Scooterotica

I have just finished meticulously building myself a monster malossi MHR 221 engine. It really was an exercise in OCD I built the whole engine with the best bits available and spent ages tuning, porting, pre jetting the carb, and setting the ignition timing before fitting it into the frame and starting it up. When first started I noticed there was a lot of noise coming from the bearings especially when the clutch was pulled in but put this down to oil circulation and the bearings being brand new. Eventually it quietend down and I felt confident taking it out for the first time, it performed well and I tried to keep the revs and speed down.

After a couple of kilometers I returned home to adjust the clutch and gear selector, so far so good. I fired it up again and it sounded well so I gave it some revs as I pulled away and instantly became away of a violent bumping under my butt. I stopped as quick as I could and realized that the kick start had dropped and hit the road forcing the quadrant to smash through the outer engine casing leaving a trail of engine oil along the road. Ever seen a grown man cry ??

I pushed it back to my garage and after drying my tears tore it down to see what had happened and the reason behind it. On closer inspection I found the kick start gear had seized to the end of the Christmas tree, whether this could be responsible for the kickstart dropping (or being forced down through the casing) and hitting the road I am not sure, I haven't ever heard of this before and neither have any of my mates. It was a perfect fit when I originally fitted it onto the end of the Christmas tree shaft.

I have researched the subject as best I can and read about the problem kickstart dropping at high revs and am now wondering if the 2 issues are related or not. Has anyone else ever suffered this problem (either one) are they related ?? Why did it happen ?? And most importantly how did you rectify it ?? My engine casing is coming back from welding next week and I want to ensure this doesn't happen again on a side note al the parts used (casing rubber buffers, kickstart quadrant, kickstart gear, kickstart gear spring, main kickstart spring, and all associated parts seals bearings etc.) are all brand new and built into a NOS PX200 casing.

Any ideas ?? Thanks in advance.

Could you have inadvertently fitted a Smallframe kickstart cog as the engagement teeth face the opposite way to a P range? This may explain the noise on initial start up which would then cause friction and weld it to the tree. When the quadrant is in the rest position it allows the cog to freewheel so there may be a problem with that not allowing the cog to clear the teeth on the tree.

wack 63 wrote:Could you have inadvertently fitted a Smallframe kickstart cog as the engagement teeth face the opposite way to a P range? This may explain the noise on initial start up which would then cause friction and weld it to the tree. When the quadrant is in the rest position it allows the cog to freewheel so there may be a problem with that not allowing the cog to clear the teeth on the tree.

Thanks for the reply mate. No everything was as it should have been, all tolerances where checked before reinstalling all the components. I have just had the casings re-welded and the engine has since been rebuilt. I have very gingerly been up and down the street on it again and it all seems to be fine this time. The only conclusion I can draw is that the kickstart cog was either dry (due to the amount of time between building the engine and actually running it) or simply too small - either way when the engine was fired up and revved up the kickstart cog locked up. Anyway I will keep and eye on it before I go too mad as I am still very nervous about riding it too hard and need to build up a bit of confidence in the engine.

Well done on getting the cases welded and having it back up and running! The kickstart thing has never happened to me or anyone I've known but I wonder did you find any debris in the front part of the gearbox above the white plastic piece that's just a push in fit? I've wrecked a cosa clutch in the past and a few rivets went walkabout. Along with marking the casing they ended up in that section where the plastic piece is. I've seen oil pump cogs disintigrate too and lock up the gearbox by getting wedged between the gear cogs, not the teeth and stopping everything turning. Did you remove the autolube or if not, is it still in one piece? Very easy to damage or weaken the oil cog by winding in a barrel stud too far. Not sure how they'd allow the kickstart to jam but it's all I can think of.

paul d wrote:Well done on getting the cases welded and having it back up and running! The kickstart thing has never happened to me or anyone I've known but I wonder did you find any debris in the front part of the gearbox above the white plastic piece that's just a push in fit? I've wrecked a cosa clutch in the past and a few rivets went walkabout. Along with marking the casing they ended up in that section where the plastic piece is. I've seen oil pump cogs disintigrate too and lock up the gearbox by getting wedged between the gear cogs, not the teeth and stopping everything turning. Did you remove the autolube or if not, is it still in one piece? Very easy to damage or weaken the oil cog by winding in a barrel stud too far. Not sure how they'd allow the kickstart to jam but it's all I can think of.

Before I started the rebuild I did actually take out the gearbox and clean the inside of the engine. As to be expected there were a few small fragments of casing under the gearbox mixed with the remnants of the oil but apart from that the rest of the engine was clear I did actually pull out the plastic thing and check those chambers within the casing but thank fully all clear and clean as a whistle.
I get the feeling this was a one off freak occurrence as I have never had it happen before or since and no one seems to have had the same issue. Hopefully it has been resolved now but I shall be treading very carefully until my confidence is restored.