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Fritz race engine has a smaller alternator pulley mounded on the inside of a single sided belt and uses that as a belt tensioner at the same time.

New engine


New engine
 
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Fast Eddie

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What kind of stator is shown in #7 ? I thought it went inside the pulley, but your comment seems to indicate there is a second alternator driven by the outside belt teeth. Anyway, I see your point about differential thermal expansion. The clutch hub will heat up with a large time delay to the crankcase and a different CTO to boot.

Couldn't the stator shown be made to supply all the current needed for a bike? I like the idea of having it inside the pully. Where have a seen something similar - was it on a HD?

- Knut
I assume you mean the smaller stator lying on the bench in post #7 ?
I presume that’s the very fancy looking solution from Fritz shown in post #61 (which really does look clever).

My comments were about the mounting of an alternator in the standard Vincent dynamo position. The standard set up works fine with a sprocket acting on the outside of the centre of a triplex chain adjacent to the clutch drum. But when I tried the double sided belt version of this, it was not a success, and I believe this was down to the issues I mentioned.
 
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118 Nm torque at 5300 rpm is a most impressing figure for a 2 valve engine. The power curve will remain high, actually it's rising all the way to 5800 rpm and probably well beyond. I am amazed! Tester probably ended the test at 5800 rpm to spare the freshly built engine.

For comparison, Triumph Truxton 1200 churns out 112 Nm @ 4250 rpm and it's an 8-valve motor w/EFI.

- Knut
Yes, the engine could probably produce a bit more power at higher rpm. The rpm limiter is currently set to 5800, valvetrain is calculated to work safely until 6000 plus some overrevving security in case of missing a gear.
 
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Nice one Buellingvincent, you must be rather pleased to say the least!

Can you remind us of the spec you ended up with?

And what you’re going to do with it?

That chassis of Fritz Jr looks purposeful and tidy.
1330cc. 100 mm stroke and 92 mm bore. Terry Prince Top End kits. Nikasil coated alu liners in Terry Prince muffs. CR 10.8:1.
TPV MK5 cams and followers, slightly re-machined and DLC coated.
Godet Magnesium cases. Flatslide Mikuni TM40 carbs. Digital crank pulley triggered ignition system from Ignitech (Czech company).
Fritz own designed two-stage oil pump (in place where the magneto normally sits), piston cooling jets, separator with coarse filter in std oil pump hole.
Bob Newby clutch and double sided 40 mm belt primary. 5-speed Quaife gearbox and a Newby double sided Belt driven Clutch. Alton alternator.
Wide chainline kit (Plate G50 and chain sprocket). Gas breathing valve inside oil tank.
 
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Yes, the engine could probably produce a bit more power at higher rpm. The rpm limiter is currently set to 5800, valvetrain is calculated to work safely until 6000 plus some overrevving security in case of missing a gear.
Excellent result!
Mk5 cams?
 

Fast Eddie

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Wow that’s some spec!

Hope you‘re gonna share the rest of the build progress with us?
 
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Excellent result!
Mk5 cams?
Yes on both! TPV MK5 cams and followers, but slightly re-machined by Fritz. According to him, Terry Prince did not make them exactly as Fritz had calculated using some special software. Both are now also DLC coated. Diamond-Like Carbon (DLC) is a process by a German company called Cewotec. Probably others do similar coatings.
 
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Yes on both! TPV MK5 cams and followers, but slightly re-machined by Fritz. According to him, Terry Prince did not make them exactly as Fritz had calculated using some special software. Both are now also DLC coated. Diamond-Like Carbon (DLC) is a process by a German company called Cewotec. Probably others do similar coatings.
I've heard that some of the Mk5s wore out very quickly, maybe that's why Fritz went with the coating.
Terry claimed that the MK5s he sent me tested RC 66, which is harder than stellite.
I took the engine apart to rebalance the crank at 1500 miles. The cams looked to be polishing up nicely, no actual sign of wear, nor should there be at 1500 miles.
I purchased a second set of these cams as they might be unavailable at some point in the future. I suppose that set could be coated if the first set gives trouble.
I can't see that they will at 66rc.
The good Norton cams are mid 50s RC, the soft ones more like 30rc iirc.
 
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