250R engine cuts out at full throttle

[cheesecake]

What's up R riders. Need a little help. '87 250R, full throttle 1st, 2nd, go to hit 3rd gear and engine cuts out. Just like turning the ignition off. Back off to 1/2 throttle and it comes back to life, but barely runs. Let it idle a couple seconds and it will smooth out. I can 1/4 throttle around all day long, wide open 1st, 2nd cuts out. R and R carb, it was clean inside. HELP

[genxracer]

sure your main jet didnt fall out? or clog?

[RUNMYTA]

Coil is breaking down!! Trust me!

[JTRtrx250r]

sounds like a fuel delivery / jetting prob

Be sure the gascap vent hose isnt plugged (steering stems will fill up w/ chit and plug the vent hose ),

then be sure the petcock flows good, if so be sure the breather hoses from the carb arent clogged(last yr caked mine w/ mud and they both clogged..wouldnt run for chit)

if your still running summer jetting it might be lean w/ the winter cold, (suprises me how many ppl run the same jetting all yr ..and wonder why it dont run right) Do a plug chop..put a load on the motor WFO in the gear that will hold, kill the motor and pull in the clutch simotainiously(sp) and check he plug...if its anything past a tan color ..then its too lean (grey/white-ish is bad!!). If its wet/black its too fat(rich), work your way up/down depending on where its is

If your compression is higher than stock ..try gapping the plug to 0.018. (btw...what is your compression?)

If none of that works t probably is your coil takin' a chit, also be sure you got a good connection on the ground wire(seen that reak havoc on ppl all on its own, prob not the deal but it dont hurt to check)

Good luck mang!

BTW..this should be in the 250R section

[elite ATV1]

Originally posted by JTRtrx250r
sounds like a fuel delivery / jetting prob

Be sure the gascap vent hose isnt plugged (steering stems will fill up w/ chit and plug the vent hose ),

then be sure the petcock flows good, if so be sure the breather hoses from the carb arent clogged(last yr caked mine w/ mud and they both clogged..wouldnt run for chit)

if your still running summer jetting it might be lean w/ the winter cold, (suprises me how many ppl run the same jetting all yr ..and wonder why it dont run right) Do a plug chop..put a load on the motor WFO in the gear that will hold, kill the motor and pull in the clutch simotainiously(sp) and check he plug...if its anything past a tan color ..then its too lean (grey/white-ish is bad!!). If its wet/black its too fat(rich), work your way up/down depending on where its is

If your compression is higher than stock ..try gapping the plug to 0.018. (btw...what is your compression?)

If none of that works t probably is your coil takin' a chit, also be sure you got a good connection on the ground wire(seen that reak havoc on ppl all on its own, prob not the deal but it dont hurt to check)

Good luck mang!

BTW..this should be in the 250R section

[wilkin250r]

None of this makes any sense. I cannot think of one single reason that your quad would run in WOT in 2nd gear, but not in 3rd, unless your tranny was shot.

Have you tried running WOT in 2nd gear for long periods of time? Is it possible that your carb is running dry, but you coincidentally try to shift to 3rd gear at the same time, so you associate the problem with 3rd gear?

Have you determined that you actually have "power" in 2nd gear? If you're running like crap with no power in the higher RPMs, it would "seem" like it is running better in lower gears because you aren't loading the engine as much.

Your engine, carb, coil, intake, all of this stuff doesn't "see" gears or ground speed. If you are running WOT at 8000 rpms, you have the exact same airflow through your carb and reeds, the exact same fuel flow, and the exact same coil rotation speed whether you are in 1st gear or 6th gear. The components that affect jetting and how your bike runs DO NOT SEE GEARS. So it doesn't make sense to say your bike runs good in 2nd gear, but not in 3rd gear.

[sam the brave]

main jet fell out

[TheX1992]

Originally posted by wilkin250r
None of this makes any sense. I cannot think of one single reason that your quad would run in WOT in 2nd gear, but not in 3rd, unless your tranny was shot.

Have you tried running WOT in 2nd gear for long periods of time? Is it possible that your carb is running dry, but you coincidentally try to shift to 3rd gear at the same time, so you associate the problem with 3rd gear?

Have you determined that you actually have "power" in 2nd gear? If you're running like crap with no power in the higher RPMs, it would "seem" like it is running better in lower gears because you aren't loading the engine as much.

Your engine, carb, coil, intake, all of this stuff doesn't "see" gears or ground speed. If you are running WOT at 8000 rpms, you have the exact same airflow through your carb and reeds, the exact same fuel flow, and the exact same coil rotation speed whether you are in 1st gear or 6th gear. The components that affect jetting and how your bike runs DO NOT SEE GEARS. So it doesn't make sense to say your bike runs good in 2nd gear, but not in 3rd gear.

Mind you 1st and 2nd gear on a 250r are VERY short. What are the chances of you holding the throttle WFO in 1st or 2nd for more than .2 seconds? Your motor would over rev and blow. 3rd gear takes a little longer to wind out so you can hold it WFO longer.

[cheesecake]

Originally posted by genxracer
sure your main jet didnt fall out? or clog?

I R&R the carb, everything is tight and in place.

[cheesecake]

Originally posted by JTRtrx250r
sounds like a fuel delivery / jetting prob

Be sure the gascap vent hose isnt plugged (steering stems will fill up w/ chit and plug the vent hose ),

then be sure the petcock flows good, if so be sure the breather hoses from the carb arent clogged(last yr caked mine w/ mud and they both clogged..wouldnt run for chit)

if your still running summer jetting it might be lean w/ the winter cold, (suprises me how many ppl run the same jetting all yr ..and wonder why it dont run right) Do a plug chop..put a load on the motor WFO in the gear that will hold, kill the motor and pull in the clutch simotainiously(sp) and check he plug...if its anything past a tan color ..then its too lean (grey/white-ish is bad!!). If its wet/black its too fat(rich), work your way up/down depending on where its is

If your compression is higher than stock ..try gapping the plug to 0.018. (btw...what is your compression?)

If none of that works t probably is your coil takin' a chit, also be sure you got a good connection on the ground wire(seen that reak havoc on ppl all on its own, prob not the deal but it dont hurt to check)

Good luck mang!

BTW..this should be in the 250R section

When I mash the throttle from idle to wide open, it has a hesitation and then revs. In warmer weather it didn't. My compression is 230psi. Just checked it tonight after I blasted up the driveway, but it ran GOOD tonight.