PISTON SWAP

hi all another ? for you all i was wondering i have been looking on ebay at 1015 & 1075 cylinders & pistons i was wondering if that is a bolt on deal oh by the way i have a 76 900 will my head work ? will the flow be good ? carbs are 29 what about them?

Make sure you are getting a 903cc block that has been bored to 1015 or sleeved for 1075. You can get a 1015cc block (from a KZ1000) in, but sometimes you have to machine the upper case to fit. Some of the kits on ebay are based around the 903c block, but many will be from KZ1000's.

Yes, it is possible to get a bolt up solution. Yes it would help to have your head ported and get a fresh valve job. However, a stock head can work. Personally, if I were spending money on pistons, then I would have the head done at the same time. 29 mm carbs should be a good choice for a 1015 or 1075. It depends on your goals for your motor.

the KZ 1000 block requires engine case mods I believe, the head would but the cases wont

Not 100% on this but a 1015 block should be a bolt on. No?

most of the ones i see on ebay are used from a kz iooo see it is good to have a site like this to ask before you buy . i am redoing my bike now and have spent most of my buget already to make it look good so if figured if i could get one of these set up for $300.00 i would bolt on and go.sounds like i need to wait till next winters buget to do the motor ...

TerryK wrote:

Not 100% on this but a 1015 block should be a bolt on. No?

I was told only if it was a 900 that had been bored to 1015

testarossa wrote:

Make sure you are getting a 903cc block that has been bored to 1015 or sleeved for 1075. You can get a 1015cc block (from a KZ1000) in, but sometimes you have to machine the upper case to fit.

Are you referring to clearancing the cases for the 1015cc cylinders? I don't believe this is very challenging and can be done by a garage mechanic, although a professional will make it look quite a bit nicer (but it's hidden when installed anyways?). I had this done on my bike as there was some damage to my cylinders and it was cheaper to buy a good core from the shop that did the work than repair.

DoubleDub wrote:

testarossa wrote:

Make sure you are getting a 903cc block that has been bored to 1015 or sleeved for 1075. You can get a 1015cc block (from a KZ1000) in, but sometimes you have to machine the upper case to fit.

Are you referring to clearancing the cases for the 1015cc cylinders? I don't believe this is very challenging and can be done by a garage mechanic, although a professional will make it look quite a bit nicer (but it's hidden when installed anyways?). I had this done on my bike as there was some damage to my cylinders and it was cheaper to buy a good core from the shop that did the work than repair.

Yes, DD that's what I was referring to. I wasn't exactly sure of the procedure, but your description makes sense. He hadn't gotten any answers, so I hoped that I could get the ball rolling even though I wasn't 100% certain on the details of the modification. Anyway, the OP asked if they would be a bolt in deal, so technically not. BTW, what did you do to keep aluminum filings out of the crankcase? How much clearance was needed? Thanks for clarifying.

from what i am getting from all of this is where the cylinders go into the block the hole o/d is smaller than the cylinder o/d so you need to bore out the block to fit ??

testarossa wrote:

Anyway, the OP asked if they would be a bolt in deal, so technically not. BTW, what did you do to keep aluminum filings out of the crankcase? How much clearance was needed? Thanks for clarifying.

Gotcha - yep, not a direct bolt-on unless the cases on your bike have already been clearanced for the 1015cc labeled jugs/sleeves.

I didn't do the work, but I don't believe much material has to be removed. I'm pretty sure I've seen others state that they have done it with a dremel, of all things. I would say this probably needs to be done with the cases split to keep material from getting inside the cases.

I'm sure someone has pictures of how much needs to be removed around here somewhere. I'm also sure someone was ingenious enough to find a way to do it with the cases assembled......

ok well i got that and that dont seem to be a real problem so what about the head that bolts up good then ?? if so i think i could do this just for alittle more power this summer and not have alot in it im pumped about it. my boys bike has a 1075 in it but we didnt build it so that is why im lame on all of this !! but it would be great to bo it without him knowing then when he wants to play which is alot i will have somthing for him ( this is great )

Top case needs to be bored for the 1000 block.

Get one of the 900 blocks bored to 1015.