Help, Rotax Clutch and Chain

[Rick Schmidt]

Doug,

Give me a call tomorrow. I’ll help you.

Rick

[Doug Haner]

Will do Rick. It’ll probably be late evening when I call. I usually sleep a lot on Sudays as I work Sat. and Sun. nights.

I found some promising info in the trouble shooting guide.

Under “centrifugal clutch does not release at idle speed of engine” it lists two possibilities. “Fouling of clutch drum” and “clutch spring fractured.” For the remedies it lists “clean clutch drum,” and “replace all 3 clutch springs.” This makes me think that my initial prognosis was correct and that some dirt from my off fouled the drum which eventually, from me messing with it, broke the spring. Looks to be a straight forward repair at this time. We’ll see though, once I get into her and get Rick’s input.

Still wondering on the chain slack, I’m sure Rick will set me straight with that though.

[Garrick Mitchell]

I feel your pain… The downside of the simplicity of the kart is that everything’s hanging out there vulnerable to damage when you drop a wheel (or 4). After multiple offs my first few times out, I’ve taken pretty conservative lines to stay off the curbs and give myself a little cushion on corner exit. I can still pull 58.5 at TTAC, which is enough to keep me entertained. :turtle

I think you’re on the money with the clutch. Go over everything with a fine-toothed comb while you have the clutch drum off, and replace things “in threes” as applicable (i.e., replace all three springs as you’ve already mentioned).

Also, I assume your clutch has the Clutch Support Plate (“rounded-off triangle” plate cir-clipped onto the ends of the posts the shoes pivot on). Take a good, close look to check for cracks and missing clips. First time I had my clutch open, mine was broken and there was actually a bit of shrapnel that had just started scoring the drum. If you don’t have such a plate, get one!

Finally, my $0.02 on the chain slack question… Assuming your engine isn’t moving (and I torque my engine-mount bolts pretty generously to prevent that), as the sprockets wear and the chain stretches, you can guess the result. Once the chain is stretched, the wear process accelerates exponentially and you can eat through sprockets in short order. Poor chain alignment speeds things up, too. I’ve been lubing the snot out of my chain (Maxima Chain Guard) immediately after each session AND at the start of each testing day after 2-3 warmup laps to heat up the chain. I’m up to 70-80 hard laps without having to make any adjustments.

Hope that helps… Still coming down from the high after finally getting my jetting more-or-less right at TTAC yesterday! :dance: :clap:

[Anonymous]

Garrick is correct on the chain situation. They stretch, need lube everytime you go out, alignment is also important. Put a straight edge from the back gear to the front gear outsides and align.

You found a small clutch spring! If that is the case you have a clutch problem. Take the clutch drum off and inspect. A new clutch assembly will cost you $325 if the pins are busted. Make sure you have a clutch support bracket installed. Do call Rick he is great, but wait till after he calls me. I am on his call list already. Spare parts are always nice to have. Don’t loose the washers (2).

good luck
rich

[Jon Romenesko]

Chain tension is kind of an art, i’ve found. It just takes experience to know ‘whats good’ and whats not. A lot of it depends on your motor mount and how you tighten it. It’s annoying at first, but you’ll figure it out! 🙂

Definitely make sure you have the support plate installed on your clutch, that will prolong the life of the posts. Might seem kind of expensive at first, but (speaking from experience) its worth it to invest in a spare clutch. Broken posts on a clutch could take you out for a weekend, and a spare clutch will make it so you don’t throw away all that hard spent money for the weekend’s race!

Also of note, take the clutch drum off periodically and clean it out. Especially after you’ve had an offroading experience, dirt & grime tends to find its way in there and would contribute to things locking up….not to mention premature wear. Try to avoid spraying brake cleaner in the holes while its still on the kart, as you could wash away some of the lubricant on the clutch drum bearing, but that’s better than nothing in a pinch. I’ve also found that the Rotax clutch will sometimes lock up when it’s hot – so if your clutch is locked up when you come off the track, dont freak out! – but when things cool off it goes back to normal.

Rick will help you out massively! Listen to what he has to say! :cheers:

[Doug Haner]

Thanks for the pointers fellas.

I’ve got a bit of “Honey do” list to complete, if I get all that done early enough I’ll get out there and take a look at her. If not, I’ll be tearing into her tomorrow night.

Rick, expect a call tonight or tomorrow night.

Thanks again folks.

[Doug Haner]

So with help from Rick, Brad, and Shockwave, I’m all set.

Rick helped immensely over the phone, Shockwave sold me the new flywheel/clutch assembly (one of the posts was broken off), and Brad helped me pull the old flywheel and lap on the new one. :clap: :clap: :clap:

All is right in the world again, she works like a champ. I was even able to get a few laps in before it got too cold for me. :loony:

Anyways, again, thanks fellas.

[Author]

Posts