MC5 handling fixed

[brian kirby]

OK, most of you know I have been struggling trying to get the '77 MC5 400 handling sorted out. The bike just would not turn, I mean it was the worst turning bike I had ever ridden. So I decided to go all out to fix it and I bought '78 38mm forks rebuilt the 'Zokes shocks with one of Rocket Rod's kits and put fresh tires on it. The bike now handles like a dream, before where I would have to tip-toe riding like I was on ice so as not to lose the front end, I can now charge the corner and not even have to think about the bike. If I did not know better I would swear it was not the same bike I have been struggling with, truly a night and day difference. I am a little upset with myself for not doing the mods one at a time so I knew what fixed it, or it could have been the combination of them all. Normally I dont make wholesale changes like that, but I was desperate and one way or another, its fixed.

Thats the good news. The bad news is I think the shift forks are bent or the gear dogs are damaged. The bike will not stay in gear, especially 3rd, but 2nd is bad too. I moved the shifter so far up it was above horizontal so I know my foot was not hitting it, it is something internal. I also got faster as the day went along and corners that I had been going through in 3rd and it would pop out of gear EVERY lap in the same place, I started to use 4th and it would stay in gear. Because of that I am almost 100% certain its not a shift lever issue.

When it pops out of gear, its very odd, it is usually on landing from a big jump or hitting a big whoop in the middle of a corner, left handers are worse but it can happen either direction. I simply cant be my foot hitting the shifter because its worse in left handers where my foot is not even on the peg. Its almost like the shift pawl spring that returns the shift lever to the middle of the throw is not strong enough to keep the shifter from flopping around and kicking the transmission out of gear. The missed shifts are also much less common, when I'm riding cross country though they do still happen. Is it possible that the shift return spring could be bad? Moving the shifter by hand it feels normal. Also I've seen in the adds for JP Morgens 400 in the for sale section and he mentions "shift drum mod to fix false neutrals" or something like that. Anybody have any idea what that is? I guess I need to get in touch with JP.

Anyway, I know this is a long post, but I want to thank everyone that has helped me in this long battle to fix my handling problems. Guys like Larry Perkins, Mike Winters, Rocket Rod, Big Mac and everyone else that gave me ideas are a wealth of knowledge and I appreciate it.

Brian

'72 Berkshire

[firstturn]

Brian,
  Do you think you changed the rake angle on the bike?  Are you telling us you did not have the neutrals before?  Thanks for the update.

Ron Carbaugh

[David Laite]

Perhaps there's a slight bind in clutch cable not letting the core wire return fully? The fact that you now have suspension that is getting compressed in the turns will help the bike turn better, along with new rubber. One other thing is to shorten the wheelbase slightly by removing a link.

1973 Penton Jackpiner
1982 Yamaha XT200
1982 Yamaha XJ650J Maxim
1987 Yamaha YZ490
2005 Honda CRF450R

[G Ellis]

Brain give me a call, I think I can help you. Later Gary

[brian kirby]

Uncle Ron,

I think the shocks I was using before were too short. They measure 13.5 eye-to-eye but the bike sat visibly higher in the rear end when I put the rebuilt Zokes back on. That alone could be the cause of the poor turning before.

I have had problems with false neutrals on several KTM engined bikes. Its strange, some do it and some dont. I rode Ernie's '74.5 250 that came from Chicago Jerry and it did the same thing, land from a big jump or really slam a berm hard and it would pop out of gear, but Ernie's other '73 250 I rode at Barber never once did it. This 400 has always popped out of gear. The most common condition for it to happen is 3rd gear flat left corner (no berm) hit a bump mid corner really hard and it pops into neutral, usually between 3rd and 4th. My foot is not on the peg or anywhere near the shift lever. If I take that same corner in 4th even faster and hit that bump harder, it stays in 4th. I am thinking of taping my helmet camera to the frame somewhere that I can see what my foot is doing just to eliminate that.

David, I did put on new chain and sprockets so the axle was full forward, where before it was almost at the back of its adjustment. That surely helped.

Gary, give me a call some time after 8:30AM tomorrow, I was out in the shop working on bikes when you called.


Brian

'72 Berkshire

[joe novak]

Check your side cover.  You must have a Sachs engine in your frame....

[garrettccovington]

Brian
What type of oil, weight and amount of oil did you use in your forks?  Did you get the forks off the guy on e-bay that was selling MC40(?) stuff.

g

72 six-day

[brian kirby]

G,

I set up all damper rod forks the same, from 6" travel vintage all the way to 12" travel PV. I use ATF 6" from the top, springs out fork collapsed.

Brian

'72 Berkshire

[tooclose racing]

Brian-are you running your forks higher in the clamps (ie taking advantage of an attribute of the 78 clamps)?

Also, just want to confirm-no damper rod mods (ie RaceTech emulators) and stock/OE springs?  

Finally-your comment about shock length. Are you saying that the re-build restored shocks to original length (13.5 or longer)?

Thanks..love the details BTW. It's what makes this site such a great resource when you go "search" for help for your bike.  Actually- on that note, you might want to add "gearbox" or "shifting" to your subject line. : - )

[brian kirby]

When I set up the forks I took the springs out, then set the bike down on the ground with the triple clamps loose. I moved the forks up until the tire hit the four bolts that hold the fender on. I then jacked the bike back up on the stand and moved the forks down just enough, maybe 1/8th inch, so the tire no longer hit the fender bolts. The forks are dropped as far down as they can go. For now the springs are stock and no emulators, but I did use a spacer to limit travel to the Historic class limit of 9".

As for the shocks, I only rode the bike once with the blown Zokes and put on some Progressive gas shocks I had laying around. The Progressives measured the same length, 13.5, but I think the rubber bushing in the Progressives allowed the shock to in effect be 12.5" once the bike bottomed a few times. The Zokes did not change length after a rebuild, but with the spherical bearing in its eyelets it stays at 13.5 when mounted. I'm actually pretty impressed with the action of those Zokes after I rebuilt them, they work very well.

I got an email from JP Morgen about his shift drum mod, what he does is eliminate the extra neutral between 2nd and 3rd which is there for when you block out 1st and make it a 5 speed. He confirmed my suspicion that there is something wrong internally, probably a bent shift fork, he has never see one of these KTMs pop out of gear unless something was wrong.

Brian

'72 Berkshire

[brian kirby]

Just for reference, do the silver engines share shift components from the 175-400 or will I have to get 400 parts if I need a shift fork? I think the black engines had a different shift drum than the silver engines right?

Brian

'72 Berkshire

[DKWRACER]

Hi Brian, just a sidebar, moons ago I send both the gears/shaft asslys to Murdock Racing in Florida, they were able to re-face the dogs, probably the best gearbox I have experienced, it was expensive...
Adios, Tom Brosius

[garrettccovington]

How far down did you drop the forks.  Mine is currently at the 2nd ring and I feel like i have to tippy toe thru the corners too.  Next race I'm gonna drop it another ring.

g

72 six-day

[brian kirby]

I dropped them all the way. My forks dont have rings on them so I took the springs out and set the bike on the ground, then moved the forks until the tire hit the underside of the triple clamp. I then put the bike back on the stand and moved the forks 1/8", just enough for the underside of triple clamp to clear the tire at full compression. The tubes stick up roughly 1.5" above the top clamp measured to the top of the steel tube not the cap.

Brian

'72 Berkshire

[tomale]

Brian, I had some trouble like this on my 78 400. Big Mac and I split the cases and what we found was and I am not sure what you call it..on the end of the shift shaft there is a sort of a hook and claw looking thing. this actually turns the shifting drum... there a few things that you need to be concerned about, if it is bent then shifting will be difficult at best.. and how far the claw is from the hook is important too because it determines how far you must move the shift lever to get it to shift..check your book for the correct distance.. Of course if anything is cracked or what ever then that too must be address as well..
To give credit where credit is due.... I would have been sunk with out my buddy Mac...In my case the claw part of the shifter was cracked and we had to replace it... Mac had one sitting on the bench... thanks Mac....

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