78 KTM 400 MC5 Transmission Enigma

[Marko]

About a year or so ago, I found a 78 400 MC5 basket case of basket cases. The goober disassembled every stinking part on the engine and frame to fix it (). I thought the huge chunk of the lower cylinder liner broken off would have given the guy a clue.

I bought the pile of boxes with a well worn collection of parts for a few pages of sheet music. Thinking I got a deal, I went home thinking happy thoughts. I'm not so happy now after working day and night to restore my prize for AHRMA racing.

Here is my problem, after assembling the tranny / cases just like the nifty service manual from Al B. for the fourth time, it appears that I have most every gear except, I got a spare neutral between 3rd & 4th and 6th (yes, I have the 6 speed shift drum)is a dead lock. I carefully inspected every gear before assembly. I had to replace 2nd and 3rd C/S gears. I elected to replace all of the tranny bearings and a couple of shims since I had it apart. I was also careful to spin the shafts by hand as I shifted the shifter to check the gears. I will prevail if someone can give me a hint of what the darn heck is wrong. Thanks.

I'm another newbie to the POG.

[DKWRACER]

Hi Marko, it is not "unusual" to come across KTM gearbox dilemas! Thankfully, your's is not an issue that can't be resolved.
There are exploded views of every part from manuals.
Stripping a KTM engine in .5, without instructions, is like being a "newbee"..There are newbees,that become oldbees...

If you have some trouble, most of the gearboxes are very much alike...
The worst, was the early 175 transmission, with it's ill fated relation between the drum, and dogs....But you have a period transmission, that should work when assembled.
Not seeing all the parts that you have, in assembled order, is an arduous task! But worthy of attention.
What part of the USA are you in?

That there be a Pogger, to come to your aid.
Tom Brosius

[Marko]

Tom,
I'm in central Virginia. I can take pictures if that helps and email them to you.  Please advise. Thanks.
Marko

[Big Mac]

Tough diagnosis by description only, but if you have it back together now, take out the inspection plugs on the top of the cases and watch the shift forks and gears moving back and forth as you work the shifter around, might give a clue.

As a guess, you might have one of the gears in there reversed on the shaft. If you can see the shift forks sliding the gears side to side, you should be able to see the corresponding gear on each side that the "sliders" are to engage with. A couple of the driven gears, as I recall, are fixed on their shafts. I'd bet a drive gear is sliding over against a backward-installed driven gear and spinning on nada. Just a hunch.


Jon McLean
Lake Grove, OR

[Marko]

Eureka! The shift forks were good. The problem was a reversed 6th mainshaft gear. Shifts through all 6 gears like "butta". Thanks to everyone for their helpful comments.