Rev and speed limiters

[Mick P]

Hi

I have read there is a speed ristrictor on the Dog set at 120/125 mph 190/200 kph?

Is this true and if so can this be changed?

Mick P.

[JörgG]

exact.
you can look here :
kb.php?mode=article&k=9

this are only in german but you can see same pic´s.
The white cable cames from the speed indicator, and must be
disconnected from the elctronic box.

[Axman]

Hi Mick,

it´s not a speed restrictor, but a Rev-Limiter (and it only kicks in in fifth gear) thus restricting your speed to about 185 kph in highest gear.

You can remedy this quite easily: after taking off the seat, the underseat-tray and the battery you´ll see a black, square plug connector. Cut the incoming, white cable (or try to get it out of the plug) insulate it properly, and...voila´...no rev-limiter any more.

The decision,whether it´s healty for your engine, is up to you. I use the engine´s full potential only on the Autobahn for overtaking...and I don´t spend a lot of riding time on the Autobahn..

What else have you changed ?

Should you have any more questions, feel free to ask.

cu Axman

[Mick P]

Hi

Many thanks for that just what I wanted to know.

I have changed the jets and air intake and removed the carb spacers, plus I have altered the standard exhaust.

My next project is to try to alter the gear ratio !!

Any thoughts on that?

Many thanks Mick

[Axman]

Hello Mick,

Why do you want to alter the gear ratios ??

To change the gear-ratios on a schaft driven bike like the Bulldog you would have to fabricate new gears - and they wouldn´t fit into the gear-housing anymore -

If you want to make your bike faster, the only way I can think of is classic engine tuning (boring the cylinders, new high compression pistons, bigger valves, new camshafts etc.) Are you sure you got the right bike ??

Haven´t you got a strict speed limmit in the UK ??

cu Axman

[Günter]

Hi all,

the only thing, I really want to change ist the gear ratio - not as mentioned above to increase the maximum speed but to decrease the level of revs.
It is not necessary for a bike like our's to run 70 mph with almost 4000 rpm. 3000 rpm should be enough.

Mick: If you succeed with your project, please give me a hint.

Günter

[Axman]

Hi Mick + Günther

whatever your reason to change the gear-ratios..the problem stays the same : it´s only possible by changing the gear sizes - and it doesn´t make a difference whether you change the driveshaft the driven gear or even gears in the gearbox..they won´t fit in the housing and, above all, the cost would be prohibitive.

Sorry guys..

cu Axman

[Günter]

Hi Axmann, hi Mick,

there is indeed a posibility to change the ratio that fits into the gear box - theoretically.
You have to change the ratio of the primary drive in that way that the larger the first gear wheel on the crankshaft the smaller the second one of the clutch. The distance of the axes has to be constant.
That is a well known method to change the ratio.
The problem seems to be that there are no gear wheels available.

Günter

[Mick P]

Hi All

Not looking for more speed just better rpm allthough the benefit is higher speed. Some times the dog just wants a 6 gear

I am thinking of changing the output gears from the gearbox i have looked into the gears on yamaha bikes with the same engin and i think thay are worse so thay might have to be made, but i know a man that can so it might not be so bad.

First i need some standard gears i take them to the man, tell him what i want, i fall over, think again, and say yes or no.!!

Mick

[Axman]

Hi Mick + Günther

tonight I spoke with a guy from Yamaha and it seems there may be a way to change the gearing of the Buldog..!

Apparently Yamaha has built quite a few different models with the same drivetrain as the Bulldog...but with different gear ratios !! So, if you find a Yamaha-dealer patient enough to leaf through his service-manuals (starting with thr TR1, XJ 900, XJ1100 etc..) maybe he´ll find a gearing that suits your needs..

Allegedly the housings are all the same (whether the length of the driveshaft is too, this guy couldn´t tell) at least it´s worth a try..

cu, Axman

[Snubbe]

I think this question has been a subject in this forum before. Anyway, does anybody know if it´s possible to change gearbox ratios in some acceptable way? The shaft, gearbox or is it primary drive wheel and clutsh wheel has to be changed to other size? I like this bike a lot but I am concerned about the engine everytime the rpm goes above 4-5000. It shold be lower rpm at 140 km/h.

Regards from Stockholm, Tomas

[jeriko]

Hi to Evrybody !!!
i'm new in the forum !
and i'm from Italy, i must say this is the best forum i found so far about our doggy !!
Sorry very much for my-self for do not understand German !!!!!

Anyway , i'm agry with Snubbe !
The byke should have 6 gear or higher ratio!!!
probably can also be changed the final ratio !!! not the gearbox but the final, if there is any final-ratio !!!!!
Especially after all exhaust change and the carbs modification, the dog ask more for hygher-ratio !!
We all should work for find a solution !!!!

[Mick P]

Hi All

Still looking at changing the ratio but so far I have looked into the ratio of most of the shaft drive bikes "Yamaha that is" and it looks like the dog has the best one at the back wheel so that looks like an of the shelf final drive is not going to happen, most of the other bikes get there speed via higher motor rpm and with straight four and v four motor this is not so hard, but I think the dragstar with the same motor is worse off than us. So I think it has to be 6 gears or the primary drive to do the middle gear all the motor has to come apart the same with 6 gears but just the side with primary gear I had hoped to pull a spare motor apart this winter but I will have to wait and see if I have time but I am still working on it

any info would be helpful

Regards Mick P