Drive belt size

[Simon]

I have a 420cc clone, removed governor, stronger valve springs. I fitted a Tav 30 series CVT which it destroyed the belt. I have ordered a 40 series driver and driven.
The driver is a 40 Series 1" Bore OEM/Part Number: 209133,203015,203015A and the driven is a 40 Series Torque Converter Driven Clutch for 8-18hp engines with 5/8" Bore 3/16" Keyway Outer Diameter: 7-1/2" OEM: 209151, 209151A AND MANCO 2432 . I estimate the centre distance between crankshaft and jackshaft between 6-11/16" and 6-6/8". When looking at charts to find what belt I need for 40 series which is symmetrical with 7/8" top width on belt, I cannot find centre distance for what I have. Is the tav 30 backplate smaller than a Tav 40.
This is really confusing as I don't want to order a belt that doesn't fit.

Any ideas would be greatly appreciated thanks.

 

[flattop1]

So your using a tav 30 back plate ?

 

[flattop1]

The way i read this is 7 1/4 inch center to center .
No fit on the 8.5 t44 . 203783a looks like as close as you get .

 

[Simon]

Yes I have a TAV30 backplate.
No the centre distance is 6 6/8.
So I don't think a 203783A would fit.

 

[flattop1]

Note the last sentence .
Or refit to proper c/c .

Study the charts to insure you're selecting the correct belt size. Comet Series, center distance and driven pulley outer diameter. An incorrect belt size can cause excessive wear and possible damage to the belt, torque converter components, bearings... even your engine. Should your machine's center distance between the crankshaft and the jackshaft fall between the center distance settings listed here, select from the two belts, the one with the larger outside circumference (O.C.) for best wear and to avoid machine "creep" during idling.

 

[Simon]

I have ordered a 203783A and will try it, I know how it should fit. So will have to wait and see, hopefully it will fit if not will have to order a larger or smaller one. Thanks for having a look anyway. Have emailed Gemini karts in the uk as they sell comet parts and belts, will see if they can help with my problem!!

Cheers.

 

[Simon]

Just had email back from Gemini karts.....

The Comet 40 Series does not come on a backing plate. The 40S are symmetrical units so the driven pulley is inboard.

Therefore my driven should be on a jackshaft. I will get it to work using the backplate, nothing that can't be sorted.
Just a case of tweaking it and finding the right belt.

 

[Simon]

Driver and Driven turned up today and as stated by Gemini karts I won't be able to use the Tav30 backplate as the Driver needs to be bolted straight onto the crankshaft.
So I have to return the Driven 5/8" bore and order a 3/4" bore Driven.
Also ordering a 40 s Torque Converter Engine Mount. At a cost of £111.25
Also I now know that a Comet 203785A Belt is required for this set up (cool cos I have ordered 5 belts already)



Will get there in the end, will need to borrow a welder now.