Bike carbs

[nova_mad1987]

Hi, I have just fitted bike carbs to my 1.6 8v ohc, when you first start the car it runs smooth, then after bout 5 seconds of it running it starts running really lumpy, causing the engine to sound ratterley, I have try altering the ignition timing but doesn't change it at all, also if you try revving it, it cuts out, any ideas? Many thanks :)

[Saloony]

Fuelling it sounds like

[nova_mad1987]

Would it running rich cause it 2 run lumpy then? Thanks

[Paul]

Yeh, running rich or lean will make it run poor.

[tom reid]

Have you drilled the jets out?, what size?
Have you used the choke?
Have you set the idle mixture screws?
Check for air leaks

[Nobby]

hmm like tom said check all of the above does sound like an air leak to me though

[nova_mad1987]

Hi, I have set the idle screws to 3 and a half turns out, I have used the choke which didn't seem to make any difference, I have not drilled the main jets out yet, the spark plugs are black. How do I check it for air leaks? Thanks

[C612DNM]

Running rich then.

[Nobby]

just check all your rubbers from manifolds to carbs are tight mate spray some brake cleaner over the inlet side of the engine if the revs pick up then thats where your problem lies, however you say that the plugs are black deffo sounds like over fueling what pump are you using?

[nova_mad1987]

I'm using the r6 fuel pump, do you have any idea of a setting for the idle screw, and the main jet, many thanks

[nova_mad1987]

I have put fuel in on the main line in the centre of the carbs, there is a plastic rail that links all the bowls together with two hose connectors at either end, am I right to jus leave these to vent? Thanks

[Southie]

Have you fitted a fuel pressure regulator?

[nova_mad1987]

Hi, I was told the r6 fuel is regulated

[Southie]

Hi, I was told the r6 fuel is regulated
It will be but wouldn't that be for the R6 bike rather than your car. I remember someone did mention before though that they've run a R1 setup on there 1.4 and they ran the fuel pump off a R1 so I could be wrong.

LINK (http://www.pngclub.com/forum/showthread.php?t=153627&highlight=bike+carbs+pressure)

[Sloth]

its overfuelling, so its either incorrect mixture or wrong jets. are you near a rolling road? id look at getting it set up properly before it eats itself.

[nova_mad1987]

I was going to get it rolling roaded once I had it at least running abit better, I'm in the midlands area, anyone know any good rolling roads in the midlands? I'm goin to turn the mixture in by a turn which I believe will lean it more?

[Sloth]

northampton motorsport?

[nova_mad1987]

This evening I have leaned the mixture, the plugs are not going black any more, light brown colour, but it is slight running badly lumpy and cutting out, so I'm guessing it can't be the mixture, I'm not sure wot it will be now

[Angus Closier]

If it runs for a few seconds fine? Then could be the pressure to the carbs is not enough and the fuel bowls are draining quicker than they are getting filled causing it to run lean/poor. Check the fuel pressure getting to the carbs.

[nova_mad1987]

Hi, it runs sweet for a few seconds then after that it run lumpy, wot is the best way to check the fuel pressure? Many thanks

[Saloony]

The R1 pump is self regulating, cant tell you if the R6 one is, sure fire way is on turning the ignition on listen for the pump priming up, should slow down then shut off after a few seconds. Start the car, as soon as its running get out and get to the pump and listen for it, it should have a constant tick at idle keeping the fuel up to the carbs and holding pressure. If no noise, your either loosing power to the pump or the pump is shagged, if the pump is going like a set of nail clippers then the carbs are possibly leaking out.

[Angus Closier]

Get a fuel pressure gauge and stick in in the fuel lines before the carbs and see what its reading!!

[nova_mad1987]

Thanks, I will give that a go tonight, I have also been told the carb balancing might be badly out

[Nobby]

mate i took mine to a bike rolling road called projex in cradley heath and he did a balance check for me different car afterwards.

http://www.projex-uk.co.uk/

[Nobby]

double post!!

[nova_mad1987]

The R1 pump is self regulating, cant tell you if the R6 one is, sure fire way is on turning the ignition on listen for the pump priming up, should slow down then shut off after a few seconds. Start the car, as soon as its running get out and get to the pump and listen for it, it should have a constant tick at idle keeping the fuel up to the carbs and holding pressure. If no noise, your either loosing power to the pump or the pump is shagged, if the pump is going like a set of nail clippers then the carbs are possibly leaking out.
Hi, I have got it idling now, the fuel pump is making a clicking noise, wot do you mean by the carbs could be leaking out? Many thanks

[nova_mad1987]

Won't rev up due to a air leak!