Do you currently have an old belt off it? when I need belts here I take it to the local farming tool store and they measure them, work out roughly how stretched they are and give me a replacement they havent failed me for getting the right size yet.
Like Joe said, only other option would be to get a genuine belt and that would be an expensive exercise.
As for the age of it, you have a guess how old mine is and i will have a guess how old yours is. They probably made them for well over 20 years. So without a picture at minimum theres no point even guessing. Someone may have info on model numbers by year but i doubt anyone here has it.
The numbers on the engine cowling will tell what year the motor was made. Assuming that is the original engine it will tell you what year it was made.
There seem to have been a succession of different models sold under the Colt 5 and Colt 8 names. V belts are normally bought under a standard industrial classification consisting of a letter that gives the belt section width, and a number that is the belt length in inches. (For example, some late model Colt 8 cutter belts were B59.) If you have the old belt, take it to an industrial supply shop and they will measure its length on their simple sliding gauge, and identify the section by just glancing at it, then they'll wander into the stock room and come out with the replacement belt. The new belt will have the letter and number painted on it, on the outside surface, so you can write it down. I take it you've looked carefully at the outside of the old belt, to see if it is still visible?
Joe, V belts don't stretch - they have built-in cords near the outside cover, and the cords are unstretchable, though they can be broken. However as the belt wears it sits down further in the pulley, and this may confuse the length gauge slightly, depending whether it just uses the inside surface or is V-shaped.
I wish it was that easy the belt self destructed. I had just finshed rebuilding it and I think I have adjusted the guard wrong and it chew up the belt. There seems to be a number of them advertised on the web site any idea which one?
You can get close to the length by running an ordinary tape measure around the pulleys, and reading it where the end reaches back to the tape. For the section you need to compare the pulley grooves with other pulleys. Essentially an A section belt is 1/2" wide at its widest part, B section is 5/8".
Put up some pictues of the machine, that might help a little. I googled colt 5 7221 and all i get thats useful is a link to this thread.
Im pretty sure its a B section belt.
Get some 10mm rope and string that around the pulleys, mark the rope where the end comes too and measure the rope. That will get you an idea on the belt length. I only see two belts for the colt cutter deck in the shop, one is 55" the other is 59"
Id say its the latter as the former is for a GT2000. But you would need to check it.
So, that is a B59 belt. The Colt 8 manual in the manuals section of this site has been overmarked by hand to show it is a B59, and now it turns out that at least some Colt 5s use that belt as well.
Thanks for everyones help on this one I will post pictures once I complete the restoration. This may seem obvious to some but the belt is listed as a (5/8” Wide x 59” I.D) I.D is internal diameter right should it be internal circumference or the belt is really really long? I really happy to have found this site as I thought I was the only one with this infliction the love of small engine. The attached is an earlier project. When you modify a 5hp briggs motor what do you do with? Build a go kart of cause. I never had one as a kid. Yes it is fitted with nitrous a small one shot hand held unit.
Last edited by Bruce; 01/11/1104:45 PM. Reason: Updated Links
The simplest form of length gauge consists of two half-circles of wood, one fixed, one sliding, with a mark every half inch to indicate a belt length in inches. That measures the circumference of the belt around the inside. This is not the length that is preferred by belt manufacturers, but it is the easiest way to measure it. The difference inside measurement makes compared with the (recommended) outside measurement is fairly small. I agree that it should not be called inside diameter, it is inside circumference. If you want to read up on the subject, here is the story according to one of the world's largest V belt manufacturers: