[Todd]

Hey everybody. i just bought a 87 250r. The previous owner told me he thought the engine was stock. It has a fmf pipe with fmf powercore2 silencer.
Anyways heres my problem. It runs good from idle to about 1/2 throttle and anything over that it just sputters and wont rev up and has no power. I did a compression test on it and it has 195 lbs of compression. I put a new k&n air filter on it and am running the airbox lid on. I have been running 111 octane gas with amsoil dominator oil at 32:1. The jets in the carb and 52 pilot and 165 main. I have tried a 158 main and 180 main and it seems to make no difference. still sputters. i have put in a new plug everytime i changed the jets and each time the plug dont change that much. it stays pretty much golden brown or slightly whiteish but everytime i pull them they seem to be wet. so i was wondering can this be an electrical issue? like above half throttle if the spark is weak or something? im pretty lost here and dont know if im missing something simple or whats going on. any ideas will help. thanks

 

[Todd]

also i have been running a br8es spark plug

 

[fearlessfred]

is it a stock 34 carb?what position is the needle at? and when you say halve throttle do you mean the throttle is half opened or midway in the rpms? the main jet will have almost no effect at half throttle

 

[Todd]

yes it is the stock 34 carb. also it is in the center position. i have tried moving the clip and and down and it made no noticable change. also i guess i would say midway into the rpms is when it starts breaking up and sputtering.

 

[fearlessfred]

yes it is the stock 34 carb. also it is in the center position. i have tried moving the clip and and down and it made no noticable change. also i guess i would say midway into the rpms is when it starts breaking up and sputtering.[/QUOTEI was trying to make sure that you are not holding the throttle wide open and that you are refering to the rpms.if you are holding the throttle wide open than the main jet size has an effect.I don't remember running anything larger than a 152 in a stock carb and that would be close to sea level in elevation

 

[Todd]

my elevation is 800 ft above sea level. and it will start sputtering when the throttle is help at half and the way up to wide open. would this mean its too rich and i should drop my jet back down closer to stock size? im sure the previous owner went up in jet size when he put the pipe on. or am i having an issue when i get up to a certain rpm i start having electrical issues with spark?

 

[R man]

Sounds like it has the wrong cdi box on it. If you can find out if it has been changed that would narrow it down, even the wrong jets would not keep it down, it should eventually rev if its too rich. If cdi is correct and working properly put the bike in a pitch black area and crank it up, rev it and look for any arcing wires/boots. You may see blue surrounding the sparkplug at high rpm's but thats normal. Does it do it if you rev it in neutral?

 

[Todd]

Yes it does it in neutral too. Is there any way to check the cdi besides swapping it with another one?

 

[R man]

Not that I know of, and if you're like me, you are the only one within 40 miles with a 250R. Here is a check list that I go thru; Screw the choke/idle all the way down and make sure its pressed down not on "choke", Gap plug to .018 or .020, make sure the carb is clean clean, ALL holes blown thru, remove airbox lid, check plug boot connection on sparkplug end and coil end, if this stuff makes no difference do the wire check in the dark and try to do it with plastic/tank removed, a bad coil wont show up, but its very seldom they HALF go out. By the way, why did the guy sell the bike?

 

[fearlessfred]

I guess theres not a chance a rag was left in the airboot when changing air filter

 

[R man]

That sounds about right, because thats exactly the symptoms it would have. Its late but if you cant figure it out by tomorrow give me a call if you want, 229 309 5109 I've worked on these things for 25 years, never had one whoop me!!

 

[Todd]

I will try all that after today. And there's no rag in airbox lol. And the guy I bought it from said he didn't ride it enough. He thought that the motor was in need of a rebuild. But a compresstion test shows 195 lbs

 

[Lasher-19]

I guess theres not a chance a rag was left in the airboot when changing air filter

LOL...too many times I have done this! I think last time it just reved to the moon and freaked me out.

But make sure the carb is cleaned really good. Did you check for air leaks on the motor?

 

[t_shee]

Is your compression tester accurare? Maybe use another one to verify

 

[Todd]

I looked and didn't see any noticeable place air could leak. All the rubber intake boots looked good with no cracks in them. And i bought the compression tester brand new and this was the 1st time I used it. I will see if someone at work has one I can use to verify.

 

[fearlessfred]

you might try pulling the left side ign. cover and make sure it is dry .

 

[cvega2274]

Try without the filter box lid and see if there is a difference or a dirty air filter try without the filter too.

 

[Todd]

Ok so i cleaned carb again (it was still clean) and took airbox lid off, put in a new plug gapped at .20, and turned the idle screw all the way in. Now it doesnt idle. it needs the choke knob/idle knob turned about 3/4 of the way up for it to idle. idk if thats normal or not??

But anyways i took it for a drive and the problem is still there. But now i have decided that the sputtering problem is caused due to the rpms increasing. IT is not caused buy wide open throttle. When i get in about 4th gear and hold it wide open it accelerates nice and hard until it gets to a certain rpm then starts sputtering. then i will shift into 5th and hold it wide open and it runs great again until it gets to the certain rpm again and wont rev up any higher.

So thats where im at. And 1st and 2nd gear are really bad because it revs up fast to that point then starts sputtering.

Any ideas?

 

[fearlessfred]

did you pull the stater cover and make sure there is no water in there ,it takes less than 10 min to do

 

[acecarlos]

Hey everybody. i just bought a 87 250r. The previous owner told me he thought the engine was stock. It has a fmf pipe with fmf powercore2 silencer.
Anyways heres my problem. It runs good from idle to about 1/2 throttle and anything over that it just sputters and wont rev up and has no power. I did a compression test on it and it has 195 lbs of compression. I put a new k&n air filter on it and am running the airbox lid on. I have been running 111 octane gas with amsoil dominator oil at 32:1. The jets in the carb and 52 pilot and 165 main. I have tried a 158 main and 180 main and it seems to make no difference. still sputters. i have put in a new plug everytime i changed the jets and each time the plug dont change that much. it stays pretty much golden brown or slightly whiteish but everytime i pull them they seem to be wet. so i was wondering can this be an electrical issue? like above half throttle if the spark is weak or something? im pretty lost here and dont know if im missing something simple or whats going on. any ideas will help. thanks

Sounds like the typical issue found with a bad coil, stator, ground, wire harness, faulty connecotrs or CDI. Jetting changes with no respnce ususally indicates an electrical issue.

Get a Honda service manual and an OHM meter and check all electrical components to specifications. The CDI can not be checked with standard tools, best to swap with a good known working CDI.

Carlos