Evilchicken0 wrote:It sounds more like the idle jets but because it affects all the carbs it could be they're the wrong size .... or maybe the choke isn't working

It has got me thinking why all four carbs appear to be playing up exactly the same, as if there is a common fault affecting them all, ie. fuel starvatiuon. But, I've checked the fuel pump, float heights, choke, etc and they appear OK. The rubbers are fine, from what I can tell so far, with no vacuum leaks. It could be the jets, being as the numpty rebuilt the engine incorrectly, he could of also had a look in the carbs.

I guess all four could be blocked, in the carb fuel ways (not the jets). That's what I'm going to check tonight.

I have managed to source some replacement carbs, so when I get them I should be able to swap parts etc.

I have just had the same problem. Just finished a full service on my Genesis. plugs, valves, coolant, filters etc.etc. Go to start it up, nothing! Carbs off and apart 4 times. ended up like yourself putting my hands over the inlets of the carbs and she eventually fired up. Battery attached to the Wifes Micra via jump leads. She now starts on the button, (the bike not the wife). Couldn't figure out why it would not start. I did leave my hands on the carbs for a little while. Oh and my choke doesn't work the cable is stretched so a new cable is on the way.

stranglerman wrote:I have just had the same problem. Just finished a full service on my Genesis. plugs, valves, coolant, filters etc.etc. Go to start it up, nothing! Carbs off and apart 4 times. ended up like yourself putting my hands over the inlets of the carbs and she eventually fired up. Battery attached to the Wifes Micra via jump leads. She now starts on the button, (the bike not the wife). Couldn't figure out why it would not start. I did leave my hands on the carbs for a little while. Oh and my choke doesn't work the cable is stretched so a new cable is on the way.

They do need the choke to start from cold, I found that out on my FZR. Hope your problems are solved.


I took the carbs off tonight to give them a clean.

First off I removed the float bowls and floats, then took the caps off and started removing the diaphrams.






Don't forget to take the little O-rings off aswell.




I turned them over and removed the jets.




MMMM, evidence someone has been fiddling. The retaining nut on the end one is different to the others.




I then removed the holder for the jets (I don't know its proper name)




While I was blowing the carbs out I noticed one of the mixture screws was leaking (it was blowing small bubbles). I removed them all and noticed the one that was leaking was different. Here's two of the screws and the odd one!




I gave all the carbs a good blowout with the airline. I also removed the guides for the slides and needles when I did this. Then started reassembling them.




I put the carbs back on the bike and connected everything up. Time to push the button again.........

IT'S ALIVE!

It took a little persuasion to start with, but then she fired up. Still running rough but with the mixture screws and balancing to sort out I expected that.
I should be getting another set of carbs soon so I'll replace the odd parts then. It will give me time to try and find a supplier for new screws, etc. (I've got a couple of phone numbers to try).

Another new tool, I'm going to use this for measuring the temperature of the headers. I gave it a quick go and 1 & 2 are running hotter than 3 & 4.

Good news huh

With the extra set of carbs you'll have a few spares for the SP too. The jet holders are Emulsion Tubes

Just an update.

The YB7's had it's carbs sorted and dyno'd. I took it in for an MOT today and it passed. Taxing it tonight and she's back on the road. Result! Looking forward to a sunny weekend now,

And a sunny Firday week huh ?

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