Hi there after much searching I have finally found a bike to ride now I have passed my A2 test (pre 19th January) I am restricted to 33bhp and have bought a honda vf400f 1983 model. I am aware that in 1983 this bike was 54.5bhp and am wondering if it is likely that it is now below the 33bhp limit? If it is above and I fit a restrictor kit to the carbs will this automatically lower it to 33bhp or take it below? (found a kit on ebay aparently matches the nc21 specs) What I mean is if the kit is designed to restrict to 33bhp does it matter what the engine size started out at? as obviously I would not want it to fall below the 33bhp (to be honest after riding it home I haven't got the heart to restrict at all, but I don't want any risks with police etc)
Honda vf400f and 33bhp
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I doubt that a bike that produced 54 bhp when new would be kicking out less than 33 now - unless it had some serious issues. Even allowing for the fact that manufacturers often used to exagerate their bhp claims in those days (because it looked good on the spec sheet and sold bikes) it is still likely that you bike will exceed the 33 bhp limit. The easy way to check is to run it on a dyno.
As for the restriction kit - the documentation that comes with it should state what power the bike produces with the kit fitted. If it doesn't, then it is not any use to you.
when the kit is fitted the only why to know for sure is to get a dyno test and see if the rear wheel is at 33bhp.
Would be completely Irrelevant, the DVLA/Police etc go by the manufacturers figures not a dyno's. You'll need to get it restricted which gets you a certificate proving it then spend two years never having it checked (unless you're involved in an accident that's your fault or you behave like an utter Pillock & get caught doing so!).
With this in mind I Know quite a few people who have removed the restrictors once they got the certificate of restriction & others who didn't bother getting them restricted at all, none of whom were ever caught.
I am certainly Not advocating any law breaking here you understand, just making you aware of what I've heard/seen
The Decision (as they say) is yours!
Congrats for passing btw & Happy Riding
If History has taught us One thing....
It's We've learnt None of Histories Lessons!
to disagree with AC.
The read out from a reputable Dyno Test centre is more than enough proof for a police officer at the roadside as it will show actual figures on the day of the test rather than figures given by a manufacturer of the restrictor kit.
Manufacturers of engines only give average figures as do the producers of restriction kits.
So to have positve figures for your bike is undesputable.
As for riding without the restrictor, if caught you could face a loss of licence, and when you return to biking an increase of premiums, and if you already drive a car it will have an impact on those premiums as well.
assumption is the mother of all f*** ups.
i made a kit for my bike and fitted and never got the paper work as it was not needed. to big home made washers.
as they the police hav to prove your bike is not at the right bhp.
are complete hogwash. They're not 'official' transcripts noting that the bike is restricted, the law doesn't recognise them in the slightest, they're just an excuse for the restrictor kit manufacturers to fleece you.
If it came to it, the police would strip the bike down to check the washers have been fitted (and the bike IS restricted) if they had considerable reason to believe the bike was not.
Otherwise they couldn't give a monkeys.
Thank you all for your help, really appreciated
Thank you all for your help, the only thing I am really concerned about is that the restriction will take it well below 33bhp if the bike has lost say 10bhp. Then there is the issue that I would need to fit restrictor, then dyno test, then if it is over repeat the process. All in all a very expensive way of doing things! Will I notice a considerable difference in performance with the restriction? given that I am a new rider and only used to a 125 anyway.
On a side note, does anyone know if the nc30 restrictor will fit an nc13 engine? the guy who makes the restrictors on ebay seems to think it will act the same (restrictor for a vfr400)