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VFR400KJ Air forks

Posted: Sat Jan 21, 2012 9:22 pm
by harvey_s
Hi Everyone, first post so be gentle guys ;)

Anyway, I've just gone and bought a NC21, a VFR400KJ japanese spec. machine (ex riding school bike maybe?) and tech. info. is non-existent, Honda UK have no info. and although I can glean some info. from the NC30 Haynes manual I've got - But I can't find any info for the air fork pressures.
Elsewhere on the net 5 psi max. is mentioned others talk of 8-11 psi...

Can anyone help with this (and any other model specific info. gratefully recieved)

Thanks for looking

Re: VFR400KJ Air forks

Posted: Sun Jan 22, 2012 5:13 am
by Neosophist
harvey_s wrote:Hi Everyone, first post so be gentle guys ;)

Anyway, I've just gone and bought a NC21, a VFR400KJ japanese spec. machine (ex riding school bike maybe?) and tech. info. is non-existent, Honda UK have no info. and although I can glean some info. from the NC30 Haynes manual I've got - But I can't find any info for the air fork pressures.
Elsewhere on the net 5 psi max. is mentioned others talk of 8-11 psi...

Can anyone help with this (and any other model specific info. gratefully recieved)

Thanks for looking
What do you want to know?

The fork air range is 8-11psi.. some people say 5psi max as if you have non-honda fork seals they dont' seem to last very long and perhaps the air makes it worse.

I tend to use close to 11psi with Honda seals (this is maybe one or two pumps from a hand bicycle pump.

Re: VFR400KJ Air forks

Posted: Sun Jan 22, 2012 10:58 am
by duncan
I would be very careful about pumping air into those valves as it is too easy to end up blowing the fork seals.The best mod you could make is to fit a pair of better quality heavy duty fork springs.The original ones were designed for a leightweight oriental rider and are probably knackered by now.I have Maxton ones in mine.I did have to send them m one of my original springs plus its spacer and tell them how much I weighed

Re: VFR400KJ Air forks

Posted: Sun Jan 22, 2012 11:08 am
by harvey_s
Thank you for the air pressure info. :grin: - if you are asking what else I would like know, at the moment I would like to learn...
1) Fork oil capacity and oil level.
2) What was the original fork spring free length.
3) Where can I find the carb ID number?, I can only see VD on the carb sides. (and what number should be there)
4) The valve clearances i assume are std.....(In. 0.11-0.15 / Ex. 0.18-0.22 all cold)

That's all I need for now :smile:

Re: VFR400KJ Air forks

Posted: Mon Jan 23, 2012 11:12 am
by Neosophist
harvey_s wrote:Thank you for the air pressure info. :grin: - if you are asking what else I would like know, at the moment I would like to learn...
1) Fork oil capacity and oil level.
2) What was the original fork spring free length.
3) Where can I find the carb ID number?, I can only see VD on the carb sides. (and what number should be there)
4) The valve clearances i assume are std.....(In. 0.11-0.15 / Ex. 0.18-0.22 all cold)

That's all I need for now :smile:
the number is on the carbs, usually on one of the sides.. it might be hard to see if you have oxidisation on the carbs.. depends on model of bike.

Valve clearnes are fine

Fork spring free length.: 379.00mm stock
Service Limit: 371.4mm

Oil Level: 151mm
Oil amount: Right fork: 340cc, left fork: 345cc

10 weight

Re: VFR400KJ Air forks

Posted: Mon Jan 23, 2012 12:12 pm
by harvey_s
You're a star - thank you very much

Re: VFR400KJ Air forks

Posted: Mon Jan 23, 2012 9:38 pm
by duncan
I also have a VFR400K,the most practical of the 400 VFRs.I think it is a great bike so good luck with yours