MC5 Project

[Mick Milakovic]

Hi all,
I'm beginning another project, this time a '78 frame with a 250 motor.  I need a pair of forks and triple clamps and was wondering something.  In order for the bike to be eligible for the Historic PV class it has to have 9" or less travel.  I know there are options for me, but what do I look for when getting the right forks?  Are they the 35mm forks only, or will the 38mm work?  What should the overall length be to limit travel to 9"?  Thanks in advance,
Mick

[Steve Minor]

I believe you'll find the 78 MC5's came with 38mm's.

[tlanders]

Mick,

I don't know if the '78 MC5 can ever be in the Historic class. AHRMA has decreed it to be a GP. Why don't you check with Dave Janiec first before you do anything out of the ordinary with it. I know you can't take a bike that came with a front disk brake and put a drum brake on it. The '78 frame is unique, different than the '76 and '77 MC5s, and built only for one year. I LOVE my '78 MC5 250 the way it came. I would hate to see you compromise it's fantastic handling characteristics by messing around with the suspension!!!

Teddy

[Chakka]

There is a 38mm pair of Cerianis on Ebay now that would work on the 78' KTM. They are the correct vintage from the looks of things

Chris

[Mick Milakovic]

Teddy - I thought the 78 frame was the same and that any of the 76-78 forks would fit.  I was hoping to build an historic bike, but GP is ok.  

Chris - what were the ceriani's listed under?  I tried searching "ceriani forks" but didn't come up with any 38s

[tlanders]

Mick,

The older forks will fit just fine, I am just worried that AHRMA won't allow it to be bumped backwards to Historic just by changing the front forks on a bike that they have already ruled to be GP.

TEddy

[James]

Some silver paint and a 76-77 swingarm would change all that.The 388 mm marzocchis are leagal as they were available then. I have not ridden a 78, but I have not ridden a 76 or 77 that did not handle great. James

7" and 4" travel? Hmm-that makes 11" Hey! I can live with that.

[Mike Lenz]

The 78's are not eligable for Historic class. I even lost to AHRMA trying to argue that only the 400 should be because its not in the same "class" as a 420 or 495, or 490 Maico...but NO was the answer. Well in GP class you dont have to worry about travel! The 250 should be competive in that class.

[Mick Milakovic]

I've decided to do the project one of two ways:  

1.  If AHRMA will let me make the changes (I've emailed what I want to do) and I can do the changes without major alterations (so it can be returned to stock if wanted) then I'm going to make it an historic class racer.  If not,

2.  I'll restore it to stock specs and sell it as a true KTM (which it is).  The only problem is the motor is from a '74 bike.  That might make a difference to a potential buyer.  I'll just have to tell them.  The bike cost me next to nothing so I should be able to do it reasonably cost effective.  

Thanks everybody, I truely think more clearly after hearing all your opinions

[tomale]

Hey mick, I think that the reason that the 78 handles better is due mostly to the fact that it has the 38 mm forks on it. It just seems to track so much better.
I for one feel like I am under powered next to some of the other bikes in that same class. Not sure what could be done about that. Reed valve and a new carb would be helful but next to even the yz400 I usually get pulled down a longer straight by at least 3 bike lenghts. The bike really shines on the rougher/tighter courses though.. This week end I had trouble with the power on the yz's but managed to pull up right behind them in the rough stuff. I nearly had him too until a kid on a 125 slammed into me and pushed me to the outside where I bumbed into the yz which took me out as I was sandwiched between to two. Over the handle bars I went and I did a forward role and stood to my feet. Started the bike and finished the race.

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
78' 400 MC5

[Mick Milakovic]

Hey Thom, all those gymnastic lessons paid off!

[tlanders]

Wow Thom, what a feat!!! What sprocket ratios are you using on the 400? Two years ago I built my 78 MC5 250 from a $250 pile of junk and it has been wonderful. In a MOVMX race, I had to race the +50 Int class and everybody else had 400s, 440s , 490s, etc. I remember one race where I lined up against 5 490 Maicos and 3 RM 500s, I was the only 250. I was the last one to the first corner, but got a third place in the race. That bike just handles so well!!!! I ended up in 2nd place nationally in MX and 1st place nationally in cross country that year on that bike. Last year I built the MC80 400 with the reed valve and now I was hole shot king!!! However, I still ended up 2nd place nationally in the +60 Int. Hmmmm?

Teddy

[Mick Milakovic]

Teddy - 3rd in +50 INT?  We might race each other this year!  

AHRMA wrote back and said I needed some documentation from a magazine test or article that talked about the similarities of the the Penton/KTM bikes, so I've decided to restore it as a legit KTM.  From Thom and Teddy's results it sounds like a good one!

[Mick Milakovic]

Were the piggyback Marzocchi's the stock shock for the '78 MC5?  13-1'2" eye to eye?  12mm shafts?

[Mick Milakovic]

More Questions:

1.  There are two sets of Marzocchi shocks on ebay right now, but they don't look like what I've seen on our bikes.  Item 4535312560 and item 4535498768 are different looking.  Would they be what I'm looking for?

2.  There is a nice looking pair of forks item 4534132511 that cam off a '81 250 bike, 40mm.  Would these work and be correct?