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Mick P: Rev and speed limiters (Montag 25. April 2005, 23:43)


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: (Dienstag 26. April 2005, 09:08)

you can look here :

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: (Dienstag 26. April 2005, 09:15)

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: (Dienstag 26. April 2005, 22:36)


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: (Mittwoch 27. April 2005, 12:38)

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: (Mittwoch 27. April 2005, 22:34)

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.


Axman: (Donnerstag 28. April 2005, 09:41)

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: (Donnerstag 28. April 2005, 21:20)

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.


Mick P: (Donnerstag 28. April 2005, 23:15)

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.!!


Axman: (Freitag 29. April 2005, 00:12)

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

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