Z1 903 Cylinder Barrel Bored to 1197cc

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Z1 903 Cylinder Barrel Bored to 1197cc

18 Jan 2026 12:06 - Yesterday 09:16
#920746
1973-77  Z1/KZ900 903 Cylinder Barrel Bored to 1197cc

Used 1197 barrel taken off a Z1 street bike - no pistons included

Barrel has some JB Weld on the front and a small chip on a top
fin near #1 cylinder.

The liners alone to duplicate this are over $400 USD

Liners in great/straight condition and measure :

#1 - 2.9930" 
#2 - 2.9925"
#3 - 2.9930"
#4 - 2.9925"

Just need a light hone to freshen up.

Would be good for street use if painted black (only reason I did not use it was cosmetics)
Would be good for drag use if O ringed.
Block has not been decked.
Pistons required are 76 mm.



$80 USD, shipping extra (part is in Ontario, Canada)
 
1978 KZ650B2 w 1197cc Z1 engine
1977 KZ650B1 w 750cc Spectre engine
1979 KZ650C3 w 831cc Hot Rod engine
1978 KZ650C2 w 762cc DFI project
1977 KZ650C1 stock restoration project
1978 KZ650B2 modified project
1978 KZ650B2 Injected Drag 831cc
1980 Z1 Custom Frame Drag 1327cc
1981 Z50R Honda tow bike
Last edit: Yesterday 09:16 by Injected. Reason: more info

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  • Mr. E
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Re: Z1 903 Cylinder Barrel Bored to 1197cc

Yesterday 11:21
#920773
Just to boost your post, 

This year I over $1000 for the labor to create this block for those that are wondering. Assuming you have a cylinder block  and buy the liners at $80 a pc and then have to have it bored 2x, once to fit the liners to the block and once again to open up the liners for the 1197 pistons. - This is a screaming deal  
1977 kz1000 - the Rooster, 1981 KZ750 Chopper, 1975 KZ400 , 1984 GPZ750

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  • asphalt900
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Re: Z1 903 Cylinder Barrel Bored to 1197cc

Today 19:09
#920781
That's not only a smoking deal but on fire. I sent a gorilla block 1428cc to Eric at Hooper in Florida and spent over 1400.00 to duplicate the liners. Too bad Injected You live in Canada, politics has separated us as a former union of enthusiasts when it comes to freely swapping crap amongst ourselves. Too bad they used an early cylinder, could of given them a later one, less valuable. What's the JB Weld all about? Did they break thru the casting when boring? I see the front tensioner shaft saddle is goofy, like something let loose. This should be easily repaired though.     

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  • Injected
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Re: Z1 903 Cylinder Barrel Bored to 1197cc

Today 09:25 - Today 09:38
#920786
I priced the liners on Ebay the day I listed it at $99/ea without shipping or tax. That groove may have been a idler rubber exploding.

This was off a street bike when I bought it (see pic) in with a package buy of a big block (1327cc) in 2017.

 

I was fully intending to use it and the MTC pistons on a street bike build. Once I saw the epoxy that ruined my plans as I don't like to paint anything black. I had to redo the block with a 1015 barrel and fresh liners so I know exactly how much work goes into getting it done.

My boring guy said that about 30% of the time 903 barrels will break out "slightly" to show the liners on a 1200 build. He mentioned its usually on the front sides of the casting and on the two inner liners. He took a look at it and was prepared to hone it for me if I was going to paint it. He was not concerned about it and took the time to measure it confirming the sizing and straightness.

I decided to redo it all because of cosmetic reasons only, my decision. I did try to move it on locally but there are increasing less people interested in these parts.

This is the "as found" condition, its not cleaned up in any way. I don't see any evidence of leaking around the epoxy.

I am pretty sure if someone took the time to clean it and apply a smoother layer of epoxy it could present better once painted properly. It could also be left as is and used for a entry level drag racing build.

Its a shame that it has been collecting dust, and too good to throw in the trash heap.
 
1978 KZ650B2 w 1197cc Z1 engine
1977 KZ650B1 w 750cc Spectre engine
1979 KZ650C3 w 831cc Hot Rod engine
1978 KZ650C2 w 762cc DFI project
1977 KZ650C1 stock restoration project
1978 KZ650B2 modified project
1978 KZ650B2 Injected Drag 831cc
1980 Z1 Custom Frame Drag 1327cc
1981 Z50R Honda tow bike
Last edit: Today 09:38 by Injected. Reason: more info

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