1983 GPZ 750 FRESH REBUILD 110PSI COMPRESSION????

I SET THE CRANK TO THE T MARK AT 1& 4 TDC. INSTALLED THE EXHAUST CAM TO "Z7XE" OR SOMETHING FLUSH TO CYLINDER TOP FRONT. INTAKE CAM "IN" MARK TO REAR BETWEEN 45-46 TOOTH. BOTH CAM NOTCHES ARE FACING IN. IT IS SHIMMED PROPERLY WITH IN A RANGE 0F .003-.007. I AM TOTALLY BAFFLED WHY THE COMPRESSION IS SO LOW. THE CYLINDERS ARE HONED FOR RING SEATING, END GAPS CORRECT. CYLINDER TO BORE CLEARANCE OK AS WELL.:S BEAUTIFUL CLASSIC ORIGINAL OWNER.

SHOULD I JUST CRUSH IT OR WHAT. THIS IS THE FULL GO THROUGH AGAIN.

WILL GETTING IT ON THE ROAD AND BREAKING IT IN BRING UP COMPRESSION?

IT IS RUNNING OK, JUST TRYING TO SET THE CARBS NOW AND I HAVE A FLOAT LEAD AT #1 CARB. MIKUNI 34'S ANY RECCOMMEND FOR FLOAT GASKETS? THEY SEEM HARD TO FIND.

THANKS

No offense skemp but the all caps thing is annoying. When I'm reading it all I can think of is you shouting like Gilbert Gottfried as if we are at a club or concert or standing next to a jackhammer.

As far as compression goes it should continue to get batter as it gets broken in. Give it 200-500 miles and try it then.

Becker wrote:

No offense skemp but the all caps thing is annoying. When I'm reading it all I can think of is you shouting like Gilbert Gottfried as if we are at a club or concert or standing next to a jackhammer.

As far as compression goes it should continue to get batter as it gets broken in. Give it 200-500 miles and try it then.

Not to get off topic Becker, but did you have to bring up Gilbert Gottfried? I haven't given that idiot any thought in years and now this. OK, maybe he is a little funny with the fact that all his impersonations sound like Dracula but that is all. Alrighty then, what were we talking about?

Thanks for all the help, I will get this beut on the road and stack up a few miles. Hope it will seat the rings and bring up compression.

blipco wrote:

Becker wrote:

No offense skemp but the all caps thing is annoying. When I'm reading it all I can think of is you shouting like Gilbert Gottfried as if we are at a club or concert or standing next to a jackhammer.

As far as compression goes it should continue to get batter as it gets broken in. Give it 200-500 miles and try it then.

Not to get off topic Becker, but did you have to bring up Gilbert Gottfried? I haven't given that idiot any thought in years and now this.

AFLAC!

Now you'll never get it out of your head.....:laugh:

like i said get another gauge and compare the readings maybe your gauge is off.

timebomb33 wrote:

like i said get another gauge and compare the readings maybe your gauge is off.

I second this. After completing my engine earlier this year, my compression was also around 110. Tried a different gauge and they all changed to around 165.

you gotta run it and seat the rings before you can do a compression check duh?

skemp101 wrote:

I SET THE CRANK TO THE T MARK AT 1& 4 TDC. INSTALLED THE EXHAUST CAM TO "Z7XE" OR SOMETHING FLUSH TO CYLINDER TOP FRONT. INTAKE CAM "IN" MARK TO REAR BETWEEN 45-46 TOOTH.

Look in your manual.
The GPZ uses Z6XE timing mark which should advance the cams and increase cylinder pressure.

I was totally stoked last night. It was still running like garbage backfiring and wouldn't get above 4000 rpm. Pulled the carbs again and this time sealed between the carb and head, which I dont think there was any sealer or gasket from the factory. Put it all back together and it finally idled. I bench set the sync on carbs, after it ran I put the stick on them and fine tuned #4 and it ran better.

still popping and backfire I worked on the air fuel screw, about 3 turns out on all it ran even better.

the story gets better, I said heck " maybe I can take this sucker for a ride". Its only been sitting for 5 or so years.

A little rough at first, then the power came back. rapping it up a couple of times to higher rmp and it is running like a champ!!! I got to feel a little of that new 810 displacement.

I have had this bike since Oct. 1983, bought new and am very glad to get er on the road.

thanks to everyones help, KZR is an awsome help forum and beyond..

thanks all!!!

Sweet. Who bored it for you?? What exhaust and filters are you using and how many jet sizes (if any did you have to change with just the 810 kit??

Oh, and do you have any pictures??

dwilliams2385 wrote: you gotta run it and seat the rings before you can do a compression check duh?

This.