Description
Gents
2.0 Zetec Blacktop now mated up to 40mm ZX9R CV carbs etc from a DanST kit. TPS fitted up and wired in to the Nodiz gen 1 (old I know) ECU module.
Took it for a first brief spin today. Air filter was off, and trumpets/stacks from the kit have been fitted - as has the bike fuel pump, the filter
and a fine filter before the carb fuel inlet.
Basically it idles well and it pulls well. I did not explore the upper end of the rev range, but it seemed as if it wanted to go there.
Couple of things
Firstly - From (I think) the carb side there was a fair amount of noise. Of course I realize this may just be intake noise, but it was more of a loud
contant popping sound under load - rather like a misfire rather than a loud rush of air. Pretty sure it wasn't actually misfiring as it did pull
well, but I wondered if this was normal? I have not tried it with the air filter on just yet. I checked all around for any air leaks at the carb -
intakes/manifold/servo offtake - couldn't see anything. If this popping noise is normal then fine - if not, what do we think is the cause? Only
thing I can think of are the main jets - maybe too small, perhaps giving rise to fuel starvation or wrong mix? Plugs look fine by the by. Light brown
in colour.
Secondly - If I did decide to hand it over to a tuning shop, what can they do? I guess they could play around with the Nodiz gen 1 somewhat, but what
else could I expect? Could I possibly do some basic tuning myself perhaps? What do you suggest?
Many thanks
Mark
I suggest you stick the air filter on and go for a drive and just see how it goes. But be very careful on damp roads, specially if you want to explore
the full rev range!
Mine does not pop (1.8 zetec, bike carbs with megajolt), but I've never tried driving without the air filter on.
Aye I will try it with the filter on. Thinking about it a little deeper, I guess the jets only control the upper 1/4 or so, with the needle controlling the mid range. I believe if the needle is grooved, then 1 groove down from the centre is a good place to start. I'll check this out. Blocking off the air "tubes" or are near the top of the carbs seems to be favoured. I'll also check the air screws. 1 turn out?
sounds like its running lean, the air filter will richen it up a bit.
Is the TPS working and the ECU receiving a signal? Base map or somthing near on there? Could be a combination of a lot of things!
Get it on the rollers and get it sorted, but make sure they will touch bike carbs first!
Yes - It does "sound" lean. Soemone will remind me I am sure, but if I drop the needles a notch will that richen it up mid range?
Effectively you are raising the needle within the jet allowing more fuel through....I think!
Nodiz is receiving the TPS signal - that checked out.
[Edited on 5/11/20 by Mark O]
i dont know anything on bike carbs im afraid, used Webers in the past, but went to ITB's instead. Someone will be along shortly to help im
sure.
Spoken to DANst about the issues? They have been very helpful in the past when i have contacted them
What is your location? There is a company in the Sheffield area that is good with Mikunis.
Lowering the clip in the needle will richen the mixture in the mid range.
The main jets in my GSXR 600 carbs on a blacktop 2 Ltr are 1.6mm. Gives an AFR of around 12 at WOT.
quote:
Originally posted by Davedew
Lowering the clip in the needle will richen the mixture in the mid range.
The main jets in my GSXR 600 carbs on a blacktop 2 Ltr are 1.6mm. Gives an AFR of around 12 at WOT.
There is nothing wrong with a few pops and bangs from the exhaust, infact it was one of my favorites 
That along with setting every car alarm off at 0600 on a sunday morning (exhaust on a crossflow is on the left)
Oh i wish i still had my car !!
I decided to pull and strip the carbs in any event and herewith my take
Silicon intake hoses - not a good idea I think. The silicone is far too slippery in the bores - for want of better words - to take the weight of the
carbs, even when the clips are fully tightened. I've ordered some thick EPDM hose.
Float bowls full of crud. Pilot jets all blocked. No wonder it wasn't idling well or starting at all well. Will clean everything out.
2 emulsion tubes partially blocked. May well explain the popping and banging.
Air correction holes - reading around these should be blocked off and redrilled to 0.5 to 0.7mm. Will block off with 2.5mm copper wire and drill
out.
150 main jets fitted. Opinion seems to be in favour of 160 - 180. Ordered 165s for now.
Needles need a shim to raise them a tad.
I never had a success using silicone hoses to hold my carbs on. Like you said their weight just kept pulling them out.
In the end I bought a set of original Suzuki intake rubbers and made an adapter manifold to fit them to the engine.
Never had any issues since with them falling off or air leaks.
I have never done any thing with the air correction holes in my carbs. But then I've never looked for them either.
I did try 170 mains in mine, but changed them back to 160's on the rolling road as the 170's were running rich.
Wideband lambda gauge for the dash was one of the best things I did as you can see instantly what the changes you are making are doing.
Dave
Yes-Silcone hoses not great supporting load. Far too elastic and pliant. Carbs are quite a bit of weight, even for rubber. May even support them from
under somehow as an added reinforcement. I think I will also reduce their lenght to reduce the cantilever effect.
Lambda gauge is interesting - cheers...Normally I simply check the plug colour.