I've bought an xl250s motor for a project and need to gear it down for trials. Anyone got any ideas for a small front sprocket, somewhere in the region of 10 teeth? Does it match anything off the shelf?

Thanks

Edited January 31, 201511 yr by bigmike1961

I use a 10 tooth on my SL230 trail bike and keep it in place with circlips. I think it's of a scorpa. Part no is TG451 made by Talon. I don't know if the shaft is the same size.

Thanks , I'll check that out, the engine seems rather larger than anticipated for the montesa 247 frame.

Some cutting will be required.

Edited January 31, 201511 yr by bigmike1961

just seen a very nice job of putting a kl kwacker unit in a 247 mont..

just seen a very nice job of putting a kl kwacker unit in a 247 mont..

Do you mean this? Its's a splendid job, very envious.

Edited January 31, 201511 yr by bigmike1961

Thanks , I'll check that out, the engine seems rather larger than anticipated for the montesa 247 frame.

Some cutting will be required.

or a KL engine... the xl250 engine seems huge in comparison to the Kwacker. XL seems to stand for extra large bottom end.

I use a 10 tooth on my SL230 trail bike and keep it in place with circlips. I think it's of a scorpa. Part no is TG451 made by Talon. I don't know if the shaft is the same size.

Any chance you could take a measurement or two of the sprocket?

I found some images but need a measurement of the gearbox output diameter to see if the sprocket will fit. If the measurements match the second pic, brilliant, third pic no go but thanks for your help.The output on the xl engine is definitely 25mm.

Edited February 1, 201511 yr by bigmike1961

Sorry big mike been out all day. Will measure first thing in morning. It does look the same. Dave.

Sorry big mike been out all day. Will measure first thing in morning. It does look the same. Dave.

No problem Dave, I've been messing about to see if the engine will fit in the frame on and off all day. I think it will but the frame will need a bit of cutting.

Thanks

Mike

Edited February 1, 201511 yr by bigmike1961

Hi Mike, sorry matches the third. I obtained my part no from a sprocket book which I lent to some one about ten years ago. Still waiting. That you can match up your measurements and find a part no. Can't remember who produced it. Looks interesting your project. Good luck.

Thanks Dave, I was thinking that might be the case.

Hi mike it's not just getting the engine in the frame there's allso chain line and chain above and below swinging arm carb.and air filter things to think about Stan

Hi Stan,

Yes, it's not a five minute job! The chain seems to line up with the rear wheel after initial tape measure waving. The engine needs to drop and I think things will line up. The bottom frame tubes might go and be replaced with a good solid skid plate. If I need to the front down tube will be cut and replaced with twin down tubes somewhere below the twin exhaust ports which exit either side of the down tube.

Carb will be interesting.

Hi Dave.

Did the obvious regarding the sprocket (with hindsight), got in touch with Talon so that should be sorted. They said TG314, 11 or 12 tooth with a 520 chain, result.

Hi mike will the 520 chain clear the gearbox oil seal with the small sprocket Stan

Hi mike will the 520 chain clear the gearbox oil seal with the small sprocket Stan

Hope so Stan, a sprocket isn't too expensive if it doesn't work. XR 250 can have a 12 tooth sprocket. It'll need a circlip to hold the sprocket on though.