530 chain conversion

[Steve R]

Talking to Steve Debben today and have decided to convert to a 530 chain, to reduce weight and cos its stronger etc.

But I think I am also going to lower the gearing as well, as standard they are geared for about 150 mph at the red line in top and I reckon if I lower the gearing to give a top speed of say 130 mph then the acceleration lower down will be that much better ? I know the fuel consumption will suffer a bit, but with the miles i do that should not really matter, what do you think?

[Pigford]

My Black Zed does about 130mph at just over 9000 rpm.....

Ideal for me..... and I got a good 45 mpg on a run up to the ACE a couple of years ago... Motorway & steady 70 mph, 1075 with 36 mikuni's

[Ginger Bear]

Don't mention gearing, it's my current bug bear!!
No seriously, I would do it. You wouldn't seriously try and get a zed to go at 150
Don't 'undergear' it too much, remember these Zed motors are full of torque.

[Steve R]

130 is what I am aiming at, how many teeth front and rear are you running? does it make much difference to the acceleration on its own do you reckon?
Have you had yours on a Dyno? I am putting 1075 kit on also, hoping for about 90 bhp at the rear wheel.

[Steve R]

"You wouldn't seriously try and get a zed to go at 150"

Have done in the past 20 odd years ago, P and M full race spec 1105 engine with 29mm smoothbores, regularly off the clock on the M1 in the secure knowledge that nothing the cops had could catch you and they certainly couldnt read the tiny numberplate that flapped up at speed!!!

[Ginger Bear]

Bloody hell Steve!!!

Was that with standard frame/forks/wheels & brakes

[Pigford]

Steve, my bike makes 90bhp on the dyno..... but it was running weak last time & I've tweaked her a bit since then.....

I'm running 15/36 with a 630 chain

It runs 11.5 @ 116 mph on the 1/4 which is good enuff for a reliable old barge of a bike

[Steve R]

Thanks for that Pigford, I thought you were on a 530 chain on your bike, no doubt debbens will be able to help. Apart from the carbs and 1075 kit what else is done to that engine to get 90 bhp at the wheel?

No GB, definately not standard, it had braced frame, taper head bearings, H**** 900 forks and front brakes, lester alloys , dresda swing arm , marzoccki shocks and an idiot that thought he was immortal clinging on to it with a big f#####g grin on his face!!

[Rich]

1075, 29 sbores, K&Ns and race exhaust will get 90 at the rear wheel. No other mods needed

[Steve R]

Its getting hold of a set of smoothbores thats the problem though.

[Robw]

Try John Browse, he had stacks of carbs on the shelves when I went to visit him.

Rob

[Pigford]

Thanks for that Pigford, I thought you were on a 530 chain on your bike, no doubt debbens will be able to help. Apart from the carbs and 1075 kit what else is done to that engine to get 90 bhp at the wheel?

Only other thing is gas flow.......I think the cams are std?, but not sure.... Forgot to check them last time I did a valve clearance check

[Rich]

17 / 37 will give 135 at 9K

[Steve R]

Is that with a 530 chain Rich? Is that what you are running?

[Rich]

Yes that is for 530, It's all in the ratio, it doesn't matter what chain you are running, but you won't fit a 17 630 in! For strength a top spec 630 is stronger, but for smoothness and less centrifugal force on the sprockets a 530 is better. Try to keep the sprockets at an odd number of teeth as the wear is more even. 16/60 17 rear tyre, when new will give 78 at 5K.