'79 KTM 250 mechanical question

[pketchum]

On my last ride I threw my chain.  After tightening it up I noticed I was leaking some transmission fluid.  The chain had derailed and loosened the lower "bolt with pin" on the "bearing cover" near the sprocket.  I tightened this bolt but it still leaks oil.

Today I got down to business and removed this bolt.  While doing so I found metal threads had come off WITH the bolt.  I've tried using Devcon Thread Repair with no luck.  I think it's still too cold in the garage for this to setup right.  I'll try again tomorrow using a portable heater to warm things up.  

Can anyone tell me why this bolt has a pin on the end of it?  What's on the opposite size of the pin?  If I built these internal threads up using JB-Weld, would that cause harm?  This is magnesium right?

Thanks,

Phil

[Mike Lenz]

My guess is you have a 78 or newer motor and the "pin bolt" is the bolt that blocks the shift drum from going into first. Is it a 5 speed? On the 78 and newer eng you could put , I think a thirty mm long bolt in that had the end machined down like a pin to make it a 5 speed, with a shorter bolt letting it be a 6 speed. I modify the older engines to be able to do this also.

[pketchum]

Mike,

It's a '79 KTM 250 MC with a 6-speed transmission. I'm worried that if I fill in this bolt hole, drill and tap it, that I may cause myself trouble.  This is why I've asked for the collective wisdom of the POGGERS to weigh in with their opinions.

I thought the Penton's and KTM engines were alike in MANY respects.  The descriptions that I have used to describe these items are right out of the KTM parts illustrated manual purchased from Al Buehner.

Phil

[tlanders]

Phil,

On one of my bikes I had to bore and tap this hole to the next size larger. The danger in doing this is that you really should split the cases so you don't end up with shavings in the transmission. If you don't split the cases, flush the tranny many times with gas.

Teddy

[Dennis D]

If you do decide to drill and tap, put some heavy grease on the bit and then the tap. Most of the shavings will stick to the grease. Dennis D