VintageVmax.com

Hey guys I was wondering how important the offset is when aligning the primary to the secondary. I smoked a couple belts the other night and not real sure what the issue is. I set a straight edge off back of my primary and then measured roughly a half inch off the straight edge at one side of the secondary and the far side of the secondary. in other words is the half inch real important or, is the important thing to make sure that they are in alignment. The clutchs are in alignment with this off set and not sure if the offset is giving my problems. I also read somewhere that were the belt rides in the primary and secondary can cause the belt to overheat and maybe this is the problem I am having. I have not yet hung the the sled to determine exactly how the belt rides throught the RPMs. also where is the best place for a belt to ride and if it is not in the specified rang how do I go about changing this? Thnaks Guys. Mike

yeah proper center to center and offset is pretty important, without you really cant move on. i would say center to center is probably more important but offset is a very close 2nd... if either are very far off you will not be getting the power you should... do you have the stock clutchs? i belive the specs are in the article index but let me look....

yeah its there... its sorta heard to read when it is cut and pasted so you might just want to visit http://www.vintagevmax.com/1986_service.htm

Drive- Engagement rpm/ Shift rpm ---- 4000 +/- 200 rpm/ 8200 +/-200rpm
Belt Length/ Width/ Wear Limit/ ---- IBM Number 1175mm/ 31.6mm/ 26mm/ 8M6
Sheave Center to Center/ Offset ---- 305 +/-1.0mm/ 11 +/-0.5mm
Primary Spring Color/ Length/ Rate/ Preload ---- Pink/ 75.5mm/ 2.31Kg-mm/ 32.8 Kg
Secondary Spring Preload/ Color/ Length ----40degrees (C-2)/ Pink/ NA

thanks tyler, i have the comet 102C on the sled and the secondary is stock. I intially set the clutches up with the belt I had (STOCK 1080) giving myself 1 and 1/4 inch deflection to detrermine center to center. I prolly need to make a tool to get this more accurate, and the offset on the money. sled runs around 75 mph and figured with new pistons rings that it should run a tad faster??? anyways thanks again for your help and hopefully a little more accrate clutch set up will give me more usable HP.

what does it rev out to? should engage at 4000 +/- 200 (very important) and rev to 8200 +/- 200

engages closer to 5K and revs out around 9K. I Have not weighed the cam arms to determine exactly what they are and how closer they are to specs. My manual show that top RPM is 9250???? thanks again

messina1974 wrote:engages closer to 5K and revs out around 9K. I Have not weighed the cam arms to determine exactly what they are and how closer they are to specs. My manual show that top RPM is 9250???? thanks again

Sounds like an 81 SRX not a Vmax540 ?
http://www.vintagevmax.com/1986_service.htm

do you have stock pipes on it?

Pipes are stock, and yes it is an 81 srx!

well then! thats makes a difference for sure... im not sure on the 81 specs... your manual should have it, doesnt it?

on second thought they pecs are most likely the same as far as center to center and offset because all vmaxs run the 8M6-#### belt, which was originally run on the 8M6 (81 srx)