Planning a reliable but fun engine, Z1000J3

Hi. I went for a trip to Norway (from Denmark) last weekend and after a long day of driving at highway speeds my engine started to rattle like crazy and lost all power. I have now learned that the #2 piston has failed. The sparkplug is filled with melted alloy and i can see the rod through the piston when looking through the spark plug hole. So i guess i will be rebuilding my engine this summer! I was wondering what experience you guys have with building a reliable engine for everyday riding (the 4-5 month a yeah the danish "summer" has to offer) but with some modifications for extra power and fun.

I'm thinking around 1100cc withe 10:1 comp, stock J head with '82 GPZ cams and my 34mm Mikuni RS carbs.
I know i can have more lift but how will that afflect reliabillity and the mild GPZ cams i can run with stock springs, valve guides right? Or is it always a good idea to run the stronger springs? I wan't a oil cooler on it as well but how big a bore can i go with and still ride it everyday ? I am offered a 1160cc kit with 10:1 comp, how would that work with oil cooler, GPZ cams, J head and RS 34's ?
I still don't know for sure what kind of damage the head has taken so i might need a new one. Should i go with a GPZ 1100 head with bigger valves or stick with the J head? Is it true the J head has higher compression because of a smaller chamber ?
I appreciate any thoughts on this.


Simon

Nice bike! I wish i could be of more help in planning an engine build, but i don't know much about the J motor. You could always email APE and ask for suggestions. they have always been very helpful for me in the past.

From what you've said, it sounds like you dropped a valve. Better size up the damage before making plans. :whistle:
Steve

welcome.
cool bike !

has the wrenchmonkee look about it ,very nice :evil: !

a lil reading for you.

www.aperaceparts.com/tech/techkz1000.html

keep us posted on your progress,

leon

Mk2Rookie wrote: Should i go with a GPZ 1100 head with bigger valves or stick with the J head?
Simon

Thinking about using one of these?

I am running an 82 GPz1100 engine bored to 1170 with 10.5-1 compression pistons, a WEB 119 grind a ported J head, Mikuni RS36 carbs, Kerker KR header and the stock oil cooler setup. Ugodly fast and absolute blast to ride. It is very streetable, I took it on a 3000 mile trip last year with no issues. Doesn't overheat and fine in traffic. With the setup you are thinking about you shouldn't any issues running it,
If it was my bike I would go ahead and install the APE valve springs and have the crank welded up while you have apart.
The head Daveo is talking about is off the 83, 84 and 85 GPz1100, the bathtub head. The 82 GPz1100 used the same head as the J model just with slightly higher lift cams.

Thank you for your replys! By now i almost have all the parts i wanted.
I will run;
GPZ UT Bathtop head with APE valvesprings and titanium retainers. Stock valves and APE guides. Right now i got a pair of UT cams but i'm thinking of getting a pair of APE's .410 or Andrews x3.
will have my culinder bored and piston made in Germany, 1166cc with 10.25:1 CR.
I got APE studs for the cylinder head and for the crank.
I will use the TracMaster clutch with a Uni Track transmission.
I will wield the crank.
I got everything blasted and will paint everything with Motip heat resistent paint.

Am i missing something ? Will the UT cams be any good in this engine or should i go with .410 lift to get the most out of it?

Simon