Worn through SIDECASE!!

[cattamer]

Hello fellow riders.My 1993 500 has a hole worn in the case behind the countershaft sprocket.In replacing the cases? (all I have seen new  come in pairs)should I take a chance on one from E-bay or just bite the bullet and go back completely new givin the age?I am going to check everything once I get in.

[Foxx4Beaver]

If it were me,I'd buy a new one.....some things are ok from e-bay,but you could be just buying someone elses trash by taking a chance on a used one.....just my opinion.
You're also gonna want to know why this happened.There are several posts on here about this problem,and there are several different solutions.My solution was to go with the Renthal 14T front sproket(the Renthal stayed away from my case more than any other)...AND I went with an RK MXU chain,which is considerably narrower than all the other o-rings,and has 9000lbs tensile strength....which is also very good considering I've always used Regina chains,and their tensile strength was around 8000-8500lbs.I put the RK on this past June,and have'nt had to touch it yet....and I have about 1/4in clearance from my case now.

Foxx

[jonny500]

pm sandblaster on here first.  he dont sell crap, he may be able to help

[sandblaster]

Thanks jonny500.
Well..... sometimes I do sell crap, just not on purpose 
The difference between us and so many others is I will always take care of a problem quickly and the vast majority are happy with that.
At the moment I don't have any cases for the KX500.
They go out as fast as I get them in.
I do have a new set of cases for my AF project that Kawrider is going to build for me when I get some money 
But, you can't have those 

[Larry Wiechman]

Hello fellow riders.My 1993 500 has a hole worn in the case behind the countershaft sprocket.In replacing the cases? (all I have seen new  come in pairs)should I take a chance on one from E-bay or just bite the bullet and go back completely new givin the age?I am going to check everything once I get in.

 Can you post some photos of the damage?

[NZ500]

I had the same problem with my '90. It had been welded up before but rather than prevent it happening again the last owner kept using the same chain/sprockets.

When I had the cases apart I drilled and tapped a piece of mild steel plate (about 20 or 25mm thick), bolted the case to it and built the whole area up with weld. Then lapped the cases on a cast iron surface plate. To prevent it happening again and continue using the (bulky) O-ring chain and sprockets which were nearly new I managed to find a new sprocket that is much thicker/same splines and machined out the difference so it offsets the sprocket away from the motor (80s DR 650 I think it was). I have a jig that bolts to the three holes in those sprockets for machining them. They are very hard though. My rear wheel spacers were miles off already so had to make new ones any way. I don't use anything smaller than a 14 tooth on the front. Might not be any use to you but someone else might find it useful.

Depending on how bad it is you might be able to put some copper/bronze under the hole to build that area up. Having a hole would be more likely to cause distortion though and you'd definately want it bolted to something flat. Letting it cool between welding parts might help too. The cast iron inserts are a bit of a pain but I managed to build up weld over top of them.

[DoldGuy]

Hello fellow riders.My 1993 500 has a hole worn in the case behind the countershaft sprocket.In replacing the cases? (all I have seen new  come in pairs)should I take a chance on one from E-bay or just bite the bullet and go back completely new givin the age?I am going to check everything once I get in.

Post some pictures for Larry to see.......He is very gifted & may save you a bunch of $$$$$$
DoldGuy

[The Flyin Hawaiian]

There was a article a while back in Dirt Rider where they rebuilt a older CRF250 and it had the same issue. They sent it somewhere and had it welded and remachined at a pretty reasonable price. Im pretty sure it was earlier this year.

[cattamer]

Upon further inspection,it has to be the seal and o-ring?The splines on the shaft are worn badly,and it has caused the sprocket to wobble and rub the case severly,but not all the way through.

[cattamer]

I will replace the shaft,and anything else worn inside.I dont know alot about this bike,and the guy I bought it from didn't take very good care of it.Do you think I should replace the crank bearings and seals,while i'm inside.I am gonna have the cylinder checked and new piston and rings. I was told that the case halves are a matching pair and therefore sold in pairs.Is this true?

[cattamer]

Thanks to everyone for the replies,and input!

[DoldGuy]

I will replace the shaft,and anything else worn inside.I dont know alot about this bike,and the guy I bought it from didn't take very good care of it.Do you think I should replace the crank bearings and seals,while i'm inside.I am gonna have the cylinder checked and new piston and rings. I was told that the case halves are a matching pair and therefore sold in pairs.Is this true?

They are sold as a set (for a reason). If you split the cases positively replace the Crank Bearings & Seals. Not a bad idea to replace the other seals too if the $ pemit as the rest of them are not very expensive. Replace the shaft, seal & the large Oring behind the shaft, but keep in mind if the sprocket has any wear it will allow it to leak (ask me how I know  )
DoldGuy

[cattamer]

Thanks man,I will try to do a complete job,and hopefully not have to go back for a while.I will also run a new set of chain/sprockets!

[NZ500]

Not sure if DoldGuy was talking about the countershaft or the sleeve on it? But it would pay to measure up the steel sleeve behind the sprocket too or just replace it. It shouldn't cost much.

I'd be surprised if your cases can't be saved. So that's got to be a bonus.

If you can afford it it's probably a good chance to have a rod kit put in as well as the main bearings and seals. Especially with a fresh top end going in. Turn all the other bearings and make sure they turn smoothly. A Clymer manual is well worth having too.

Good luck