Kick start slip with a bridged coil spring

[JimF]

Having finished the 5-speed 250 with the leaf springs and the very bad case of kick-start slippage, I figured to transition right over to the Mach 1 while all the tools were out and the repair details were fresh in my mind.

To my surprise it appears that the Mach 1 has the bridged coil spring as I see the bridge peeking out from behind the outer clutch hub.

m1_bridge.jpg

So the symptom that made me think I did not have the bridge is the random occurence of an abrupt slip on the kick-start lever that always begins with a rather sharp metallic clack noise.

I figure to still take the clutch out so as to inspect the gears involved, but I would like to hear any theories about what might be wrong so as to be thorough in my inspection as I work my way in.

Thanks.

Jim

[DewCatTea-Bob]

" it appears that the Mach 1 has the bridged coil spring "

____ Then it must be that your Mach-I is a 1966-model.
Which model-year did you think it was, previously ?


" So the symptom that made me think I did not have the bridge is the random occurence of an abrupt slip on the kick-start lever that always begins with a rather sharp metallic clack noise.
I figure to still take the clutch out so as to inspect the gears involved, but I would like to hear any theories about what might be wrong "

____ I've never before experienced such malfunction, but perhaps the kickstarter-gears were once reinstalled without their corresponding teeth being meshed-up as originally aligned & set, (although it's doubtful that such misaligned-setting would actually lead to your uncommon-issue).
Perhaps the two sets of ks.engagement-teeth (of the driven ks.gear & 1st.gear) have become partially chipped-up, leading to chance of poor engagement.
Or perhaps the bushing within the ks.gear has become loose-fitting, and occasionally slips out of it's place and temporarily prevents full-engagement, by random-chance.
It is also doubtful as-well but, perhaps it's coil-spring is broken. _ Does it make any difference at all, if the bike is leaned-over to the right while kicking the starter-lever ?
__ How about more pix, as you disassemble each part, one piece at a time ?


Hopeful-Cheers,
-Bob

[joe46ho]

Jim, let me know when you get your primary and k/s parts removed... If you have damaged k/s gear teeth I am sure I have some gears you can have. One other note, I hope this isnt the case, but if the engine case is damaged, or any of the bushings are shot I.E. where the k/s shaft slides into the engine case halve, the bushing in the "driven" gear (under the spring/plate), or the bushing in the clutch/engine side cover... this could cause a problem like you have. I do have a few oversized (o.d.) k/s bushings (for the case side only) that I got from an old dealer that sold off a bunch of stuff recently... If you end up needing one of those let me know.

The outboard bushing and fit of the k/s shaft in relation to it cant be overlooked either, because if its loose, every time you kick the engine over you will put excessive side load on the internal case bushing and the case itself, best case scenario this will wear out the bushing rapidly...Not to mention the gear teeth of the k/s shaft/gear, and the k/s gear will not be held parallel to each other (which is of course critical on all gears of this type, since they by nature try to push away from each other as they turn)

Also, just as Bob mentioned your Duke must be a 66' unless it was previously rebuilt and a newer case was used, Im not sure if the internal casting numbers mean a whole lot, but the 66' case I have is a 0603.49.330 (found inside the l/h case, not sure if you can read it without removing the flywheel/rotor though) This is a 66' scr case though, but I doubt ducati made more than one casting, im sure they just added stampings, holes for the chain guard on the scr, etc... and all 250/350 cases in 66 probably had the same cast # just a guess though...

Joe

[JimF]

I had to stop working on the Mach 1 for a while as other job/bike issues took precedence. I will start reporting again as work commences. The engine was rebuilt after I purchased the bike by Syd's.

Jim

[DesmoPro]

Jim,
Hopefully you'll find time soon ( if not already ) to look after the kickstart issue and beyond the good points made previously by others, I'll urge you to dig deeper to find the culprit. Though the pictures are not quite clear it would appear that it could be any one of a number of things and if I am seeing things correct, your problem may be uniquely caused or compounded by some previous modification or modifications. First hint is that it looks like you have some sort of formed sheet steel baffle in where the typical cast in shelf would be just below the breather pipe fitting....makes me think something else in that area may have been fixed by welding or other means and that things have gone wobbly. It looks like I see an additional hole in the steel bridge that is much nearer the area where the compression spring is too?? Maybe this thing ( if it's an OEM type bridge ) has been "creatively" installed and failed? Looks like you've got straight cut primaries too....nice...but not what's causing the trouble. Bottom line, it's a poke in the dark until you pull the primary/clutch basket but I bet once you've had the moment, the mystery will unfold. Happy to help if I can.
Rich

[JimF]

I should be getting back to this soon now. I had six designs to churn out for two clients, all rush jobs of course not to mention my own designs.

In the meantime I had to pull the M1 off the table and work on the other 250's brake light circuit. The M1 is back on the table - stay tuned!

After the kick start issue is dealt with I'll be starting a thread on a compression issue (lost compression.)

Jim