1980 KZ750 / 4 Carburetor questions .. help WG ???

OK ... I started rebuilding my Keihin CV-34-30 carbs today ... primarily to solve a float bowl leakage problem.

So ... The 4 kits I bought included each a primary needle, spring, washer, O-ring and plug .... float bowl gasket, float needle and wire clip plus two more O-rings. The kits look to be quality kits ... the brand name escapes me at the moment.

1. So I started with exterior cleaning a bit .... then I removed the float bowls and cleaned them thouroughly. I loosely replaced the bowls and moved to the primary needle assembly. The original plugs were no longer in place. So I carefully removed the old needle, spring, washer and o-ring after checking the turns to seat. 3 of the needles had 1 1/2 turns to seat .... one of the needles had only one turn to seat. The manual states the US models have this adjustment preset from the factory (hence the plugs) but all other models require adjustment to two turns out from seat. Should I start with the two turns out setting ... or will this be different for US models ?

2. Back to the bottom end ... I removed the float bowls again and started by removing the floats and old needles ... then a good spray cleaning. I'll check float levels once I am closer to done .... as per the service manual instructions .... The problem I found in the bottom is that one of the plastic plugs over the pilot jet is gone. Now ... my bike has been running for one and a half seasons apparently without this part ??? Will it run better with it ? And does anyone have an extra one laying around ... or will the Kawi dealer have one ??? I'll post a pic of the part tommorrow. I assume that one of the new O-rings goes under this plug.

3. The last new o-ring ... does that go to the float bowl drain plug ?

4 Last but not least ... jetting ??? My 1980 KZ750H1 LTD 4 cylinder has had some mods over the years ... I was told when I bought it that it had an 810 kit in it but I cannot veryify that as I've never had the head off ... plus it has Emgo pods in place of the stock air box and a V&H 4 into one header ... The secondary main jet is a #62 the pilot jet is a 35. I think she's runnin' a bit lean ... but the local motorcycle speed shop dyno'd it and said everything looks good ... with a peak horsepower of 64. The manual states that this engine should make 74 hp. Any suggestions as this parts combo should be quite common and I'm sure someone has rejetted for this exact combo before.

After I get the carbs done I'm gonna tackle the valve adjustment procceedure. My bike is already very fast for a 750 ... but I think she should have a bit more just from tweaking and maintenance.

Here's a picture of the plastic plug I'm missing .... you can see the orangish plug sticking up in the inboard carb ... but missing from the same place on the outboard carb.

[IMG size =- 550] i13.photobucket.com/albums/a262/2M4Dale/Carb1.jpg [/IMG]

Since you had the bike dyno'd by a local shop and they told you the jetting was OK, why call me out? I won't argue with the results of another professional as it isn't very professional to do so on my part. The plastic plug is there to plug the slow jet well. Gas for the slow jet is drawn across from the main jet well via a cross passageway and the well must be plugged else the cylinder will run rich at the bottom of the rpm range. Two turns out on the mixture screw is a good starting point. wg

Hi Dale

1) 2 turns out is good. It's what I have on mine but then I'm in Canada and probably have the UK model without all that anti smog tubing coming out of the head.

2) Like WG said, you need that plug. Bike will run much better with it. Kawasaki.com says part # 11012-1128 is available so I would give it a shot and order one up.

3) That last O ring probably does go on the drain screw. I think the last rebuild kit I got had 3 O rings. A tiny one for under the air mix screw, one for around the plastic plug and one for the drain screw.

4) If the local shop did a dyno run and saw 64hp at the rear wheel then this could equate to 74 at the crank ??? You mentioned #s for the pilots and primary main jets. What # on the secondary main.

All the above just my 2 cents but then what do I know, I'm an amateur.

Hi Dale,

Not sure which carb rebuild kits you have, but I used some K&L kits last your on my CV-34 carbs. My only word of caution is be careful about switching out the plug o-ring. Fortunately I only did one at a time, so when I ripped off the old plug o-ring and put the new one on.I found it wouldn't fit back in the hole! My only alternative was to try and trim the o-ring with a razor to get it to fit. Took me three of the little suckers to get it right. Needless to say, I didn't bother with the rest.

Well George ... you seem to be the resident, trusted, expert and the week I had the local shop work on my bike they just seemed distracted and swamped with work ... I kindof felt a little shorted by the service they provided.

No disrespect intended towards the local shop ... I still do business with them ... and what they hey ... a second opinion never hurt anyone !

I will order up that plug tommorrow ...

JR ... my bike no longer has the air pollution crap ... I've removed it all.

And thanks guys !!! Never done this before so ..........

I'll be careful Link !!! Thanks !!!