Keihen CV34 Issues and Question

I was cleaning my original CV34s and managed to strip an idle mixture screw. I thought I could drill into the screw and use an extractor to remove it. Instead I managed to break off the outside portion of the tower the screw sits in. Great. If looking at the engine side of the carburetors, it was the second from the left that was wrecked.

I managed to find another set of Keihin's at a farm nearby. My original understanding was all four carburetor bodies were identical and I could use any of them to replace the one I ruined. Upon a closer look of the new rack I am thinking I was incorrect. Can someone confirm that the carburetor body from the same position on the rack must be used to replace a carburetor body on a different rack?

Another question is that I am having a great deal of trouble getting the screws out that hold the rails to the carburetor bodies. Does anyone have any tips other than heat? I have seen suggestions of using ATF and acetone mixed equally. I live in an apartment and would like to minimize the amount of chemical mixing I have to do due to lack of space.

Finally, I have noticed stripped/seized idol mixture screws in the second rack of carburetors. Any tips on getting them out?

kz750saskatoon wrote:

...am having a great deal of trouble getting the screws out that hold the rails to the carburetor bodies. Does anyone have any tips other than heat? I have seen suggestions of using ATF and acetone mixed equally. I live in an apartment and would like to minimize the amount of chemical mixing I have to do due to lack of space....

...getting the screws out that hold the rails to the carburetor bodies.... --- impact driver

Not to say it shouldn't be considered, but I have never replaced a damaged carb with anything but another carb which matches the other carbs remaining in place.

Good Fortune!

hey saskatoon go to princess auto or canadian tire and buy what is call an impact driver use that on the screws just like patton say's now is the tower broken bad enough that fuel or air can leak past because if it isn't then i would epoxy things back and try running them.by the way i'm from leader.

I managed to get the carburetors separated. Thanks for the tips guys.

The more I looked at the bodies the more I saw differences in them from one position to the other. I will just use the body from the same position.

I am left with the other question about how best to remove the idle mixture screws. This one is stripped and seized as well and I am a bit hesitant to try to remove it. Should I just leave it and try to synchronize the carburetors based on its setting?

Finally, I am trying to get the body cleaned up and there is a discoloration at the top of the carburetor where the diaphragm would cover (see attached picture). I have tried boiling it in lemon juice but that did not do much. I have been spraying it with carb cleaner and rubbing at it but again I don't think I am accomplishing much. I'm fairly new at fixing my bike so I am not sure if this is varnish or rust or something else.




The entire tower pretty much broke. I don't think it would hold a screw. I am pretty certain a new body is my only solution here.

I have yet another question about the screws that hold on the choke plates. Does anyone know the dimensions of them? The repair manual mentions purchasing a special choke shaft repair kit. Can any screw of comparable dimensions be used and crimped to keep it from unscrewing?

if your pulling them out first grind down the thread end as they are peened over so they wont come out if you dont that then you will wreck the throttle shaft, i had a student do that this winter not pretty.if i remember correctly they are 3mm screws also for that discoloration try spray nine don't let it sit for more than about an hour and then rinse the part off really well in warm water it works amazingly well but it will leave a really bad crusty residue if not rinsed off enough and if you let it evorate it really gets gross but you would be suprised what it will clean.

Is the discoloration something that would affect performance? I am not worried about it if it will not.

Again about the screws, how would you recommend reinstalling them? Some internet research suggests peening them over by using a sharp chisel. Is this how to do it?

In case this topic comes up in someone's searches, I managed to get the idle mixture screw out. I purchased some penetrating fluid sold by a GM dealership here in town that is made by ACDelco. It was highly recommended by a couple guys around here. For two days I was spraying some of the penetrating fluid onto the screw every 4-6 hours. Today we used an impact screwdriver and the screw came out perfectly.

kz750saskatoon wrote:

For two days I was spraying some of the penetrating fluid onto the screw every 4-6 hours. Today we used an impact screwdriver and the screw came out perfectly.

Happy Endng...

I am unable to find any brass 3mm x 6mm screws to keep the choke plates in. The best I could find locally was some steel 3mm x 8mm screws that I filed down to the appropriate length. The problem is I am not having much luck peening them because they are too strong (obviously).

Is red or blue thread locker acceptable for this use? I know if I use the red I'll have to resort to heat to get it out later.

Any comments or suggestions on where to find the appropriate screws? I would like to avoid online as I only really need 8 and do not want to wait for them to ship to Canada.