Carburettor Issues... again :P

[HD]

[HD]

Thought a minute ago, when we moved the clip on the needle, the revs were a bit high and the screws needed fannying around to get it back to decent revs. It ran lovely when the needles were clucked but it idled really high. When its idle was put back to normal, it had the same problem.

So a minute ago I fannyed around with the needles.

This is what it sounds like with the revs up high. It runs absolutely lovely but when it idles it drops after a couple of seconds and (like you'll see) the engine cuts out.

I tried to get it back to what it was before to show you what I like the revs to sit at. At the beginning it is a little high and doesn't get caught up as much but a little bit. If you listen carefully when I rev it from idle you can hear it.

I then turn it down to the normal idle speed and you can hear it get caught up. It does this when I rev it from idle and it does it when I am riding in that particular rev range.

Don't know if that clears anything up at all? Give a hint or something? Is it anything to do with the pilot jet?

Thanks guys
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Rusty '02 Vito Camper + CBR600F3

[spyuggy]

If your bike does not need choke to start in the cold, then it is definitely running too rich.
It is possible that the choke is stuck on, this would use more fuel and create the symptoms you have described.
Try running the bike with the choke half on and if there is no difference, your problem is too much fuel getting in, probably a stuck choke.
It's worth a try.
Good luck mate
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Treat each day as if it was your last, because one day you will be right.

[HD]

Don't think it is that because if the choke is put up, the bike cuts out

It was like that when bought it and I have rebuilt the engine and most of the bike and replaced the jets in the carb with the correct ones and it still does it. Is my choke jet too big? Or does that only come on when you apply the choke?
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Rusty '02 Vito Camper + CBR600F3

[spyuggy]

You are right, it only comes into play when you apply the choke(which enriches the mixture). I am wondering if it is sticking slightly, as your problem sounds like a rich mixture. No doubt you have checked your plugs to see the colour and if they are dry.
It may help to upgrade your main jet with a slightly higher one, but don't go too high. It is worth a try.
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Treat each day as if it was your last, because one day you will be right.

[spyuggy]

I have replayed your videos and it sounds like it is getting choked to death,maybe worth changing your idle jet and upgrading your main jet.
The problem definitely sounds like too much fuel at low revs, when you tried to restart it, did you smell fuel?
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Treat each day as if it was your last, because one day you will be right.

[HD]

Plugs show typical richness.

Can't really say I smelt a stench of fuel but I want sniffing for it like.

And surely I need to go down jets if I want more air?
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Rusty '02 Vito Camper + CBR600F3

[temeluchus]

check the choke lever, cable and mechanism on the carb itself for proper operation. Give it all a good clean and lube.

inspect the float needle for wear and the float for proper adjustment.

make sure the air filter is clean and that the airbox and inlet isnt obstructed (inlets covered with tape are obvious signs of bodgery).

rich running is usually related to one of those three on a bike in stock condition.

other than that you will need to lower the needle to lean out the midrange (buy moving the clip UP towards the top of the needle- the blunt end) and check the idle screw isnt set too rich which will make it bog at low revs and also make it start too easily with out choke.
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Some shite cruiser. Now with guns and FREEDOM!

[orac]

personally i would be tempted to tweak the mixture needle before jumping in with new jets. if its running rich 1/4 - 1/2 turn in, if it still does it then its running lean and the screw need to go the other way - dont forget to check the number of turns it has before making any ajustments (presume you know how to do that).

if this is an after market exhuast thenthe fuel misture would have to adjusted to match. does it still have stock air filter. the simplest option would be to bolt the stock exhaust back on.

also if you think there may be an issue with the choke, disconect the cable and push the plundger in to elimate the cable being the issue.

other than that strip clean and check everythng like everyone else has already said

[HD]

There is no cable for the choke, it sits on top of the carb. I know that one woros because the bike cuts out if I turn it on (which leads me to thinking get more air in). And also cos the plugs show richness.

Think orac could be right with the needle situation though as when I fanny around with the needles, it makes it run better, BUT it has to idle high.

How would I check the float and float needle for wear/adjustment. I'm alright with most things but I don't really get carbs.

Air filter is stock and clean and bolting on the standard exhaust is not an option. And I'm running the main jet the people who sold me my exhausts recommended. They did say that it can often vary though.

Cheers for the help guys!
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Rusty '02 Vito Camper + CBR600F3

[temeluchus]

[orac]

if it idles high then adjust the idle setting with the idle adjuster.

as for checking float hight, drain the carb and take it off the bike, take the float bowl off and turn the carb upside down, keeping the bottom of the carb (the flat area where the bowl touches) level with the ground take the reading as shown in the manual (most nomrally go to the bottom of the floats). check that reading against the one listed for your machine.

you shold be abl to remove the float needle easily now your in the float chamber. it atached to the float/s and has a seat that it slide ino and out of. the needle shold not have any wear on the top sufaces.

if the bike needs more air, turn the mixture needle/screw in by 1/4 turn to start with and see if that start to improve it

[temeluchus]

[orac]

yeh true, but reducing the fuel will be the same as adding air, unless he has a blocked airfilter, or somethinb blocking the venture, or a sticky slider there is only a few way of adding air.

adding air is very hard, but the turn on the mixture will help in figuring out what the problem is

[HD]

If I turn the idle down, then it goes back to how it was before.

And I'm not gonna bother with all of that, because it takes like 2 hours to get the throttle cable/slide/needle back together and in the carb. So ill just accept it how it is, I have for nearly 12 months anyway.

Is there literally nothing I can do without taking the throttle cable from the carb?

Is it anything to do with the pilot jet? Cos its when its left idling for any amount of time or just rolling with no throttle it does it. Or the main jet?
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Rusty '02 Vito Camper + CBR600F3

[orac]

you most likely need different size jets in both. you need to know how far to go, as a general rule, 10% for the main.

start with the mian if you can the right one for your carb, be warned tho they can be expansive. last time a bought any they were £2.50 each

[HD]

I fannied around with it earlier again when I got home. I got to the stage where I could have the air screw quite far out and the idle out pretty far and it runs lovely. Thing is it cuts out after like 10 seconds and you have to bump it. So I will perfect it tomorrow but I took it round the block and it is soooooo much better.

I pulled away slowly and it doesnt splutter and rode it quick and didnt splutter. It revs sooooo high now aswell, powerband well before this so I dont rev it that hard anyway. Before, it almost had a rev limiter sort of thing going on where the fuelling wouldn't allow it to go any higher (sort of good thing).

Would it have anything to do with the screw being slightly bent or is it purely the mixture? It was bent when we got it and I couldn't source a screw but now I can and its £8 and I don't think I need to bother if this is going to be fine.

Cheers for the suggestions though guys
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Rusty '02 Vito Camper + CBR600F3