My New Bitsa - Quiz time!

[Rob Farmer]

The bings should be fine. Do you know what main jet you have in there? Looking at the setup you have you should have a 160 main jet, needle on the third from top notch, 2.66 needle jet and 45 idle jet. This assumes nothing's worn.

check the diaphragms. It sounds like you may have a split in one of them. 3.5k is around 60mph which sounds about right for a torn diaphragm.

They do two sizes in ate front calipers, you will need the 40mm ones. A handlebar master cylinder will go a long way to sorting your brakes out. Perfectly acceptable mod among people who want to ride them.

I'm a bit confused about what you want out of this bike you seem to be planning changes to help boost the value but will still have a light flywheel 1000. To be worth decent money your going to need a heavy flywheel r90s engine and gearbox.

 

[markjackson]

The bings should be fine. Do you know what main jet you have in there? Looking at the setup you have you should have a 160 main jet, needle on the third from top notch, 2.66 needle jet and 45 idle jet. This assumes nothing's worn.

check the diaphragms. It sounds like you may have a split in one of them. 3.5k is around 60mph which sounds about right for a torn diaphragm.

Cheers Rob I'll check the jets at the weekend, but the split diaphragm was the kind of thing I was imagining as I've had similar feelings with sticky slide/leaky chamber SUs on old cars. I could hold 65, but overtaking cars doing 65 was like being back on my old SS50

 

[markjackson]

They're all the same from the early 80s. Check the bevel box, it should be a 33:11. If your really lucky it will be 32:11

I'm lucky

Except for the wheels, obviously

 

[markjackson]

I'm a bit confused about what you want out of this bike you seem to be planning changes to help boost the value but will still have a light flywheel 1000. To be worth decent money your going to need a heavy flywheel r90s engine and gearbox.

My thoughts are still developing but either:

"Standard looking but better performing"

Or "near standard"

Are appealing. The problem with the latter would (I imagine) be finding the right cases and having a worse gearchange. Are the cases rare/expensive?

I was also told that it may be 900 barrels on 1000cc top end, so will need to check.

 

[Rob Farmer]

I'm lucky

That's known as the autobahn gearing. Good stuff

Yes 90 bottom ends are pretty rare. The cranks have a different throw to the 1000.

Is there a 90 stamped on your barrels need to where they join the crankcase? 1000cc bikes have a 10 stamped on them.

I was going through my swag today. I have a pair of wires to suit an ate front end and decent set of twin disc ate sliders and internals but no tubes.

Does your swinging arm have a well defined waist on it or is it a thick tube the full length of the driveshaft? I've 5 early swinging arms and driveshafts.

 

[markjackson]

Is there a 90 stamped on your barrels need to where they join the crankcase?

I was going through my swag today. I have a pair of wires to suit an ate front end and decent set of twin disc ate sliders and internals but no tubes.

Does your swinging arm have a well defined waist on it or is it a thick tube the full length of the driveshaft? I've 5 early swinging arms and driveshafts.

The barrels have a stamp that I thought was 96, so it sounds like 900cc.
I'm certainly interested in the wires and forks, if you want to drop me a PM on the costs.

I'll check swingarm tomorrow.

Ta!

 

[markjackson]

check the diaphragms. It sounds like you may have a split in one of them. 3.5k is around 60mph which sounds about right for a torn diaphragm.

Good trouble-shooting! one was perfect, and….

One looked like this!