Have you finished the throttle pedal connection to the carbs? I've got a very nearly identical set up but having never done anything like this
before I'm not too sure whats the best connection method ?
Jason
Hi Jason, yes I used a generic Venhill kit off eBay, about 18 quid I think. Comes with all the fittings you need.
Photo Archive
Building: MK -INDY 2 LT ON zx9r bike carbs Now sold
posted on 2/3/20 at 07:32 PM
quote:Originally posted by Memphis
Yes you'll have no trouble with the manifold under normal conditions on the road, but if (when) you come to tune the engine for serious power,
it will be very restrictive.
[Edited on 2/3/20 by Memphis]
[Edited on 2/3/20 by Memphis]
Hi Memphis
I'm interested for you to tell me why you think that manifold will not be good
the manifold is like that to miss the distributer
Graham
Yes you'll have no trouble with the manifold under normal conditions on the road, but if (when) you come to tune the engine for serious power,
it will be very restrictive.
[Edited on 2/3/20 by Memphis]
[Edited on 2/3/20 by Memphis]
Hi Memphis
I'm interested for you to tell me why you think that manifold will not be good
the manifold is like that to miss the distributer
Graham
Sharp turns in the manifold create large amounts of turbulence on both sides of the turn, thus restricting the cross sectional area of the inlet
runner to a fraction of the original internal diameter. Airflow doesn't want to go around corners, and would far prefer to slam into the far
side of the inlet runner. Ok on a mild road engine to a point (I suppose) but no good at all on a high performance application.Two sharp turns just
compounds the problem.
I know a certain supplier of bike carbs manifolds sells hundreds of these things, but my heart sinks every time I see one! By far the best solution is
to respace the carbs so you get as straight as possible shot down the inlet port. If you need to change direction, the curve must be as gentle as
possible. Respacing is a faff and quite expensive, which is the main reason people don't do it; generally nothing to do with avoiding
distributors, (and with semi downdraught modern carbs that isn't a problem anyway).
quote:Originally posted by Memphis
Sharp turns in the manifold create large amounts of turbulence on both sides of the turn, thus restricting the cross sectional area of the inlet
runner to a fraction of the original internal diameter. Airflow doesn't want to go around corners, and would far prefer to slam into the far
side of the inlet runner. Ok on a mild road engine to a point (I suppose) but no good at all on a high performance application.Two sharp turns just
compounds the problem.
I know a certain supplier of bike carbs manifolds sells hundreds of these things, but my heart sinks every time I see one! By far the best solution is
to respace the carbs so you get as straight as possible shot down the inlet port. If you need to change direction, the curve must be as gentle as
possible. Respacing is a faff and quite expensive, which is the main reason people don't do it; generally nothing to do with avoiding
distributors, (and with semi downdraught modern carbs that isn't a problem anyway).
Quite right.... However have you actually looked inside the manifolds at how they are ported and finished off? There arent any 'sharp'
corners inside at all. They are smoothed off nicely.
I agree a straight inlet runner would be preferable. I even have the tools and skills to re-space the carbs accordingly, but like I said... lazy...
Even re-spaced there would have to be a curve in the inlet manifold to position the carbs at the correct angle - would it be better? Yes, but still
not perfect.
It all depends whether you are chasing the last few HP or not. I'm not, so chose to take this route. If it was a race car and I was going for
maximum power I would have fitted throttle bodies to tuned length, straight inlet runners (actually matching the port angle in the head too) but
I'm not. So this will do.
Photo Archive
Building: MK -INDY 2 LT ON zx9r bike carbs Now sold
posted on 4/3/20 at 05:33 PM
Sorry if I've opened a tin of worms but as has been said above most of these cars are road cars not race cars and a small bend is not going to
make that much difference
I would like to say the engine I built was / is as far as I know as good as the day I built it
And as I was told years ago you need a bit of turbulence in a manifold to help mix the fuel and air
But of course I may be wrong as I often am lol
Graham
Drained the oil from the first run and refilled with fresh and a new filter, all looks OK at the minute. Using cheapo 20w50 mineral oil for bed in.
Stripped the carbs off (again) - it would intermittently run on 2 or 3 cylinders, after making certain it wasn't an ignition issue (it
wasn't) it was time to pull the carbs. It was always likely to be fuel as cold starting was a nightmare.
Appeared the idle jets were at least partially blocked. Fired up spot on after refitting. Balanced the carbs and tweaked the idle mixture a little.
Will see how it starts from cold again tomorrow.
Cooling system seems to cope OK, although it's not building pressure. I put it down to the cheap crappy header tank as there are no leaks.
I've already put a genuine Ford cap on it, but it's still not pressurising. The fan and everything seems to work though, so I'll
just get a genuine tank at some point.
Next job is clip the fuel hoses at the back, fit a different oil pressure send that doesn't need a load of adaptors, and tidy up a few cables.
Then its going to have to wait until we can find some money for the bodywork. And I have a bike to get mSVA'd before that can happen!
quote:
Appeared the idle jets were at least partially blocked. Fired up spot on after refitting. Balanced the carbs and tweaked the idle mixture a little.
Will see how it starts from cold again tomorrow
Are you using the choke? Makes a big difference on my zx6 carbs.
The bike carbs on my old locost that I've got back and rebuilding since i sold it ten years ago, I drained down the petrol, flushed out the very
yellow liquid it had turned into in the tank, pipes and carbs, refilled the tank with about 5 ltrs and they worked straight away when i got the new
ignition system installed, so all in all I'm sure bike carbs seam fabulous, although my car now has a deep throated bang/pop from the exhaust
occasionally while ticking over? it does make me smile though
The bike carbs on my old locost that I've got back and rebuilding since i sold it ten years ago, I drained down the petrol, flushed out the very
yellow liquid it had turned into in the tank, pipes and carbs, refilled the tank with about 5 ltrs and they worked straight away when i got the new
ignition system installed, so all in all I'm sure bike carbs seam fabulous, although my car now has a deep throated bang/pop from the exhaust
occasionally while ticking over? it does make me smile though
Jason
Sounds like it's a bit lean.
Would probably benefit from a strip and clean if they have sat with old fuel in
The bike carbs on my old locost that I've got back and rebuilding since i sold it ten years ago, I drained down the petrol, flushed out the very
yellow liquid it had turned into in the tank, pipes and carbs, refilled the tank with about 5 ltrs and they worked straight away when i got the new
ignition system installed, so all in all I'm sure bike carbs seam fabulous, although my car now has a deep throated bang/pop from the exhaust
occasionally while ticking over? it does make me smile though
Jason
Sounds like it's a bit lean.
Would probably benefit from a strip and clean if they have sat with old fuel in
Yeah sounds about right, I'll keep an eye on the plug colours and asses them before i book the IVA.
quote:Originally posted by jps
Any update Sera?, I was enjoying watching your progress and just looked back on the thread to remind myself of the Polo rad/pinto piping arrangements…
I sold it as a part finished project a couple of months ago. I'd simply run out of bandwidth to do it and it's better that it went to
another person to get it finished.
quote:Originally posted by flak monkey
I'd simply run out of bandwidth to do it and it's better that it went to another person to get it finished.
A shame - was a good (and motivational) watch to see you roaring through it - but understandable, I know at times in the past my project has felt like
a millstone round my neck!
