Assembling Carb bank

[dswalker]

Hi guys,
I'm hoping someone out there can help as I'm having a couple of problems.

Firstly the bike (a GK76 SP2) was running fine then all of a sudden decided it didn't want to play while I was riding home from work on friday. It wouldn't rev past 12K and wouldn't maintain that anyway, the revs would fluctuate and then the engine would die but it would start up and idle pretty much fine.

Not knowing what it was I started with the usual coils, pickup, regulator but they all seem to be giving the correct readings. (The regulator is chucking out 13V regardless of revs, is this right?)

Took the carbs off and under each diaphragm was a huge amount of bits of black rubber. These weren't coming from the fuel lines so I started looking for other possible sources. I had replaced just about every breather and the O-rings when I noticed fuel was leaking from where the fuel enters the carbs.

Now I did what everyone says not to do and took the bank apart to fix this leak. The rubber that was on the plastic T piece was split so I replaced with several O-rings. The problem is that when I put the bank back together and tighten everything up the butterflies won't move.

What have I done wrong and how can I fix it. Thanks for any help and advice.

[dswalker]

OK, so I figured it out.

For anyone wondering I took out the 3 adjustment screws and the springs then bolted the carbs back together. I then put the springs and adjustment screws back in and adjusted the butterflies back to their correct position by turning the screws one at a time and checking the butterfly fit with a set of feeler gauges.

I'll post tomorrow with how it runs as tonight it is time for bed.

[4hundread]

R

[dswalker]

Tried starting this morning and fuel poured out of the overflow on carb #3.

Time to take them off again.

[Variablevalves suck]

Seeing as youve had them completely apart it my be worth while filling them with fuel before fitting to the bike, that way you will know they hold fuel and will not have to strip the bike again if they leak, set the floats up well before refitting and check the float needle on the leaky carb.

[dswalker]

Thanks for the advice.

I'm going to be tackling this this weekend but was wondering if anyone could explain how to set the float hights. I don't know if they are set wrong on my carbs but at least 1 of them sits lower than the rest and I know that can't be right.

Cheers again

[Variablevalves suck]

There is a picture and explanation on Tony's blog -
http://tonysleep.co.uk/gsxr400carbs

[dswalker]

Thanks for the link was quite helpful.

As an update, the bike is now running, although it won't idle nicely but I suspect that is down to the carbs not being balanced properly. As for the fuel out of the overflow initially it was down to a sticking float but fuel continued to pour out of the overflow. At this point I discovered that when the bike was last set up, to compensate for the fact that the float heights were way off, the mix screws were wound out almost 4 turns! Turning them back to 1.5 turns meant that the bike starts and runs but I think it may still be a little lean but whilst it runs and I can get back and forth to work I'm not going to complain.

Thanks again for all your help guys.