Jump to content
Sign in to follow this  

DRZ400 SM Sluggish/Slow after restriction

Recommended Posts

Hi all, I have a DRZ400SM, and have got it restricted due toot he 33BHP UK Law. I was riding it around for a few days without the restriction and it was fun! Now it is really slow and will only pull about 60-65MPH and takes a while getting there...! I used to get 94MPH out of it!!! Is there anyway of making it go faster? I dont have much knowledge about mechanics etc. so explanations would help :bonk: Thanks guys Sam

Share this post


Link to post
Share on other sites

You willingly had your bike restricted , due to UK law . Surely you must realise the only way to make it go faster is to derestrict it ? :bonk:

Share this post


Link to post
Share on other sites

How is the 33BHP measured? These bikes only make around that stock, so what the heck is it making if it only does 65mph? Is this for a certain class of license or what?

What was done to limit its power?

Share this post


Link to post
Share on other sites

there be a washer between your carb and airbox boot, as above there putting out about 33 bhp any way!

the only way they could test it is a dyno,

so take it out just keep hold of the certifcate if anyone ask's :bonk:

Share this post


Link to post
Share on other sites

It is 33bhp max. When you have a lighter bike you are penalised with a bigger restriction. Pathetic uk law. I did a lot of homework for when my sons license was restricted and found the GSXR400 GK76A one of the best options for power to weight, also very cheap to insure. You can put up with a slow bike or ride illegally.

Share this post


Link to post
Share on other sites

From Merriam Webster Online.

Main Entry: re·stric·tion

Pronunciation: \ri-ˈstrik-shən\

Function: noun

Etymology: Middle English restriccioun, from Anglo-French restriction, from Late Latin restriction-, restrictio, from Latin restringere

Date: 15th century

1 : something that restricts: as a : a regulation that restricts or restrains <restrictions for hunters> b : a limitation on the use or enjoyment of property or a facility

2 : an act of restricting : the condition of being restricted

I think that 1b fits this situation.

Share this post


Link to post
Share on other sites

The UK official DRZ restrictor is a replacement carb top that prevents the slide fully opening.

That said it should not make much difference to top speed.

You need to check that the restrictor was fitted properly, I would guess either the carb top has not been fitted as it should be (missing "O" ring), or a vacuum hose etc. has been left disconnected by mistake.

Neil. :bonk::bonk::ride:

Share this post


Link to post
Share on other sites

Thanks all for replies

The UK official DRZ restrictor is a replacement carb top that prevents the slide fully opening.

That said it should not make much difference to top speed.

You need to check that the restrictor was fitted properly, I would guess either the carb top has not been fitted as it should be (missing "O" ring), or a vacuum hose etc. has been left disconnected by mistake.

Neil. :bonk::bonk::ride:

Thanks neil. Shall i just check all connections? how do i get the standard carb top?

How is the 33BHP measured? These bikes only make around that stock, so what the heck is it making if it only does 65mph? Is this for a certain class of license or what?

What was done to limit its power?

Thats waht i was thinking. 33bhp shouldnt make it go 65! Its for a restricted licence, which is the maximum licence you can have under 21 in the UK

Share this post


Link to post
Share on other sites
Thats a ridiculous law!!!!! Luckily we dont have any of that BS law here.

oh , theres a lot worse than that over here, sayin that, it may be likely its fitted wrongly as someone has said,

if it did 94 before , why not try re gearing it so it pulls better?

Share this post


Link to post
Share on other sites

Just curious, does this apply to motorcycles only? Coz im also a member at ek9.org (civic type R forums) where most members are from UK. Most of them mods the hell out of their cars. never heard of any restrictions.

Share this post


Link to post
Share on other sites
Just curious, does this apply to motorcycles only? Coz im also a member at ek9.org (civic type R forums) where most members are from UK. Most of them mods the hell out of their cars. never heard of any restrictions.

As long as you declare the modifications to the insurers then should be fine....and yeh the restriction is just for bikes :bonk:

oh , theres a lot worse than that over here, sayin that, it may be likely its fitted wrongly as someone has said,

if it did 94 before , why not try re gearing it so it pulls better?

I GOT IT FIXED :bonk::bonk::bonk:

basically got my mate to look at it. The air pump at the top of the carb was detached. He just put it back on and the bike is the same as how it was before it was restricted....wonder if it has been restriced slightly :S

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×