Comet 40 series

[Nickstout653]

This is my first ever post! I built a diesel rat bike/chopper with a yanmar clone and a genuine comet 40 series clutch setup. I can not figure out what to do to get the drive clutch to engage at a lower rpm. The clutch just starts to engage when my engine is almost to its highest rpms! I know many people on here use the comet 40 series so any pointers would be great!

[Diesel Dave]

Do you know what internals are currently fitted?

Ideally you need the heavy rollers (part number 20343) and yellow springs (203648)

[Nickstout653]

Yes I do have the heavy rollers and yellow springs. That is why I’m wondering if I have something else set up wrong

[Diesel Dave]

Do you have a garter spring fitted?

[Nickstout653]

What is a garter spring?

[Diesel Dave]

It’s a spring that runs around the outside of the weights like a garter on a ladies thigh.

[Nickstout653]

No I just have the normal yellow springs. What does this garter spring do and where can I get one?

[Diesel Dave]

You don’t need one as your clutch is engaging too late anyway (might only be the 44 series anyway).

What colour spring do you have in the secondary pulley.

[Nickstout653]

Red spring

[Diesel Dave]

With that setup it should engage around 2000 rpm, with the yellow spring this would come down to about 1600.

All i can suggest is to strip them down and check the sliding parts are ok and not dragging also check the alignment as it can be tricky to set up initially.

Dave

[Nickstout653]

I sure appreciate the help! I think I’m going to invest in a tachometer to start with

[Nickstout653]

I just ran the bike without the belt on and the drive clutch engages and opens all the way so with the belt on the driver clutch must be preventing my drive clutch from fully engaging

[garbs]

Just a guess but maybe the belt is too long for the clutch center to center distance you currently have. Sounds like you have the correct weights and springs to get the primary working with the lower rpm range of your engine. The drive clutch engaging all the way with no belt on is proof of this. If the belt is too long, the driven will have to engage almost all the way before it takes up enough slack to make the belt tight enough to start grabbing and trying to turn the secondary and move the bike.

[Nickstout653]

I will check this thanks!