Suzuki 2 Strokes

'75 GT250, slurping down gearbox oil, but seems to idle quite steadily (not much air leakey)... Which seals are suspect?

Are seal/gasket kits available? ...any write-ups known?

...my having never cracked a suzuki case is really showing through here, and a pointer to any repair manual that I can view or purchase would be much appreciated.

--billyM in Greenville, SC <--noob

Hey Billy,

Did you pressure test the cylinders to see which side is the issue? I describe how to do a pressure test for about $25 here:

http://www.motorcycleracer.net/phpBB2/v ... ssure+test


Amazon has the Haynes 250 & 350 service manual here but it's an insane $56!!!:

http://www.motorcycleracer.net/phpBB2/v ... ssure+test

If you can hold out until next week, I'll bring in my T250 factory manual and scan the relevant sections for you. If not, you'll want to check ebay for a manual or maybe check the used book stores in your area:

http://www.google.com/search?hl=en&q=us ... oq=&aqi=g1

Also motorcycle salvage yards often have old service manuals for sale:

http://www.google.com/search?hl=en&q=mo ... f&oq=&aqi=

Athena gasket sets are decent and you can get them on ebay pretty easily. Crankseals should be available from the dealer still. You can look at on-line fiches at places like BikeBandit.com or Temecula motorsports:

http://www.temeculamotorsports.com/fiche_select.asp

Although Ridenow.com or Ronayers.com often have better prices on parts.

Hope this helps!

Jim

Jim, I can't thank you enough!

That is the type of information I was looking for, and can absolutely hold out a week or so for the scans (they come much appreciated) to get me by until I can source a manual.

I hope the internals are OK upon disassembly, and I'm crossing my fingers for an outer oil seal being the problem, but seeing extra smoke from both cylinders upon fire-up leads me to believe it could be the inner seals.

Thanks again Jim.

--billyM

Has to be the right side crank seal behind the clutch cover, I replaced one on a '73 GT250 without splitting the cases. Remove the seal and before replacing the new one chamfer the case where the seal goes in because it is machined so sharp it will mess up the new seal when you press it in.

Barry, good to know. Outer seals more-often the culprit than the inners? I'd hate to have to rebuild a 2500 mile crank.

Latest development...

I also found when the gearbox is filled (pulled both drain plugs with the bike on the center stand, refilled with 1300cc of oil) and then the bike is left setting on the side stand (need a stock sidestand, if anyone has one) it leaks from the left cover (I have not pulled yet).

--billyM

It could be the seal around your output shaft that is leaking. If your crank seals are leaking it would smoke alot and i presume the spark plugs would be black and oily.
If the smoke you are experiencing are from both exausts it's more likly to be related to the fuel system since it would require two seals to be shot to have gear oil into both cylinders.

Alright I have been losing gear oil for 2 years and had no clue where it was going, will lose about 200-300 cc every 700miles or so. Idle is strong, no extra smoke and no leaks. However the right spark plug is black compared to left which is brown. Had the carbs professionally rebuilt 2 years ago and synched. So I am assuming I have the same problem???? Let me know what you find please and any other help from the board would be greatly appreciated....Thanks Brett

It would be wise to replace the right side crank seal first, this means the clutch cover has to come off so you'll need a gasket etc for this job. The reason youre doing this is to confirm its the right side seal that was leaking and sucking the transmission oil into the engine.

My 2 cents, if you want a reliable old two stroke you need to go ahead and replace ALL of the seals in the engine, period. You'll just come to greif later if you don't. Also it is CHEAPER in the long run. The seals are 30+ years old and ARE hard, its just a matter of time before something major happens and destroys an other wise good engine. Dofin