Kawasaki C2SS Not Reaching High RPM

Curtis Riendeau /

I have a 1967 Kawasaki C2SS and it is not reaching high rpms, it bogs out well before.

The manual calls for a 150 main, mikuni hex. but that jet is mega rich, I found someone else with the same bike and he is running a 120 main with no issues.

SO I tried a 120 and it would still just fall on its face. Currently I am down to a 100 main and the needle clip full lean and it is still way to rich.

I feel like I have another issue somewhere.

So I checked my compression and I was getting 120, but my gauge wasn't sealing well so I assume it is higher.

I installed new points and condenser timing is set, i noticed it runs a bit better if I set it a hair advanced.

I did a plug chop and the plug was dark grey.

The weird thing is when the bike starts to bog out it doesn't matter if I'm half throttle or full it does it no matter what.

The only thing I could think of is I had two head gaskets installed because one alone wasn't sealing, I measured the thickness of the head gaskets together and it was 1.66mm the manual says after the gaskets are crushed it should be 1mm, so that tells me that my squish area is .66mm larger then it should be, which would lower compression but I don't think it would cause the issues I'm having.

The bike has a oil pump to supply out so I don't have to pre mix, the pump is set by the book and it doesn't seem to be getting excess oil until it bogs out and it can't burn the oil any more.

Im sorry for the long post but I tried to get everything in here.

It is almost acting like the points are floating but they are brand new, BTW I did try another ignition coil and it did help it a little but not much (edited)

Re: Kawasaki C2SS Not Reaching High RPM

Overpriced Parts /

First set timing and or clean/set points because if timing is off then you will have no power/it could feel like it's four stroking.

If point gap and timing is correct You could have the wrong atomizer, needle or slide it in your carburetor or the wrong carburetor/parts altogether

You need to make sure you have exactly the right carburetor and or parts .

Kawasaki motorcycle shop specialist?

fallout Survivor /

Find a Kawasaki guru is one option you have.

Rich running suggests not an air leak but possibly some restriction in the air box.

Did you decoke the piston, exhaust port and muffler?

Ditto on the timing and gap.

If it was me I would find a torque wrench and a proper head gasket to get the proper squish.

Consult Kawaskaki C2SS forums?

Re: Kawasaki C2SS Not Reaching High RPM

Curtis Riendeau /

I was looking in the factory manual and here is what it says.

Type of carb: VM 18 SC

Setting Table: Main Jet #150 Pilot Jet #20

Air Jet 1.5 Pilot Output 1.2

Jet 4J9-3 Pilot air screw 1 1/2 back

Needle Jet E-0 Starter Jet #40

Throttle Valve 2.5

Re: Kawasaki motorcycle shop specialist?

Curtis Riendeau /

The piston and rings are new, I tried running the bike without the baffle toe see if maybe it was plugged and it ran the same, just a lot louder.

I fixed the head gasket and again it ran the same.

My carb has a 4j9 needle that is the only difference I can see, also my needle is bent a little bit.

I was searching ebay and there is a carb rebuild kit that comes with a new needle , main jet, pilot jet. I might give the kits try.

As for timing there is only one mark on my rotor and case so that is how I timed it, the points are opening .4mm The book say .3-.4mm.

On this bike it has a rotary valve so the carb is right behind the side cover on the crank. it runs the same with the side cover off as it does with the cover on.

What gets me is cmsnl has different carb parts for the carb, here is the linkC2SS Carb

Honestly the only difference I see is the jet holder mine is a E-0 while on cmsnl it shows a E-4 & E-2, I'm guessing one holds the hex and the other would hold a large round jet.

But then again in the diagram the jet holder looks different.

Re: Kawasaki C2SS Not Reaching High RPM

Overpriced Parts /

Jet holder is the atomizer so having the wrong atomizer could be way rich like night and day different

Re: Kawasaki C2SS Not Reaching High RPM

Curtis Riendeau /

I will do some more research but i might try and order an atomizer and see what happens

Re: Kawasaki C2SS Not Reaching High RPM

i worked on an old ke100 and the dude fucked up taking the carb apart to replace the float and lost a little washer thingy that sits at the end of the atomizer/diffuser that the main jet channel feeds through.

Re: Kawasaki C2SS Not Reaching High RPM

Curtis Riendeau /

Yeah I have seen carbs like that as well, I ended up pulling up a diagram just to see if I was missing anything and the only difference I see is the diagrams online give me different numbers for the jet needle and needle jet.

The jet needle I have installed is a E-0 while on cmsnl it shows two a E-2 and E-4, but not a E-0.

In my manual though it shows a E-0.

What is the difference from a E-0 to E-2 or E-4

But even though the jets are different we actually and the bike running pretty decent with this set up, but now I can't seem to get it to run that way again, it just has no sack.

But It has new piston and rings, honed cylinder 130psi compression. and timing is set spot on.

Re: Kawasaki C2SS Not Reaching High RPM

Overpriced Parts /

I don't know what kind of high revs you expect but I had several Kawasaki rotary valve induction bikes and they only revved about 6,5-7,500 RPM with max power @ around 6,500 rpm. Kawasaki reed valve engines rev higher

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