MC5 handling fixed

[brian kirby]

Thom,

After talking to a few people about my shifting problem I am pretty sure its that "claw" thing on the shift shaft. Apparently that is a fairly common problem, it seems more so on the 400 than the 250 or 175. I am going to split the cases to inspect everything in there just to make sure there is not also a bent shift fork or a damaged gear.

Brian

'72 Berkshire

[Big Mac]

Brian, the transmission gears and shift mechanisms will interchange between the '74-'77 250 and 400 motors. Not sure about the 175s. Black '73 motor had an old style, not so good shift drum. Somewhere around '75-'76 (Larry Perkins knows for sure) the side dogs on the gears were back-cut, ie they "locked" in after shifted together with the angle on the dogs. These gears in good shape shift together better and stick, much less popping out. Suspect you have worn side dogs with no back cut.

Good news is there are lots of good transmissions around, out of water-damaged cases. And splitting cases is real easy, and not much to jiggling gears in and out. I've bent a couple of the shift pawl arms back to the spec'd gap and they've worked fine. Get a decent set of gears out of a '76 or '77 and a spare center case gasket, and you can swap it out in a couple hours.

My old '73 Harescrambler was a shifting nightmare, but when I swapped in a complete '77 drum and tranny, it was sharp, snappy and perfect no-miss shifts...best shifting vintage bike I ever owned. Good luck with it.

[tomale]

Brian, Good luck.. I am sure Mac thinks its an easy thing. but then He would...Mac is quite the KTM Guru.. we are blessed to have him in the Northwest...

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)

[Mike Lenz]

Trannys in the silver motors are all the same. Check claw, shift fork straightness to it's shaft and dog edges on gears and you will prob find problem.  However, I have a 72 175 engine I built that is doing this and I tore it down and checked everything and can find nothing wrong??? Im wondering if something may have been welded wrong as the old ones have welded shift drums.  Dont have that issue on silver motors. At least your half way there now with the handling straightened out. Good Luck

[brian kirby]

Mike,

That is good to know the silver engines are all the same transmissions. I am pretty confident I will find something obvious when I get it apart.

I also have to agree with you on the MC5s being competitive in classes that lump all 75-81 bikes together. After I got the handling fixed, that bike will absolutely RAIL corners. I am really without words to describe how much better it turns now and I would not be afraid to race it against any age bike on the right track.

Sunday I went to a new track that just open a few weeks ago to test my suspension upgrades. There was a long 3rd gear 180 degree left hand corner with a big sandy berm in it. After I got loosened up and got confident in the bikes newly improved handling I started railing this berm and kids were stopping to take pictures! I'd come in hot, downshift to 3rd, lay the thing over, slam the berm and buuuuurrrr-RRRAAAAAAPPPP! Front wheel in the air, it was awesome except for the times it would pop out of gear in that corner. I am so pumped about this bike now, I had just about given up on it and had serious doubts about spending the money on buying the 38mm forks and Zokes shock rebuild kits but I am glad I did now.

Brian

'72 Berkshire

[Rocket]

Brian
I would look at the engagement dogs on the back side of the gears.  The edges should not be worn or rounded off, if they are, that is probably your biggest problem with it slipping out of gear.
Rod G

[tomale]

I have been told that the shift drum from the silver motor fits right in on the black motor. I have a friend that was having trouble find parts for his black motor so he replaced the shift drum  with a shift drum from the silver motor and it worked great...

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)

[garrettccovington]

I blew my seals on my 38's today,  I ordered the ones listed in the book and Al carried the same part number last week and they came today.  Thankfully they were a snap to pop out.  My 38's had 2 seals in each leg and the book and Al's only list 1 per leg.  My old ones were 7 mm thick each and the book list 1 and it measures 10mm thick.  Is that what you experienced.  Should I pop in the 1 10mm and call it a day?

I took my bike out today after moving the Bars father forward, (a la Victor Monz) my forks are now at 1/2 inch from the top clamp.  I wish I read your post before I went riding.  I'm gonna go another 1/2 inch for next week test. Definitly headed in the right direction.  All I did was practice corners and berms.  With the bars moved forward, the longer Clutch and front brake lever I felt pretty good.

72 six-day

[tomale]

Garrett, yes I went through the same thing when I replaced my fork seals. I do not think it is a good Idea to put another 10mm seal on top of the other 10mm seal. it would create too much stiction. besides I think a second seal will not fit all the way in. I think the problems stems from the fact that we are using new seals and not seals built as an exact replica of the orginals.. It would be too expensive.......

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)

[garrettccovington]

I ordered the 7mm seals from Al B this morning

G

72 six-day

[tomale]

I didn't know that the 7mm seals were even available. they were not the last time I ordered any... thats good to know...

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)

[Mike Lenz]

Brian, Glad to hear you like your bike now.  I love mine.  You know Penton or KTM knew they were on to something in handling. Every frame fron 72 to 79 measures the same from the bottom of the steering head to the swingarm bolt, every frame except the 73 and pre long travel 74 250 engine frames...which I never liked back then...before I knew this fact! The steering head is extended out on those frames.  I bet they thought they would need to do that for a bigger engined bike for stability...and later found out it was not a good idea to violate the golden measurement!

[garrettccovington]

Got the seals in and added ATF per Brians recomendation.  I dropped the forks to 1 inch (4 rings).  Definitly cornered alot better.  For right now I'm gonna call it a day and see how it works on the track this weekend.  
Brian, thanks for the tip!
G


72 six-day

[tomale]

Brian, I am so glad that the bike handles so well for you, and I am excited to see how the bike handles now that I have copied what you have done... well as best as I could considering that I am using Fox gas shocks instead of the stock shocks....Had to try and use them, first because it is what I had and because I just had them rebuilt a few months ago and last because they have been on the bike since 77'

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)

[garrettccovington]

Brian
Lowering the front forks 1.5 inch's down (6) rings is definitly the hot set up.  The bike cornered fantastic.  Thanks.

G

72 six-day