Bike slower when up to temperature, faster when cold.

[racefactory]

It could be even a case of one fowling after a period of time that is causing it to be sluggish when warm....

excellent mate thanks... i've realised it is quite sudden when it looses that 'bite'. I think this is what i need- simply new plugs and balance. Fuck knows where i'm going to get a balance from though...

[quickbuck]

...... they said something fucking rediculous like 800 bucks...
...

Yep, that is very ridiculous!
Okay, the room in the VFR is tight, but heck.... not $800 tight!

Bound to be somebody around who can help out.

[lostinflyz]

yea ive hadthe same bullshit from our local honda dealer before.

as i said its not too hard to doon your own but anywhere that does m/cycle tuning should be able to do it. i do know some places often refuse to do the v4's but someone'll do it.

[PirateJafa]

...they said something fucking rediculous like 800 bucks...

That's pretty much their way of saying they don't want to do it.

[lostinflyz]

That's pretty much their way of saying they don't want to do it.

haha yea and that was the polite way. I went to get mine done and they charged me 100 bucks and then told me that eveything in the carbies needed replacing which was gonna be 1200 bucks.

Took the bike home and took the tank off. the wee marker i left on the air box hadn't moved so they never even took the carbies off. thats what you get when you go to CASBOLTS!!!!

[racefactory]

where's casbolts?

[lostinflyz]

Christchurch.

see if you can find a dyno tuner. usually they do it or know the best guys to do it.

[sir]

Ive got an nc21 and im pretty sure the socket size for the plugs is a dirty old 16mm . I dont think panty hose will do it any justice as I went for a blat up the road on mine with out a filter and too much air just made it die when i tried to give it a fistfull . Maybe you clould look at your cooling system , it might need a flush and some coolant .

[Rob Taylor]

Change your plugs,thats easy......Dont think it will be carbs, Could be a spark issue though as in lack of.Before you change plugs ,pull them out and check the gaps..Rule of thumb is thickness of a hack saw blade ..Close the gaps up so they are closer than normal (which allows spark to jump if you have weak spark),reinstal and take for a run ,see if it still does it,,,,If it runs perfect, check coils>>>> If no better back to drawing board..Good luck

[racefactory]

excellent thanks. I'll try that taylor.

Oh and i ran it without the main air filter element... not much difference really, maybe a tad quicker but its probably just me.

Yes if you roll on the throttle and don't beat the engine to the revs its good, just when it's warm, and you grab full throttle from low revs it will change engine tone and sound mushier and accelerate slower.

Hopefully it's a plug problem!

By the way... when you guys were talking about 'fouling plug' , what do you mean exactly? Because i have not felt any misses or more extreme behaviour, don't know what this is...

THANKS

[quickbuck]

2 Strokes are renowned for fouling plugs, but it can happen on 4's as well.

What happens is that plugs are designed to be a certain heat range to stop them causing pre ignition. This is when the base of the plug glows red hot, and ignites the fuel air mixture on the compression stroke... well before the charge provided by the coil gets a chance.
As you can imagine this is BAD.

Anyhow, conversely if they are too cold, then the fuel air mixture doesn't ignite properly, and the base of the plug gets wet with fuel. On a 2 stroke remember there is an oil component in there to make matters worse.

As the VFR is obviously a 4 stroke, it is the fuel wetting the base of the plug, and then it can't do it's job properly. Obviously the longer it runs without igniting the charge, the wetter it gets..... Then sluggish motor.

On a four cylinder, the other three will help a bit... but it will sound like a Subaru... Well the IL4's do, a VFR... Well, yep, it will sound crap. It may just die off, and you don't really notice, apart from a lack of acceleration... Or, willingness to rev.

So, long story short, run the recommended heat range for the motor, unless it is severely tweaked, and you have an issue with pre ignition....

Hope this helps.

And anybody, if I'm slightly misguided in anything, please let me know.
It has been a while since i have done Reciprecating engine theory.

[xwhatsit]

Yes if you roll on the throttle and don't beat the engine to the revs its good, just when it's warm, and you grab full throttle from low revs it will change engine tone and sound mushier and accelerate slower.

Sounds like standard slide carb behaviour, do you know if it's got slide carbs or CVs? You come from two strokes, too, don't you? They're far more responsive like that than four strokes, four strokes have to be babied with the throttle a bit more otherwise they will gasp and take a while to catch up when you crack open the throttle too quickly. CV carbs mitigate this a lot, s'why they're fitted to most modern bikes, but they've got their own set of problems.

I dunno what the problem is with finding a plug wrench, they're NGK E, right? Just get an E-sized plug wrench. I suppose there is that whole watercooled four-cylinder thing where you need a plug wrench the length of Sarah Jessica Parker's face.

[racefactory]

Yes I'm really really hoping its fouled plugs now! Sounds right.

Na I just couldnt find a right sized plug wrench when i had it all apart... i'll get one of those... the problem now is just these $50 DOLLAR EACH spark plugs.

[limbimtimwim]

the problem now is just these $50 DOLLAR EACH spark plugs.

After shipping this might work out cheaper: http://tyga-performance.com/site/pro...roducts_id=886

My NC35 is the same. Much happier when it's cold. It always feels better riding it on a cool night.

Do you still have the heat shield in place between the airbox and the fuel tank?

[racefactory]

Yeah thanks i was thinking of getting from TYGA.

What about those 8's, as opposed to 9's??