Bent emulsion tubes

[neechiekeech]

Evening all, I bought myself a GK76A a little while back for an absolute bargain, because it has carb issues. After a little research it seemed that all it would probably need was O-rings and a balance. No worries.

Anyways, I finally got round to striping the carbs and ordering the O-rings (bargain from polymax). But this is where things have gone a bit wonky. My first worrying discovery was the new stainless screws on the float bowls, hmmmm someones been in here recently. I take off the float perch and the O-ring looks surprisingly new. Someones recently replaced these and it's still not running right, hmmmm. then I remove the first emulsion tube. very bent, then the next again very bent, all of the tubes have been super bent. Aha this could be where my problem lies me thinks. Anyways I had a quick scout on the net and couldn't find a way of getting spares. So I picked up a second hand set of carbs of ebay instead, hopefully I can make one good set out of the two and the new O-rings I have.

Are bent emulsion tubes common or am I just really that unlucky?

Cheers,
Neechie

[gsxr400 91]

Cant say that the tube should be bent so guessing you've been unlucky. Cant hurt to have a second set of carbs as some spares are becoming harder to find. But seems to me your starting in the correct place. The carbs are a real pain in the a$$ . If not done correctly. Id say once carbs done cleaned n repaired move on to coil pack spark plugs etc if not starting. Hope this helps.

[Variablevalves suck]

Makesure the new o'rings are Viton as cheap Nitril are no good.
The emulsion tube only goes in one way around so if fitted incorrectly it could be damaged by the metal insert at its base.

[neechiekeech]

Cheers for the advice guys, don't worry I made sure I ordered some Viton O-rings, don't fancy doing this again in two months time.

It looks like whoever rebuilt the carbs just kept tightening up the tubes until they buckled, all four are like it. I'll try and take a pic tomorrow but it will be hard to show.

the bike was a runner just miss firing and running lumpy, but over 9000 rpm seemed ok (not under load). The guy I bought it off said it would ride ok for about 20 mins then die, if you removed the plugs and cleaned them it would fire straight back up. he thought one of the float bowls might be cracked??? They seem fine to me, is this a usual problem?

Also on a separate note, I'm doing the fork seals as one is leaking badly. I'm finding conflicting amounts of oil to be used per leg. Anyone know a definite standard amount?

Cheers for your help guys,
Neechie

[gsxr400 91]

Im not too sure but i think in the guide section i came across some use full info on carb setting bike dimentions and i think may also have oil levels ???? Might ve worth a check.

As for running 20 min then cutting out clean plugs then it working again would kinda suggest plugs are getting wet??? Could be down to float perch o ring or incorrect set float hights. Or again main jet or idle rings or even bent tube. Im in the process of rebuilding my carbs also. So changing all o rings . Check float hights and adjust if ness. N setting the mixture screws n that. But just awaiting delivery on o rings .

[gsxr400 91]

Its in the gk76a spec sheet. Shows fork oil cap and air gap. . . Think thats what your looking for.

[neechiekeech]

I noticed in the spec sheet it says 398cc's but I've also found figures of 429cc's.

I take it you guys go by the spec sheet here, that's cool. I'll do that and check the air gap. It's only a temporary thing anyway.

Thanks for all your help.

Just looking forward to getting her on the road/track while the weathers good.

Cheers,
Neechie

[ben2306]

if after everything, seems unable to start every now & then. may be the pick up coil...