help about belt sizes??

vmax540liq · Post by **vmax540liq** » Fri Mar 14, 2008 4:10 pm

hi i have a comet 108 primary and a stock secondary my belt is pretty worn out i went to a local dealer to get a new so i got a carlisle ultimax 2 which is pretty much the best one you can buy so i put it on and it fit better and quite a bit tighter and went to start it and it instantly took off like the belt was too tight so i countinued using the old one and took the new one back and i was wondering if my belt is too worn at higher speeds like 45 and above if it would affect the speed because i have a hell of a time getting past 55 or 60 and after going a little ways like 100 yards and i let off completely im almost positive i can hear the belt hitting the belt guard?? so if someone could please help me i would greatly appreciate it. thanks Travis

jefflanthier · Post by **jefflanthier** » Fri Mar 14, 2008 6:04 pm

You might have had the right belt but sometimes you gotta put shims in the secondary clutch to get the belt to sit 1/8 or so above the secondary sheave. How many miles and has the engine ever been rebuilt?

srxvmax50 · Post by **srxvmax50** » Fri Mar 14, 2008 6:29 pm

Don't run too short of a belt on your Vmax, or whatever it is you got. The belt must be of adequate length to smoothly transfer torgue at whatever rpm's. If you go for shift-out and your bellt is too "tight" you may likely bend the crankshaft. Bigtime clutch wobble and engine teardown is what to expect. Save yourself a bunch of money and dismay and slide your engine back or forward until you get on to spec-ed belt defflection. Then you will be getting close. Aftermarket overdrives, etc. require different belt lengths (usually longer) then as listed in the oem manual. You can figure it out. Good luck, MJD.

vmax540liq · Post by **vmax540liq** » Fri Mar 14, 2008 7:56 pm

hi yea im not very framiliar with the building i mean i know what the difference is but not about all the sheaves? and it has rite around 4450 miles on it and dont know if its ever been rebuilt i know it has a new cylinder on it on the clutch side so i do know that was rebuilt at one time but the guy i got it from said he didnt know anything about sleds but did say it was too fast for his kids and himself to ride, but i did tear the top end down to do a topend gasket job because the right hand cylinder was sucking air because the base gaskets were really bad and that cylinder is scored a bit and has 109lbs compression which it will still run but not the best and the other side has 119 which is average i know a guy with a set of really good cylinders for it but there bored .40 over any ideas how that might turn out like too many problems or no?? but keep the advise coming guys it really helps me out a lot theres a lot of tricky things to these old sleds and the advice is greatly appreciated!!

vmax540liq · Post by **vmax540liq** » Fri Mar 14, 2008 8:00 pm

yea the last thing i need is a bent crank that wouldnt make my day you know, and i understand the too tight deal that your talkin about to, iever since i got the sled because the sled before this one i had was a 95 vmax 600 and wondered if that motor would bolt up to this tunnel?? it would be neat if it did because those are real good motors just like the oil and gas tho, but thanks for your advice!!

jefflanthier · Post by **jefflanthier** » Sat Mar 15, 2008 9:39 am

Just curious as to what your rpm goes up too when you give it full throttle?

vmax540liq · Post by **vmax540liq** » Sat Mar 15, 2008 10:13 am

well actually that was kinda odd too because i think it wont go over 6500 or 7000 and i think they should at least go to 8000 to 8500 rite??

vmax540liq · Post by **vmax540liq** » Sat Mar 15, 2008 10:21 am

vmax540liq · Post by **vmax540liq** » Sat Mar 15, 2008 10:27 am

vmax540liq · Post by **vmax540liq** » Sat Mar 15, 2008 10:30 am

well the pics didnt show up to good on here but im proud to show it off let me know what you guys think, and also what you think it would be worth??

vmax540liq · Post by **vmax540liq** » Sat Mar 15, 2008 10:35 am

sorry guys i forgot one more thing when i go to give it full throttle its like it only wants to run on 1 cylinder but after it gets past the bottom end bog it picks rite up like its running on 1 and picking the other one or trying to pick the other one up also like its fully reved and wont go over 6000rpm to 7000rmp? let me know what you guys think it really helps me out and its nice to see a forum where you can join and get this much help and to see how much people are dedicated to these ol sleds!!!!

jefflanthier · Post by **jefflanthier** » Sat Mar 15, 2008 4:43 pm

It could be a number of things. Turn your primary clutch with the key off rotate it and listen and feel for rough spots. If you find grinding or rough spots when rotating it then i,m gonna say the crankshaft needs work. A worn clutch will give you a bog as well, check your pins rollers and weights they should be tight and not oval. Check your coils in the engine the specs are the 1986 ones they should be the same its in the article index at the top left hand side of the page here. Clean your carbs if you havent done that it always makes a difference with clean carburetors. Good luck

vmax540liq · Post by **vmax540liq** » Sat Mar 15, 2008 5:28 pm

ok yea ill check it out and i cleaned the carbs fuel pumps and cleaned out the gas tank at the start of season so thats all good, so i dont know its irritating

VintageVmax.com

help about belt sizes??

help about belt sizes??

belt too short?: Big trouble