vfr probs

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

why wont my vfr 400 go above 8000 rpm? Sick

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

NC24 by any chance?

Change the sparrk plugs and take out the restrictors.

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

any ideas how it would be restricted, ive heard its either a black box behind the clocks or washers in the carbs or exhaust. to be honest i wouldnt know what to look for cos im thick as shit.

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

its an nc 21

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Same engine and frame pretty much.

Not restricted unless its been 33bhp'd.

Ever been serviced?

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

it has been restricted to 33bhp supposedly but even so i would expect a ton from it and it has just had new plugs and carb clean.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

It won't do a ton, 90mph if you're lucky.

The NC21/24 react very badly to be restricted via the FI washers. From complete lack of power, very low top speed, starting problems to flooding and oiling plugs. As well as this your reg/rec will fry itself unless it has already been changed for a CBR600 one.

The restriction is washers in the inlet tract. There is no top speed restriction from the factory on an NC21 as this didn't appear on the 400's until 1989.

Just thought which NC21 do you have? the faired on unfaired with crash bars version?

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

its the faired version.

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

in neutral it will rev all the way. but as soon as your in gear 8000 rpm max. how difficult is it to remove these washers?

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

yet another symptom i go flat out about 75mph for about 2 miles then it starts shuddering and slowly dies so i pull over and just as im changing down gears to come to a halt it stalls. i ask myself wtf have i bought.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

You've bought a bike that doesn't take to restriction very well. Other than that I can't say.

Valentino Mossy · World Chat Champion Joined: 13 Jul 2003 Karma :

Do they have the same sort of restrictor box like the nc30 has ?
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sickpup · Old Timer Joined: 21 Apr 2004 Karma :

EuropeanNC30R... · Gay Hairdresser Joined: 20 Jun 2002 Karma :

The CBR600 reg's aren't much better. Reason they fail less on cbr6's is because where they are doesn't get as hot. Better off getting an aftermarket finned item for around £60ish, or using one off another make of bike that has fins.

The Honda reg/rec replacement part now does have finns btw, but is fairly expensive.

DukeRed · World Chat Champion Joined: 07 Mar 2004 Karma :

https://www.400greybike.co.uk/Wksp-NC30Derestriction.asp

Might help.
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john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

just so i know what is the standard top speed like on these vfrs and should the revs climb quickly.

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

hate to sound stupid but what is an inlet tract?

EuropeanNC30R... · Gay Hairdresser Joined: 20 Jun 2002 Karma :

Standard I'd expect it to crack 120. Restricted, who knows, it's guaranteed to run crap though.

john345453 · Derestricted Danger Joined: 04 Oct 2005 Karma :

only 50mph off mark Crying or Very sad