GT550 crank seals

[Toystoretom]

Hi Guys and Girls!

I just bought a 1974 GT550 that won't start. Long story short, I've gone through the carbs, have fresh gas, petcock works, good spark timed right, good compression, new battery and so on. If I'm lucky when I spray a bunch of carb cleaner in the carb throats it might hit on one cylinder. I pulled the exhaust and fabbed up a steel plate with a gasket to seal it off. I made a fitting that will go into the carb boots. Hooked up a pressure gauge and tried to pump each cylinder up to 6 psi. The center and right sides won't hold squat, in fact on the right cylinder I can hear it hiss out behind the points plate. The left cylinder will hold a little pressure for about 15 seconds. The crank seals have to be shot.

So I have started to yank the engine to split the cases to get the crank out. Where is a good place to get replacement seals that aren't 30 years old and already petrified? Also, who do you guys use to rebuild the crank and install the seals? I haven't seen the crank yet but this is a 5000 mile bike that is in very nice shape (except for the crank seals) so I'll bet the crank is in pretty good shape so it shouldn't need much.

I have a nice shop press and bunches of things like bearing splitters and all kinds of plates and adaptors. Is a GT550 crank something that I could press apart? I was thinking of buying a junk one off of Flea Bay and practice on that. Or should I leave it to the pros.

I live in Kansas City so maybe you guys know someone local to me. You would think a machine shop the does dirt bike cranks or 4 wheeler cranks could do this.

Thanks!

Tomo

[TLRam1]

Bill Bune
http://www.billbune.com/index.html

[oldjapanesebikes]

Cranks seals are still available from Suzuki - should cost around $50

[Toystoretom]

Thanks! I'll check this out!

[Toystoretom]

OK.... I'm making progress. I've got the motor out of the bike and the head and cylinders are off. I should be able to split the cases and have the crank out sometime this weekend.

Is it possible to visually inspect the seals and tell if they are bad? After inspecting the head and the cylinders, the left cylinder had been firing (it was dry) but the center and right cylinders were wet with gas. Pretty much what I expected. The pistons look pretty decent, a little carbon buildup but really no scratches or gouges and the rings are free and look OK.

I'm going to try and swing by Donnel's (local Suzuki Dealer) and order the seals. I see engine gasket kits on Flea Bay for about $40... are those OK?

Thanks for you help guys!

Tomo

[TLRam1]

Is it possible to visually inspect the seals and tell if they are bad?

Tomo

If you did the leakdown test and it failed assuming all other ports were closed, the seals are no good. Anyway, when you have it this far down, go back together right and you will be done with the internals, you don't particularly want to do this again do you?

Depends on the brand of gasket sets, some have had better luck than others.

[jkevinlilly]

I used an ebay set on mine three years ago, do not remember the brand, but it worked fine.

Kevin

[Toystoretom]

I guess I ramble some, for sure I'm going to replace the seals. I just wondered if you could "see" a failed seal. I know that seals on cars become so stiff they no longer ride on the shaft.

That didn't sound good......

I'll try and get some pictures up this weekend just for the heck of it, I'm sure you guys have seen this a hundred times before.

Tomo

[TLRam1]

I'm sure you guys have seen this a hundred times before.

Tomo

But we always like seeing it again.

[Toystoretom]

I split the cases but ran into a bit of a problem. On the end of one of the transmission shafts is the electric starter drive gear, and from what I can tell it should simply slide off of the trans shaft when you pull the clutch, and stay with the clutch assembly? This gear is also part of the (sprage) clutch for the starter built into the clutch assembly. Mine has become one with the trans shaft and pulled out of the clutch assembly. Upon further inspection I discovered that the large bearing right behind that gear is locked up also. It probably got hot at some time after it started to lock up and probably welded the electric start drive gear to the transmission shaft.

The transmission oil that I drained out of the transmission was nasty and smelled bad, almost like gas does when it goes stale. It wouldn't shock me to find out that was the OEM oil in there from 1974. I guess that the previous owners didn't believe in preventive maintenance.

Anyway, I'm going to try and press the electric starter gear off of the shaft and see how much damage there is. That bearing looks to be discontinued so I'll probably buy a used tranny off of Flea Bay, unless you guys know of something better. I'll probably need that shaft also.

Tomo

[Toystoretom]

I forgot..

I ordered the crank seals from my local Suzuki dealer. He actually had the two center ones in stock! He said that he had the two outer ones also up to about a week ago but someone came in and bought those. We had to order the outer ones for me, the total cost with tax was $71. Inflation, huh???

[Toystoretom]

I was able to press the starter gear off of the transmission shaft. It turns out that the bearing behind isn't locked up after all. It appears that the starter gear was bound to the transmission shaft by the washer and spacer that is outboard of it and as soon as I took the pressure off by pressing it off everything became free and spins as it should. The bearing and the starter gear look good and the starter gear has a plain bearing with oilways that allows it to spin on the transmission shaft freely. The problem appears to be with the outboard washer and the spacer, both of which won't slide onto the transmission shaft. These should move freely on the shaft and they don't, I guess I'll need to hone them out.

It's almost as if that washer is too big and locks the inner bearing race with the outer one. I guess that washer is there to keep the starter gear from moving outward on the shaft but its kind of a poor setup. If you overtighten the large nut on the transmission shaft the holds the clutch basket in place it will lock this whole assembly up.

[Toystoretom]

I finally got around to checking out the crank seals. The left outer seal has lost the little retaining spring, I can see it loose down around the crankshaft. The two center seals have a buildup of rubber particles around them and if I slide them to one side I can SEE through them, the inner part of these two seals are GONE. I can't really see the right seal, I'm sure its a gem...

[Toystoretom]

I finally got around to uploading some pictures of this project. Let me see if I can get them from there to here

[/img]

It shows up on the preview anyway... that would be the GT550 after I pulled the engine.

Here is the ratty GT380 project that has the broken timing gear. I have all the stuff to go back together to fix the gear (except time, it seems):



Here is the GT550 motor in various states of disassembly:





Here is the starter drive gear and spacer that was stuck on the transmission shaft:



I have the crank out and seals bought and am awaiting a reply from the crank shop....

[garyscc]

Hi, I had a local shop do some work on my gt550 that I just bought. I get home and its leaking oil from crankcase. Where is the oil level indicator? I cant find it. What kind of oil should I add? I put 10w40 in it, and it literally came out quickly, from the seam beteen the crankcase. Do I need to pull engine out to fix, or can it be done with engine installed. It was running well besides this leak.