bought a new 85 250r, ran into trouble. help?

[dream3wheeler]

Bought a 250r for $1000 on saturday. Bought a carb kit and reeds hoping to solve my problems with idle and high speed. It was spitting back a little, nothing bad really but I figured Boyesen reeds would be better than stock any day. Anyway I'm waiting for parts and decided to clean everything and go for a ride today. Around 3/4 throttle in 6th gear it surges and I start to slow down. Feels like spark timing problem. Any suggestions for any of this?

[dream3wheeler]

here it is

[dream3wheeler]

I don't see why an air leak would really cause it to slow down and surge like it did. its not leaning out or anything and I sprayed that whole motor down with starting fluid and the rpm never changed. sprayed it with soap and nothing bubbled up. It really does seem like spark timing to me, I just don't know weather it would be the ignition coil or cdi, and im hoping to hell it wouldn't be the stator. I checked out the flywheel and it didn't really smell like gas but their was a brown liquid that came out when I opened it up.

[dream3wheeler]

I mean I can put it in 3rd gear, hit the throttle and it'll rip my arms out of there sockets and take off without any hesitation when revving it up, but once I get to maybe even half throttle or higher in 6th gear it feels like the spark starts to break up and I start slowing down until I ease off the throttle and shift down. I should almost put it on video

[82 250r]

An air leak will manifest itself at lower rpm's...probably not your problem but with that being said, the brown liquid in your stator cover is 2 stroke oil from a bad main seal.
Clean all oil from your stator, flywheel, and pickup because oil is a good conductor of electricity.

What main jet, needle position and carb are you currently running?

[dream3wheeler]

right now Im running the stock setup im assuming. the main jet is 142 and I know that's stock but I never checked anything else out, but the needle and seat leaks so that could maybe be part of the problem? but I ordered a carb kit already, and new boyesen reeds. I ordered the new reeds cause when I first cleaned the carb I ran it without the air box and tubes to see how it ran, and it looked like as it ran it spit back a little bit of fuel as it ran so I figured the reeds weren't responding as well as they should. But just a bit ago I took the gas tank off to check the ignition coil and do some electrical tests and noticed the spark plug was starting to come out and the cap wasn't sitting properly on the plug. so I fixed that but its too late in my neighborhood to do any test runs. im hoping the carb kit and reeds + the spark plug fix will solve the problems. I also noticed im running too hot of a plug according to the manual. its a br8es, its been 80 degrees out.... should probably switch to a br9es? would that make a difference in top end?

[82 250r]

do you have a stock round slide pe carb?

[dream3wheeler]

yup. looks the same as the one on my old 85 except I never took that one apart. I don't know what cutaway I should be running or anything, or if theres even a different sized cutaway slide available for this carb or not.

[82 250r]

Well that carb has known issues...i can't help you but maybe someone else can.
While you're spending money on reeds and such, look for a flat slide 34mm pj. Will be worth it.

[dream3wheeler]

im sure any flat slide mikuni 34mm carb would work with the right jetting. does the flat slide help with throttle response too?

[dream3wheeler]

any more thoughts?

[BOB MARLIN]

Leak down test?.

[Outlaw #24]

The Spark plug is /was the trouble and It wouldn't hurt to change the Main seal on the stator side as it is 29 years old, and you don't have to split the cases to change it!

[dream3wheeler]

Well soon ill have to invest in a pressure/vacuum tester, that should tell me where a leak is if ive got one. as for splitting the case, im not ready to do that yet, if there is a way to change that seal without dismantling the whole thing I think thatd be best. after tightening down the spark plug and securing the cap, I took it out for a test run, same stuff different day. Ive got the carb kit on the way still and reeds, if those don't solve my problems ill go with changing the seal. as for a pipe, that'll come later when I feel like showing it off, right now im just trying to rip up some dirt roads.

[82 250r]

1: replace the round slide pe carb with a 34mm pj. (you can get one from ebay and rebuild it.)
2: clean the oil off the stator and flywheel.
3: replace the stator side crank seal.