TOPIC:

Hi everyone, recently got my hands on a crusuing image big bore kit for my kz1300 (1370 big bore kit). I believe it's a 2mm larger size bore, and was just wondering how reliable this big bore kit is, how my engine would be with the much thinner cylinder walls, and how I should re-jet my carbs
Thanks to all!

I recall these big bore kits being mentioned on several occasions here on the forum. Member zed_thirteen fitted one. Maybe he’ll chime in.

поставил себе на zn 1300 такой 5 лет назад, пробег около 300000 км. компрессия в норме, расхода масла нет. но мне кажется сильнее греется в пробках.
I set myself this on zn 1300 5 years ago, the mileage is about 300,000 km. compression is normal, no oil consumption. but it seems to me that it gets hotter in traffic jams.

I have one fitted and it's running at the moment but not yet on the road. I taxed it on the morning of 4th January and we went into another lock-down later that day so I still haven't got the damn thing out onto the road yet for a proper test. I had a lot of trouble with coolant leaking from the weep hole that kept the bike off the road for ages - nothing to do with big bore kit - just trouble with mechanical seal after rebuilding

The quality of the big bore it is fine. There are better pistons available but these should be fine for my light use. I used the head gasket that came with the kit rather than a standard Kawasaki one as I was worried about the size of the fire-ring compressing in the bore rather than outside of the bore . Because of this you have to put some sealant (Yambond 13?? or something like that) around the water jacket holes.

I also broke one of the rings during installation. I had to buy a complete set of 6 sets from cruzin image but I believe they have since offered buyers single sets.

I start both of my bikes in the garage every weekend for a few minutes just to keep things lubricated. My Z13 kicks out tons of white smoke on starting (it always has done and was the reason I did the rebore - could be guides?) but as yet I don't know if it clears when the engine is up to temp

Single cylinder components: www.facebook.com/photo?fbid=330781631265...t=a.3307816695990532

kit: www.facebook.com/photo?fbid=330783686265...t=a.3307816695990532
(Standard fire ring is about 63mm and big bore fire ring is about 67mm)

Big bore piston was 4g lighter than standard piston: www.facebook.com/photo?fbid=330784026598...t=a.3307816695990532

Thanks for the response and insight. Have you had any concerns about how thin the cylinder walls become after boring 2mm off for the big bore kit?