So Jim, how about them there timing gears?

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BrianK

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Jim, any update on availability and cost of your gears? I apologize for buggin' ya (the other guys here put me up to it! - no, actually, I'm about to put on an automatic camchain adjuster, which I'll delay/belay if your gears are coming out soon). Thanks. - BrianK
 
Well I have learned that putting a date on things that aren't ready yet is not a good idea. So far I have only built prototypes on a manual machine, but I did buy the rest of the tooling to do them on the CNC this week and a couple of pieces of bar stock. I still have one jig left to build. Should be ready to cut the first few gears in the week after I return from Lake O the Pines on the 7th. Then they have to be hardened and trial fit and any fine tuning to the CNC machine can then be done. If everything goes right the first time [doubtful] they could be ready in a month. It will more likely be a couple months barring unforseen problems . Jim
 
I don't want to slow you down but would it be feasible to incorporate some kind of slot, cast into the outside of the gears that would align and allow a flat "key" to lock the gears for torquing the cam nut and oil pump drive nut (and prevent us from jamming a screwdriver into the teeth to do same)?
 
I may be able to put something there to hold the cam gear to torque the cam nut. Torquing the crank nut would require holding the crankshaft.Torquing the crank nut by holding the camshaft or intermediate gear would apply a dangerous amout of stress to the unsupported intermediate gear spindle and may cause case damage. Jim
 
comnoz said:
I may be able to put something there to hold the cam gear to torque the cam nut. Torquing the crank nut would require holding the crankshaft.Torquing the crank nut by holding the camshaft or intermediate gear would apply a dangerous amout of stress to the unsupported intermediate gear spindle and may cause case damage. Jim
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This might be an ignorant question but if you hold the crankshaft and tighten the crank nut, once that's tightened wouldn't it then hold the camshaft gear while you tighten the cam nut?
 
Sure, but if you are holding the crank and tightening the cam you are still applying a lot of force to the intermediate gear pinion which is not supported when the side cover is off. Jim
 
Also if you put a shaft into the balance holes on the crank it rests against the thin casting above the cam which isn't the strongest part of the engine case. Both the crank and cam nuts can take a lot of force to get off sometimes so it's nice to have other options. You can support the rods through the small end along the top of the cases too but it's hard to tell if you have the support nice and square and equal. It's nice to have some options in different situations.
 
Well the first short run of timing gears has been cut, hardened and tested. They came out slightly softer than the original timing gear but well within range. The next test was a stress test. The original pinion gear failed at around 1000 lbs pressure. The new gear failed around 4000 lbs. so I guess I don't need to worry about tooth failure. Now on to cutting the jigs for machining multiple gears at a time and getting the indexing worked out. May have some gears available in a few more weeks. Jim
 
Good to hear, Jim. Winter project time approacheth here in New England!

Then again, the economy sucks so funding for said projects is, um, thin....!
 
Durability tests have yet to be done but I would expect them to last as well as the original crank to intermediate gear does and that's pretty much forever. Jim
 
The first run of timing gears has been done and tested but I was not happy. They had noise problems at certain speeds due to harmonics that I had never noticed on a noisy racebike but sounded pretty trashy on a streetbike. With a second design I used a different tooth design and a bearing with less clearance that only made a small improvement. I am now on a third design that uses a ball and ramp loaded idler gear to eliminate all backlash. I finished up the first three sets this week and plan on having one installed this afternoon. If it works as planned that will just leave figuring out how to manufacture the preloaded gear in a method to make it affordable. Jim
 
The new anti-backlash timing gears now have 200 quiet miles on them and show no distress. Wish it was warm here so I could do some major miles. James

So Jim, how about them there timing gears?


So Jim, how about them there timing gears?
 
Could these be developed to mate with a starter motor in the old magneto position, likely to be easier than adapting the primary side.
 
comnoz said:
The new anti-backlash timing gears now have 200 quiet miles on them and show no distress. Wish it was warm here so I could do some major miles. James

Very nice indeed :!: :!:

Comnoz why is the extra intermediate a three piece gear :?:
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Yes, I am working on a gearset to put the starter back on the timing chest. That is what got me involved in this.

The idler gear is three pieces with ramps cut in the sides. Ball bearings fit in the ramps and the three gears are pressed together with a wave spring which causes the teeth to be offset and take up the backlash. This is what keeps the gears from rattling at certain speeds and is why this has turned into more of a project than I expected. James
 
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