Norfolkluegojnr
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| posted on 21/8/14 at 09:33 PM |
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Bike carbs first start - engine rocking heavily
Evening all,
Finally got my zzr600 carbs on my crossflow. After a bit of frigging around, and electrocuting myself twice (don't ask) I got it idling.
Idle screws all out 2.5 turns. Using a new zzr600 pump, fast dan manifold, new gaskets etc.
First thing I noticed is The engine is rocking heavily - I'm sure I remember some one telling me this indicates something? Carbs out of
balance?
Presume next steps are balance airflow, then tune idle, then start playing with needles and jets?
Currently running 150 but suspect this maybe to large.
Suggestions?
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19sac65
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| posted on 22/8/14 at 03:28 AM |
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It does sound like balance,are you happy theres no air leaks
Main jets wont effect idle
Did you mean 2.5 turns for idle mixture - thats ok for a starting point
Easy basic way to balance
Get a piece of mig wire or similar
Adjust the tick over cable on the master carb , the one the cable goes to , so that you can get the mig wire under the butterfly - like a feeler
gauge
Then set all the others so that theyre the same
Start the engine and reset tick over
I got mine almost perfect this way
If youve got tps that will need resetting
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redturner
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| posted on 22/8/14 at 08:19 AM |
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I would suggest that you need to go bigger on mains, up to 180 will be ok.....
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Norfolkluegojnr
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| posted on 22/8/14 at 08:31 AM |
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quote:
Originally posted by redturner
I would suggest that you need to go bigger on mains, up to 180 will be ok.....
Really?! i ran 160 on my 2ltr Zetec - this is only a 1600 Crossflow!
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redturner
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| posted on 22/8/14 at 08:48 AM |
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I run 180 in my Zetec with air correction set to .075mm.......
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Norfolkluegojnr
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| posted on 22/8/14 at 09:03 AM |
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Ok thats useful thanks.
any other input on the rocking issue?
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Ugg10
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| posted on 22/8/14 at 09:24 AM |
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Rocking usually means not all four cylinders are working.
Usual suspects are - air leak in inlet, no or weak spark, no fuel or low compression
Start by checkingwhich cylinder is off, remove the soark plugs one by one to see which makes the least difference (removing a good one drops you to
two cylinders), then check for spark, easiest to do. Then compression check. You can check for inket leaks by quirting wd40 or easystart around the
affected inket joints, if none of that shows anything then check carb ballance anfpd fueling (spark plug colour, wetness)
Hope this helps.
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Norfolkluegojnr
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| posted on 22/8/14 at 09:35 AM |
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quote:
Originally posted by Ugg10
Rocking usually means not all four cylinders are working.
Usual suspects are - air leak in inlet, no or weak spark, no fuel or low compression
Start by checkingwhich cylinder is off, remove the soark plugs one by one to see which makes the least difference (removing a good one drops you to
two cylinders), then check for spark, easiest to do. Then compression check. You can check for inket leaks by quirting wd40 or easystart around the
affected inket joints, if none of that shows anything then check carb ballance anfpd fueling (spark plug colour, wetness)
Hope this helps.
Thanks Ugg.
I thought hat might be the case. Defintely got spark from all four leads, checked that last night.
Plenty of fuel going in (possibly to much!) but havent pulled the plugs yet. All four exhaust headers were hot to touch, so i guess i am getting
combustion in all cylinders.
Air leak is possible, i'll check all fixings.
Compression - did a check recently, came back ok, but one cylinder was a little low. Will redo this as well and report back.
Presume its worth attempting to balance the carbs to rule that out?
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jacko
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| posted on 22/8/14 at 05:50 PM |
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180 seem's too big to me also i only had 170 on a tuned 2l pinto zx9r carbs
Jacko
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redturner
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| posted on 22/8/14 at 06:19 PM |
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It was a suggestion based on my own experience. I run up to 190 mains in my FF1600 engines through the 32/36 dgv carb and the Zetec B/Top I run in a
single seater runs 180 mains. This engine is absolutely standard except for the R1 carbs. On the rolling road it made 156 @ 6500 and the afr readings
were 120bhp 13.2, 154bhp 13.2.. 156bhp 12.8, The air correction jets were set to .075mm. I use a solid state pump with the regulator set to 3.4 lbs.
Fuel pipe is 8mm, carbs are installed with the float chambers set level, on a DanSt manifold I use Weber main jets as opposed to drilling out the
originals. When the installation was first started it certainly rocked a bit giving the impression that it was missing but removing the plug leads
independently proved they were all firing, it was just weak...
I would point out that the car is used for hillclimbing /sprints and the engine is flat from the word go
[Edited on 22/8/14 by redturner]
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David Jenkins
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| posted on 22/8/14 at 06:37 PM |
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It's probably worth trying to balance the carbs - it's an easy job if you've got the right tools. Can't remember what
it's called, but I've got an air-flow meter that you shove in each air inlet in turn. Once you get the same number in each inlet,
you're done.
FYI: my x-flow shook, spat and shuddered when I first started it. It was as smooth as silk once I'd balanced it properly.
[Edited on 22/8/14 by David Jenkins]
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whitestu
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| posted on 22/8/14 at 07:26 PM |
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My Zetec runs 1.6mm mains in ZX6 carbs and if anything is a bit rich.
Careful balancing makes a huge difference to engine movement at tickover.
I use a Morgantune on mine but if you have an aftermarket manifold youmay not have vacuum takeoffs you can use.
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Norfolkluegojnr
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| posted on 22/8/14 at 08:08 PM |
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Thanks all- all experience appreciated.
Picked up a balancer and borrowed a color tune for tomorrow, so will report back with findings. I suspect it just needs setting up, but your comments
have encouraged me after a difficult evening!
Last point. A lot of talk on various posts about blocking an air corrector? Do I need to do this, and where would I find it?
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redturner
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| posted on 22/8/14 at 08:36 PM |
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I was also told that I needed to block the air corrector jets, but the man who did my RR session said that he had heard all these reports and
suggested that they need to be in use. Why would they be fitted and lets be fair, all carbs have them. He blocked them up with plastic padding type
stuff and starting small, drilled them out until he was satisfied.....
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19sac65
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| posted on 22/8/14 at 09:33 PM |
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People block the air corrector if they have trouble running too weak
Closing the air corrector usually allows a smaller main to be fitted - but no two engines are the same
Bogg bros have used 2.2 jets in standard zetecs,others are happy on 1.6 ( some 1.3 with air corrector blocked)
As i said above i dont think your far out on what youve done
Before you start messing get them balanced and idling nicely
Then see what its like on WOT on the road
Only then will you know where to go regarding main jets
Get it hot ,roadtest flat out in third , then kill the engine - dont let it idle
Whip a plug out and see what colour it is
Thats a guide as to whether the mains are ok
Just finished my conversion and its a bit of faffing but well worth it
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Norfolkluegojnr
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| posted on 23/8/14 at 07:03 PM |
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Ok, so a quick update.
Luego Snr came over to give me a hand to see if we could figure out the running issues on the carbs.
Firstly, we did a compression test - carbs off (so WOT) between 150-156 across all four, so im happy there are no HG or ring issues now.
So, carbs on. First, we balanced the carbs using a gunson Carbalancer - not a high quality bit off kit, but it did the job enough to kill most of the
rocking.
So, onto the Colortune. all going well - cylinder one and two both showing a little lean, but easily adjusted.
Got to cylinder three - clear spark, but no ignition. very odd. carbs off, all seems ok, so back on. Same problem.
After a lot of dicking about, turns out my rocking issue was running on three! Im amazed how well it ran like that. The pilot jet on carb three was
hopelessly blocked - i think old fuel had left some sort of jelly like goo in there.
Managed to unblock it, and hey presto, running quite nicely. It needs a final tune up, and i think the mains are to big, but all easy to fix. I think
i'll replace the pilot jet too, just incase its not completely clear.
Thanks for the input, once ive had time to fine tune again, i'll report back.
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coozer
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| posted on 23/8/14 at 07:21 PM |
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The air correctors are there to balance the pressure in the float chamber on the bike where they run the standard box with the scoop at the front of
the fairing. As the bike picks up speed air is forced into the air box front where positive air is split to go into the bell mouths and some into the
air inputs on top, this balances the pressure right through the carb.
Not needed on our cars. If you get a dynojet kit you will find four little grub screws and a tap for blocking these. Without blocking them air bleeds
across the main jet and the motor runs lean.
Back to the main Q... Get the carbs perfectly balanced before anything else as you'll be chasing ghosts without getting them equal across
allfour cylinders first. The vacumn gauge type are the best plumbed into each carb runner.
Good luck,
Steve
1972 V8 Jago
1980 Z750
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redturner
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| posted on 23/8/14 at 08:09 PM |
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If that is the case why do all the other carbs we use have air correction,.,both my 32/36 carbs have them and as far as i know, all the twin choke
Webers have them..
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whitestu
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| posted on 23/8/14 at 09:13 PM |
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I think blocking that air correctors depends on the type of carb. My Zx6r carbs don't need anything blocking.
Stu
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