256 Cam in 447 Engine - Best Way to Install?

[eazyrider]

I've got the cam from my XS1 that I'd like to put in my new 447 build but I'm not sure how to go about swappin the sprockets.

• Do I just pop them off and reallign it(matching the original sprocket timing mark position on the 256 cam)?

OR

• Will it need to be degree'd before pressing it back on?

Any advice is appreciated.

 

[gggGary]

Haven't done it but yeah what I've read is it's a bit trial an error on a one off sprocket swap. Press n check.

 

[MaxPete]

Haven't done it but yeah what I've read is it's a bit trial an error on a one off sprocket swap. Press n check.

@eazyrider - it is good that you recognize the issue with the sprockets - but this is not (AFAIK) a commonly done swap, so proceed cautiously as piston-valve clearance on XS650s in not generous and they are interference engines.

Certainly, swapping a 256 cam in without switching the sprockets will absolutely not work - even for an instant.

 

[Jim]

You press the sprockets off and back on. If I have to remove the sprocket to degree it, I'm gonna heat the sprocket with a torch first, during the install. But yeah, try as you might, getting it right the first time boils down to luck. I'm sure I'll have the sprocket off several time before I get it right.
Have a read here. https://www.xs650.com/threads/jims-speed-twin-build.54889/post-718263

 

[MaxPete]

I suggest you follow @Jim on this one @eazyrider - he is an expert.

This one rates:

Pete

 

[eazyrider]

Haven't done it but yeah what I've read is it's a bit trial an error on a one off sprocket swap. Press n check.

Certainly, swapping a 256 cam in without switching the sprockets will absolutely not work - even for an instant.

You press the sprockets off and back on. If I have to remove the sprocket to degree it, I'm gonna heat the sprocket with a torch first. But yeah, try as you might, getting it right the first time boils down to luck. I'm sure I'll have the sprocket off several time before I get it right.
Have a read here. https://www.xs650.com/threads/jims-speed-twin-build.54889/post-718263

I suggest you follow @Jim on this one @eazyrider - he is an expert.

This one rates:

Pete

Thanks for the quick responses guys.
I'm gonna give it a shot then and play with it til it's right. Fingers crossed and prayers prayed that I get it close the first time lol

@Jim that write-up is perfect, exactly what I was lookin for. Appreciate ya!

@MaxPete agreed, Jim is the man.

 

[Jim]

I amended my comment above to reflect I'll be using heat to install the sprocket, not for the removal of the sprocket. It presses off fairly easily, so there's no need for heat. Pressing back on however, can crack the flange of the cam if it's pressed on with too much force. It's all in the comments in the link above.

 

[5twins]

This is something mrriggs was good at, so I P.M.ed him and picked his brain about it. Yes, you press the sprockets off as Jim did, but you don't press them back on because, as Jim said, you run the risk of going too far and breaking the flange. Instead, mrriggs told me to freeze the cam and "bake" the sprocket to heat it up. I was going to put it in a toaster oven for, like, 45 minutes at 400° or so. Then he said you simply drop the sprocket on the cam. It should slide right on the frozen cam being that it's heated (and expanded). Then you'll have, like, 30 seconds to a minute before it cools and tightens up to move it around and get it perfectly aligned.

 

[MaxPete]

This is something mrriggs was good at, so I P.M.ed him and picked his brain about it. Yes, you press the sprockets off as Jim did, but you don't press them back on because, as Jim said, you run the risk of going too far and breaking the flange. Instead, mrriggs told me to freeze the cam and "bake" the sprocket to heat it up. I was going to put it in a toaster oven for, like, 45 minutes at 400° or so. Then he said you simply drop the sprocket on the cam. It should slide right on the frozen cam being that it's heated (and expanded). Then you'll have, like, 30 seconds to a minute before it cools and tightens up to move it around and get it perfectly aligned.

….and that is, almost certainly how Yamaha installed the sprockets back in the day.

 

[Its been a long time]

If you have access to one, a bearing induction heater would be perfect for getting that sprocket nice and warm.

 

[eazyrider]

This is something mrriggs was good at, so I P.M.ed him and picked his brain about it. Yes, you press the sprockets off as Jim did, but you don't press them back on because, as Jim said, you run the risk of going too far and breaking the flange. Instead, mrriggs told me to freeze the cam and "bake" the sprocket to heat it up. I was going to put it in a toaster oven for, like, 45 minutes at 400° or so. Then he said you simply drop the sprocket on the cam. It should slide right on the frozen cam being that it's heated (and expanded). Then you'll have, like, 30 seconds to a minute before it cools and tightens up to move it around and get it perfectly aligned.

Hell ya thanks for that! This is what I'm gonna do then.