crank seals

[Dale Sonnenschein]

I am almost done with a long project of my 75 250 harescrambler. I put a new top end and a new mikuni carb along with a long list of other parts. I went to start it today and it almost started once but now it doesn't even try. Is there a way of telling if the crank seals are bad? It ran when i got it but it had to be jump started. When I pulled the top end apart, the top ring was broke and a piece of the piston between the rings was broke too.When i check the plug, it's barely wet after a good 20 to 30 kicks. It has spark too.any ideas?
Thanks
Dale

74 puch 175 SD
73 Husky 360 WR/RT
75 Penton 250
10 ktm 250xc
02 bmw r1150r

[454MRW]

Dale,
If you are using a Bing carb, are you holding the tickler down until fuel starts to run out of the overflow hoses onto the engine or ground? It takes a very rich mixture to initally start a cold KTM engine, especially in cool or cold weather. Mike
** I missed the part about a Mikuni carb, so make sure the choke works properly and the float level is set high enough, and even try leaning the bike over to flood the carb before starting**
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Big Mac]

Double check the float level to be sure bowl fuel height is right--needed along with choke on a Mikuni.

Crank seal bad on left side will suck and burn oil, right side seal would have to be almost gone to prevent it from wanting to start. Kinda like kicking it with the throttle partly cracked. Usually with a right side bad seal it will run, just poorly with a high idle you can notice clearly if you squirt some WD40 in behind the flywheel.

If a new Mikuni, you shouldn't have a plugged pilot jet, which makes for very hard or no start. Check around here to be sure you have the right jetting combo to be in the ballpark, be sure float level's set right, and if nothing, pull plug and leak in a dribble of gas to see if it's truly fuel starved. If you've got spark, compression, timing in the right ballpark and fuel, it has to start...law of physics.

[Dale Sonnenschein]

I put a little gas in the plug hole and tried to start it. Nothing. So I got tired of kicking my bike so I threw a chain on it and jump started it. And it started. It ran for about a minute and it quit. I think it ran out of gas. I turned on the gas and couldn't kick start it. So I jumped it again. It started and ran for a couple minutes. It stalled and wouldn't kick start again. What could I be looking at. Timing? I have no equipment to check timing. Weak ignition? It has spark, looks mostly white. The top end is new,carb is new, new plug too.

74 puch 175 SD
73 Husky 360 WR/RT
75 Penton 250
10 ktm 250xc
02 bmw r1150r

[Dale Sonnenschein]

I've been picking my brain trying to figure why this bike won't kick start. I went back to the garage and tried to jump start it again and it wouldn't start. Now I'm starting to get heated up. If I have a problem, alot of times I will go back to basics and make sure I haven't missed anything. The carb is getting gas, everything looks in place.  I checked the compression and its around 170. I went to put the plug back in and I thought, maybe I should try another plug. Low and behold, 2 kicks and the bike runs!!!. A defective NGK plug.It showed spark but I checked it again and the spark was coming from deep in the plug. Jeeez, that could drive a guy nuts!! Now to see how close the jetting is. Thanks for the help.

74 puch 175 SD
73 Husky 360 WR/RT
75 Penton 250
10 ktm 250xc
02 bmw r1150r

[Big Mac]

Oh yeah, forgot my "won't start" experience checklist includes Try a fresh plug, even if the current one is young and showing spark. Haven't been fooled with that one for a long time, but kicked on a bike for 3 days when I was 13, showing plenty of blue spark, had gas...some plugs will only give up the ghost under compression I've heard, go figure.

On timing a motoplat...it's not real hard, turn motor to a couple mm (see manual) before TDC and slide a skinny pin through the hole in the flywheel, wiggle back and forth a bit, should slide all the way into the rotor if it's right. I made up a simple dial indicator plug adapter and use a $9 HFT special. You can get away with a manual measurement in a pinch, a cheap depth gauge will work. Usually only goes wrong if the flywheel gets loose, shears the key and moves on the shaft, with an immediate shut down and no re-start.