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Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 7:24 pm
by ojs
As the title says but is this due to the 33bhp restrictor? these are just washers on the inlet to the carbs i think. the bike
pulls well up to about 7.5k then boggs down and the engine cuts out. any thoughts?
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 7:45 pm
by CMSMJ1
Sounds a bit rich to me. Is it fluffy on the thottle?
Does it get worse if you slip the choke on?
clean airfilter? Some of the lads on here have restricted bikes and they either bullshit us or they work OK..
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 7:54 pm
by ojs
Well the air filter is new along with a new set of plugs
It revs fine when holding the clutch in, it only seems to do it when in drive.
I just did the old check of holding a sheet of paper on the exhaust and the outcome was black!! quite a lot of soot
came from there.
Excuse my stupidity but what exactly do you mean by fluffy throttle?
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 8:04 pm
by wullvfr
hello-
has it done this for the whole time you have owned the bike?
there is someone on here,spike i think who has restricted vfr and it does over a ton.
like cmsmj1 says,try the choke next time it happens,does it get worse or clear!!!.....this gives you an idea if it is running rich or possibly lean.
also inspect the plugs to see if they show signs of running rich etc.
what exhaust system does the bike have?
william
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 8:19 pm
by ojs
Well ive only just passed my test so its been sitting in the garage for 2 months tonight was my first ride on it and i went about 8 mile doing roughly 50 ish because it wouldnt rev.
The exhaust is not standard its something like cobra? i think but not sure.
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 9:36 pm
by CMSMJ1
you are looking like a carbs off and check the main jets kind of job here matey!
The best bit is that we have all been there and had to do it the first time...so get a manual, or do some searching on here and get cracking.
Fluffy throttle.. well... imagine the bike is running lovely..you crack the throttle on and it leaps to your command, sharp, crisp and direct. This is the opposite. You roll on and it is neither her nor there, sluggish, no real go and does ont want to go zooming around the rev counter..that is what I call a fluffy throttle.
A real basic fuelling gauge is how does it rev.
If it is fluffy then usually rich - it bogs down and does not like to rev. I might get a bit better at real high revs
If it is lean (too lean) the it will rev and zoom round but will not really go for it...it will be limp.
In the middle you have the grin factor where your bike works, you know it...and you love it!
lol - sry..got carried away there..
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 9:48 pm
by ojs
You got it in one there your description of a fluffy throttle is exactly how it was behaving.
Up to about 5k it was fine then over 7k it was sluggish and would not respond but if you hold the clutch in and hold the throttle open it will burble for a bit then the rev pin shoots up to the red.
The can is dragon btw... oops i knew it was some sort of animal
So you reckon strip the carbs and clean them? is it worth getting new needles and jets?
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 9:57 pm
by CMSMJ1
it will be rich so you need to get the carbs off and see what jets are in it - did you restrict it or was it bought restricted? Did the person you get it from say it worked OK?
no need for needles but probably want to go down a jet size or two. If it is not standard jetting then it might have had the jets changed to take into account the can and so ith the restriction discs it will be really really rich.
Easily fixed dude..the geeks on here love to help any and all 400's and especially V4's get sorted!
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 10:04 pm
by ojs
bike was running fine before, the guy i bought if from drove it a few miles with me following him.
I restricted the bike through the nearest dealer.
What jets do you recommend and where can i get them?
Thanks for all the help anyway.....lifesaver!!!
Re: Restricted vfr wont rev past 8k
Posted: Wed Jan 21, 2009 10:11 pm
by wullvfr
did the bike run like this immediately after restricting the bike?
i suspect the jets may be the correct size as it ran great before restriction and usually they don't need touched for restriction.
william