Ke70 Acceleration Problem

[conan]

Hey my little pano poped its head gasket a little while ago n now its snowballed out of control... I got another head n decked it cause my one was shaved to oblivion put a new exhaust on n tried to run a much larger nikki carby i got off a mate but i couldnt tune it after a rebuild so i went n got another 4k carby my original was full of gasket goo thanks to a mate but its still not going it idles n revs fine but once u take off it kicks pops n farts all over the place n its ok once u get into a higher rev range n i have no idea what to do

[conan]

Just thought id mension that ive done the valve clearences new points leads plugs fuel filter oil filter n the timing

 

[altezzaclub]

The Federal Government may establish a national inquiry into the teaching of reading because of growing concern that many students are barely literate.

 

Well, yes...

 

So you have a new head, a new exhaust, a random stock Aisin carb and new points etc. The problem is that it revs fine without a load, but leans out when loaded.

 

I'd suggest you strip the carb, take out the jets, pump petrol through them with a syringe and then pump petrol through the drillings in the carb with the syringe. ...or if you have a compressor, use that. It sounds like a blockage in the carb, or an air leak in the inlet manifold, so it has enough fuel to rev it OK, but not enough to do any work. The idle system is suspect as it runs the motor up to two or three thousand revs before the main jet takes over completely..

 

Check the carb/manifold gasket while you have the carb off. Make sure the second choke closes completely on the carb too. Its unlikely not to, but that carb could have been mucked around with by the previous owner.

 

Seeing you have just put a new inlet gasket on with the new head, the inlet manifold should be fine.

 

Ah- and did you fit a new condensor with the new points?

 

Found a picture, worth a thousand words.. the red was for someone else's problem, but it shows the jets. It could be that your accelerator pump has dried out and jammed, so make sure you check that is working too.

Edited March 20, 2013 by altezzaclub

[ke70dave]

The carby is full of gasket goo????

 

Wont work with gasket goo in it.

 

Crburettas need to be perfectly clean to work well.

[conan]

stupid question but if ive got a compressor just blow through with air?

and my original carb was full of gasket goo due to my mate being a bit to liberal with it so i bought another one, any advice on air fuel mixture

cheers for the feed back

[conan]

i also pulled some of the polution crap off the inlet mani when i put the exstractors on the big 32mmish bolt with the hole on my main concern is that may not be lining up right so could it be leaking? ive got another mani at home so i reckon il swap them out n i got a condensor

[altezzaclub]

OK, electrics are hopefully good and inlet system is the suspect.

 

Are the inlet and exhaust manifolds the same thickness in the flange?? If they are extractors they are probably different and one manifold will not be clamped on properly. You might need to slip a length of wire behind the washer at the thinner flange.

 

Use the compressor to blow out the jets but don't blow them out of your fingers and across the garage! Blow through the drillings in the body too, any crap in there will run it lean. If the carb has dried out in the past the fuel evaporates to a tarry jelly that blocks everything. Do it all carefully on a big sheet of newspaper on a clean bench.

 

You should be able to spray something, CRC or WD40 or Startyabastard, around the inlet manifold and listen for any change in idle as it gets sucked into a hole in the inlet manifold. You could take a length of plastic tube (whch I use for brake bleeding) and put an end in your ear then listen around the inlet manifold for leaks. You'll hear them quite easily. ..or get flash and buy a stethoscope made for that purpose.

[GJM85]

If its popping and farting when you take off its possibly leaning out in the progressive circuit or primary main. The first thing i'd look at is the accelerator pump.

 

Check what size your main jets are also. A stock 4k should run 106 or 108 primary main jet and a 153 secondary main. If your running a fair amount of compression with a shaved head and a decent exhaust the primary main jet may need to be enlarged.

 

The progressive circuit of your carburettor is a series of tiny holes just above the primary throttle plate fed from the idle cicuit. Fuel is drawn through these holes as rpm increases from idle to around 1500rpm where the main circuit takes over. You need to make sure these holes are clean of any carbon build up as well as the idle jet.

[B.L.Z.BUB]

Sounds like an inlet manifold leak, same thing happened to me when I removed my pollution gear.

It was leaking around that big bolt you mentioned. That and my timing was out.