ESE's works engine tuner

[FastFred]

reed engines don't need really long rods 54 stroke reed engine 110mm is perfect. No real advantages for going that long.

It is a NSR250 MC21 cylinder grafted onto a rotary valve Suzuki GP100 bottom end. The motor needs a long rod so as to be able to fit an adapter plate for mounting the cylinder.

From all accounts with the long rod and 12mm extra width in the cases and the old super large transfer ducts in the original GP cases this engine should be exploring the outer limits of of crankcase volume. Hopefully TeeZee will post the crankcase volume and CR figures.

Reed engines like a crank case com ratio of about 1.3:1 but TeeZee is all about maximizing the case volume on his RV engine. I guess if anyone was wondering if there is an upper limit for case volume on rotary valve engines then I guess we are about to find out.

[Grumph]

Here You go.

I have a question unrelated to Rob engine. Could someone point me some directions what to do with frame (bracing) and suspension when bike starts to wobbly on the road under hard acceleration and after passing 115km/h it's dancing all around the lane? There are no free play in bushings in swing arm as they are new and front suspension was maintained (new oil , seals everything is within spec , forks are from GN250) wheels are new ones. Any info would be appreciated

Here is pic of the frame

If you're using leading axle GN250 forks, you may have insufficient trail for stability at speed. Quick test is to reverse the fork legs so the axle is behind the leg and try it. This will give a major increase in trail and inherent stability. If it still wobbles, use another frame....

[J.A.W.]

Here You go.

I have a question unrelated to Rob engine. Could someone point me some directions what to do with frame (bracing) and suspension when bike starts to wobbly on the road under hard acceleration and after passing 115km/h it's dancing all around the lane? There are no free play in bushings in swing arm as they are new and front suspension was maintained (new oil , seals everything is within spec , forks are from GN250) wheels are new ones. Any info would be appreciated

You are absolutely certain that the wheels are accurately aligned in the same track?
One track vehicles wont go straight when the wheels don't line up ( unless its got one of 'em - off the ground..)

[TZ350]

TeeZee is all about maximizing the case volume on his RV engine.

The traditional transfer duct is like "A", the one on the left, where the transfer duct length extends down into the crankcase and the transfer duct entry window is well down in the crank case.

But because the original GP transfers are much wider than the NSR110 cylinder I was wondering about making the transfers like "B" on the right. Because of the significant change in volume it would effectively shorten the transfer duct proper and add volume below the new transfer duct entry window which is now at the cylinder part line.

Shorter transfer duct and more volume at the entry, could this be a good idea? ....

[wobbly]

You can try the short duct in EngMod, along with a change to better "rounded" entry conditions to the duct if its not
already specified as such.
I dont know if the alternative larger entry vol will be of any benefit, remember there is no "flow " from the case into the cylinder
when the ports are open.
And make sure to put the ball nose radius on the bore/duct entry joint corner.

[peewee]

hey guys am i correct in thinking these engines have 3 forms of heat transfer ? conduction as the combustion and friction heat passes through the cylinder to the water jackets and forced convection as the water carries heat to the radiator and the radiant heat given off at the engine exterior

[peewee]

And make sure to put the ball nose radius on the bore/duct entry joint corner.

it also appears he has a bullnose on the transfer roof / bore. i think either frits or jan said a sharp edge would lessen exh gas backflow into the transfer passages

[J.A.W.]

hey guys am i correct in thinking these engines have 3 forms of heat transfer ? conduction as the combustion and friction heat passes through the cylinder to the water jackets and forced convection as the water carries heat to the radiator and the radiant heat given off at the engine exterior

+ Latent heat of evaporation from fuel/air mix passing through.. & this has to be compensated for - with DFI 2Ts..

[marsheng]

I purchased 2 YZ250 rods. The ProX has a w cage and the HotRods has a plain cage. Guess I'll use the HotRods one.

I have now have to machine the webs for the wider rod and I though I would check the whole arrangement before machining. What clearance is normal for between the crank and the casings ?

Cheers Wallace

[Frits Overmars]

What clearance is normal for between the crank and the casings ?

Not less than 1 mm all around, taking axial movement of the crank into account as well.

[husaberg]

Not less than 1 mm all around, taking axial movement of the crank into account as well.

Frits is it possible or worthwhile, to convert cranks to the pressed in Bronze or was it brass washer sleeve (as below) while he's at it allowing him to delete the washers?

Bearing In mind he's an engineer with a well equipped workshop.

[Frits Overmars]

Frits is it possible or worthwhile, to convert cranks to the pressed in Bronze or was it brass washer sleeve (as below) while he's at it allowing him to delete the washers?

Bearing In mind he's an engineer with a well equipped workshop.

Sure it's possible (it was bronze, not brass). But then I would go one better, forget the pressed-in washers and have the insides of the crank cheeks flame-sprayed with bronze. This offers the same friction/lubrication properties and it does not require cutting (thus weakening) the press fit area.

[husaberg]

Sure it's possible (it was bronze, not brass). But then I would go one better, forget the pressed-in washers and have the insides of the crank cheeks flame-sprayed with bronze. This offers the same friction/lubrication properties and it does not require cutting (thus weakening) the press fit area.

So you can delete the washers then? because that would stop him needing to machine the crank I think.

[Frits Overmars]

So you can delete the washers then? because that would stop him needing to machine the crank I think.

Yep

Better now?

[husaberg]

Yep

Better now?

I opened that MSG I can't see PNGs without opening them in a new tab
that should work out for Wallace than as I think the rod he has is about 2mm wider so deleting the washers might work out for him.