Hey guys,

I just got sum Hitachi SU's from Sidedraught. I cant get it to rev. She gets up and goes right up till 4000 revs. Then........Nothin. It just dies in the a$$. If I feed it throttle slowly it picks up ok. But if I try to put my boot into it, it dies.

I have tried to change the mixture and balanced them up good...but still nothing above 4k.

I am thinking that the needles are too small. I think Sidedraught had them on an A12gx.

Cheers for any advice

PS Do the SU, SU's needles fit the Hitachi SU's??

su tech pages

I'm not sure what the cause is of your problem, you might be leaning out.

Out of curiosity, what needles are in those carbs?

Damn I thought you were asking about SU's because I've been dying to know what needles as well.

If it is leaning out that means the needle is Too BIG, not too small. More fuel will flow around a smaller needle, so that's what you need- a smaller needle - but only in that specific area of the needles operation (above 4k.)

Some people have reshaped the needles by chucking them into a drill and using sandpaper. I'd be sure the car is running lean and not suffering from something else, like an ignition problem or fuel pump starvation issue.

I'm curious to know if you get this worked out. I'm told that these carbs are higher quality than Su's, but harder to get tuned (IE harder to get needles for?).

I have no idea what needles are in the carbs. How do I find out??

Also It revvs freely past 4k. but under load it dies at 4k

my 1200 coupe does that sometimes it goes alright till ya get t 4 5 grand and then it dyes down i find if ya just keep reving it it starts to get better i think cause the su carbes flood them selvs or somethingwonder would it helped iv you wound the fuel down
i dont know much but correct me if im rong

u might have problems starting it after it has been sitting for a couple of days if so i thought it was my battery but its the carbs i find hold the peddle flat to the floor lol correct me if im rong lol

if i hold it flat it goes strong up to 4k exactly every time then it hits a perverbial brick wall. it stops accelerating.

Am going to grind me needles down very gently tonight. I strongly belive that it will fix it. as the carbs came off a a12 GX and its on a a14.......It needs more fuel at that part of the rev range. at least thats what I think

Good luck. be careful not to scratch the needles when measuring them.

Yea, good luck.
What I have trouble with is try to determine what position the piston/needle is in at different rpms and load. At least with a weber 32/36, you can feel the secondary spring when it opens so you have some idea.
I can't see the carbs while I'm driving and my wife won't agree to help and hang-out in the engine compartment while I run my test.
So, I've gone as far as to mount a cheap little "Surveillance" camara pointed at the carbs and have that hooked up to my camcorder. I then go full blast up on ramps and hills, all the while looking at my camara.
Ok, so the camara was recording and I was just taking peaks at it.
Anyways,
I could see the position of the piston as it moved up and down and hear the engine load up as it reved.
I could also see a cloud of reversion but that's another story.

Hey, I managed to get it to rev......But It will only rev when I feed it throttle slowly. It manages 6K easily. It gets there quickly too!!

There is something that says to me that maybe the exhaust ports are too small and the exhaust may be too small at the back of the car where it goes to 1 1/2 inch.

Here is the list of stuff i have from intake to exhaust.

A14 Block
A15 Head w/coolant Galleries
A12 GX Manifold w/hitachi SU's
Mild portwork on the intake
Factory valves and springs
Factory exhaust ports
4 into 1 extractors into 2 inch exhaust
Changes to 1 1/4 at the back (no I didnt do it)

Is there someone in Perth here that I can either take it to and gimme some advice for free/cheap?? Or am I stuck feeding it to get power