Topic: Building of a CB500 classic racer

[scottly]

He says now , when you have drained the oil after the engine was opened and fill it again, always remove the oilpass plug on the left side under the crankshaft, then starting without ignition on till the oil comes out the plug.
So you are sure that the oil is everywhere in the engine.
Nexs time we do it this way.

Are you familiar with "pre-lubrication" techniques, using an external oil pump, or oil from a sealed canister pressurized with air, tapped into the oil gallery somewhere? This way, oil can be forced into the whole system before the motor is ever turned.   

[Howell]

He says now , when you have drained the oil after the engine was opened and fill it again, always remove the oilpass plug on the left side under the crankshaft, then starting without ignition on till the oil comes out the plug.
So you are sure that the oil is everywhere in the engine.
Nexs time we do it this way.

Are you familiar with "pre-lubrication" techniques, using an external oil pump, or oil from a sealed canister pressurized with air, tapped into the oil gallery somewhere? This way, oil can be forced into the whole system before the motor is ever turned.   

No , I don't know this techniques.

[scottly]

maybe this will help..http://www.carcraft.com/techarticles/ccrp_0906_budget_pressure_luber_build/index.html

[Howell]

Yesterday the 'new' crankshaft was ready , now I can rebuild the engine for the next season.
First picture , above the old one with the blue heated conrods and the new one .

[turboguzzi]

Yesterday the 'new' crankshaft was ready , now I can rebuild the engine for the next season.
First picture , above the old one with the blue heated conrods and the new one .

That was quick! from David Silver spares?

Good luck with the build, you will sure know better what and what NOT do now
TG

[Howell]

Yesterday the 'new' crankshaft was ready , now I can rebuild the engine for the next season.
First picture , above the old one with the blue heated conrods and the new one .

That was quick! from David Silver spares?

Good luck with the build, you will sure know better what and what NOT do now
TG

That was indeed very quick , that's when the tuner is your friend.
I have learned another lesson.

[Howell]

I have bought a new rearset from a guy of germany.
Homemade and excellent work.
They rotate on small bearings.

[Howell]

Yesterday the 'new' crankshaft was ready , now I can rebuild the engine for the next season.
First picture , above the old one with the blue heated conrods and the new one .

The engine is again ready to install in the frame.
But before doing that I refurbished the complete frame by sanding it and making some reinforcements with my new Mig welding machine.
I made the reinforcements the way Turboguzzi did and some more around  the stearing head.
I did this because sometimes we had handling problems , wobling and shaking.
Another tool I bought is an secondhand lathe/mill combination, I had an old chinese lathe with to much mechanical clearance.
Today I sprayed the frame with a black Hammerite paint.
First a picture of the welding machine and lathe/mill.

[Howell]

Pictures of the refurbished and reinforced frame:

[Howell]

Pictures of the refurbished and reinforced frame:

[Howell]

Another thing we will try to get a better handling is a longer swingarm.
We used a swingarm with the same length as original but I had still another longer swingarm from a CB750 F2.
This swingarm is two centimeter longer as the one we used.
I had to weld new brackets for the shocks on it and made new bushings to fit the rearwheel.
This swingarm is a little bit wider at the end.
Now we have the choise between two swingarms.
Another reinforcemnet I want to do is to make an alu bracket on the breather cover just like Turboguzzi did.
(thanks for the drawing TG)
But before doing that I have to install the engine in the frame.
See the picture of TG's bracket.

[bwaller]

I think the interesting part will be determining whether or not the handling is improved by eliminating all potential "flexing areas". Believe me when I say that I don't know the answer, but like everyone else, I've read that no flex may not be the answer either. Maybe this thought applies more to modern chassis design than these?

Steering head & swingarm area would seem to need to be stiff. I always liked the idea of reamed fit engine mounts, which would especially help the swingarm. TG's head steady made sense to me too.

Too bad we need to wait until spring to see what your work has accomplished.

Nice job.

[Really?]

I wanna watch

[turboguzzi]

Hi howell

nice work

some comments though

I think that the bracing near the rear bottom engine mount on the left is where the chain passes... check it out.

not much a believer in bracing towards the rear  seat frames, as you essentially bracing against a tube that has nowhere to transfer the forces to, but that's my engineering logic....

one last little tip, weld a bracket between the top, rear left engine mount and the sheet bracing so it doesnt bend.

[bwaller]

TG did you use a later model CB750 swingarm in the end?

[turboguzzi]

no, didnt got around to... but if i did it would be a K's which is supposedly SHORTER than a 500's = quicker steering.

dont have one to measure or confirm the theory but i seen it on a friends bike...

how's the sun down there?

TG

[bwaller]

Yea the earlier K arms are shorter.

Weather may not be too hot the next few days, bikini's may be on hold. 

[Howell]

A Merry Christmas and a Happy New Year to all the readers of this thread:

Christmas]http://www.youtube.com/watch?v=OEIMFrSrKoY] Christmas

[Howell]

Hi howell

I think that the bracing near the rear bottom engine mount on the left is where the chain passes... check it out.

Indeed the brace touched the chain I grinded some metal off it.( you made the same mistake TG ?)
The engine is back in the frame so I now could make the alu plates/brackets on the top of the breather cover to the upper frametube.
They are a little bit different from those Turboguzzi uses.
They are mounted directly against the upper frametube with a stud, a spacer and a nut, see pictures.

[turboguzzi]

rene, in my bike i also have a teflon chain slider at this point that raises the chain above the triangle bracket and it also helps keeping more constant chain  tension.

since i run quite a strong angle of swingarm, without it the chain becomes too slack when the suspension is fully open.

its a bit like they use in off-road bikes.

[Howell]

rene, in my bike i also have a teflon chain slider at this point that raises the chain above the triangle bracket and it also helps keeping more constant chain  tension.

since i run quite a strong angle of swingarm, without it the chain becomes too slack when the suspension is fully open.

its a bit like they use in off-road bikes.

Hi Yossef,

With the longer swingarm now we have also a strong angle of it.
How did you make that tensioner ? I was already thinking about to make one.
I have already made a teflon guideplate on the uppersite of the swingarm.

[Howell]

rene, in my bike i also have a teflon chain slider at this point that raises the chain above the triangle bracket and it also helps keeping more constant chain  tension.

since i run quite a strong angle of swingarm, without it the chain becomes too slack when the suspension is fully open.

its a bit like they use in off-road bikes.

After Turboguzzi came with the idea of a chain tensioner , I have made one this afternoon.
Therefore I used the roller and bearing of an old CB750 primary chain tensioner.
On the paddockstand it works , I hope also on the track.

[voxonda]

Hey René,

Did you consider the 'old' ATK system? Are you familiair with that? It contained a roller above and under the pivot of the swingarm. Kept the chainslack even on shocktravel. Must have a article about it 'somewhere'.

Cheers, Rob

[Howell]

Hey René,

Did you consider the 'old' ATK system? Are you familiair with that? It contained a roller above and under the pivot of the swingarm. Kept the chainslack even on shocktravel. Must have a article about it 'somewhere'.

Cheers, Rob

Hey Rob,

I know that system  a little bit complex to make that , but this took only two hours to make it.


gr.René

[turboguzzi]

hei rene,

thats nice, some dirt bikes have it too, but is this robust enough?

i would make that wheel fixed instead of spring loaded

my solution was just a big chunk of white nylon (or teflon?), like 5cm wide that i bolted to the bracing bracket, will send you a pic.

TG