Ask an Engineer

[Grumph]

Firstly the disc carrier - fercrissake make it with some decent blending radii - avoid sharp section changes like your example pictured.

Sprocket carrier - the Honda style drive pins on the sprocket are a royal pain when it comes to changing gearing if you only have one set.Removing from one sprocket and putting into the next usually requires a vice to hold them....not fun at the track.

I'd put studs into the carrier and retain the RS sprockets with nylocs myself.

Everybody is right - for this application you don't need a cush. If you did or if you're being stubborn (bloody coaster)...what I've done previously is holesaw abt 35mm holes in the sprocket and use urethane bushes with large top hat alloy retainers held on with a countersunk capscrew. If you're short of space outboard of the sprocket this only comes out about 3mm from the sprocket face.
If you're not short of room, again,studs and nylocs.

[schrodingers cat]

Right not everyone knows this but all the late era MV Augustas (the Real MV's that finished in the 1970's) actually had aluminium alloy disk brake rotors.
I know many have experimented with plated and plasma coated aluminium alloy disk rotors without success.

MV supposedly had no trouble with the plain aluminum alloy rotors but what alloy might they have used and what sort of pad material would be suitable.

yes i realise an MMC material would be probably better but does anyone have any ideas?
I are picking that it would have to had a high silicon content....

Sprint car guys use alloys discs on occasions. How about starting your research there?
Mind you, why do you want an alloy disc?

[Grumph]

Right not everyone knows this but all the late era MV Augustas (the Real MV's that finished in the 1970's) actually had aluminium alloy disk brake rotors.
I know many have experimented with plated and plasma coated aluminium alloy disk rotors without success.

MV supposedly had no trouble with the plain aluminum alloy rotors but what alloy might they have used and what sort of pad material would be suitable.

yes i realise an MMC material would be probably better but does anyone have any ideas?
I are picking that it would have to had a high silicon content....

Just to finally clear this up - and stop Hus wasting time searching the net.....they were Harry Hunt plasma sprayed discs usually on Morris mags - bought as a package deal from California.
Harry kept his methodology close to his chest...it was believed there was a high bronze content in whatever he sprayed onto the alloy and he never said what alloy he used either AFAIK.
I think Harry may be dead now....

[husaberg]

Just to finally clear this up - and stop Hus wasting time searching the net.....they were Harry Hunt plasma sprayed discs usually on Morris mags - bought as a package deal from California.
Harry kept his methodology close to his chest...it was believed there was a high bronze content in whatever he sprayed onto the alloy and he never said what alloy he used either AFAIK.
I think Harry may be dead now....

Remember guys, i now have a mild steel Chinese disk made from recycled Woks............
the Works BSA and triumphs used aluminium disks that were sprayed (with some sort of steel)
from 1970 on but cast iron rotors were used for the long races to aleviate overheating (classic racer winter 88)

Firstly the disc carrier - fercrissake make it with some decent blending radii - avoid sharp section changes like your example pictured.

Sprocket carrier - the Honda style drive pins on the sprocket are a royal pain when it comes to changing gearing if you only have one set.Removing from one sprocket and putting into the next usually requires a vice to hold them....not fun at the track.

I'd put studs into the carrier and retain the RS sprockets with nylocs myself.

Everybody is right - for this application you don't need a cush. If you did or if you're being stubborn (bloody coaster)...what I've done previously is holesaw abt 35mm holes in the sprocket and use urethane bushes with large top hat alloy retainers held on with a countersunk capscrew. If you're short of space outboard of the sprocket this only comes out about 3mm from the sprocket face.
If you're not short of room, again,studs and nylocs.

Yes us coaster are stubborn
it will have a nice radius like the fillet on a crank.I was too lazy to draw a pic...........
I are undecided the cush and more undecided about the pins. Some yams have the built in stud as part of the cush drive bush.
i have not measured the pins i have but i are guessing the RS sprocket holes are 2mm larger anyway.
with the STD Honda pin i put a spanner on them to remove them (They have a flat) but now there is no wreckers. i shudder to think what Honda would want for them new if i was to purchase 4-5 sets.

[Ocean1]

with the STD Honda pin i put a spanner on them to remove them (They have a flat) but now there is no wreckers. i shudder to think what Honda would want for them new if i was to purchase 4-5 sets.

I'm with everybody, the massive torque hammerstroke from an F4 combustion stroke doesn't warrent a cush.

If it did, I'd weld home made pins to every sprocket, the only thing you need to change one then is circlip pliers.

[ducatilover]

I got one!

Are two 6-8mm ish plates of alloy going to be strong enough for the front engine mount on my GN/DR600 thing...

And Bogan, I should have them covers done by tomorrow after milking takes a bit long with the indented stuffs because I haven't got the dremel up here

[bogan]

Got the aformentioned spline shaper going today, see me other thread for details.

And Bogan, I should have them covers done by tomorrow after milking takes a bit long with the indented stuffs because I haven't got the dremel up here

Chur, rather you than me with that shit! And me frame/swinger and a few pairs of rearsets are waiting for a good polish whenever you get tired of pulling tits...

[Ocean1]

I got one!

Are two 6-8mm ish plates of alloy going to be strong enough for the front engine mount on my GN/DR600 thing...

Plenty. In fact I'd be looking for areas to make big holes. If there's spacer tubes involved I'd use some heavy washers against the alloy or the compression will distort the surface and they'll work loose.

[husaberg]

I got one!

Are two 6-8mm ish plates of alloy going to be strong enough for the front engine mount on my GN/DR600 thing...

And Bogan, I should have them covers done by tomorrow after milking takes a bit long with the indented stuffs because I haven't got the dremel up here

Plenty. In fact I'd be looking for areas to make big holes. If there's spacer tubes involved I'd use some heavy washers against the alloy or the compression will distort the surface and they'll work loose.

I am no engineer (that's for sure)
but one thing you must do is make sure the tread on the engine bolts are the correct length so the shank only bears against the alloy plates. Other wise it will wear the holes in the alloy plate bigger in no time, then it will vibrate, and then wear the holes bigger, etc, etc.

That's a tip from old pommy specials like Tritons.

[Brian d marge]

Sorry due to time I'm only able to the quick flippant reply
I flick through this thread , one minute brakes , now we are on to engine mounts , for a 150 four stroke ?
How much vibration and how much polish do we want
And what engine frame combo?

Steel and reamed holes is a good practice but as u may have read of people putting big singles in a alloy frame , the load , vibration paths weren't considered and it vibrates too much
Give me some calculations ,,,,,,:-) :-) :-) :-) ,,,
Stephen

[ducatilover]

Got the aformentioned spline shaper going today, see me other thread for details.



Chur, rather you than me with that shit! And me frame/swinger and a few pairs of rearsets are waiting for a good polish whenever you get tired of pulling tits...

Choice, I'll pick 'em up one of these days

Plenty. In fact I'd be looking for areas to make big holes. If there's spacer tubes involved I'd use some heavy washers against the alloy or the compression will distort the surface and they'll work loose.

I am no engineer (that's for sure)
but one thing you must do is make sure the tread on the engine bolts are the correct length so the shank only bears against the alloy plates. Other wise it will wear the holes in the alloy plate bigger in no time, then it will vibrate, and then wear the holes bigger, etc, etc.

That's a tip from old pommy specials like Tritons.

Cheers chaps!

Sorry due to time I'm only able to the quick flippant reply
I flick through this thread , one minute brakes , now we are on to engine mounts , for a 150 four stroke ?
How much vibration and how much polish do we want
And what engine frame combo?

Steel and reamed holes is a good practice but as u may have read of people putting big singles in a alloy frame , the load , vibration paths weren't considered and it vibrates too much
Give me some calculations ,,,,,,:-) :-) :-) :-) ,,,
Stephen

150cc?
Mine's a 589cc (currently...) in a shit steel frame I want lots of polish, that's all I know... mine's a DR600 in to a GN250

[pete376403]

To save a bit of weight my bro-in-law made an aluminium rear disk for Bruce Ansteys TZ years back. It was only ever used in scruitineering.
when Bruce was on the brakes in a race the back wheel was usually off the ground anyway.

Oh and Kawasaki used plasma sprayed ally disks on the H2Rs back in the day

[husaberg]

Decent foundry to cast ally cylinders in CHCH is...............
From a very well made professional spec mold.
Add in costs if you know them 2kg.one of 1-20 there of........
I seriously want to do it out of old pistons Bert style but it's not a deal breaker

[koba]

I got one!

Are two 6-8mm ish plates of alloy going to be strong enough for the front engine mount on my GN/DR600 thing...

And Bogan, I should have them covers done by tomorrow after milking takes a bit long with the indented stuffs because I haven't got the dremel up here

Again, I'm no engineer but a big single in a small frame is going to be interesting.
Have you got a build thread?

[pete376403]

Take a look at a speedway bike as an example of "big engine minimalist frame" Engine plates on those are 6mm aluminium