Can you use a stock belt with a pulley mod?

fireblade · Post by **fireblade** » Tue Feb 05, 2008 2:25 am

Can the rear pulley give enough to enable the retaining of a stock belt with the pulley mod?

Farfignugin · Post by **Farfignugin** » Tue Feb 05, 2008 10:34 am

probably but by keeping the original belt and not getting a longer one you actually double what you are trying to do and in most cases with a spree that will put too much of a load on the engine (the rear pulley will open making the contact area smaller and decreasing the ratio (ex: 3:1 compared to 1:1)).

Most spree engines unless extremely modded cannot take much of a load and that is why everyone says to get the longer belt when doing the speed pulley mod.

fireblade · Post by **fireblade** » Tue Feb 05, 2008 3:29 pm

So as long as I take note of how much longer the new belt needs to be, it will still work with a stock belt ? And if need be I can get the right belt later. I've got a few spares now, I might shave a head and drill out a few baffles first, then see how it copes with the extra load. I'm too mean to buy a new belt unless I absolutely have to.

stillspeeding · Post by **stillspeeding** » Thu Feb 21, 2008 3:36 am

All scoots from New Zealand or Australia are Japan models, also its not a longer belt that makes speed its a wider belt that rides pulleys higher

Farfignugin · Post by **Farfignugin** » Thu Feb 21, 2008 8:39 am

Yes, but if you have already done the pully mod for speed, it would be pointless to get a wider belt because you would double the effect, and a spree engine really can't power that.

fireblade · Post by **fireblade** » Sat Feb 23, 2008 12:13 am

How would a wider belt make the gearing higer.

Kenny_McCormic · Post by **Kenny_McCormic** » Sat Feb 23, 2008 11:40 am

fireblade wrote:How would a wider belt make the gearing higer.

It rides higher on the front pulley and lower on the rear pulley.

Post by **noiseguy** » Sat Feb 23, 2008 1:09 pm

The front pulley gets a fixed width, with the rear pulley taking up the slack by changing effective diameter.

It's hard to explain, easy to visualize if you pull off the pulley cover and take a look.

The pulley is really sensitive to changes; you need to remove material in the .010" range and see how it goes. Too much ratio change and you'll bog the engine. Of course, you can also raise compression / lightly port the exhaust to help offset that too.

rac

DrZ34 · Post by **DrZ34** » Sat Feb 23, 2008 5:36 pm

Kenny_McCormic wrote:
fireblade wrote:How would a wider belt make the gearing higer.
It rides higher on the front pulley and lower on the rear pulley.

It rides higher on BOTH pulleys cuz its fatter,

and beofre some one challenges my AUTHORI TYE. I own a 40 mph drag tractor with a similar belt type drive , ive been throughm my share of belts , and i did a plug chop to boot!

Kenny_McCormic · Post by **Kenny_McCormic** » Sat Feb 23, 2008 6:15 pm

DrZ34 wrote:
Kenny_McCormic wrote:
fireblade wrote:How would a wider belt make the gearing higer.
It rides higher on the front pulley and lower on the rear pulley.
It rides higher on BOTH pulleys cuz its fatter,

and beofre some one challenges my AUTHORI TYE. I own a 40 mph drag tractor with a similar belt type drive , ive been throughm my share of belts , and i did a plug chop to boot!

Your forgetting that the rear pully SEPERATES AND ALLOWS THE BELT TO RIDE LOWER when the belt tension is increased by the belt riding higher on the front pulley.

fireblade · Post by **fireblade** » Sun Feb 24, 2008 1:38 am

I might just try machining the pulley down in very small increments.

Kenny_McCormic · Post by **Kenny_McCormic** » Sun Feb 24, 2008 9:23 am

Now that I think about it, just running a wider belt might give the same effect as milling the pulley. I will have to try this when my 22 year old stock belt finally goes.

stillspeeding · Post by **stillspeeding** » Wed Feb 27, 2008 2:04 am

22 yrs on a belt? i have belts that dry rot after 2 yrs of just hanging, tires will last 5 yrs and fuel will break down after 30 days!

Kenny_McCormic · Post by **Kenny_McCormic** » Wed Feb 27, 2008 3:38 pm

It only has a little over 3k miles on it. and it is all cracked up, so is my front tire.