40 series clutch slipping

[JaySweenor]

Hello,
I just installed an 18hp engine in my manco rattler. I have the proper belt and alignment. I have 18in tires, 10 tooth sprocket in the jackshaft and a 50 tooth on the axle. The belt slips when I get on the throttle...
Anybody have any suggestions on how to stop this? I do only trail riding so, this wont do. Thanks for your help!

 

[mckutzy]

I'm going to guess the motor is a little too powerful for the TC to handle...

Also... Why is this in the FAQ... Not in general section???

 

[bob58o]

You need to flip the driven unit around so the spring is installed inboard.
Or you need a reverse wound 40 series spring for the driven unit.

 

[bob58o]

http://www.gopowersports.com/40-series-reverse-wound-spring-yellow/

 

[anickode]

I agree with bob, plus some:

A reverse wound spring would be the correct setup for an outboard mounted driven, however the symmetrical design on a 40 series means it really SHOULD be mounted inboard to maintain belt alignment through the full range.

5:1 gear ratio may be a bit tall for 18" tires, unless you only run on flat ground. Based on those knobby tires and my idea of "trail riding", I assume you do not only run on flat ground.

18hp is the upper limit of what a 40 series is rated for.

Cheap Chinese belt = cheap chinese performance. You might consider a genuine comet belt.

 

[JaySweenor]

I'm going to guess the motor is a little too powerful for the TC to handle...

Also... Why is this in the FAQ... Not in general section???

When I bought the clutch, it said it was rated up 18hp. I'm new at this, so I have no idea where I'm posting...thanks for response.

 

[mckutzy]

All's good...

As for the TC...the more experienced above shall have a better weigh in than I...

 

[JaySweenor]

You need to flip the driven unit around so the spring is installed inboard.
Or you need a reverse wound 40 series spring for the driven unit.

I've never heard of that. I will definitely try it. What are the circumstances that changes it to be inboard or outboard? Thank you Sir!

---------- Post added at 01:47 PM ---------- Previous post was at 01:40 PM ----------

I agree with bob, plus some:

A reverse wound spring would be the correct setup for an outboard mounted driven, however the symmetrical design on a 40 series means it really SHOULD be mounted inboard to maintain belt alignment through the full range.

5:1 gear ratio may be a bit tall for 18" tires, unless you only run on flat ground. Based on those knobby tires and my idea of "trail riding", I assume you do not only run on flat ground.

18hp is the upper limit of what a 40 series is rated for.

Cheap Chinese belt = cheap chinese performance. You might consider a genuine comet belt.

What would you think would a good ratio? I've used this ratio with a 6hp and it was just fine. I also have a genuine comet belt. What are the circumstances that change an inboard or outboard mount? Thank you, I appreciate your knowledge.

 

[bob58o]

I've never heard of that. I will definitely try it. What are the circumstances that changes it to be inboard or outboard? Thank you Sir!

The direction is determined by which spring you use.

The spring you have is probably the standard spring for inboard mounting.
If space determines you need to mount outboard, then you need the yellow reverse wound spring I linked above.

I use 60T : 11T with my 420cc engine and 40 series with 18.5" Tires

http://www.bmikarts.com/pdf/comet_40series.pdf

 

[anickode]

The direction is determined by which spring you use.

And whether or not you care about the alignment.

When mounted outboard, the driven must either float on the jackshaft, or you just have to live with the belt going more than a full belt-width out of alignment as the gear ratio tops out.

The driver squeezes in from the outside, moving the belt towards the engine. The driven opens up to the spring side, moving the belt towards the spring. If you have the driven mounted spring outboard, the belt is moving opposite directions as the gear ratio changes, taking it way out of alignment.

A 30 series works the same way, but uses an asymmetrical belt with a 2° bevel on the back sides, so while it does go out of alignment, the difference is negligible.

 

[JaySweenor]

http://www.gopowersports.com/40-series-reverse-wound-spring-yellow/

SPRING ORDERED! Thank you, Sir

---------- Post added at 02:06 PM ---------- Previous post was at 01:58 PM ----------

The direction is determined by which spring you use.

The spring you have is probably the standard spring for inboard mounting.
If space determines you need to mount outboard, then you need the yellow reverse wound spring I linked above.

I use 60T : 11T with my 420cc engine and 40 series with 18.5" Tires

http://www.bmikarts.com/pdf/comet_40series.pdf

Ahhh, ok. I musta read that pdf 100 times and never noticed that inboard mount.... Isn't a 5:1 lower then that?

 

[bob58o]

And whether or not you care about the alignment.

When mounted outboard, the driven must either float on the jackshaft, or you just have to live with the belt going more than a full belt-width out of alignment as the gear ratio tops out.

The driver squeezes in from the outside, moving the belt towards the engine. The driven opens up to the spring side, moving the belt towards the spring. If you have the driven mounted spring outboard, the belt is moving opposite directions as the gear ratio changes, taking it way out of alignment.

A 30 series works the same way, but uses an asymmetrical belt with a 2° bevel on the back sides, so while it does go out of alignment, the difference is negligible.

I think others have said that it is better to have the belt aligned when already shifted (and running at higher rpms) than to have the belt aligned when in low gear.

Either way, without it floating - there will be some kind of misalignment. Which I guess is ok, GPS still sells their kits. I haven't heard too many complaints that I can remember.

 

[anickode]

I think others have said that it is better to have the belt aligned when already shifted (and running at higher rpms) than to have the belt aligned when in low gear.

Either way, without it floating - there will be some kind of misalignment. Which I guess is ok, GPS still sells their kits. I haven't heard too many complaints that I can remember.

I think the backplate 40 series kits are misapplication of a good idea. They are great on a TAV2. Then somebody had the idea to make a bigger one and smack a 40 series on it. Does it work? Yes. But I've got to think Comet never sold em that way for a reason.

 

[bob58o]

SPRING ORDERED! Thank you, Sir

---------- Post added at 02:06 PM ---------- Previous post was at 01:58 PM ----------



Ahhh, ok. I musta read that pdf 100 times and never noticed that inboard mount.... Isn't a 5:1 lower then that?

60:11 is 5.45 :1.

Tall Gears (High Gears) have lower Numbers.
Short Gears (Low Gears) have Higher Numbers.

5.00 is a lower number than 5.45,
so it is a taller (higher) gear ratio.
But the increase displacement (440cc???) and decreased tire size would make it about the same as what I run.

 

[JaySweenor]

And whether or not you care about the alignment.

When mounted outboard, the driven must either float on the jackshaft, or you just have to live with the belt going more than a full belt-width out of alignment as the gear ratio tops out.

The driver squeezes in from the outside, moving the belt towards the engine. The driven opens up to the spring side, moving the belt towards the spring. If you have the driven mounted spring outboard, the belt is moving opposite directions as the gear ratio changes, taking it way out of alignment.

A 30 series works the same way, but uses an asymmetrical belt with a 2° bevel on the back sides, so while it does go out of alignment, the difference is negligible.

I see. So if i get the yellow spring, I would not have the shaft collars tightly against the driven, correct? I hope i have enough jackshaft length to make this happen... Thanks again!

 

[bob58o]

I have to ask...
Did you cut the JS to the perfect length after you thought you had everything perfectly aligned???

---------- Post added at 01:28 PM ---------- Previous post was at 01:24 PM ----------

I see. So if i get the yellow spring, I would not have the shaft collars tightly against the driven, correct? I hope i have enough jackshaft length to make this happen... Thanks again!

You would want the Driven to be able to slide towards the pillow block.
The pulley will open in the other direction, so you want the pulley to slide opposite to try to keep the belt straight.

Maybe just remove the lock collar on the pillow block side of the driven unit????
I can't see where lock collars are used. Are you using lock collars with those bearings or just the set screws?

Check that the driven unit will not hit the engine mount if it is allowed to float.

 

[JaySweenor]

60:11 is 5.45 :1.

Tall Gears (High Gears) have lower Numbers.
Short Gears (Low Gears) have Higher Numbers.

5.00 is a lower number than 5.45,
so it is a taller (higher) gear ratio.
But the increase displacement (440cc???) and decreased tire size would make it about the same as what I run.

Ok, yes, that's what i was thinking. Yep, it's a 440, with 18"(printed on the tire) but measured, they are 18.5". This should be sufficient as long as I either mount inboard or get the yellow (reverse wound) spring, right? Thank you!

---------- Post added at 02:34 PM ---------- Previous post was at 02:28 PM ----------

I have to ask...
Did you cut the JS to the perfect length after you thought you had everything perfectly aligned???

---------- Post added at 01:28 PM ---------- Previous post was at 01:24 PM ----------



You would want the Driven to be able to slide towards the pillow block.
The pulley will open in the other direction, so you want the pulley to slide opposite to try to keep the belt straight.

I ordered the JS to the size I measured out to get around my mount, not knowing what I know now...Yes, I also considered alignment. May need to order a 16", this one is a 12".

---------- Post added at 03:24 PM ---------- Previous post was at 02:34 PM ----------

Thanks Everybody for your knowledge. I moved the engine over and had enough room to mount the driven inboard. It completely solved the problem, thanks again!