Just picked up a 78 Z1R

I’ll take some detailed photos of the cylinder block tonight. I’m interested in exactly what I have too. I don’t have any reason to doubt the claims made by my neighbor, we are good friends and he doesn’t have any reason to be less than truthful.

I do have the original front end and it came with all the gauges and brackets attached. My plan is to install the bigger fairing on the ZX7R frontend and use digital gauges.

Those are the side covers that came with it, I’ll ask about the originals.

Nice score on the Z1R but a few things jump out from your posts.Like Don said earlier,I'm not picking on you so don't get ruffled - sometimes posts on forums are misunderstood when read rather than heard in person.

Av gas isn't really a good gas for street bikes- it's a 2 octane rating type with special additives so it won't freeze at altitude.Smells good burnt, but no performance advantage.We used it dragracing in the late 70's/early 80's until race gas became easy to source.

If you don't have a block like the one in Plummen's pic the pistons likely are not that big,iirc the largest bore recommended for a stock block is 1200 cc.and even a 1327 would put the sleeves out of round very shortly in an OEM block.

Never heard that the gears from the 1300 would convert a Z1/KZ style tranny into 6 speed- gonna run that one by Paul Gast when I see him at Indy in August. Have seen close ratio trannies but all 5 speeds- never heard of a 6 speed for a Kaw.

180-210 mph. You need to take that bike to Bonneville.
Kilometres Per Hour maybe...but you're not in Canada or Europe lol.

If you change out the sidecovers to Z1R and want to sell the MKll covers send me a pm with your price.Good luck with the Z1R,always one of my favs.

Thanks Jack, I got a little education and a chuckle out of your post, don't worry no feathers ruffled here.

I talked to the previous owner last night and he was adamant about a couple of things like the speed and the 1428 kit. He agreed the walls would be thin, but the engine builder "Jap George" a very well respected KZ builder recommended going that big. Eight years ago in South FL the mind set was if Jap George built it then it was as good as you could get.

The 6 speed trans story did change a little, it's a 5 speed trans but the 5th gear from the Z1R was swapped with the 6th gear out of a KZ1300. Sorry for the misinformation.

I'll include a couple of photos of the cylinder. You guys have me concerned about the longevity (if any) with this cylinder block.

Head Stamp

Air Pass Thru

yep,thats a stock block.no problem ive built many scary fast 1170-1197 motors with stock blocks!

got the pics for you kawzilla.(sorry bout the funky look it is in line for resto/modding:) )
this is the back off the leftside(inside),


leon holmes

and here is the right side.


you can click the pic square and the picture will come up,not sure where i screwed up at:huh: .

left side

Kawzilla wrote:

Head Stamp

I have a 1260cc with my stock block but I don't think a 1400 would fit. It would depend on the sleeve OD but I'm not sure it would be possible. Maybe APE Jay will chime in.

Even if they're stock pistons it's a great find! I sold my '78 Z1-R a few years ago and still regret it...

Keep us updated with lots of pictures and details. Good luck

Just came by to see what additional info. you picked up on your Z1R- if the George you refer to is George Babor,Babor Performance Motors ( BPM ) out of Pinellas Park,Fla.and he built the motor ,then it's likely a good one.

Thanks Leon, thats a huge help.