Well guys finally fitted my carbs today. cbr900 on a dan st manifold.
The car does run. but it bangs like an offbeat drum from the exhaust..its not smooth at all.
Dan st ally manifold with new silicone cuffs.
sytec regulator set at 2.5 psi.
all mixture screws set at 3 turns.. also tried at 2.5 and 3.5. seems best at 3.
balanced with a syncronometer and all equal.
Wont take large throttle openings... it holds back and revs drop... not been out on road. this is on the drive
any ideas ???
First thing I'd do is get rid of the regulator and fit a bike fuel pump at the back of the car before trying anything else.
What size main jets are you running on what motor 1.6 or 2l, 1.65 seems to ring a bell on my old 1.6 pinto.
Cheers
Rich
[Edited on 26/5/13 by RichardK for sh1t grammar]
[Edited on 26/5/13 by RichardK]
Pump and regulator work fine. Yes it can be improved by bike pump, but the set up you've got will work fine
Though 1.5psi was right for bike carbs?
Anyway, ignition timing sounds off? What ignition is it? Have you got your firing order right?
Are all plugs sparking right?
[Edited on 26/5/13 by blakep82]
Have you done anything to make sure or attempt to get the fuelling correct accross the rev range? if not chances are it is going very lean. As in
don't push your luck, could end in tears.
Best bet is either an air/fuel mixture gauge, or better still pop along to a rolling road. Lean fuelling kills engines pdq....
Some good advice there, if you took the ign leads off to fit the carbs, yep check they back on in the right order, presumably she was running fine ish
prior to the bike carbs going on?
What are the colour of the plugs, if you can't get access to a rolling road or AFR meter then I've had a bit of success with a gunson
colourtune to get it safe and not lean like Clifty quite rightly says.
Cheers
R
Take all the jets out and check them/give them a blow through.mine does something similar when one of the jets gets blocked.make sure you check them all,not just the mains as the holes are smaller in them and more likely to get blocked.
What does it run like on initial start up when the float bowls are full ? Whatever is said above bike carbs do not like regulators, they regulate pressure fine but restrict flow terribly at the low pressures bike carbs like ?
The timing and leads etc haven't been touched.
It was running fine yesterday with the standard 32/36 weber on.
I only removed the old one and fitted the bike carbs
I spoke to the guy at the rolling road he told me to set the mixture screws as it is and the regulator too.
I haven't changed any jets yet. as im unsure what to change to.
its a 2.0 pinto with no mods afaik.
If it was me I'd be drilling the main jets out to 1.55 and working up from their and definatly putting on a bike pump, yes you can get the reg
etc to work but the amount of threads I've seen about getting them to work properly certainly out ways the simplicity of just throwing a bike
pump on.
I'm also guessing that on your old set up you had a fuel return? Have you just blocked that up? Maybe check your not using that as the supply
Jets is the first thing mate, don't want to be holing your pistons mate by running too lean.
What air filter you using as this will affect jet size, as said previously I was at 1.65 with those cheapo cone filters on, Dave Boggs didn't
approve and took them off! I did sneak them back on though.
Cheers
Rich
If the carbs have been sitting arround try cleaning the pilot jets they are small and block easily and some times only new jets will cure the
problem.
I have bike crabs on a into running of the manual pump through a filterking regulator without problems.
As the main jet only effects the carbs on 2/3 throttle plus changing them will have no effect on you current problem.
If it was me take crabs off and get them check at a bike shop who should have a sonic cleaner and if they are cv crabs will check the rubber diaframs.
Good luck
Nigel
quote:
Originally posted by Nigel fury
If the carbs have been sitting arround try cleaning the pilot jets they are small and block easily and some times only new jets will cure the problem.
I have bike crabs on a into running of the manual pump through a filterking regulator without problems.
As the main jet only effects the carbs on 2/3 throttle plus changing them will have no effect on you current problem.
If it was me take crabs off and get them check at a bike shop who should have a sonic cleaner and if they are cv crabs will check the rubber diaframs.
Good luck
Nigel
^^^^ Haha must talk about crabs a lot if you are getting auto corrected!
2.5psi is too high, you need a bike pump that stops when the carbs are full.
I have a zx9 pump if interested, like others say, it pumps up to pressure and then stops
Looks like I found a problem. .inlet manifold leak. Ill get a new thicker gasket and try that 1st
The carbs were working fine my mate was breaking his bike
I got the mechanical pump and regulator from a mate who had bike carbs and did over 8k in it.
So im not changing the pump or reg as I know it all works.
Its a jetting issue imo. But obviously an air leak first.
[Edited on 26/5/13 by maccavvy]
oops double post
[Edited on 26/5/13 by maccavvy]
If it's any help I've just replaced my Facet electric pump and pressure regulator and fitted the bike pump instead and the difference is
remarkable. Bike pump primes up so much quicker and quieter, idle seems better as well, more consistent.
That DanST on Ebay where you got the manifold also sells 1mm thick novus manifold gaskets which he says take up any distortions in the inlet manifold
face.
He does a Pinto gasket
Ford 1.6/1.8/2.0 Heavy Duty PINTO INLET Manifold Gasket, Bike Carbs, Kit Car | eBay
[Edited on 26/5/13 by Scuzzle]
I've always used thick gasket paper and gasket sealant. Costs next to nothing to make your own inlet gaskets.