z1 - compression low after wiseco kit rebuild?

A year ago I bought a junker z1 900 for $580. It was a POS.
Spent a year getting it all sorted and dialed in.

4 months ago I tore the top end apart.
List of things I did / had done:
- 1015 wiseco kit - 10.25 to 1 compression
- 118 web cams - stock cam gears
- new valves / springs / seals / guides / 3 angle valve job
- has a dyna s advanced a tiny bit
- keihin CR 29 carbs
- kerker with competition baffle
- lockhart oil cooler

I had a legit machine shop do the stuff I can't do.
I did all the assembly work.

The bike seems to run great. It definitely hauls ass. Smooth with no weird noises. No smoking.
Valve clearances are all .13 - .15mm. Double checked them all.

I just did a 3K mile trip around all the great lakes literally 2 weeks after the engine rebuild.
So I've put a ton of miles on it so.
Bike rode great. No issues.
I even pulled the valve cover off after my trip to check things out and it all looks good, and clearances are good still. Cams show no scoring. Good oiling up there.

So my questions are below.

1)
Compression test
My compression on all 4 cylinders is 125psi.
Checked a couple times... hot and wide open throttle.
My gauge is good. All my other bikes read fine.
Shouldn't my compression be way higher? Like... closer to 150-170 ish. Especially with a high compression piston kit?
Isn't 125 too low?
Do the webcam 118 lower my cranking compression to the point where my readings will be this low?

2)
My idle sucks.
I can't get it to idle under 1500rpm to save my life.
No air leaks. New intake boots and used ultra black sealer.
Any thoughts?
If I'm riding the bike, and then come to a stop very quickly, the bike will want to stall. I have to whack the throttle real quick... then it's good and will sit at 1500rpm.

3)
CR 29 carb jetting.
I can't seem to find anyone with a kz and these carbs and find what their jetting is.
My jetting is:
- 110 main jet
- 65 slow jet
- needle in middle position
- uni air filters
Seems okay, but I think it's a hair too rich still.
Plugs look decent. But it's not perfect yet.
Does anyone else have these carbs and let me know what type of settings you have?

Any input is appreciated.
thank you.
-Ed

Did you hold the throttle open, and was the engine warm during the test?

@Motor Head
Yes. I did the compression test hot and wide ope throttle.
I checked it a couple different times on different days after doing rides.
-Ed

I had a 79 with a 1045 10.25-1 and Harmon cams that are a little more than what your 118's are.
My compression was 165 on all 4 and it would idle down to 900 just fine.
I'd recommend you degree those cams before you do anything else. Do a wet compression test in case the rings never seated, doubtful that could be a problem, 125 lbs is enough for it to idle properly. When I bought my 79 it had the intake cam advanced 1 tooth, when I put it to spec the compression changed by 30 lbs per cylinder. The compression was 210 when I got it, 180 with the stock cams in the correct position and 165 when I installed the Harmon cams.

I think member OldManRock used those carbs...maybe check with him for jets/settings recomendations. the WEB 118 grind is considered a "drop in" street or turbo cam......but since you did not degree them ........looks like you bolted them into non adjustable sprockets from the pics :S To answer your question, Yes it can effect compression readings :blink: (Camshaft overlap). Your cams really need to be degreed to specs as they could be off index a few degrees... :pinch: ....I even degree stock cams when I use them ... :huh: also what head gasket (I assume cometic) what bore size? ....how far down the hole were your pistons? (deck height).... :huh: did the shop that performed your valve job cut the crap out of the valve seats.....all of these things will effect cranking compression readings :huh: Cams are in time not a tooth off? (recheck cam/ignition timing). just throwing all this out there...... HTH keep us posted

@Roadflyer
Good input thanks.

Take a look at the pictures of my advancer / and cams...
I'm pretty sure my cams are set right aren't they? I set the exhaust cam and then counted 28 pins for the intake one.
I'm using a 76 kz900 advance mechanism.
let me know.... thanks again.

Also, maybe this is a dumb question, but how do I degree my cams using stock non adjustable cam gears?

-Ed

slot the sprocket holes with a 1/4" round file by hand or have them machined (rotary table) or buy a set of adjustable sprockets (ape or suncoast)$48 at schnitz.... :dry:

any camshaft can still be out of index, (production tolerances)......... :dry: like I wrote, I even check/degree stock OEM cams..... :pinch:

@turboking
thanks for the response.

Yes, Cometic head gasket - CFM20.
I don't know how much they cut the valve seats. It looked normal to me, but I'm a hobbyist. Not a professional mechanic.

I did not degree the cams.
Yes, I just bolted them in to the stock non adjustable cam gears and put everything back to the same settings they were at before.

Based on my pictures... My cams are set in the right positions aren't they?
I guess I don't fully understand how to degree cams with stock cam gears.

-Ed

@turboking

ah. gotcha.
sounds good. I'll pick up a set of adjustable cam gears and give it a try. Maybe it is off a hair.
thank again.

-ed

I had that exact same build the first time so a couple things....

Those cams are designed for 105 lobe centers, pretty tight but you have them at stock 110 LC...
So you will notice a difference (lower compression) in psi measurements with wider spread... As long as all 4 are reading the ~ same @ 125psi you're ok... 140-150 would be the normal reading on that build.





Slow jet and needle Jetting is rich...

I'm @ 1200 elevation, high temps so may be different than your location.
slow jet 52...
Needle YY9 clip position 4
Main 120

Maybe this will help...

I would still pull the valve cover and recheck cams, and you started counting pins ? :huh: starting one pin above the arrow