having some problems with my newly aquired '99 xr250r. posted this on a local forum here too but u guys know your shit, so please if anyone has an idea lemme know!
So i've been thru my carbs and started a discussion here on it. basically tried all of my jets and adjustments and still can't get it right. what i know:
1. i adjusted the valves. it was my first time.
2. i put a new air filter in.
3. oem snorkel was removed
4. unsure how bike ran before this season as i got it, make sure it ran and shifted then took it apart.
5. bike runs good 'til mid, even mid/high RPMs as long as the throttle is below 1/2 or 1/3.
6. after that with higher throttle positions at higher rpms shit goes downhill.
it almost seems like the choke is still on. so to try to help i've tried the following, and the symptoms are same. it pops (not backfires or anything) and just won't accelerate smoothly. sometimes it will pull thru but maybe 25% of the time.
tried to:
1. tape up most of the air box hole so its similar to the stock snorkel (richen it up)
2. remove air filter so it leans it out
3. tried mains 128 - 138 (stock is 130)
4. Tried all settings on needle (5 way adjustable).
all of those sometimes making the popping worse, but it will still bog down.
old plug looked wicked rich, not wet, but black. new plug after maybe 1/4 mile looks as it should. golden, maybe even a bit lean.
someone had recommended to check exhaust leak. i checked, couldn't feel any air, but the clamps were loose. tightened them down and it felt a tiny bit better but not great.
breakdirt916 came over tonight and we wrenched for a couple hours with no luck. since my exhaust has some aftermarket spark arrestor its hard to tell but it really does feel like his when the choke is still on.
if anyone has ANY ideas
, please let me know. i'm at my witts end with the damn thing and would love some help. house calls will be provided unlimited beverages of your choice if someones willing...
my next idea is to try a very lean or rich jet and see if that helps at all.
the only other thing i can think of i know with vmax's if the airbox is off and the carbs don't have an air adjustment plug they won't rev past 4/5k rpms, and it almost sounds like that. i checked for intake leaks with carb cleaner too, nada.
anyways thanks in advance.
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a guy came over to help me with it tonight and he added:
So i've been thru my carbs and started a discussion here on it. basically tried all of my jets and adjustments and still can't get it right. what i know:
1. i adjusted the valves. it was my first time.
2. i put a new air filter in.
3. oem snorkel was removed
4. unsure how bike ran before this season as i got it, make sure it ran and shifted then took it apart.
5. bike runs good 'til mid, even mid/high RPMs as long as the throttle is below 1/2 or 1/3.
6. after that with higher throttle positions at higher rpms shit goes downhill.
it almost seems like the choke is still on. so to try to help i've tried the following, and the symptoms are same. it pops (not backfires or anything) and just won't accelerate smoothly. sometimes it will pull thru but maybe 25% of the time.
tried to:
1. tape up most of the air box hole so its similar to the stock snorkel (richen it up)
2. remove air filter so it leans it out
3. tried mains 128 - 138 (stock is 130)
4. Tried all settings on needle (5 way adjustable).
all of those sometimes making the popping worse, but it will still bog down.
old plug looked wicked rich, not wet, but black. new plug after maybe 1/4 mile looks as it should. golden, maybe even a bit lean.
someone had recommended to check exhaust leak. i checked, couldn't feel any air, but the clamps were loose. tightened them down and it felt a tiny bit better but not great.
breakdirt916 came over tonight and we wrenched for a couple hours with no luck. since my exhaust has some aftermarket spark arrestor its hard to tell but it really does feel like his when the choke is still on.
if anyone has ANY ideas
my next idea is to try a very lean or rich jet and see if that helps at all.
the only other thing i can think of i know with vmax's if the airbox is off and the carbs don't have an air adjustment plug they won't rev past 4/5k rpms, and it almost sounds like that. i checked for intake leaks with carb cleaner too, nada.
anyways thanks in advance.
-------------------------------
a guy came over to help me with it tonight and he added:
gamorg pretty much got the major stuff, so the only thing I would add is how it feels: from idle to low/mid rpm's, the roll off is smooth. But once you get to a certain point, the bike hesitates (independent of throttle position) and the engine speed just won't accelerate. It does "catch" and continue through the power band occasionally, but for the most part it just hesitates when it gets to that rpm range.