Remove the bevelshaft without dismounting the crankshaft?

[Jordan]

The reason for needing blue is that the teeth are curved, cupped as such. The convex side of one tooth needs to sit in the concaved side of the other, small sideways movement away from alignment will mean the teeth will drive on one edge, increasing load. When meshed correctly you will get a wide contact patch in the middle of the tooth.
...
Nigel

Thanks for the explanation, Nigel.
I'd not understood until now the significance of the cupped teeth shape, and why correct shimming isn't just about zero backlash with no binding.

Jordan

[machten]

Kev,

My last post may not have been that clear. I was trying to point out that the gear tooth geometry is quite sophisticated to achieve the the smooth transmission of rotation from one shaft to the next. The diagram and text I hope gave an appreciation of the problems in designing this geometry. If this is appreciated, I think it will counter any 'rough enough's good enough' attitude.

Yes. Thanks Stewart. Your diagram and explanation was most useful, I explored some more on those aspects afterwards and discovered a useful animation of helical gear enagagement and the involte curvse also for straight cut gears but I didn't save it unfortuately. I'll see if I can find it again.

Regarding Rocla's releiving of the bevel gear housing...well it's not what I would have done, but I'm comfortable splitting an engine. That being said, if I knew that modification had been made, I wouldn't be prepared to buy the bike. It seriously diminshes it's value for me and I suspect, many others.

And that being said....it may make no difference at all in engineering sense (I have no idea), I'd just rather split the engine and maintain the integrity of the design.

Just my opinion.

Kev

[Rocla]

Hi again...

I reiterate the question of my previous post (maybe my post was too long), I think it can better help me than anything: after the setting up, when my engine is running, there are 4 types of noises :
- the exhaust
- the inlet rocker (but very low)
- the exhaust rocker (very low too)
- and a new noise that replaces the clinking sound before : the sound of the bevel gears. It is a very soft and continuous noise, a kind of gentle hiss, not loud at all, that looks like the hiss of the Harley Davidson Electra Glide engines for instance.

I have some difficulties to analyse this sound: is it normal, a good clue, or on the contrary, a bad signal? Are bevelgears usually noisy? Which kind of noise is expected to be normal? Many thanks for your support

[machten]

It is difficult to give you advice on this. Given that you haven't heard the sound of good bevel matching before, it's a bit like trying to describe the colour red to a blind man (and I mean no offence by that!!). It's possible you are hearing the sound of imperfectly matched bevel gears (they were originally released from the factory as matched horizontal and vertical pairs). You can expect a well oiled "whir" noise, but not a high pitched "whine"that increases with RPM. Basically, I wouldn't expect to hear my bevel gears at all over all the other engine noises I'd expect to hear.

Kev

[Rocla]

Thanks Machten for your reply,

The sound I tried to describe seems to be somewhere between what you call a "well oiled "whir" noise", and a "high pitched "whine" but it doesn't increase with the rpm at all, just the frequency is changing but not the pitch. It is a soft noise, with a low intensity. It is more audible on the low speed engine

I am sure a specialist could tell me it it is a good noise or a not one... The noise summarizes everything. If it means that my bevelgears setup is too tighten, I dismount everything again, it is not a problem for me...

[DanM]

If you have a video recorder, you can record it and post it to You Tube.

[LaceyDucati]

Rocla

Whatevever the noise you describe is not normal for a Ducati single. As the noise was not there before you reset / changed the bevel gears, simple deduction should tell you it is probably the gears or something you have done. You should be able to deduce by listening using the hammers shaft as a stethoscope roughly where the noise is coming from and then you need to investigate.

Nigel

[Rocla]

Hello both,

To Lacey: as I wrotte, the noise was huge before, and now very low since I've changed the bearings, the ciclips, the bottom bevelgear and since I've setup all that stuff!
The simple deduction would have been not to be anxious, moreover the noise that I can ear from my engine is soft and steady, but I am pragmatic. Even if the noise was very loud before (with clinking sounds on the head cylinder, of course there was 1mm play on the camshaft bevel, as I wrotte before), it is not why the noise decreased significantly since my setup that this setup is absolutely perfect.

To DanM : right, it is a good idea, I will try to record the noise. I hope all the frequencies will be kept...

[Rocla]

Here is the video. The noise is a little bit modified by my video recorder but don't forget it is recorded very close to the engine (the engine is not really noisy in comparizon with other videos on youtube).

You can ear the rockers, the exhaust (especially when the microphone is in the back or the bike) and the hiss I am speaking about. At the end of the video, I've accelerated the engine.

http://www.youtube.com/watch?v=kBRBlJTy ... e=youtu.be

[Bevel bob]

Sounds a bit whiney, but so did my very fast new Mach 1.Did you find the article by Roy Creasey on bluing the gears?. By the way, a bad bearing is not fired---its shot!, a subtle difference.Nice looking bike.