GT550 crank seals ?

[h2okettle]

My GT550K has a pinging problem on the left cylinder. I have a newtronics on it and the timing is set correctly. The carbs are like brand new inside. All passages are clean and jets perfect. The compression is good on all 3 cylinders (140-145). Spark plugs are burning a light chocolate brown. The problem is the left cylinder pings at idle and it idles like it has a vacuum leak, sometimes revving up high and not coming back to idle It also only idles when about 2Krpm or higher.. All the intake boots are pliable and the carbs are on tight. The air screw on the left carb does not seem to affect the idle at all. I did pull the head to look for any problems, but found none. Will a bad crank seal cause any of this, and how do you check to find out. If it is the left crank seal, does the cases have to be split? If so, I guess it can't be as bad as the GT750 was.. The bad part is I was getting it ready to ride to the 2 stroke rally next month.
Thanks for any help.

Allen..... Back to riding the cb350

[Coyote]

Hey Allen. I was looking at the fiche on Alpha Sports. The seal does not appear to have a retaining lip on it. You might be able to drill and tap 2 small holes and work it out with a slide hammer. I'd say it's probably pretty tight if it has been in place since 73, but it's worth a shot. Be careful though. The left crank bearing is right behind that seal.
The seal is still availabe from Suzuki. Part no. 09238-25048

[johnakay]

1st of all Allen before you do what coyoty say's..
does the bike bike smoke a lot once warmed up or after a run.
if all look the same on all 4 pipes.
then I doub't much if the seals gone
sound to me you've got a leak else where.

check that your heads are tightened down no not your head the bike
I'm sure more knowledgable chaps will give a better answer. john

[Cliff]

I would synchronize and balance the carbs., retard the timing a few degrees, install colder plugs and fill the gas tank with premium 0% ethanol fuel and see what happens before I'd think of pulling the crank!!
Cliff!

[h2okettle]

The bike does not smoke excessively.. My GT750 did lose a crank seal that caused the trans oil to go into the crankcase.. Now that motor smoked !!! The head gaskets are fine and not leaking. I was thinking the left seal as the problem cuz it idles up and down, like a vacuum leak does and continues to ping/detonate on the #1 cylinder.. Soon as I pull the plug wire off of #1 the ping goes away, so its only the one cylinder with the problem. Is there a way to check this seal for the problem? I did have an idea, but if its a bad one let me know.. I was gonna pull the alternator off and then pack some grease around the left seal. This should stop any air from leaking in if the seal is bad, and the engine should smooth out for a few minutes anyway. If not then the seal is not the problem. Cliff, I did sync all the carbs right before I set the timing. All 3 dots are lined up. I have also tried high test gas. It is strange that its just the one cylinder. This was my reason for suspecting the seal. It did this even before I installed the newtronics, and to be on the safe side, I have 2 newtronics brain boxes, and tried them both. Same results. I also changed plugs. I am really hoping to find an easy fix and not have to split the cases. Again, thank you for your help and if anyone has had this problem and found a cure I would appreciate the info.

Allen.... Still sitting in the smoking section !!

[Cliff]

Is there any injector oil in or around the alternator? If that seal is bad it will leak oil out as well as suck air in. Grease is a good idea but try this first. With the engine running, spray the area behind the alternator with chain lube or WD40 or engine oil or even quick start (ether) and see if anything changes. That seal is a flanged seal so the cases will have to be split to change it.
Synchronizing the carbs. is one thing. It makes sure that the slides are at the same point and move at the same time. Balancing them is another thing. Follow these instructions, "idling adjustment, method 1": http://www.3cyl.com/mraxl/gt/manuals/gt ... 550-40.htm" onclick="window.open(this.href);return false;
Check the SRIS line to that cylinder. Is it OK? A cracked/broken/damaged line to one cylinder will cause it to run lean!
Before I pull the crankshaft out I'd make sure it's not something simple or easy to fix!!
Cliff.

[h2okettle]

Cliff, thanks for the ideas... I will try those, as the very last thing I want to do is split the cases.. The bike will just have to sit if the seal is the problem.. I'm gonna ride aother bike instead. I will let ya'll know what I find out.
Thanks again !!

Allen

[Cliff]

I might see you at Deal's Gap in May! I'm riding down from Toronto, Canada if it's not raining!

[jaybob]

If it is the left outer crank seal you can replace it without splitting the cases. It does have a retaining lip on it though. I pulled mine out with some screws and a slide hammer. then ground the lip off of the new seal and installed it with some orange silicone. Works perfectly.