posted by racer135 on 5/26 9:57 GMT

Could it be possible that only cylinder 1 was leaning out because of the acceleration and all the fuel moved towards the rear carbs? No sign on the spark plugs?

posted by unfamilia on 5/26 10:03 GMT

Havent pulled plugs yet but no engine leans to the rear. 4 carb bowls under pressure unlikely fuel only going to flood one cyl in my mind.

Need new plugs once I sort this to read properly.

posted by racer135 on 5/26 10:16 GMT

By lean I meant fuel mixture not angle of engine. I suppose thinking about it the forward hung floats wouldn't be affected by forward movement when mounted sideways in a car.

posted by unfamilia on 5/26 10:26 GMT

Yes I under stand your meaning of lean lol for plugs. I added my lean of engine for fuel float levels.

Ive confused us all.

posted by unfamilia on 5/27 14:33 GMT

Ok pulled carbs out and adjusted the floats up or down to try and get around 55 ml per float bowl give or take up to 5ml.

been reading tuning manuals not blogs to try understand these things better.
ive identified the carbs now as 38x4 mikuni bdst im 90% certain.
they arent a true verticle down draught abd sit b on an angle of about 45-50 deg verticle. So shoukd work with right manifold angles and float settings.

Cyl 1 I made float come up more about 2ml travel now
cyl 2 came up about .5mm maybe
cyl 3 I brought down a hair
cyl 4 brought down about .5mm

I did this due to more fuel cyl 3 and 4 when I measured them due to manifold slant on motor I think. So floats can adjust to compensate slightly.
I also noted where the fuel level lines where in tge float bowls.
As the carbs sit at 45deg approx the seals at the base are always partially submereged and wet.

floats done- couldn't start it up to test at 11pm so made my other adjudtments relating to the suspected leaning out and detonation

redilled the main jets to 1.8mm while bowls were open as the car leaned out at 5000rpm last test at wot.

also had leaning out in the mid range so I raised the needles to the bottom clip position. Yes bike carbs have adjustable jet needles for mixture from 1/8 throttke to 3/4 throttle.

I dropped needles to lowest position but also used 2 washers to drop the equivalent of another clip.


this is a known test method to see if you need thinner needle so it allows more fuel in past the needke jet that the jet needle slides out of when the cv slide pulls up under vacum.

See washers



see jet needle in the middle of throat under the slide


needle jet when looking into to throat of carb like air would



theoretically you are supposed to lean off the main jet when you richen the jet needle position but both parts of that part of rev range were lean
so trial and error til dyno. Rather a bit richer currently.

posted by LittleFireyOne on 5/28 11:22 GMT

those are pretty lean needles man, my black set of 34's have needles sharp enough to shank Satan from..., hmmm, well somewhere funny. Didn't think that far ahead in the joke :S

posted by unfamilia on 5/28 14:15 GMT

Stock needles on a fzr 1000 but thats why space em up.

you running yours yet firey?
Jokes..im king of dud jokes.

posted by unfamilia on 5/28 14:29 GMT




look at this nifty way I saw on net to seatvthe floats to set them better.




im getting good at this.
had to reset all floats again as 3+4 read just over the top of overflow and 1+2 as well.
but I got all of them before resetting at 65ml petrol except cyl 1, 80ml- I adjusted too much and it spat 15ml into an overflow I set up for testing floats. Just bent tangs again so hope to get 55-60ml now.

Test tomorrow.

Also was rich on idle and needed more needle height for midrange, needle lifts out of jet at idle so I adjusted idle leaner as fuel is being fed from needle jet now too slightly.

Also forgot I need 98 octane not 95 thats in there due to head on motor. Should stop detonation I hope.

this has a great midrange just off idle to 5k currently. Pulls harder and more responsive than the dcoe45. Not as fast yet but more responsive by far.

posted by LittleFireyOne on 5/28 15:43 GMT

Was going to hit up a mate in the holidays to make the manifold

posted by unfamilia on 6/2 12:31 GMT




hope these work out ok. Get a slight mist of fuel mist just off idle.mainly cyl 1 & 3.
Read that the lip slightly stops air being rammed down air jet holes in the bell helping reduce the issue with reversion.

id go for a drive but had a couple now. Monday night lets get wasted