Offset front sprocket clearance issues on GS400

[Guest]

I am in the parts gathering/planning stage of the suspension overhaul on my 1980 GS400.

I will be running a 4.5in rear wheel with a 150 tire.

Now I will have the hub of the rear wheel machined to bring the sprocket as close to the 150 tire as I safely can.

For now, my bike is running a 120 and it clears the chain just fine in stock configuration.

150-120 = 30 30/2=15. So there needs to be 15mm difference between what I am running now and what I'll be running next year.

I am also going to convert to a 520 setup so that will help me gain some clearance.

So I need a front sprocket that will have about 15-17mm offset when compare to the stock unit.

I have been searching the forum and I have yet to find any onfo on front offset sprockets.

I'm just curious to know if the chain case will need to be machined any.

Hopefully the chain doesnt rub on the frame either.

So does anyone on here have any experience with an offset sprocket on our litte twins?

[pete]

You could be entering uncharted territory here... I've never seen anyone mess with the chain drive on the twins before. I've seen front ends swapped around, but never the rear wheel...

Might even be worth posting this in the tyres and suspension forum to get input from the guys who have done this work on the bigger bikes...

[jfman]

You could be entering uncharted territory here... I've never seen anyone mess with the chain drive on the twins before. I've seen front ends swapped around, but never the rear wheel...

Might even be worth posting this in the tyres and suspension forum to get input from the guys who have done this work on the bigger bikes...

I'm having a tough time even finding a 520 offset sprocket. Seems they are mostly 530's and up(for drag bikes)

Guess I'll have to tearin into it to find out.

[323D]

where did you end up with this

[Agemax]

where did you end up with this

considering the last post to the thread was almost 9 months ago, my answer would be "nowhere"

[jfman]

ended up buying a 530 and gonna get it machines down some to match a 520.

Project is coming along allright. Gonna post up some new pics soon.

[Agemax]

A 520 chain has a roller width of 6.35mm, and the 530 has a roller width of 9.52mm, so you are only saving 3.2mm. is it really worth the extra cost of machining when you can buy an off the shelf 530 sprocket?

[Mekanix]

Could make one.

Other options would be to swap the output shaft for one from a 500 and have all the options made for the 500 in the 520 chain variety.

[jfman]

Ran into somewhat of a roadblock today.

The 5/8 offset sprocket touches the actuator assembly for the clutch.

I wonder if there is a way around this?


I may have to go to a 3/8 offset sprocket...

Do you know what the GS500 guyz do to solve this?

[Mekanix]

take the assembly out and have the case machined down a bit and refit the assembly. Then just screw the adjustment in a bit more to compensate.

or shim the whole casing out just a bit with washers.

[intrigue175]

Not sure if this helps but you can buy 520 sprockets all day that will fit for im betting, any Suzuki on here. I say this based on reading many other people doing the conversion to include myself on my 83 GS1100 79 GS425. All just took a small amount of research at the bike shop with sprocket manuals. That includes offset ones like i have on the 83 GS1100. 3.2mm is a lot of space.

Good luck mate,