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'96 RM250 bog and smoke

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'96 RM250. Recent top end, and FMF pipe.
When I bought it three years ago, it took several kicks to start cold, and ran good once started.
Restarting when hot took several more kicks. The jetting was 168 and 52. Occasionally it bogged in the mid-range off throttle was flat.
I have since replaced the stator, pick up coil and ignition coil, and jetted to 175 and 58, air screw about 2.5 out on a recommendation.
It starts and idles OK for about three minutes, then starts to idle rough, and boggs coming off idle , yet cleans up with a big rev.
Restarting hot is very difficult. The gas is fresh, using Redline two stroke oil, 32:1. Lot's of white smoke. I have messed with the clip setting in 1,2 and 3 position. I sprayed carb cleaner at the left side crank seal and no idle change, so it's intact i'm guessing. The right side crank seal maybe bad, as the trans oil was very black and odor of gas. Anyway I can test it while I've got it idling, without taking it apart? Any other and needle recommendations? Are these Keihin carbs prone to cracking or leaking by on the choke? Any suggestion would be great.
I love the feel and power of the bike and want to keep it for awhile. Thanks !

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21 hours ago, HomerDodd said:

'96 RM250. Recent top end, and FMF pipe.
When I bought it three years ago, it took several kicks to start cold, and ran good once started.
Restarting when hot took several more kicks. The jetting was 168 and 52. Occasionally it bogged in the mid-range off throttle was flat.
I have since replaced the stator, pick up coil and ignition coil, and jetted to 175 and 58, air screw about 2.5 out on a recommendation.
It starts and idles OK for about three minutes, then starts to idle rough, and boggs coming off idle , yet cleans up with a big rev.
Restarting hot is very difficult. The gas is fresh, using Redline two stroke oil, 32:1. Lot's of white smoke. I have messed with the clip setting in 1,2 and 3 position. I sprayed carb cleaner at the left side crank seal and no idle change, so it's intact i'm guessing. The right side crank seal maybe bad, as the trans oil was very black and odor of gas. Anyway I can test it while I've got it idling, without taking it apart? Any other and needle recommendations? Are these Keihin carbs prone to cracking or leaking by on the choke? Any suggestion would be great.
I love the feel and power of the bike and want to keep it for awhile. Thanks !

White smoke is normally coolant, being a 1996 I would suspect it would be a good ideal to freshen it up now than if it gernades. If the trans oil is disappearing then that seal is out and it will burn it and run hot. If it was me I would tear it down and take a look see to find out what is going on.

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Sure sounds like the crank seal to me. It's only about a $10 dollar seal and relatively easy to change I would just do both and rule it out

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Agree with everything ar2stroke said. 

I’ve also seen gear oil burn white. Only way to really tell is take a whiff and see if it smells sweet or nasty like oil. 

Kinda sounds like your float is cracked and sinking. But another thing is you’re way too rich on the pilot with air screw having to be that far out for decent idle. Where did you have it set with the 52?

Many carb cleaners are not flammable nowadays. Even though it smells flammable, and evaporates quick, you can’t assume it’s flammable. Spray some on the ground and check with a lighter. I use propane instead.

Magneto side can be checked by blowing some in the magneto drain hole, and clutch side can be checked by removing fill plug and blowing some in with a rag wrapped around the torch tip so oil doesn’t go flying everywhere. If it’s too rich (Which it sounds like it is) you need to get it leaned out so the extra fuel actually makes a difference in how it runs...

Bogging can often be a plug starting to foul. Sounds to me like that’s what’s going on.

Keihin carbs (and others) wear the needle jet (jet that needle drops into) oval with time and let in WAY too much fuel just off idle (1/8) throttle position. Unfortunately non-replaceable part. The wear can be compensated for by using a needle with a larger straight diameter.

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Thank you all very much. It gives me some starting points to check. I like the propane idea; sounds fairly easy and accurate. BTW, the coolant level has not dropped, so it must be oil burning. I may go to a 48 pilot and retest. Will that make it easier to start hot and cold? Thanks again guys.

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3 hours ago, Jeremyf1 said:

Keihin carbs (and others) wear the needle jet (jet that needle drops into) oval with time and let in WAY too much fuel just off idle (1/8) throttle position. Unfortunately non-replaceable part. The wear can be compensated for by using a needle with a larger straight diameter. 

 Does that mean replacing the entire carb? Lot's of Sudco Keihin PWK 38's all over e-Bay and Amazon.......will that work?

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19 minutes ago, HomerDodd said:

Thank you all very much. It gives me some starting points to check. I like the propane idea; sounds fairly easy and accurate. BTW, the coolant level has not dropped, so it must be oil burning. I may go to a 48 pilot and retest. Will that make it easier to start hot and cold? Thanks again guys.

Yes 48 or even a 45. All my 250’s have 45 pilots and I’m just a little above sea level. 

17 minutes ago, HomerDodd said:

 Does that mean replacing the entire carb? Lot's of Sudco Keihin PWK 38's all over e-Bay and Amazon.......will that work?

Not necessarily, but not a bad idea. If your carb has ever been dunked in the chemical carb cleaner in the can by a previous owner, it could have gooey mess for a metering block o-ring. 

Suzuki carbs almost always have #6 or #6.5 throttle slides which are rich. The aftermarket PWKs have #7 slides which are much more ideal jetting wise.

Beware of the clones. Getting harder to spot. If it not priced close to $200, it’s most likely fake....

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