1980 rm250 wheel spacing chain issues.

[mainline]

I've got an rm250 with chain throwing issues. Putting a straight-edge along the rear sprocket shows the wheel needs to move to the left (in the direction of the rear sprocket) as the straight-edge looks to be centred or even worse on the front sprocket.

The wheel looks close to the swingarm (by comparison to my PE175) already, but has some room to move by playing around with spacers. I can't think of any other reason why it would be throwing chains?

[Ted]

You put the link in, right

Only saying 'cause you know Barsby

[oldfart]

Paul what measurement do you require ..... as I can measure from mine.

[mainline]

You put the link in, right

Only saying 'cause you know Barsby

Fair call. No the link is in, and both sprockets are on the same side of the bike.

Thanks Stu, any measurement you can give me relative to the sprocket side of the wheel to the inner edge of the swingarm would be a good start. Looking at that photo it seems the bearing on that side is pretty close which confirms what I'm thinking to some extent. Cheers

[bazza]

mainline for get it and finish the BSA !!!    adjuster up high enough?

[Tomas]

You are missing left hand spacer part no. 19  and possibly right hand spacer part no. 18  http://www.partzilla.com/parts/search/Suzuki/Motorcycle/1980/RM250/REAR+WHEEL/parts.html 
Also if your rear axle is original Suzuki part it is sticking out a lot on left hand side. Your swinging arm may be bent in a bit from not using  correct spacers when installing wheel.
Hope it helps.

[oldfart]

Ok  just come back from shed .... LHS    the washer welded to the adjuster should be 4mm thick  then you have a 10mm alloy spacer that rests against the hub bearing .....
On the RHS you should have a 7mm alloy spacer against the brake hub and a 4mm washer welded onto the adjuster.
 
Back to LHS again ..... you should have 7.5 mm clearance at the sprocket and swingarm ( steel sprocket ) and you should also have 12mm at the arm and hub face (measured just above  axle ) 
Me thinks you have the spacers in arse about face 

[mainline]

Thanks very much for that Stu, that should get me out of trouble

[rocketfrog]

While we are on the subject, where do I find a replacement spoke set for a 1980 RM250T?

Also, can anyone help with the off set of the rim to the sprocket flange and /or the offset on the brake side.

I will be building one of these soon and I plan to use a PE250T rear rim which should be a decent match.

Because I am just starting with the hub and have no original wheel to copy, any measurements would be gold.

Cheers Jason

[crabO]

Regarding your back wheel rebuild. I got a pair of SM Pro rims and spoke kit from John Titman Racing. They have the specs for 1980 RM250 wheels on file and drill the rims to fit. I got stainless spoke with Ni plated nipples and they fitted perfectly. I made up the wheels my self and they have survived several hours riding with minimal loosening. If you are going to do it yourself try to get a picture of an original wheel to study the spoke cross pattern. The rear rim is a 2.15 x 18. The space between the very widest part of the rim and the inside face of the swing arm is 50mm on the left and 48 on the right and I took that measurement from my stockers before I took they apart. I run a 110 tyre and the nobs clear the chain easily. Put some kind of guard inside the left rear shock or the chain will eat the spring. My chain looks to run straight with those measurements with no signs of uneven wear on either sprocket or chainguide.
Do a google for vintage Suzuki parts and several US dealers have parts diagrams with all the spacers. I was able to order several which all arrived in the original little plastic bags with a big red S on them.
Good luck