[pantera]

I got a free 80 pantera 500 fan cooled that had been sitting for 5 years or so. Cleaned the carbs right away, new plugs, etc. It ran right away, but would not idle at all. Seemed to run better cold. I've had the carbs apart and cleaned about 5 times now. Tried to spray wd-40 around the pto seal, but did not get a reaction. I've heard these are notorious for center seals. Would that cause the plugs to be different colors? I took it on a vintage run last weekend and about 8 miles in, started to loose power. Now, one cylinder is dead. I've accepted that it is likely a crank seal problem from what I've heard from other old cat guys. Sound right?
What special tools do I need to perform this myself? does the clutch and stator have to come off? I've never had a two stroke torn apart before, but I am cheap and would like to do it myself. Not to mention the satisfaction. Also, when I look at the parts picture on denniskirk, I only see two rubber type seals. Are these the outside seals? What does the center seal look like? Is there a center seal? I'm a little confused on that one. Is this a good time to put new rings in? THey seem to be cheap. But, will the pistons even be out of the jugs for this job? Sorry about all the questons.

 

[kccats]

Get a sheet of plate glass and some 400-600 grit sand paper. Work the case halves back and forth to clean the matting surfaces. Then use like 1104 3 Bond to seal it.

 

[SB49]

Have you checked compression yet? If you have a dead cylinder you will need to do a rebuild anyway. Is there oil leaking from the seal area if there is then seals are bad. Not too hard to put in seals you can pop the bottom and sneak them in there.

 

[pantera]

I haven't checked compression. I don't have the tool for this. There does seem to be even resistance on both cylinders when I turn the engine over by hand. There was some oil leaking from the bottom of the pto side. I pulled the motor out yesterday and made a restrained effort to bang the stator and clutch off using a 2x4 and hammer. No luck, as I expected. I may end up buying a auto parts store puller and trying that. I know I found some threads about that on here. Am I going to be completely dismantling this thing, or can I just seperate the bottom half of the motor? It looks like there are some bolts that thread from the bottom of the crankcase.
kccats, the 1104 3 Bond is in addition to a gasket, right? Plate glass because it is flat and true?
Thanks, all.

 

[SB49]

I am not that familiar with cat engines, but generally you will need a chicken foot puller if your flywheel has threaded holes in it to put the bolts from the puller in. The clutch may need a special puller that threads into the clutch. Now many times you can split the lower case and gently lift the crank a half inch or so to put the new seals on. The lower case may not have a gasket the 1103 3 bond is like a silicone sealer that glues the cases together. You will need to get the right torque values and a torque wrench to put it all together again. Again if you can get your hands on a compression tester check the engine out this is all easier to do when the engine is fully dissembled.

 

[Case450]

You can take the motor apart in halves, but might as well strip it all and clean everything, install all new seals and visually inspect everything.
If your going to replace the crank seal then the bearing needs to be replaced too. Now your rebuilding the bottom you might as well rebuild the top too. New pistons, rings, and cylinder sleeves and you will literally have a brand new engine.

You can go to the local autoparts store and get a compression tester, they cost about 20 dollars. While your there pick up a harmonic damper puller (aka "chicken foot puller" lol i've never heard that before but makes sense) and I think you need M6 bolts to get the stator off.

New parts for these motors are really cheap and the motors are easy to work on. So that's a plus.

The very first thing to do is the compression test. Buy the tool, take out a spark plug and thread the tester into the hole and pull the recoil or hit the starter for a bit until the needle stops rising (make sure the other spark plug wire is disconnected when you do this) and make a note of the pressure. Repeat for the other cylinder. Ideally you want a minimum of 120 psi per cylinder. Anything less then 100 your cylinder is shot. More then 100 and less then 120 you will be rebuilding soon so dont forget your cell phone when you ride.

Does this sled have an oil injector or do you pre-mix?

 

[pantera]

alright. Got my gasket kit ordered. I hope it includes all the seals req'd. I'm going to get a compresson gauge next time at the parts store. I think I may know people that have pullers I can borrow. I have a torque wrench and I downloaded an old service manual so there should be specs in there. I'm ready to break stuff.
btw, this is an oil enjected suzuki spirit.
Thanks for the help.

 

[pantera]

UPDATE
Well, it turns out I need rings and pistons. There were some pieces of piston missing between the rings. One quick glance in the exhaust port by an experienced wrench and I was informed of the news. I've almost got it all the way torn down. I'm pretty slow. The flywheel is being stubborn. So, turns out my seals were probably fine. I'm doing them anyway now.

 

[SB49]

Don't worry about being slow. Rebuilding engines is not a race better to be a turtle here and make sure there aren't pieces of that piston down in the crank. Good Luck