New front stops (cam chain guides) Beta test sale

Hi Bill,
better yet, stay with the chain (or even a toothed belt) on one side so it'd be fixable without having to pull & dismantle the motor.

I donno, the bevel drive is a gear drive. On cars such gear drives often last 100,000 to 300,000 miles. That's a lot of fixing that never needs doing.

Besides, on an XS, even replacing a timing chain requires that the engine comes out of the frame, does it not?
 
I would like to have a Hy-vo chain. Stronger and long lasting.
 
I would like to have a Hy-vo chain. Stronger and long lasting.

And wider! The pistons would have to be further apart and the XS650 engine's rocking couple is bad enough as it is.
Putting (whatever kind of) cam chain drive on the OUTSIDE of the engine instead of up the middle would make it feasible to swap the chain without pulling or dismantling the engine
 
And wider! The pistons would have to be further apart and the XS650 engine's rocking couple is bad enough as it is.
Putting (whatever kind of) cam chain drive on the OUTSIDE of the engine instead of up the middle would make it feasible to swap the chain without pulling or dismantling the engine
A stock XS has ZERO rocking couple, but pretty bad primary and secondary imbalance. A rephased XS or a Honda twin is different. Kawasaki were the first japanese bikes with outside cam drive
 
There *could* be enuff room in the camchain tunnel to fit a gear train column.

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The camchain adjuster could be modified to adjust an idler gear fore/aft, to tweak timing...
 
like 2M sez, Honda used gear cam drives in the high perf versions of the 750 V4's That might be a hint, after a chain it's hard to beat gears for skinny.
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These are the intermediate gears cam and crank gear not pictured. Note loaded split gear to reduce whine, an integral feature of straight cut gear sets.
But you could swap out a cam chain 10 times from running to running quicker than you could build one custom cam drive. With the factory racing stud mod you could change the chain without removing the motor or even the carbs, getting it down to a one hour job with practice? IMHO the chain is easily good for 20-30K miles. Seems like there was a Euro guy that really racked up miles and he did top jobs at about 60K intervals.
If you want to get fancy methinks the factory design could readily be modified to accommodate an adjustable front guide allowing for easy external cam, crank indexing. Those two threaded front guide mounting inserts changed to longer threaded pieces with locknuts instead of fixed heads, done.
 
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like 2M sez, Honda used gear cam drives in the high perf versions of the 750 V4's That might be a hint, after a chain it's hard to beat gears for skinny.
View attachment 158919
These are the intermediate gears cam and crank gear not pictured. Note loaded split gear to reduce whine, an integral feature of straight cut gear sets.
But you could swap out a cam chain 10 times from running to running quicker than you could build one custom cam drive. With the factory racing stud mod you could change the chain without removing the motor or even the carbs, getting it down to a one hour job with practice? IMHO the chain is easily good for 20-30K miles. Seems like there was a Euro guy that really racked up miles and he did top jobs at about 60K intervals.
If you want to get fancy methinks the factory design could readily be modified to accommodate an adjustable front guide allowing for easy external cam, crank indexing. Those two threaded front guide mounting inserts changed to longer threaded pieces with locknuts instead of fixed heads, done.

The wheels are turning in my head. Blew my engine recently, got a build to do.
 
A stock XS has ZERO rocking couple, but pretty bad primary and secondary imbalance. A rephased XS or a Honda twin is different. Kawasaki were the first japanese bikes with outside cam drive

Hi arctic,
YES. It's 180º parallel twins that have a rocking couple.
The XS650 engine is a 360º parallel twin which, balance-wise, is a single and NO, you can't balance a single.
What I was trying to say was that IF the cam drive was on one side or t'other instead of up the middle it could
perhaps be accessed without pulling & dismantling the engine.
 
Hi arctic,
YES. It's 180º parallel twins that have a rocking couple.
The XS650 engine is a 360º parallel twin which, balance-wise, is a single and NO, you can't balance a single.
What I was trying to say was that IF the cam drive was on one side or t'other instead of up the middle it could
perhaps be accessed without pulling & dismantling the engine.

Yes a "single" where only half the engine fires at a time!

Could be why even my Sportsters vibrate less at some speeds than the XS650! At least the Harley pistons hit top center 45º apart!
 
Yes a "single" where only half the engine fires at a time!
Could be why even my Sportsters vibrate less at some speeds than the XS650! At least the Harley pistons hit top center 45º apart!
Then you should try out a 90 degree V twin. Like a Ducati, Suzuki SV or a Guzzi. Minimal vibes at all normal riding rpm on a Ducati. A bit snatchy below 3k, then just sweet until 6-7k. I could cruise my M600 all day at 6-7000 rpm without any issue. That would be 130-150 km/h or 81 to 94 mph.
 
Don't know about the Goose or the Duck, but one reason that vibes on the SV650 aren't so harsh is that it has a counterbalanced crank.
 
Hi arctic,
YES. It's 180º parallel twins that have a rocking couple.
The XS650 engine is a 360º parallel twin which, balance-wise, is a single and NO, you can't balance a single.
What I was trying to say was that IF the cam drive was on one side or t'other instead of up the middle it could
perhaps be accessed without pulling & dismantling the engine.

A belt drive cam on the left side of the engine has been done: https://xs650chopper.com/2009/03/daves-custom-650/
 
Never been a fan of belts on an interference engine.

indeed. A bit of a recipe for disaster.

Sort of, like certain Opel and European Ford engines, which had some really shitty design features.

Not a problem on properly maintained Toyota and BMW car engines. And Honda GW or Ducati engines for that matter.
 
Totally agree on the financial commitment point Gary. It is well worth supporting these folks and I sure hope that people do. I am not in the market for timing chain guides, but if I was, I’d give them a try.

I wonder if these folks would take on the starter hair clip and do one that is both thick enough to last and the correct dimension so as to provide reliable starter engagement. If they did that, I would pick up half a dozen just to have some spares.

Pete
 
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