Makeing a v belt pulley

[sbrumby]

Was doing a bit of maintenance on my small bike (superdream with a 6hp yanmar onto a 3 speed hand change)
it has chain from engine to clutch and v belt engine to altenator. The chain laid out had 1/2" of play. This I saw in the second build I did but in a shorter time. I would advise anyone not to use chain on the primary unless you have an enclosed oil filled chaincase, as in the enfield.I am now converting the clutch to v belt. Not easy as standard pulleys are all cast iron. So I got a piece of steel 7"X7"X1" this took a day on the lathe to make it round, spent at least another day on it and I might have it done tomorrow. The front pulley I can just buy as long as I can get the correct size then its just the length of the v belt.

[alexanderfoti]

I am also working in this too. I will jewel everyone updated. My chain showed a fair bit of wear in only 500 miles!

[sbrumby]

Been out on the bike today complete with new v belt drive, works just fine and it seems to pull much better. The drive of the engine is going through 1 gates xpz quadpower belt. The formula for the belt length is radius of 1st pulley X pi + radius of 2nd pulley X pi + 2 X center distance of pulleys. The cost of the front pulley was £20 the taper lock I already had from the original chain cog. the belt cost £10.

[alexanderfoti]

Awesome, What setup is this in?

Top speed and gearbox?

[sbrumby]

This is in the first bike I built, honda superdream with a 275cc yanmar 6hp hand start only coupled to a rotovator 3 speed gearbox that is handchange. It only does 40mph but does 225mpg. So I use this bike over the winter till April then claim the tax back and tax the big bike for the summer months.

[alexanderfoti]

Thats great!

Any pictures of the build?

I am working on getting mine built up, and doing the vbelt install.

Just got to get the bits together, and then get them turned out

[sbrumby]

If you mean did I take some pictures of me makeing the pulley sorry no, but I can take a picyure of the finished pulley if required. And I have a spare gearbox so could take a picture of what it looked like originally also. I had to make a tool to cut the v in the pulley. Just got a lathe tool and ground it down till it was a good fit on an original pulley then welded this to another lathe tool at 90deg ,as to get an edge cut on a 7" dia you would need a very big lathe.

[pietenpol2002]

Sam, I admire your ability to produce your own pulley from raw stock. And a bit envious of your access to a lathe big enough for the task. But, for those of us who possess neither, I wonder whether the GM and Ford crankshaft pulleys would accommodate the clutch in question. The larger ones start at nearly 8" OD and are found in increasingly smaller diameters in 1, 2, or 3 groove versions in either steel or aluminum. The examples below are a bit pricey. However, if you can source them from a breaker they are a fraction of that. Salvage yards here in the states are littered with these. Any chance one of these could be mated to the clutch?

http://tinyurl.com/d93vfjd (7.3" OD)
http://tinyurl.com/crxjxdw (7.6 OD)
http://tinyurl.com/c3so8m6 (7.3" OD)
http://tinyurl.com/cgrtq5k (7.9" OD sincle groove)
http://tinyurl.com/celrpfl (7.9" OD double groove)
http://tinyurl.com/bqx4mpf (7.9" OD triple groove)

[alexanderfoti]

If you mean did I take some pictures of me makeing the pulley sorry no, but I can take a picyure of the finished pulley if required. And I have a spare gearbox so could take a picture of what it looked like originally also. I had to make a tool to cut the v in the pulley. Just got a lathe tool and ground it down till it was a good fit on an original pulley then welded this to another lathe tool at 90deg ,as to get an edge cut on a 7" dia you would need a very big lathe.

I meant pictures of the finished product

[alexanderfoti]

Sam, I admire your ability to produce your own pulley from raw stock. And a bit envious of your access to a lathe big enough for the task. But, for those of us who possess neither, I wonder whether the GM and Ford crankshaft pulleys would accommodate the clutch in question. The larger ones start at nearly 8" OD and are found in increasingly smaller diameters in 1, 2, or 3 groove versions in either steel or aluminum. The examples below are a bit pricey. However, if you can source them from a breaker they are a fraction of that. Salvage yards here in the states are littered with these. Any chance one of these could be mated to the clutch?

http://tinyurl.com/d93vfjd (7.3" OD)
http://tinyurl.com/crxjxdw (7.6 OD)
http://tinyurl.com/c3so8m6 (7.3" OD)
http://tinyurl.com/cgrtq5k (7.9" OD sincle groove)
http://tinyurl.com/celrpfl (7.9" OD double groove)
http://tinyurl.com/bqx4mpf (7.9" OD triple groove)

I think it will be very difficult without knowing the depth of the pulley, and it MAY be difficult to source the correct V belt size.

Still, looks promising.

[gearhead1951]

http://www.backyardmetalcasting.com has info on casting and machining pulleys and on the forum http://www.alloyavenue.com they cover how to machine a pulley wihout a proper lathe

[tappy]

Standard pulleys from Gates, Anti-friction etc are indeed cast iron, but dig around on the net - there are PLENTY of companies making aluminium V-belt and toothed pulleys for all sorts of applications.

[sbrumby]

Interesting I hadnt looked at pulleys on engines as most of them over this side of the pond now are cast multi v with a center that has a bonded rubber in it. Anyway I was very tight on space. Bigger than 7" and it would hit the swing arm, smaller and it would not have fitted onto the original clutch plate.

[sbrumby]

here are the photos.

[gilburton]

How do you find the 3 speed Albion box performs? Does the clutch stand up and do you think it would handle 8/10hp??
I only ask as they are quite slim and come up on ebay quite often.
I was considering fitting a manual box on my MZ/Robin but room is at a premium and the only other box that might fit would be a Villiers but the prices are getting silly.
I believe you are in agriculture maybe you know of a source??

[alexanderfoti]

Looks great! Many thanks for the pics

[sbrumby]

The Albion box seems to stand up ok and the clutch never seems to slip, I got both mine from the Stafford motorcycle show and autojumble, from memory about £25 each. I suspect they were fitted to rotorvators so would probably have been married to maybe a 10hp petrol but that is just a guess. I quite like the hand change as going up the box i just change with my knee.

[gilburton]

Yeah the ones on ebay are usually advertised as vintage motorcycle boxes. Whether that's true or not I don't know but they look more agricultural to me. By the way do they have a positive stop or do you need a gate??

[sbrumby]

There is a sort of clunk so i havn`t got a gate on mine. There is only three gears and neutral is between 1st & 2nd.
So if you make your lever right the movement for the different gears is obvious.