Kawasaki 750 hard tail (was rear end ratios)

[kapri]

Meanwhile back to axle ratios , don't forget it is overall gearing that is important so the tyre diamter is very important .From memory Regal /Supervan ran on 13" rims and later Robin / Rialto ran on 10" rims. If you are sticking taller rims still on it you will lose performance and a gear ( effectively) ie The OVERALL ratio will be so tall that pulling of in 'trike gearbox first' will feel " Reliant car second gear' .

[minimutly]

Hi and welcome 
Perhaps the following Reliant info From my site might help .
...................................................................
AXLE RATIOS ;

AXLE ; STANDARD RATIO { 850cc } ; ..... 3.23
{ The Crown wheel has 42 teeth and the Pinion has 13 teeth}
...........................................................
AXLE ; HIGH RATIO { 850cc } ; .... 2.78
...........................................................
AXLE ; STANDARD RATIO { 750cc } ; .. 3.545
{ The Crown wheel has 39 teeth and the Pinion has 11 teeth }
...........................................................
AXLE ; FOX RATIO; .... 4.11
...........................................................
AXLE ; REGAL SPLIT CASE TYPE ; .... 4.354
...........................................................
STAMP MARK ;
A = 3.23 { The Crown wheel has 42 teeth and the Pinion has 13 teeth }
X = 3.23 { The Crown wheel has 42 teeth and the Pinion has 13 teeth }
No letter = 3.23 { The Crown wheel has 42 teeth and the Pinion has 13 teeth }
B = 2.78
L = 3.545 { The Crown wheel has 39 teeth and the Pinion has 11 teeth }
F = 4.11

Well the marking on the axle is FW40C6, my tippex  rolling test showed it to be 3.23:1, as near as I can tell.
I took it to a local track this morning, 70mph is not quite cruising, and I dont have a rev counter, but it feels about right, it pulls like  a train, despite the added weight of the back end. Any higher and 1st would be too high, any lower would create a screamer. Wheels are 15 inch with lowish profile rubber - just checked, 195 50 15s.
The front end woble all but dissapears over 40mph, looking at the front tyre I would say the odd wear pattern on it could be a factor - does it need to be a round profile tyre, surely a flatter profile would be better?
The ride is diabolical, certainly not enjoyable, but I guess taller tyres with less pressure would improve that. Going round corners leaning the wrong way takes some getting used to...
At 6ft6, it looks way too long, especially now I've chopped off the rear bench seat, also the front bars are turned in too far, on a long spin it would be murder on the wrists.
Plenty to think about.

[Olds]

Lot of debate over tyres. I can only say what works for me.
 At the front I changed to a 19" (Austin 7) car tyre rather than the usual sidecar fitment as it had higher load and speed ratings. Changed the handling slightly ( less flop at very slow speed ).Never had any wobbles, but the forks are quite raked. The main gain was increased contact patch / better braking and steering in the wet.
At the rear I have 205/50x15 tyres. These are run at 13 psi. Ride is a bit jarring at slow speeds, but gets better with speed ( go fast everywhere ) I do however have a sprung seat
It takes a while to get used to riding a trike and wide bars are a good way to go.

[terry t]

Huw  what the steering, rake and trail on your trike. to much will cause steering wobble, heavy steering, pulling straight when going round a roundabout hard on the arms
I run on a 19" flat profile front tyre with 28psi. and rear tyres 205/55/15 35psi soft tail with no shake or heavy steering mind you I only have 45mm trail

[minimutly]

Good question, I have plans to take some measurments, it will need a spirit level and laser level, but needs doing. I'm a bit confused about rake,and trail, not sure what the target settings should be. I would like to see more rake on the forks, but this will put more strain on the headstock, as well as the forks. I've read more rake is good to reduce wobble, but too much creates it?

This lead me to thinking of girders, then leading link, however, where do you mount the calliper?
I'll try to take some measurements first, no point rushing into anything. The front tyre has worn unevenly around the zigzag cut, which on its own could be causing some wobble. To my mind a flatter front tyre would be better, what's the point in having a bike front tyre?
Need to sort out the easy stuff first, I wont be cutting up the frame until I have the irs ready to weld on. I would also like a single silencer, which means a 4 into 1 collector and some pipe bending and welding.
Huw

[ByzMax]

2 inches of trail on a Trike is about perfect. Girders or leading links will allow a cool looking rake and maintain the 2 inches of trail.

Brake calliper on leading links is mounted on the front axle with a bracket. This must be fully floating. Tat means it should be able to rotate freely when the axle/wheel spindle is done up. You then secure it with an arm that runs from the leading link fork leg. It should run parallel to the leading link arm.


On girders, mount the calliper straight to the leg.

[digger06]

Meanwhile back to axle ratios , don't forget it is overall gearing that is important so the tyre diamter is very important .From memory Regal /Supervan ran on 13" rims and later Robin / Rialto ran on 10" rims. If you are sticking taller rims still on it you will lose performance and a gear ( effectively) ie The OVERALL ratio will be so tall that pulling of in 'trike gearbox first' will feel " Reliant car second gear' .

well put, thats what i was TRYING to say....

[minimutly]

Good point about overall ratios, I now know I need a 3.23 or lower diff ratio, lower will allow me to run bigger wheels, I'd like 16 or 17s to balance the front/rear look, but its not the end of the world
I know, pics would be nice...

Big thanks on rake /trail info, there is a lot of conflicting stuff out there, maybe because of the bike/trike difference, so its good to here what actually works.
 
Huw

[kapri]

Other way round taller numerically ie 4.1 will , for the same tyre size will rev higher and lower top speed, as you add diameter to it so the top speed will get higher . So (for demonstration only ) 4.1 WITH 13" TYRES = say 18mph per 1000rpm, 4.1 with tall 15" tyres = around 21 mph/1000rpm ,both quoted in 1:1 ratio gear.

What overal speed per rpm are you trying to get back to ? I'd recomment slightly lower than standard bike to make up for extra weight if you want to maintain same performance as stock bike.

[minimutly]

No, a lower diff ratio - lets not get into numrically vs actual- I'm talking a lower ratio, will allow me run larger wheels. Simple as that. If I cant get a lower ratio then I'm stuck with the 15s and tyres I have now. One thing I do know, the 3.23 I have now, combined with the existing wheels gives an ideal overall ratio.
Thanks,
Huw

[scannerzer]

which i believe is how mr kapri's example works out

[minimutly]

Well that was an anticlimax, v5 turns up today, it's taxation class tricycle, no weight recorded, nothing else of note other than in special notes it states it was registered/used overseas and declared manufactured 1983, registered in 97. If dvla know any more about this why not state it in the notes ?
Also, how does the mot tester know the weight for testing, is there a rule that if nothing is recorded it falls in the lower/higher? It surely must have been inspected in 97?
Pooo!
All the best,
Huw

[BikerGran]

What does it say for Make and Model?

[minimutly]

Make kawasaki, nothing down for model...
Huw

[BikerGran]

Oh well clearly properly registered as a trike anyway!  Not sure that my trike V5 says anything about the weight either.