Screaming Primary Gears, noise fix

[misteright1_99]

dumb question, but gotta ask.

What would prevent the noise in the first place ?

Probably a thicker cover, or a better metal...I think the noise is resonance(sp?) coming from the cover....

 

[BoltsMissing]

I was thinking along the lines of the actual gear material itself. There does not seem to be any of that shiny case hardened on the teeth of the gears.
Ofcourse, this would add to the cost, but..,less noise at source level.

 

[Phil_McCracken]

The primary is so noisey because of the cut of the gears, if they where helical cut they would be quieter, I just put a layer of silicon inside mine, some oil in there would also quieten it down, pity its not a wet clutch.
The barrel fins make a racket to, you can chock them, see Ghosts pic. I used fuel hose. (see pic) both of these mods make for a way quieter engine.

 

[Snax]

Der, what phil just said.

 

[fastboy9]

The primary is so noisey because of the cut of the gears, if they where helical cut they would be quieter, I just put a layer of silicon inside mine, some oil in there would also quieten it down, pity its not a wet clutch.
The barrel fins make a racket to, you can chock them, see Ghosts pic. I used fuel hose. (see pic) both of these mods make for a way quieter engine.

These gears are what are called straight-cut gears. On a car the gears usually mesh at a slight angle, making it quiter. On high performance transmissions and race cars, the gearboxes are straight cut. Much more noisy but there is less friction therefore less power loss.

 

[BoltsMissing]

On high performance transmissions and race cars, the gearboxes are straight cut. Much more noisy but there is less friction therefore less power loss.

So the HT is considered as an ambitious piece of machinery.

 

[Phil_McCracken]

Lol dunno about ambitious, probably they made them straight cut for ease of manufacture, or they just copied somthing else, a lot of motor cycles have straight cut primary gears, though some also have helical, some even have a chain.
Straight cut gears have more direct application of force, so yeah less drag and also have a higher failure point.
When you watch the touring cars you hear that high pitched whine, thats the gear box, all straight cut, jump in your manual transmission car and reverse, you hear the whine, they make reverse straight cut and some of the older cars with partial syncro box's had straight cut 1st.

 

[BSA]

Lol dunno about ambitious, probably they made them straight cut for ease of manufacture, or they just copied somthing else, a lot of motor cycles have straight cut primary gears, though some also have helical, some even have a chain.
Straight cut gears have more direct application of force, so yeah less drag and also have a higher failure point.
When you watch the touring cars you hear that high pitched whine, thats the gear box, all straight cut, jump in your manual transmission car and reverse, you hear the whine, they make reverse straight cut and some of the older cars with partial syncro box's had straight cut 1st.

Straight cut sounds cheaper as well, that's the only reason why the Chinese engines have it.

BSA

 

[BoltsMissing]

Yeah I know all that stuff Phil,( admitedly I forgot, been years since working)
but when I look at a HT overall and compare apples with apples, it's obvious the steel and alloy mix is low quality, and fair enough ya get what ya pay for, ain't complaining.

But IF those gears have straight cut, high quality finish, hardened etc etc, then it ought to reduce that whine significantly.

Heck, I'd go for the helical gears and work on the engine's other standard issue nigglers to compensate power loss from helicals.
At least there will be no noise at the source, rather than band-aid methods we gotta put up with.
Or the HT gurus can offer a choice, straight cut for the speed freaks, or helical for the cruisers.
Personally I'd go for cruise.

 

[blime81]

Thanks for the cardboard tip bluecollar..... Did it last night and couldn't believe how much of a difference just a piece of cardboard could make!