MC5 experts...I need help

[brian kirby]

I rode Wendell's newly acquired '77 MC5 400 Sunday and I must make it turn better. It has the stock 'Zokes on the back and the stock forks on the front but it has the later triple clamps with the rear set handlebar so you can slide the forks up farther. As the day went on I would stop and slide the fork farther up in the clamp until I got to where I could not go any farther without the tire starting to hit stuff. It was much better but it was still not turning to my liking so clearly I need longer shocks. I did some searching here and I see where people have posted they used 14.5 shocks, so I tried some off my '79 Maico which are that length. They are too long, the swing arm hits the cases and with max extension 14.5 will not fit. By allowing the swing arm to fall to full extension with no shocks and measuring center-to-center on the mount holes it appears to me that 14 or at most 14.25 will fit.

So I guess my question is, what is the longest (or if shorter than the max the preferred length) shock that will fit and how did those folks get 14.5s to fit, did they modify the swing arm?

Also, as a side note, I have only ridden two KTM engine Pentons so far (a '74.5 250 and this '77 400) and both of them popped out of gear at the most inopportune times like on hard landings from jumps. Once this weekend the 400 popped out of 4th 50 yards after I shifted and 20 yards before a jump, it was not a missed shift, it just about killed me. Is this something that can be adjusted? Or maybe I am hitting the shifter with my foot and not realizing it? The 400 has the stock non-folding shifter and it seems REALLY short.

Brian

'73 Berkshire

[tomale]

Hmm, that is intesting, I have 14 ? shocks on mine and I never had to modify anything. but I am also wondering about the type of tire that you are using and how much air pressure. If it is an old tire it is too hard and a new tire needs to be used. when I went to a Micheln M 12 I was amazed what a difference it made...

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

[Dennis Jones]

Brian, with a short shifter on my bikes I will always be kicking them out of gear, especialy on jumps. Find or make one of the longer shifters and that problem will go away.

Dennis Jones

[brian kirby]

Thom,

The bike did not have new tires, but they were not 20 years old either. It was getting new tires already I just didnt have them in time for the first ride. By my rough backyard measuring 14" is just about the longest that will fit.

Dennis, thats for confirming that, I had already thought that the shifter needed to be longer before I rode it.

Thinking back, it seems the front spring rate was very stiff and the rear seemed very plush, so maybe the rear springs are sagged out? That would make any bike turn bad.

Brian

'73 Berkshire

[tmc3c]

Brian,
   Dennis is spot on about the shifter! Mine was also short and I would always hit it and not know it.I assume the forks are leading axle and I have heard if you use the Ceriani forks it will corner better.I am not sure if this is poss. on the MC5 you will know better than I.



Thomas Carmichael


1970 125 Six Day
1976 250 Hare Scrambler

[rob w]

Brian, Try turning the forks around, so the offset axle is to the rear. [xx(][}:)][B)] I'm not really a MC5 expert, sorry. No matter how she turns, I believe you'll figure out a way to make it go fast.
Bawb

[john durrill]

Brian,
 Can you sag the front end and see whats what with the springs? I would think if the front is stiff then in a turn the forks would not compress as much as they should and that would make it slow to turn? Same with the rear shocks. If they are to soft that would add to the problem?
 Just a thought.
John D.

[brian kirby]

You are right John, I have multiple things working against me. The forks that came on the bike were bent, I had to put together parts from three sets of Zoke forks to get one good set. The three pairs of springs were all different, two the same length one straight wound and one progressive wound that needed no spacers, and the set that was in the forks the bike came with were strait wound but 2-3 inches shorter than the other two and had spacers. The progressive wound springs were out of a pair of '79-'81 Can-Am Qualifier 175 forks so I figured they would be the softest at least in the initial travel. I will have to swap spring sets to find the ones that work the best. The springs on the back are black, which from searching past threads on MC5 shocks should be stiffer rate than the purple springs. One thing I was not able to mess with at the track was the rear pre-load, it was set on the second softest position. I somehow left my channel-locks at home and did not have my shock spanner tool either so I could not experiment with increasing rear pre-load, too little preload could also cause my issues.

I think with a little longer shocks and some fine tuning of the fork it should get better.

Brian

'73 Berkshire

[John Doud]

Hi Brian,

Wendell purchased the MC5 from me last summer? and we went over everything that I knew was going on with the bike at that time; hence, the good price...

Your problem is with the shocks; there is no damping at all. They either need to be rebuilt (pitting on one of the shafts) or replaced. My '76 MC5 400 has 13.5" Zokes on it and it turns great. I know that others are running different lengths, but I have never felt the need to do so.

Call me at 714-655-9747 if you would like me to go over the bike with you.

John

[brian kirby]

Hi John,

Yes, Wendell bought the bike last summer and we just got it back east a few weeks ago. I knew of all the things to be fixed on the bike, but I had forgotten about the shocks. I have some 13.5 Progressives I can swap on just to test ride it and see if they help, Progressives are not the best but these are new and they have damping. On other parts of the track the shocks didnt "pogo" like they were blown, but that must be part of it for sure.

I will say one thing, the bike is a rocket. It pulls clean from really low and has a monster hit in the midrange. I was really impressed with the power considering its really a 360.

Brian

'73 Berkshire

[Tahitian_Red]

Brian,

I think you guys have hit the nail on the head.  I had a similar problem on my Husky at last weeks AHRMA CC out west.  My mechanic added spacers to preload the saggy forks and I didn't have time to replace the old Girling shocks with new ones, so it felt like I should have been wearing a stars and stripes helmet and had Jack Nicholson on the back when I went through a corner.

Replace those rear shocks with some Works Performance or Ohlins 13.5" shocks and make sure your front forks are working correctly through the full length of travel.  Front sag is important to cornering also, so set you springs up accordingly.  A bent tube is no good, but you should also to make sure the front wheel is centered correctly and not putting the forks in a bind before full travel (this happened on Can-Am Marzocchis).

Hopefully I'll get to meet you out here in June!

Racing the "FaltaNator" in 2009

[gooddirt]

From your 100 to the mc-5 it is going to feel like you are driving a loaded bread truck, I rode and raced my  76 400 and never did get the used to the Euro/GP track handling of the bike. And canned the bike; I can only ride 4in / 7in bikes. Some of the Russians even up to 1978  would run the 8inch travel Ceriani front forks with the ridge down them , those were even moved up in the triple clamps. Its how high do you want to jump [:0] or rail in the corners .

[Larry Perkins]

I am sure this info will get me beat somewhere but alas you guys are so nice and I can not help myself.  So here goes.

Okay, here is the trick and it is from a bike that has won 4 AHRMA National Championships for 3 different people in MX and Cross Country.  I have to give Bobby Lucas credit for the setup, however.  First of all lose the 35mm Zokes.  They wag too much.  Go to the legal length 38mm Zoke forks and run later model damper rods because the damping hole is better.  Get some good progressive springs that are NEW not old ones.  Run the forks up in the triples 1-2 inches according to your preference. Here is a critical piece to the puzzle-Use the later 38mm triples with bar backs.  This helps even with the 35mm forks and there are 35mm versions.  Run Zokes, Works, or Ohlins 13.5 inch in the back properly sprung.  With this setup you can dive under like a jap bike, the high speed handling will still be good, and you can sail like the Cycle News photo of me doubling at the Pennsylvania National in 2001. My all-time favorite "Penton Man doing that Penton thing" picture if you have ever seen it.

Have fun and if you want to see the setup in person I will be at quite a few AHRMA races this year with my MC5 including Mid-Ohio.

Larry P

[Tahitian_Red]

You're in trouble Larry.

Racing the "FaltaNator" in 2009

[tomale]

Yea larry, your suppose to hint at the right set up not come right out and blab it out.. what were you thinking...[8D]
my 76 has the 35mm forks which are stock but when I rode the 78 400, boy could I tell the difference.. and part of my trouble was the fact that the rear shocks were to soft which gave it that chopper feel, which is really bad since I hate harley and I mean all of them....

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