Capstan belt has been melt away, some request : = capstan belt size : thickness,diameter,width ( millimeter ) = drawing the track of them from motor to the two capstans ever yours

What I suggest you do is measure the diameter of the belt and the thickness in MM and put the Diameter measurement and words "drive belt" into Google and search for that. You need not be spot on with the size. You can either work out the thickness of the belts from the results, or narrow it down later.

seem problem with the gear belt.

It is a simple process of either taking the old ones off and measuring or if they are broken use a string and measure then subtract 5% or the easy way is to just order the belt kit from Marrs Communications where he has done all the ground work for you but then you still need to put them in. This may require a bit of dis-assembly such as removing the transport from the chassis and then taking off thrust plates or motor support brackets to get to the place you need to get to put the belts on. There are no service manuals that give you step by step instruction- at least I have not seen any in 42 years of service. If you want to save money you will have to do the job yourself. If you want a professional, well I am here but depending on the amount of time it takes it might not be cheap. If you really want to get the parts cheaper then MCM Electronics or Mat Electronics can sell you the belts for a little bit of money as long as you know the size. Size refers to Inner Circumference, Width and Thickness. In the case of square belts Width and Thickness is the same number but with Flat belts used on most Capstan and flywheel systems the width and thickness is important.

Hello Projocs03,

Tires are typically measured tire width (sidewall)/tire ride height/wheel size. The differences of the two tire sizes you published are .4 of an inch difference in width/sidewall. And about .55 in over all diameter which would impact you revs per rotation. Depending on your wheel size.

Attached is a comparison of the two given the variable of 17" rim.

Stock Tire >Search Tires Tire 1 - 255/70R17 >Search Tires Tire 2 - 265/70R17 >Search Tires Section Width: - - Section Width: 10.03 in 255 mm Section Width: 10.43 in 265 mm Rim Diameter: - - Rim Diameter: 17 in 431.8 mm Rim Diameter: 17 in 431.8 mm Rim Width Range:
Rim Width Range: 6.5 - 8.5 in Rim Width Range: 7 - 9 in Overall Diameter: - - Overall Diameter: 31.05 in 788.67 mm Overall Diameter: 31.60 in 802.64 mm Sidewall Height: - - Sidewall Height: 7.02 in 178.30 mm Sidewall Height: 7.30 in 185.42 mm Radius: - - Radius: 15.52 in 394.20 mm Radius: 15.80 in 401.32 mm Circumference: - - Circumference: 97.54 in 2477.5 mm Circumference: 99.27 in 2521.4 mm Revs per Mile: - Revs per Mile: 669.8 Revs per Mile: 658.2* Source http://www.1010tires.com/TireSizeCalculator.asp?action=submit

I added the above link so you can research further or change any variables you need to know. However, the most important thing to understand is the impact of your speedometer. Different sizes will have different impacts. For example going to a bigger tire will show a slower speed on your spedo that your traveling.

Good luck

An o-ring from ace hardware's plumbing department works perfect for 49 cents. Size will be 1-1/2 ID X 1/16 thick O-ring....or the official o-ring part is AS568-029.( 1.489 x .070) Nitrile rubber.

The best is to take a thick thread - the size of the belt and place it around the flywheel- capstan and the motor pulley. Now take the correct length of this loop and buy a belt with a fraction of size smaller than the thread loop.
The belt size must be just correct to be tight around the pulley and capstan.

Just measure the diameter in MM and put the result into google with the words 'cassette drive belt'. Belts are not maker specfic.

start with the seatpost itself, most of them have the size stamped on them below the minimum insertion hash marks. It is almost always measured in metric, millimeters usually, like: 25.4mm (which is 1 inch).

If the size is not stamped on the seatpost (it was most likely cut off or scratched beyond recognition) then you can measure the diameter in inches, multiply by 2.54 to get the metric measurement in centimeters, multiply that by .10 to get millimeters and then call your local bike shop for a replacement.

Dyno bikes are made by GT, it was there "budget" brand of BMX bikes, so you can google GT bikes and find a local dealer or you may be able to order direct from GT. From the year of your model, most likely the bike is steel (cro-moly or hi-ten) and these bikes normally have a smaller seatpost size, like the above mentioned 25.4mm. Aluminum frames usually have larger diameter tubes with thinner wall thickness and will require a larger diameter seatpost.

Belts are measured in mm by the diameter. Though you will also need to measure the thickness. Belts are generally none specfic, to makers, so you have a good chance of getting them.
A good place to try first is online parts shop CPC.

If the motor is running but the belts are not, then they are probably shot. You can buy belts by size or buy a belt kit at MCM Electronics.

If the motor is not running it could be 2 things: 1. A bad motor or voltage to the motor.... 2. A bind. I've seen the grease on the capstan bushing get old enough to turn into a very hard tar. So check the motor and capstan for freedom of movement.

Hope that helps you get it working...

Geno