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SOHC.co.uk Forums => CB500/550 => Topic started by: MIKE550/4 on May 26, 2011, 09:00:06 AM

Title: is it possible to restrict an f2 to 33hp
Post by: MIKE550/4 on May 26, 2011, 09:00:06 AM
been taking lessons on a 125 ,if  i pass my module 2 , i have this f2 ready to go

i also have a 125 but would like to take the 550 out every now and again just to get some experience on it

purely asking to see if it possible
Title: Re: is it possible to restrict an f2 to 33hp
Post by: SteveD CB500K0 on May 26, 2011, 09:31:28 AM
In theory you can restrict anything by merely restricting the amount of air that flows through the inlet.

As the 550 only made 50bhp when it was new, restricting to 33 should be fairly easy.

Easy that is if you have access to metal fabricators. You'd need restrictor plates for the carb inlets.

Then you'd need a "certificate" from a dyno to prove the output.

Then you'd need to convince your insurance company that it is kosher.

Is it 33 at the rear wheel? It's probably not far off that now!
Title: Re: is it possible to restrict an f2 to 33hp
Post by: MIKE550/4 on May 27, 2011, 08:05:58 AM
well no access to metal fabricators, a forum member on here has told me a dealer could possibly use a "kit" to restrict the carbs

and i take it you would then get a print out as evidence to prove this ? ie dyno results
Title: Re: is it possible to restrict an f2 to 33hp
Post by: SteveD CB500K0 on May 27, 2011, 09:02:31 AM
These "kits" didn't exist 30 years ago and I don't suppose anyone has made model specific kits foir these bikes. Hence the DIY approach.
Title: Re: is it possible to restrict an f2 to 33hp
Post by: K2-K6 on May 27, 2011, 09:32:14 PM
Just make a throttle cable with a longer inner cable so the carbs won't open all the way, put it on a dyno to get it checked for output and bosh, Bob's your restrictor.

In all seriousness if "a kit" consisted of a purpose made cable to restrict the maximum output to the legal limit and could not be bypassed in normal use plus a verified output map, then it should conform and not require a whole setup of jets etc to run properly.

Just a latteral thought.
Title: Re: is it possible to restrict an f2 to 33hp
Post by: mickwinf on May 30, 2011, 09:31:22 PM
look at this website  http://www.fiinternational.com/ShowDetails.asp?name=CB550K&type=Honda (http://www.fiinternational.com/ShowDetails.asp?name=CB550K&type=Honda)
Title: Re: is it possible to restrict an f2 to 33hp
Post by: z1100r on May 30, 2011, 09:42:00 PM

 funily enough the guys at the place where I took the CB for its MOT were in the process of limiting a Virago to 33bhp. I asked them what they would do for mine....they just laughed, saying the thing about the whole charade is that you are paying for a certificate, anyone can restrict the bike, but only certain kits come with a certificate..thats the problem and thats what you are payingf for. The Virago just had 2 flange like washers in exhaust between head and header pipe.