Help rejetting my XR650R carb

I think ive already asked this in a previouse thread but i didnt get anybody who was 100% on what needed to be done. So here's the story, i did my own homemade airbox venting (pictured below). And know the bike isant running right, i origonally had the following

175 main

3rd needle pos

68S Pilot Jet

After the airbox mod my bike had a flat spot where it would bog if you hit the throttle hard, so i turned the idle mixture screw 1 full turn out. (it was in stock setting before) This helped a lot but its still not 100% responsive, so my question is what should i do first? Do i just turn the mixture screw up even more? Or should i try to plug in a 70 Pilot or 4th needle clip posision? I tried a 178 main and it made the bogging worse so i know its not the main that is the problem, i wanta get this figured out so im ready to go early in the spring.

thanx,

tyler

XR650Rsidepanelventing003.jpg

What exhaust system are you running?

What exhaust system are you running?

Stock exhuast with HRC tip...

My only problem with expirementing is it takes some time to get everything apart, then take the carb apart and do either a needle or pilot and put everthing back together and relize i made something worse or didnt do anything then have to take it apart again:bonk:

The flat spot is definatly under half throttle, like when i do 2nd gear roll on's it wont pull up from a low RPM like it used 2, its gota be wound up.

Mine would blubber\bog when I hit the throttle after i let off while climbing a hill. I went to a 165 main and it's perfect now. It's also at third clip 68 pilot open air box with a white bros. R-4 full pipe. @ 3000 ft. and above.

Try a 70 S pilot.

Or put some duck tape over some of the airboxmodholes (= richer jetting) and look.

BTW: that rear tire can use some more "angle" :banghead:

Try a 70 S pilot.

Or put some duck tape over some of the airboxmodholes (= richer jetting) and look.

BTW: that rear tire can use some more "angle" :banghead:

its not a 70S for the kiehin carb right? its just a regular 70, thats the next size up from a 68S.

So Scalejocky you say you went down to a 165 after a vented side panel, i have a 172 main already maby i should throw that in to see if it makes it any better.

How does going down in a jet work? more airflow forces more gas through a smaller jet?

Try a 70 S pilot.

Or put some duck tape over some of the airboxmodholes (= richer jetting) and look.

BTW: that rear tire can use some more "angle" :banghead:

those are some serious chicken strips

those are some serious chicken strips

I'm able to scrape pegs and it still doesnt scrub in a half inch of the tire, the lean angle on them is amazing...

Ya , my bike came with a 170 in it when i bought it 2 years ago and it had a full pipe on it already. But it was real rich when i would let off and hit it again.so tried several mains and ended up with a 165 .It has the stock pilot. But i ride at 3000 up to 10,000 without changing jets. You might run it a while and check the plug. The porcelin should be light brown.

My only problem with expirementing is it takes some time to get everything apart, then take the carb apart and do either a needle or pilot and put everthing back together and relize i made something worse or didnt do anything then have to take it apart again:bonk:

BOO HOO HOO :banghead: thats why carbs are so fantastic.

dunno if this helps, but i had stock header, fmf Ti4 can (free flowing) side panel cut, uni air filter.....my carb was running pretty sick down here on long island with a 185 main, 68s, clip in 3rd position IIRC..... now, keep in mind, when its cold out like it is now, things change a lot...the bike will be running much leaner due to the cold, dense air.

You just gotta tinker with it (yes it sucks to tear it down)...you'll get it goin. good luck.

It's easy to change the main with a main jet T-wrench. Just leave the needle on the 3rd clip for now.

It's easy to change the main with a main jet T-wrench. Just leave the needle on the 3rd clip for now.

Yup, i have the T-wrench, just spin the floatboal cap off and there it is, thats why going up in the main jet was the first thing i tried. But no success

hey guys

where can I buy a 68s and 70s pilot jet?

hey guys

where can I buy a 68s and 70s pilot jet?

Your local dealer. I've found on really small parts like these you don't really stand to save a ton of cash by going elsewhere...and they can usually get the parts pretty quick if they don't stock it.

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