GT185 Crankshaft Seals

[sandsz]

Hello! I just bought a GT185 and using the shop manual, I'm pretty sure I have a busted crankshaft oil seal(s).

Bike won't start after previous owner did fresh rebuild, ran it and it sputtered out. Doofus bypassed the CCI and just did premix, so from what I read that means bad crankshaft oil seals.

140PSI on both cyl, both coils test within spec, carbs clean as a whistle, timing is good, exhaust looks good and good pressure out the tailpipes, motor is easy to spin. Carbs off, using my hands I felt only air pushing out of the intake ports, no vacuum.

I have the top end off and gaskets look new, is there any way to confirm visually bad oil seals by looking at the crank or in the crankcase? I did notice between the old and new pistons a difference, but I don't think that has anything to do with the problem.

If it is the crankshaft oil seals (maybe just the outsides or one side), can that be done on-bike or does it require a complete tear down?

Any help would be great, Thank You!

[Vintageman]

Just because of premix I would not assume seals ruined.

If you have the jugs off and can see into crankcase one crude way is to fill one side at a time with premix for example. Keep bike level as posible.

Once filled it should hold the fluid and not leak through seals etc.

before you do this drain gear oil fully. If it does leak down fluid will be going into gear case and/ or flow into other cylinder or out of generator side cover.

[sandsz]

Well I finally got around to taking the motor apart and cleaning it. I have a 5.5 gallon heated ultrasonic cleaner which helped get a lot of the grime off, etc.
Here is what I have, it looks like the crank did in fact heat up and the rubber on the seals looks like it melted a bit in contact with the bearings. Everything spins very smoothly so I think I'm good on bearings.

I can continue to shine up the crank where it seems I have some burn marks from the oil seals melting a bit... I usually use scotch brite pads for stuff like this.
I'll also most likely put the case halves back in to the ultrasonic cleaner for another round to get them as clean as possible.

I already have both outer and inner seal and I've re-integrated the CCI oiling system so I'll make sure its outputting the correct amount of fluid. It seems the board is not going to allow me to post any pictures

Anyone more experience with this want to give me some crank dis-assembly pointers? I have access to a press and air tools. THANKS!

[sandsz]

I'm going to try to post some photos from my google drive.... lets see if this works!

[tz375]

Nice little design. The two outer seals can be replaced easily but the inner one heeds the crank to be split. It looks like the spring in the left seal is misplaced but that may have happened as it was stripped.

Now it's apart, it would be appropriate to replace all 3 seals and you should be good for another decade or three.

[Vintageman]

Kid is more tallented than me -> https://www.youtube.com/watch?v=-kErQcpfg4k" onclick="window.open(this.href);return false;

https://www.youtube.com/watch?v=Po2KmMWD1k0" onclick="window.open(this.href);return false;

Outer bearing removal to get that one seal at least is easy-> https://www.youtube.com/watch?v=aec19QVTfwo" onclick="window.open(this.href);return false;

Should be easy to split to get the center one > http://www.ozebook.com/compendium/t500_files/crank.htm" onclick="window.open(this.href);return false;

here is the crank specs -> http://www.ozebook.com/compendium/techb ... %206-9.pdf" onclick="window.open(this.href);return false;

Go for it!

I would have done this for inner at least and if OK vroom vroom -> https://www.youtube.com/watch?v=ApRnAdT435A" onclick="window.open(this.href);return false;
maybe a bit of seal conditioner too if OK ... maybe not

Oh I would verify side to side rod play and main roller bearing.. if these no good it can be a mess in short time

If innerds bad I would hire bill bune or crankmaster (seals and needle bearings) min. >$300 for I have no experience and that means I messed it up or at least no desire

And, then took a second job at Mac Donalds for a time to pay for it

[sandsz]

Awesome links, thanks Vintageman. I completely forgot, yes I actually do have the middle seal as well. Hopefully I can split the crank without issues. There seems to be no play on anything and in fact everything seems as tight as it should and all the bearings spin freely, the connecting rods have no play, etc...

The motor over all looks and feels very nice and I hate someone decided to "cafe" it out, but that just means I got it cheap so there is that. The only problem was it was that there was absolutely no intake pressure what so ever... no intake, no air/gas, no combustion. Top end compression was great with a new set of pistons and rings. Everything is very very clean now so I guess I'll get to cracking on taking the crank apart. I'll most likely work on it on some spare time during the winter as I just got a V65 that needs a little lovin' too.

Thanks again!

[Vintageman]

No intake suction ... both sides?

No suction. you should see real signs of seal damage for sure and fluid fill test would leak real fast for example.

No rust stains in rod eyes from needle setting in one spot too long catching moisture?

I have one of these 1975 GT185. 2.0mm OS, Jemcos racing chambers (was a kit), carbs bored from ~20mm to ~22mm, intake opened to match, 0.020" off head and close ratio tranny gear sets 2-5 from a TM00/125. I was lucky and found a nos crank even though the one in it was very good but about 14K miles so why not change.

fun little bike

[sandsz]

Ok I started pulling the crank apart. I got the generator side seal and bearing off. Now I'm at crank #1. I'll have to see what I need to do to get that apart... I have no idea haha.

But the middle seal is completely shot.. I can wiggle it up and down... it wallowed out. Also i'll see about the bearings but I might have a bad one. I won't know completely until I take it off and hit it with the ultrasonic cleaner then oil it back up.

[sandsz]

Woo hoo, another day another bearing. Now either I drive over to my brother's and use his press or I buy one to get the con rods out. Also most likely would help to get things back in

Gotta come up with some good talking points on buying a 20ton press... lets see I think the bearings on the cars are all starting to sound a bit funny....

[Cliff]

Here's a link to the crank specs.: http://www.ozebook.com/compendium/techb ... %206-9.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Runout should be .002 or less.

[sandsz]

Ok so I convinced everyone that a 20-ton press was a good thing. A few car wheel bearings later I was proved right.
Anyways I had to drill and extract two screws from what I'm assuming is a balancing plate on one of the crank parts. After that it was smooth sailing to pull/press off the crank piece and two bearings to get to the center bearing.

The results are that the center seal is *toast* and one side seal was starting to show damage. I have all three replacement seals and I guess my next big step is to press everything back on and not destroy anything and or mis-align everything so it self destructs. Jee I hope not! At the very least I did strike a straight edge line across the crank so I have some sort orientation putting it back together.

** I'll submit pictures when I get a chance to upload them **

Honestly and truly... it wasn't exactly all that hard (other then extracting screws) but we will see how I feel about that putting it back together.

OH and recently I was offered a pair of gt250 and a pair of gt350 bikes on the cheap... missing stuff here and there. I'm debating if its worth getting in to that at all since I haven't even completed the GT185 yet.... but that's how it goes. Making my wife see that is another thing.

[sandsz]

As promised, here are the photos. Remember kids, don't bypass your CCI or you may end up with this.

** WARNING, VIEWER DISCRETION IS ADVISED **

[tz375]

Ugly looking seals and for sure in need of replacement. Check the crank to be sure it is clean and shiny where the seals run.

The cause of torn seals is usually a motor that has sat for years and the seals stick to the crankshaft and when the motor is turned over, the seals just tear.

Running without the oil pump will usually just wear out the seals and bearings much faster, but if teh cranks runs without oil the seals will melt and tear in short order.

If you don't mind me asking, what sort of jigs did you need to build to press the crank apart and what press did you get

[Alan H]

Don't run CCI engines on premix. The cranks are designed to move oil AWAY from the bearings & seals. Perhaps the oil pump wasn't working too good in the first place which caused the seal problem originally.
make sure everything is well lubed - seals & bearing wise when you rebuild,- but check the pump and prime the pipes before you start it!.