Derestricting Jap Import Vmax

[bigcadwolf]

I 've bought a 98 Japanese import Vmax. I gather these are restricted so not on full power. I beleive there is an exaust modification I need to make, but what exactly do I do?
What other modifications do I need to make?. Do I need to change the vboost?.
I have a workshop manual on CD however is there a paper workshop manual available available. The PDF version seems to be focused on a complete strip down and not general servicing etc.
Any help appreciated.

BIGCADWOLF

 

[shawn kloker]

I have heard the diaphrams are different.No vboost.Smaller jets.Not sure about the exhaust being different though.

 

[diggerzmound]

I read somewhere claiming that there were stops on the vacuum slides that could be removed.

 

[gleno]

I 've bought a 98 Japanese import Vmax. I gather these are restricted so not on full power. I beleive there is an exaust modification I need to make, but what exactly do I do?
What other modifications do I need to make?. Do I need to change the vboost?.
I have a workshop manual on CD however is there a paper workshop manual available available. The PDF version seems to be focused on a complete strip down and not general servicing etc.
Any help appreciated.

BIGCADWOLF

Here are three responses by European users from Ingo's World that tell you how to bypass the Janaese restrictions. (at least this worked for them).

Speed restriction on the japanese model #01
by Morten, Jun. '98 I'm a danish Max'er with a 1990 Jap-home-model. It's been fitted with the original Yamaha V-boost (of course!), 'cause without the boost it's not "The Real Thang", right? I have a problem though....

My Max is still limited at top speed 190 km/h. Do you know how to get rid of that limitation? I've tried to open the speedometer, but it's one whole encapsulated plastic "house"....so that you can't tamper with the milage I guess. Some say, that the top-speed limitation is in the speedo, and other says, that I need to get an ignition-advancer to get the full potential of the bike. I don't know where to turn! There's no limitation at all at the revs - it boosts from 6.000 rpm to the redzone like it's supposed to. But you know in 5th. gear your "flying" with app. 180 when it turns open, but at 190 (homemarket models have this sorry speedo..) it turns off until the needle hits the mark 190 again and you fly on... Hmmm !

Can you help me? I hope so. Ya' see, not many know much about our beloved Mr. Max here in Denmark. Hope to hear from you or others !

Multi-Max Greetings
Morten "MadMan" Valbj?rn


The Solution

Earlier I tried this HELP-site to find out how to get rid of the Speed-restriction on the 1990 Jap-homemarket model....

The answer came from VMax-club Norway...
One is to buy a "Speed-Restriction Modification". It is to be mounted in the headlight. It's a small box which goes between to wires to cheat the electrical system. I haven't got hold of one yet,so I can't tell you much more about it, yet. You should be able to fit it in app. 5 minutes with the use of a screwdriver - niiiice!

Where to get it?
Speed & Dyno Shop, Oslo Tel. (00)47 6706 0882 (9:00am-12:00am)
Cost: 2614,- Nkr.

See ya' Morten "MadMan" Valbj?rn

​

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Speed restriction on the japanese model #02
by Morten, Aug. '98​

Well after a while I also got this e-mail from greece:

> I' ve seen your problem with Speed-restriction on the 1990 Jap-homemarket model and I own a 85 model vmax.
>
>Try to do a very simple move. Take a small piece of thin cable and sort circuit the tiny capsule in the speedometer with a soldering station, or take it away from the hole that sits. This capsule is nothing but a magnetic switch that opens and closes with a frequence depending on how fast you drive. This thing is the only device that the CPU knows your current speed. When i asked an authorized technician of Yamaha here in Greece told me the same things plus that the capsule is enabled in some models in Greece that came from Japan and disabled in models came from USA.

>Try to think logical before you spend money buying black boxes that someone wants to sell.

>Regards
>Menos, Thessaloniki/Greece
Morten​

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Speed restriction on the japanese model #03
by Morten, Mar. '99​

Hi Again MadMan's back !
This time with the absolute cheapest way to get rid of the speedrestriction !

Cut the Speedo open with a small saw - now you have access to everything - but DON'T TOUCH THE COUNTERS (shame on you !) Anyway...You will find a printed circuit. On this is mounted a two-legged magnetic switch, that works with the electronics. On the back of the speedo-needle a disc with two different diametres is mounted. On idle - one end of this disc is between the two legs of the switch. When running, the disc is turned away from the switch untill you reach 190 km/h. Then the other end of the disc reaches in between the switch, blocking the circuit...This activates the restriction (puts out one or two of the cylinders). Take a pair of cutting nippers...he-he-he.... Remove the 2/3 of the greater disc opposite the idle-position. Now the disc is still between the switch on idle but the rest is looong gone = Full Throttle available ! (Nothing's blocking the switch) YEEEHAAAA ! Off ya' gooooo into the sunset....(without having screwed up the elcetrical system).

Well, it took me some time, but finally - IT'S HACKED !
Thanx to the ones, that tried to help - especially Menos, Greece who has been great inspiration to the fiddle-fingers....
See ya' out there !
Morten, DK​

 

[gleno]

If the restrictive controls for 'full-power' are in the speedo head you could try swapping the speedo head with a U.S. speedo? See what difference that makes before hacking a solution.

You should also check your exhaust system. Some Japanese Vmax exhausts have a much smaller exhaust outlet. I'm not sure if this is always the case because it may vary between years models.

 

[gleno]

On re-reading my earlier posts I can see they deal with speed restrictions but may not address the issues of horsepower restrictions.

I'm making further inquiries through a grey importer and I'll let you know what I learn about the derestricting the Jap model.

 

[gleno]

After asking around this advice was provided by Kevman on the OZ Vmax Club forum

"ok after hours and hours on the net i have found that there is a protrusion on the diaphram 12mm from the top which can be removed .the full power cdi number is 3jp-82305-00-00 ,the non vboost is 3lr-85302-12-00. red line is 9500 and 8500 and the final drive ratio is different"

It would appear that engine internals are the same as full power version for both models.

 

[maleko89]

I believe they're limited in top speed too. There's something in the speedo and/or ignitor....if I recall correctly. Try vmaxchat.com, a lot of those guys have converted their Vmaxes to full power.

Mark
#1098

 

[Buster Hymen]

I believe they're limited in top speed too. There's something in the speedo and/or ignitor....if I recall correctly. Try vmaxchat.com, a lot of those guys have converted their Vmaxes to full power.

Mark
#1098

Mark, I remember reading it also from someone that derestricted their import. There was an electronic limiter in their speedo housing. I'll see if I can find where I read that.

 

[shawn kloker]

Do you mean the Japaneese were afraid of their own creation?They never do well in racing either.

 

[gleno]

Mark, I remember reading it also from someone that derestricted their import. There was an electronic limiter in their speedo housing. I'll see if I can find where I read that.

See my post in this thread dated 05-12-2007, 09:57 AM which discusses this workaround.