engine mount in frame

[fowler]

if i was to mount my engine in a frame with swing arm suspension should i have a tensioner pully
or is it ok without and shoud i have a wheel at top to stop it rubbing or is a chain slider ok

 

[KieranM]

what is the distance from the engine sprocket to the axle sprocket?

 

[Kaptain Krunch]

depends on how far your engine sprocket is from the swing arm pivot point, the closer it is the less your chain tension will change.

 

[Doc Sprocket]

You always want consistant chain tension. Ideally, you want the swingarm pivots exactly lined up with the engine (or jackshaft) sprocket. If you can accomplish this, your chain tension will not change thru the suspension cycle, no tensioner required. If this is not possible for you, rig a spring-loaded chain tensioner, ideally with an idler sprocket, or secondly with a wheel or slider. When you setup the chain, measure the distances between the sprockets throughout the entire suspension cycle. Size your chain so it will be very slightly slack at whatever point the sprockets are furthest apart. Then add the tensioner assembly, locating it on the slack side (generally the bottom) of the chain. Once set up, cycle the suspension to ensure that at no point is the chain either too tight or too loose, and the tensioner is capable of doing it's job.

If your drive sprocket is WAY out-of line with the suspension pivot, you may have a problem with the chain having to slack to the point of the two chain runs hitting each other. If this occurs, your best bet is to alter your design, placing the drive sprocket closer to being in line with the suspension pivot.
Cheers!

 

[fowler]

what is the distance from the engine sprocket to the axle sprocket? QUOTE

it is about 8cm (3.1in) from the pivot

you want the swingarm pivots exactly lined up with the engine QUOTE

the swing armis off a quad so it tapers out from the narrow back end

thanks for all your coments