spuker1
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| posted on 23/7/13 at 10:02 AM |
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I was looking into ITG filters with blank back plates, but they are quite pricey. I mean it would probably set me off more then the entire bike carb
conversion, including carbs themselves... I think those filters have got enough flow for my needs, I just need to get suited jets for them now.
I'm running on 90 jets at the moment. What would you think would be the size of jets I'm looking for? 120? 150?
Regarding fuel pump, stock mechanical one is more then enough I recon.
[Edited on 23/7/13 by spuker1]
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mcerd1
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| posted on 23/7/13 at 11:21 AM |
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I know the sausage filters arn't cheap and the likes of the pipercross airbox is silly money...
http://www.pipercross.net/competition/products_600_airbox.asp
but you could make a DIY back plate and airbox in the style of the pipercross one and then all you need is one decent cone filter - which you can then
position to draw from cold air
quote:
Originally posted by spuker1
Regarding fuel pump, stock mechanical one is more then enough I recon.
its not that its not enough - rather its too much !
when the bike pump senses enough pressure they acutally stop pumping, they are tunned to the needs of the bike carb's and your mechanical pump
is not and regulators arn't always enough to correct this
I know at the moment lack of fuel is your biggest issue, but once you get the jet size sorted you may find you have the opposite problem (although I
have to add that some folk do have them working well on mechanical pumps, but a bike pump is easier to get right and needs no regulators  )
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spuker1
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| posted on 23/7/13 at 12:06 PM |
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I could just as well just get standard CBX550 air box and attach some tubing with a filter to it, there's one for £10 on ebay now but I
don't think it will fit in there to be honest, the carb is too close to the firewall, don't forget that this Honda is like a shopping
trolley with an engine and a bit less understeer 
The stock mechanical pump is ok, because it's self regulating and it has return so if it senses that carb bowls are full it just keeps on
pumping but returns the excess to the petrol tank. It's pressure is high enough for most applications but for bike carbs it's actually
running on fairly low pressure, so low infact that the fuel pressure gauge isn't showing anything. I've got my fuel pressure reg opened
all the way at the moment. I could probably run it with out it at all actually. So yea, I don't think that fuel pump would be ever an issue.
As an alternative to taping up the filters I've been suggested using restrictors that you put right in front of slides in the carbs. Not sure if
it would work though because after all I'm still not sure if it needs vacuum before slides to lift them or was it just too much air flowing for
the carbs. If it's the former it won't work...
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spuker1
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| posted on 23/7/13 at 12:06 PM |
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double post, sorry.
Regarding that pipercross airbox, that could be good for bike carbs + turbo 
[Edited on 23/7/13 by spuker1]
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deezee
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| posted on 23/7/13 at 12:41 PM |
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First off, great that your trying all this, but I'd be surprised if you got more than 10% power increase over your stock 60bhp (25 years ago...
probably 55 now). Your engine driven fuel pump isn't magic. It doesn't sense anything. It just pumps away, at 4psi. Quite high for the
seals in old bike carbs. It will run fine, then start pushing fuel past the floats. Just buy a bike pump for a tenner and fit it.... problem
solved.
Don't ruin your engine with silly fixes. Just allow more fuel in by drilling / replacing the jets. Blocking up parts will be a disaster. Just
accept that many of us have tuned different bike carbs with lots of different engines so we know what we're talking about. This isn't
RedPepperRacing Foums so we've done this properly and it
works.
Also on your EV2 engine, have you connected up the vacuum advance to the distributor? Or the vacuum back to the brake servo?
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whitestu
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| posted on 23/7/13 at 12:59 PM |
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quote:
It will run fine, then start pushing fuel past the floats. Just buy a bike pump for a tenner and fit it.... problem solved.
Spot on - the key thing with a bike pump is it will produce zero pressure when needed - i.e it switches itself off when the float chambers are full
and the float valves close.
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jacko
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| posted on 23/7/13 at 01:13 PM |
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As the others say fit a bike fuel pump and drill the main jets out go up in stages on zx9r carbs there is a air correction hole that some people have
had to block o stop the carbs going week at high revs
If you do drill the main jets hold the rill bit in a vice and twist the jet by hand don't use a machine
If i was you i would ring Bogg Brothers and they will give you the best advice on bike carbs there very helpful
Jacko
http://www.boggbros.co.uk/index.html
[Edited on 23/7/13 by jacko]
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mcerd1
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| posted on 23/7/13 at 01:42 PM |
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where abouts in the country are you ?
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spuker1
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| posted on 23/7/13 at 02:39 PM |
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quote:
First off, great that your trying all this, but I'd be surprised if you got more than 10% power increase over your stock 60bhp (25 years
ago... probably 55 now).
First off, thanks! You'd be also surprised if I told you that I'm not doing it in hope of turning it into NSX Type-R right? European EV2
had around 70-80bhp when it was new. 60bhp is american model that had CVCC system. My goal is 100bhp but even if I won't get back to factory
stock spec with those mods it still won't matter. I want to make my car just a little bit more special and I'm doing it for personal
satisfaction more then anything else.
quote:
our engine driven fuel pump isn't magic. It doesn't sense anything. It just pumps away, at 4psi.
I've never believed in magic and I've never thought that the pump can sense anything. I have been told by the people who have used those
pumps with different fuel/intake systems that this pump will pump fuel until the float chambers close down and then instead of pushing the fuel anyway
it returns it into the tank until the carbs are open again (sorry for not being technical this is how I understood it). If it really just pumps away
at 4psi why does my fuel pressure regulator doesn't show any pressure at all? And where did you get those 4psi from anyway?
Other then that, the guy who suggested my restricting airflow for now has been a car/bike mechanic for most of his life. If he said to me (I'm a
person who doesn't know much yet and learns along with every project taken up) that fuelling is fine and he had the same problem with loads of
carb fuelled bikes, that they came with restrictor plates (plates with holes in them to restrict airflow) and when taken away all of them would run
just like my car did, I DO BELIEVE HIM. He could be wrong though, but somehow we taped my filters up and the car started to run very well with
noticeable improvements over stock set-up.
quote:
Just buy a bike pump for a tenner and fit it.... problem solved.
I don't mind doing that except I can't see a problem there, pump works fine, there's fuel going through, no leaks so far...
quote:
don't ruin your engine with silly fixes. Just allow more fuel in by drilling / replacing the jets. Blocking up parts will be a
disaster.
I don't think that restricting air would be silly actually. I know jetting it properly for the airflow those carb allow to the engine would
generate much more power, but I don't think that in the long run my 30 year old 1.3 run around engine could take it. I'm not doing it only
for power. How would blocking up the air intake be a disaster? I'm not being sarcastic, I really want to know
quote:
Just accept that many of us have tuned different bike carbs with lots of different engines so we know what we're talking about. This
isn't RedPepperRacing Foums so we've done this properly and it works.
Have I ever told any of you that you don't know what you're talking about? Have I ever disregarded any of your advice? I think it's
quite normal that I ask around in different places and I try to take all the options into consideration right? Plus how do you know if people from RPR
haven't done it properly and it haven't worked?
Well done on your excellent google research skills by the way (I am being a bit sarcastic now )
quote:
Also on your EV2 engine, have you connected up the vacuum advance to the distributor? Or the vacuum back to the brake servo?
How stupid do you think I am, sir? Of course I did!!!
quote:
As the others say fit a bike fuel pump and drill the main jets out go up in stages on zx9r carbs there is a air correction hole that some
people have had to block o stop the carbs going week at high revs
I think I will stick to my magical fuel pump anyway. I will have a go with jetting soon, I will get 120 jets though and drill those out if
necessary.
quote:
If you do drill the main jets hold the rill bit in a vice and twist the jet by hand don't use a machine.
Good tip! Thanks for that!
quote:
where abouts in the country are you ?
Worcestershire
Thanks for all the feedback guys! I know I'm on the right path now!
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deezee
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| posted on 23/7/13 at 03:06 PM |
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Obviously I've hit a nerve, I'm not here to get you wound up, sorry if I've come across like a knob. Its just with a dozen
experienced people telling you to use a lower pressure pump and to fix the AFR you need to drill the jets, you've opted to stick tape on the
filters and leave the pump in. I'm sure you trust your friend and I'm not going to speculate on his experience with engines, so
I'll just not get involved. Best of luck with the car and regardless of how you get there, I hope it runs ok.
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spuker1
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| posted on 23/7/13 at 03:11 PM |
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quote:
Obviously I've hit a nerve, I'm not here to get you wound up, sorry if I've come across like a knob. Its just with a dozen
experienced people telling you to use a lower pressure pump and to fix the AFR you need to drill the jets, you've opted to stick tape on the
filters and leave the pump in. I'm sure you trust your friend and I'm not going to speculate on his experience with engines, so I'll
just not get involved. Best of luck with the car and regardless of how you get there, I hope it runs ok.
Nah you didn't hit a nerve, it's all good I've got it all mate, the thing is before my mate turned up and taped my filters up I
wasn't sure if it was the pump or the jetting or vacuum leak or lack of vacuum somewhere or god know what else. Now I know it's just wrong
AFR and except that is all good. I'm opting to keep my stock fuel pump because I don't know how to convert it to bike one. I have no idea
how would I have to blank the hole after stock pump off and definitely don't want to leave it in turning over completely dry... I won't
leave it taped up either, If I decide to leave the jetting as it is and just restrict the air I will get proper restrictor plates made up for it. It
just idles perfectly now and revs very well too, I don't want to make it worse that's all.
Thank you!
[Edited on 23/7/13 by spuker1]
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whitestu
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| posted on 23/7/13 at 03:38 PM |
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quote:
loads of carb fuelled bikes, that they came with restrictor plates (plates with holes in them to restrict airflow) and when taken away all of them
would run just like my car did
That could well have been to restrict the power the bike was making. With the restrictors removed and a re-jet they would make more power and run
fine.
I'm sure like all of us you want to get the best out of your car so if the problem is it is getting too much air and not enough fuel you can
either restrict the air and limit the breathing and hence power of the engine or increase the fuelling and maximise the power.
I know which I would aim for!
ps, bike pumps are dead easy to fit - you would need to make a blanking plate as you suggest for the mechanical pump.
Stu
[Edited on 23/7/13 by whitestu]
[Edited on 23/7/13 by whitestu]
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spuker1
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| posted on 23/7/13 at 03:55 PM |
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quote:
I'm sure like all of us you want to get the best out of your car so if the problem is it is getting too much air and not enough fuel you
can either restrict the air and limit the breathing and hence power of the engine or increase the fuelling and maximise the power.
I know which I would aim for!
Exactly that! I think I will keep it restricted for now if it prooves to run right after couple of test runs and just treat it as a sort of
'stage 1' thing and de-restriction and jetting as a 'stage 2'.... I think it's actually a perfect moment to stop working
on the engine while it's running right and fix other things like clutch that is slipping badly and address some rust and generally witner proof
my car.
Thanks a lot you guys!!! I would still be clueless without you lot!
[Edited on 23/7/13 by spuker1]
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mcerd1
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| posted on 23/7/13 at 04:08 PM |
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quote:
Originally posted by spuker1
I'm option to keep my stock fuel pump because I don't know how to convert it to bike one. I have no idea how would I have to blank the
hole after stock pump off and definitely don't want to leave it in turning over completely dry...
if its the normal type of diaphragm pump (which I'm fairly sure it will be) there will me a small cam inside the block/head, via little little
push rod or lever this moves the diaphragm which moves/pumps the fuel with the help of a coulpe of valves - when it gets up to preasure is designed so
it doesn't return to get pumped again (or if your is sligtly different form the ones I've delt with it could be pumped back dow the return
line instead)
it does however need some pressure to cause it to stop sending fuel to the carb's and bike carb's can be 'very' sensitive to
this (it migh not be enough to have fuel pouring out of them, but it could give unexpected results when tunning them)
your fuel pressure gauge migh not show anything, but is it calibrated and reliable ?
if you should be able to remove the fuel pump and any push rod / lever then just blank off the hole with a bit of steel and fuel pump gasket - it
would be very unusial if this was interconnected with any other system...
the bike pumps just need 12v switched of the ignition with a suitable relay & fuse
if you think blanking off the fuel pump is a bodge - thats the way most manufactures did it when they changed to EFI versions of the engines back in
the 80's  (inc my 89 ford pinto)
[Edited on 23/7/2013 by mcerd1]
[Edited on 23/7/2013 by mcerd1]
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spuker1
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| posted on 23/7/13 at 04:14 PM |
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Thanks for that. I think it's definitely a way forward.
quote:
if you think blanking off the fuel pump is a bodge
How could I think that? My engine genuinely runs on duct tape now!!!
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mcerd1
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| posted on 23/7/13 at 04:20 PM |
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also if your really worried that the engine won't take the full power that your carb's can give them you'd be better off fitting
even smaller carb's (my googling suggests your's have 30mm chokes ? )
the logic being its best to have everything working near 100% of its capacity with nice smooth air flow, rather than something working at 70% of its
capacity and strangled with a restrictor that messes up the air flow
if nothing else fitting restrictors would be a bit like driving at max. of say 70% of wide open throttle - the efficency of the carb's like this
will be much, much worse than say just fitting a set of carb's with 25mm chokes and getting a fully open throttle
or to say it a different way, pick carbs the right size for the power you want to achive - then make everything match that
so your manifold, ports, valves, cams, exhaust pipes and even max. rpm etc. should all match as closely as possible to make the most efficent engine
you can - well thats the theory at least
you may find this site useful for background info on your carb's:
http://www.gadgetjq.com/keihin_carb.htm
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spuker1
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| posted on 23/7/13 at 05:44 PM |
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https://www.youtube.com/watch?v=pw9h1zD_XPA
Ok, this is how it runs now. It actually ran much better last night or I was so excited about it not cutting out as much anymore I thought it's
perfect. Obviously it drops AFR in midrange, so definitely need to lift the needles a bit and definitely bigger jets!
[Edited on 23/7/13 by spuker1]
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spuker1
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| posted on 30/7/13 at 08:24 AM |
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Right then! I've ordered 120 jets and they are still too small, I might go straight up to 150-160 ones to be fair. I've come across first
major problem though. Needles aren't adjustable in those carbs and there's no way I could put spacers under them because of the design of
the thingy that holds them in place... How much can I adjust the way they will work just with size of main jet and adjusting the air screw? Does it
mean that even if I tune it well with needles like that I will get nice idle and low range, no midrange and decend high range power?
I could always shave the needles a bit but because there obviously won't be any going back I will get the jets right first I think... How does
the size of the needle affect the changes that bore of main jets made? I mean, If I get main jet's size right and full throttle AFRs will be
spot on, will it change much when I get needles shorter/thinner?
I've sort of realised yesterday that I might have to get different set of carbs because of that... It got me a bit depressed to be fair.
Please help me out with that one...
Cheers,
Tom
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whitestu
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| posted on 30/7/13 at 08:58 AM |
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I Think Dynojet kits include adjustable needles, but not 100% sure. However they aren't cheap.
Stu
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spuker1
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| posted on 30/7/13 at 10:47 AM |
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Thanks, that would be good but there's no replacement kit for the carbs I've got. I was looking for alternative needles from other Keihin
carbs but all of those with splines in them are much longer then mine. Mine from the tip to it's mounting head thing is about 40mm long, the
other ones are 60mm+...
Other suggestions?
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mcerd1
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| posted on 30/7/13 at 11:18 AM |
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if there are no kits avalible I belive you can get custom needles made - but the cost will give you a shock
its sounding like you'd be better off with a set of carb's from a more upto date bike (or at least one you can get adjustable needles for)
there might even be set thats better suited 'off the shelf'
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spuker1
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| posted on 30/7/13 at 04:33 PM |
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I was considering that... There's a reason for most of the people using R1 carbs for those conversions right? Anyway, I will try to fit bigger
jets (ordered 150s today) and see how far this will take me. If car will be still undriveable I will consider getting different set of carbs. Probably
won't loose much money on it as I've bought them dirt cheap and gave them a good clean and rebuild
What set of carbs would you guys recommend for 1.3 SOHC engine? ports are around 35-38mm the stock output is around 70bhp. I'm also on a tight
budget so the cheaper the better!
Thanks,
Tom
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mcerd1
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| posted on 31/7/13 at 07:42 AM |
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R6, ZX6R, ZX9R, GSXR....etc are all just as popular as a R1 carb's - but I suspect they are all too big for your little engine 
I think you should be looking for a 4cyl bike with say ~80-90 bhp from the late 80's onwards
so at a guess that maybe a CB750 (75bhp, 34mm Keihin's) or GS650 or maybe even one of the GSX's
never used any of those carb's for anything so not sure how good they would be - so you'll need to to your research on any carb to see how
tunnable it is before you buy.
[Edited on 31/7/2013 by mcerd1]
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spuker1
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| posted on 31/7/13 at 10:19 AM |
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Thanks a lot mate, yea I suppose. I've bought these ones as they popped up on ebay in my area for very cheap, so decided to give it a go. I will
give it one more chance with massive jets and air screws all the way to the rich side and see how it goes... If there's no luck still I'll
sell those on and find something else...
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matt_gsxr
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| posted on 31/7/13 at 11:25 AM |
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You could consider gsxr600 carbs, or if you want smaller then gsf600.
Personally I hate bike carbs (they just leak and cause fires), so I'd go with gsxr600 throttle bodies and megasquirt it but that will cost you a
few quid.
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