Fouling plugs and weird carb overflow issue

[graeme]

Finally did my 3en1's valve clearances :D but... Now she's fouling the plugs almost immediately. I tried with float heights at 26mm but they started overflowing!?! Interestingly - only when the engine was running, if I just cycled the ignition allowing the pump to run they did not overflow. Any ideas what would cause this? Anyway, I set them back to 25mm and they don't overflow, but still fouling the plugs - even with the pilot screws wound down to 1/2 turn out.

Any ideas?

Oh, this is a jap spec 3en1 with the 600's carbs.

Thanks

[Evilchicken0]

Have you balanced the carbs

[graeme]

Yeah I did a while back - guess I could check them again, though not sure why they'd have gone out since. Was chatting to my brother about the sliders moving at idle (can't remember if I mentioned that in my initial post) - he reckoned his VFR's didn't move at all, so I'm going to try stronger springs and see. Bike's always run rich even on leanest settings - my needles are currently on leanest position too - so maybe my carb springs are shot too.

[Evilchicken0]

Its a bit difficult to say when the carbs are from a 600 I don't know the settings for either bike or if the parts are different from one set to the other.
If your on the weakest settings and its still to rich you should go down a jet size. Just to make sure, you know the main jets to cylinders 2 + 3 are one size up from 1+ 4

I've probably said this before but it might be better to find a dyno a d get them to set it up rather than chasing the settings around.

[graeme]

Dynos for bikes aren't common around here unfortunately... I'll have to do it the old fashioned way heh heh.

[Evilchicken0]

Yes - I think you said that before.
I think I also suggested you get some 400 carbs but people don't post much down there huh

[graeme]

You got that right

I think these carbs are stock tho, I stand corrected but apparently the japanese editions of the 3en1 and 3en2 had the carbs from the 600 (3he I think), but jetted differently - these models are pretty common (grey) imports here in SA and australia too, apparently. I did get a spare set of carbs off a 3en2, but they're in pretty poor shape

I'm quite interested to see how she behaves with stiffer carb springs... I'll report back soon...

[rockTJ]

The 3TJ FZR400RR and the FZR600 Genesis do indeed have the same carbs (Mikuni BDST32's) but obviously the mainjet, pilot jet, needle, spring, air jet and possible the emulsion tube itself will all be different.

If you keep an eye out they do pop up every now and again

http://www.ebay.co.uk/itm/160915621605

Chris

[Evilchicken0]

True, true .... the 3EN1 carbs are the same as 3EN2 so you might find a set of those ... ask the seller if they'll send them surface mail, it takes a while but it's cheaper.

[graeme]

Right so I firmed up those carb slider springs temporarily (by putting spacers in the slider bodies where the spring sits) and it's made a massive difference - I even took a chance and set the needle clips to the stock, middle position (from the leanest position) and then had to set my pilot screws from 1/2 turn out to 3 turns out (which I believe is factory) to get her to idle. Think the springs are too firm now as she's not very responsive... But this is a huge improvement :D

I'll have to source some new springs and move onto my next issue... When she starts getting warm this odd noise starts - kind of like compressed air escaping a container that's suddenly been opened - originating from one of the exhaust valves. It was there before I did valve-clearances and I'd hoped it would clear up... Guessing that valve isn't sealing properly.