ABF 16v engine + ZXR750 bike carbs into mk2 1.6 driver

It's a runner!

 

on the fourth day she ran
timing issue user error!!!!

Cheers Danster

 

okay so the car is back together..
throttle is normal golf driver one just 'made to fit'.

revs sit at 1100 ish and can be dropped with the adj screw and is more or less wound right down so the throttle is closed, it will wind down more and allow it to stall, so it's just above that point..

the revs don't like to come down too quickly once revved.

the throttle is very very sensitive, just a touch on the throttle and the revs climb right up high.

I'm thinking the idle screws may be too high and just way over fuelling when I give it throttle.


considering this it is quite a steady idle.

The injectors have been taken out of the fuel rail and the rail has been plumbed to the brake servo and ECU vac, there seems to be no leaks that I can hear!

In regards to the timing, that is sorted to TDC (cyl no1) and on the notch on the dizzy, Danster you mention on the phone yesterday to turn the dizzy a bit to get some advance etc?

 

I would turn the dizzy a little clockwise (from passenger side) to advance it a little from the last pic I saw.
The mixture and timing will need to be finely adjusted for your particular engine.
You could try turning the mixture screws in a turn or two and see if it makes any difference.

 

You need more fuel at idle from your sypmtoms of how the revs are rising and not falling quickly back to idle. YOu either need to wind out the mixture screws a bit more Or you have an air leak somehwere.

 

now it's sucking off the manifold. Had enough

 

You cannot have the silicone hoses un supported for any great distance or the vacuum on tickover will try to collapse the hose.
Can you slide the silicone hoses down the manifold a little so it leaves about 15 to 20 for the carb stubs to fit on. This will leave a very small amount un supported and may stop the hoses collapsing.

Did you try adjusting the dizzy to advance the timing a little? This may help the tickover a lot.

As M1keh mentions, the revs not falling back is symptomatic of a weak mixture on the progression phase, This is the problem with bike carbs jetting on a 2.0 engine. A 1.0 bike engine ticking over at 1000rpm is different from a 2.0 ticking over at 1000rpm. Tends to mean the car is ticking over in the progression phase a little, and may need tweaks to jet size to help the situation.

 

in regards to the high revs and not coming down I think the throttles weren't closing fully.
when i lifted the throttle and let it close itself they would stay high and slowly come down to the 2k ish.
however if I kept hold of the throttle and closed it fully with my hands the revs would drop immediately to 1k.

think I may need a new manifold, the one I had made up has runners on an angle which is causing the problem of them coming off because my carbs are too closely fitted together. if I move the silicone down any further down I will really struggle to get them on the carbs.

 

Cut and re weld?
Would you manage to fit a slightly longer manifold in? Have a good look around it as it is now, and then decide if any changes could be made that would help the situation.

Revs not dropping sounds like the cable not allowing the throttles to snap shut properly. You will also have to check that you are not getting full throttle before the pedal hits the stop, as this is a sure fire way of busting the stupid rubber donut at the top of the pedal where the cable attaches, or pulling the cable out of however you have fitted it too the carbs.
Getting this sorted will save having a breakdown at the side of the road.

 

If I get some additional 45mm piping welded onto the runners to extend them straight out about 30-40mm they should line up perfectly with the carb spacing, the outer 2 will still be at an angle but there will be almost zero unsupported silicone.

 

great thread and congrats on getting it running.

it reminds meof when i bike carbed a polo 1.4 16v, i had similar problems getting the revs to drop down, i added a spring to my acc pedal to help pull the cable back when i liftedmy foot off. might be able to do that.

if you remove your manifold again, would you be kind enough to post up a pictureof just the manifold?

excellent thread and danster is a star, he has helped me out with engine stuff as well.

 

cheers bud, I'm sure there is more to come though!

carbs and manifold are off the engine at the moment.
manifold goes to fabricators tomorrow and should be all sorted on Fri.

I'll get a pre and post picture up to show the difference.

 

excellent. good work.

 

Progress







when I first cut the manifold down I was left with about an inch of bolt hole, see prev posts.
No other bolts would fit and the 5inch long ABF lower manifold bolts could'nt be cut down as they only have thread on the bottom inch or so.

You can see here that I had to cut away 20-30mm so that the bolts from the oil filter housing and the mechanical fuel pump from the driver engine would fit.




Here is how the manifold fits upto the carbs, I thought it would be okay with the silicone on them but they are just too far apart and the silicone wants to come off the outer two intakes without any vac from the engine pulling on them.




I have room to under the bonnet to extend the carbs forward so here's the plan..
using a length of ali tube 45mm OD 2mm thick I plan to get the fabricators to weld straight onto the old runners thus bringing the intake closer to the carbs.
The middle two pipes will be welded on straight forwards and the outer two straight on from the angle runners then I'll get them to machine them all off straight so they line up perfectly.
this should also eliminate any unsupported silicone.
I've use paper to illustrate this.

 

runs so much better, no un-supported silicone and fits well under the bonnet.

when the engine is cold it doesn't like to rev up and stalls on WOT.
and tries to stall if choke is opened for over a few seconds.
once warmed up it runs quite well and can rev right up with no splutter etc.
nice steady idle though and sounds amazing.

 

tried adjusting the idle as it wasn't up for revving and was undriveable.
wound the idle fuel screws out to three full turns, nothing.
wound to four full turns out, nothing wouldn't fire unless on choke ~(engine hot)
wound back down to two full turns out and nothing......
I was winding up and down on the main throttle position too.......
now it won't fire...

 

now the battery's died........

 

Fuel pump still working?

 

yup.
if the idle screw mixture is out and the idle screw is out and the carbs are out of balance, it should still run, just like shiz?