Needle position

[bugsy46]

Hey folks,

Just thought id share something with you

I bought a 99 sv 6 months ago with a micron system and "dynojetted". Bored sunday night i ripped the carbs off and decided to have a look at what postition the needle was at. It was near the top so I decided to raise the needle position by setting it one notch from the bottom ie lots more more fuel. And boy what a difference!! The mid range power is incredible as opposed to before, and its less fluffy down the bottom, very crisp. And its accompanied by big flames on the overun! Beautiful! The main jet size is a 138 which I thought is pretty small? Anyone else adjusted their fueling?

[northwind]

138 might be standard in Mikuni sizes, not too sure about that though. It sounds like whoever jetted it made a pig of it to be honest, or possibly it was done for the really old K&N filter that was more restrictive than standard?

[bugsy46]

Hmmmm, yes could be. Had a stock filter in when i got it though, which means not very much lol! Just went out on it earlier and it seems to when on closed throttle low speed, whacking it on wide open, there is a short delay then BOOOOOMF!!! But also noticed it seems to change gear so much smoother than before. I think it needs more running and more attention. I think I may have gone overboard raising the needle so much! When on the over run, which jet is the manifold pressure using, ie, when its pulling **** loads of fuel through bang bang bang?

[northwind]

Has it still got the stock filter in it? That'll make a huge difference for a carbed SV, mine runs DJ 180s, frinstance :rolleyes: But with a K&N filter, it'd probably be 150 or 155 at a guess, smaller with a stock filter.

Hesitation in the mids for an SV usually points at the main jet, in my experience, undersized mains can lead to a stumble before picking up and that'd fit the bill here, though to be honest if I was you I'd get it on a dyno since you never know what else has been done. It took me a looong time to jet mine right by trial and error, it was a good result but I don't really recommend it.

Pops might be an air leak in the system more than richnes on overrun, I think. Not too sure on that, it's not something i've really encountered much of.

[yorkie_chris]

Can you get the jets that fit the same numbering scale as the originals?

[northwind]

Aye... Not quite so easy to find though, PDQ make it so easy to get DJ ones that I just found it easier to learn to think in DJ numbers. Plus, they're bigger, and therefore more exciting.

[bugsy46]

hmmm, theres definalty no air leaks. And from my experience an air leak tends to produce maybe one or two loud bangs as I had loose headers once. Definatly think its fuel, and yes it has the stock filter in. On another note, what is your experience with cam chain tensioners? there was a strange noise coming from the front cylinder. On inspection it turned out that there was side to side play of the inlet camshaft. Taking it out and refitting stopped this as it somehow made the chain tighter than initially seen, am I right in saying both the cam holder AND cct play a part in preventing the camshaft movement?