Crank Seals Vs. Rich Running

[curtis966]

I had a bad ground on my build once and it was pretty speratic like your seems to be. Any adjustments to the carb didn't change anything. And had a high idle but you couldn't give it much throttle or it bogged out. Could be that. Just a guess though. I hooked up a new ground and everything was perfect was really weird actually.

[lakehouse]

I had a bad ground on my build once and it was pretty speratic like your seems to be. Any adjustments to the carb didn't change anything. And had a high idle but you couldn't give it much throttle or it bogged out. Could be that. Just a guess though. I hooked up a new ground and everything was perfect was really weird actually.

At this point, it's well worth a try. Having owned, and still do, a plastic car (Corvette) I know how critical a good ground is. In fact, my C6 Corvette has 7 different ground areas, if I remember correctly. Thanks for the hint, and as soon as it gets warmer, I'll run a new ground wire and see if it has any effect.

[lakehouse]

you'll end up with leaks, running with the air set screw, usually turned off, which stops the pilot, and youll have the idle up to make it run on a different jet.

Pilot off was only done trying to get it to idle, run smooth, and rev up like it is supposed to. I don't leave it turned off, and I agree with your statement too. To me, I feel as if somehow the engine is getting so much fuel that it is overpowering the idle circuit. I think, in theory anyway, if the main jet was completely blocked off, the idle jet and circuit should be sufficient enough to allow the motor to idle. Of course, there would be no rpm at all should you try to give it any throttle. Might be an interesting idea to try, but this cold weather has brought everything to a screeching halt. I don't think my better half would understand why the scooter has to be in the living room in front of the fireplace. LOL

[LMH]

I would nix the idea of crank seals causing a rich condition. Logic and physics tells us its not possible.
I would look into a spark issue or compression issue if your carb is clean and correct. Correct as in right slide and needle as you know for a fact its the correct jet when you dismantled it a 68 was stamped on it.
If there is no compression there will be a rich situation. Weak spark rich situation. Bad reeds rich situation. Improper set float and metering needle will be a rich situation. Slide not filling in the venturi will make for a horrible idle and possible rich situation at idle as it will pull too much on the idle circuit (depends on air filter and flow). Needle not seating all the way into main jet tube will definitely be a rich situation.
Bad seals will never be a rich situation.
Sounds like fun!
What does asotfomh stands for? Fndsman?

[kingkamehameha]

Any case leak or intake manifold leak will cause a lean condition. Do your reading in the jennings two stroke articles. Your mechanic is a moron.

[lakehouse]

I would nix the idea of crank seals causing a rich condition. Logic and physics tells us its not possible.
I would look into a spark issue or compression issue if your carb is clean and correct. Correct as in right slide and needle as you know for a fact its the correct jet when you dismantled it a 68 was stamped on it.
If there is no compression there will be a rich situation. Weak spark rich situation. Bad reeds rich situation. Improper set float and metering needle will be a rich situation. Slide not filling in the venturi will make for a horrible idle and possible rich situation at idle as it will pull too much on the idle circuit (depends on air filter and flow). Needle not seating all the way into main jet tube will definitely be a rich situation.
Bad seals will never be a rich situation.
Sounds like fun!
What does asotfomh stands for? Fndsman?

All of your probabilities sound extremely reasonable to me. And I agree with you entirely. I have about 115psi compression, reeds look perfect, and have no reason not to believe that I am the one and only person who ever attempted to do anything with the motor itself. As previously stated, original (and only) owner was not mechanical savvy, nor did he have the desire to tinker with it. Everything there is OEM from Honda, including carb slide and needle. The only possibility at this time might lay I the ignition, being a weak spark. It is strong enough to run the engine, but don't know what it is like under compression or when actually running. Know of any tests for that other than R&R the CDI and everything related to it? And is the compression low enough to warrant doing a ring job, especially since it has set up for so long? Interesting to know what you would do if you were in my situation. And thanks for your post and theories.

[lakehouse]

Keep I'm mind just because the jet is stamped that size doesn't mean it is. I use a special drill bit index to up size jets. Someone could have cleaned/drilled it out.

I have no reason to believe that anybody has been into this bike prior to me. Definitely not the previous (original) owner would. I agree with your thoughts on the jet issue. I have drilled out many a jet myself when I was building race cars. Thanks for the thought though.

[PorterGuy85]

What's the verdict on this?

[paulpauly7]

buggered crank seals cause a lean condition not rich

[lakehouse]

In reading all my posting from about a year ago on my rich running condition, I did finally solve the problem. Not only is it weird and unique, but I'll bet that I could never duplicate it again if I tried. Maybe some of you are experiencing the same problem, and I'll tell you what I had finally found to be the cause of all my problems. When I vatted my carburetor, I had it sit overnight (disassembled) in a 20 year old can of carb cleaner. To make a long story short, the chemical became so strong that it actually ate into the metal that the carb was cast from. In turn, it enlarged the extremely small, machined idle jet in the main body, allowing excessive fuel into the engine during start up and trying to idle. That is why the engine grabbed RPM like crazy when compressed air was introduced into the inlet of the carb. I was actually SUPERCHARGING it, and leaning the mixture out to a near proper fuel.air ratio! After replacing the carb body from a donor carb, it ran perfectly with only minor idle adjustments necessary. The only way I could visually tell the difference, was to hold up the two carb bodies side by side in direct, bright sunlight. The idle jet enlarged just enough from the solution, to cause all the problems of running too rich. It's been running perfect ever since.
I hope this can help someone who is also pulling their hair out of their head! Good luck, fellow riders!

[Dr_Craw]

that's a good catch! glad you found the problem!

[lakehouse]

I probably could have resolved the problem a lot faster had the carb I bought from a supplier in Hing Kong been the right one. But the one they sent me had the bistarter on the inside towards the center line of the bike, and NOT on the outside. The bistarter interfered with the suspension and wouldn't fit. But for 28 bucks, I wasn't about to try to exchange it, or send it back. And since it was manufactured by a different manufacturer, the parts, and main body would not interchange. Only the bistarter would. All the other dimensions were dead on and would probably work just fine on a different application. I was lucky enough to find a "junk" carb on Ebay, although it was overpriced for what it was. But the body was usable, and is what I am running now without any problems. For once I beat the bear instead of the bear beating me! LOL