks did you put in (or what % over stock)? We're about to order stiffer forks to go with our 37L tanks and I wonder what works - + 20% has been mentioned...
Just did the derestrict and it runs and responds as it should: ie, a heavy XR. Low comp ratio is OK with me if it means it can runs on poor fuel.
I must say the forks dont feel too floppy to me on doing the 'handlebar waggle' test - when I did it to a KLR they were still oscillating 2 days later!

Ch

Desert Riders 2003
http://www.adventure-motorcycling.com/riders

Hi Chris,

Just curious, what is the 'handlebar waggle' test, how do you do it and for what?

Chris,
Unfortunately, I don't know exactly what was done to my forks - I just sent them to Pro-Action who used to sponsor me in my old motocross days and told them to set them up for the bike's weight, my weight, etc. I will try to call them this week to figure out what they put in, though they may have no record and I doubt they've done more than a few 650Ls.

I can tell you that even after they put heavier springs in and re-valved, they still feel a tad soft, though admittedly I still try to ride it like it's an MX bike.

Unfortunately, I still haven't taken my XR on an extended trip with it loaded down heavily, my Sahara plans for last fall fell through and I've picked up a new GS for long trips.

Wright

You don't need to re-jet. I tried a Unifilter on my 650L, it was okay, and probably the best for dusty conditions. But I ended up going back to a stock paper filter. Even though I have a re-jetted carb, my engine seemed to run better with stock. Also, there is a considerable amount of intake noise when using foam, it even sounded better to me with a paper filter. Foam does breathe better, but I could not tell any difference in performance.

Waggel test = sit on the bike and waggle the bars hard side to side. With long pencil forks you will feel the front wheel flop around as the forks flex - with better forks and a light wheel/tyre set up there is less or no movement felt.
A fork brace takes care of bad waggling.

CS

my '97 XRL650 (CA model) after 7000 miles (NEW) refused to start. Diagnosis: stuck rings in the piston. Reason: UKNOWN. It is being retrofitted right now with a new piston and a cylinder job. Was bought new, broken in properly, run with hi quality oil, but still.....

I just hope it was not rejetting (done by a pro mechanic) that caused this problem.

anyone with a simialar experience?