Some 903cc questions

I'm starting a new job on Monday so hopefully I'll be able to finish my 810 to 904cc rebuild. 68" wheelbase, 45psi and 11:1 should keep some of those pesky 1428s at bay for a while longer...

:woohoo:

i thought i had it bad but compared to you lorcan i'm a freakin puppy. that is one bad ass scoot buddy. and ditto to what plummen said you must have a set as big as coconuts

It's going to be setup very much like a ProStreet bike, heavily front biased weight distribution, zero offset yokes, 16" front wheel, a loooooong Spondon arm, fibreglass body, intercooler in the headlamp space, 8 x 900cc injectors, Wolf V500 ECU, M&W CDI ignition, ZX10R shortened forks with reversed radial calipers, plastic fuel cell under the seat.

Think Stotz CBR1000RR but made out of an old Kwak 750 turbo :laugh:

I've already gathered all the parts (except the cooler), just need to finish it. I'm shooting for 7 second quarter miles without bars. Dunno if it's possible but I'm going to try. I ran 8.6 nearly 10 years ago with just 760cc, 23psi and 8:1. I reckon with more cc, boost, compression and a better chassis setup it might be possible. I wasn't sure 200mph was possible, but you never know til you try

Hardr0ck68, the biggest piston they sold back in the day for the 650 motor was the 831cc kit, I know because I have a set.
The piston is 70mm with a 15mm wrist pin at the proper deck height for a stock 650 barrel and the proper shape for
the combustion chamber.
A few companys sold them... MTC is the brand I bought because they were heavy into drag race sponsorship and they
used the best forged aluminum.
I bought the 10.5:1 street version that I bored into heavily
reworked 900 liners... I had a 1.5mm wall left in those liners.
The liner OD and flange gets trimmed and the flange thickness reduced... they will not brake out into the fin
area but there is not a lot of casting to properly support
the liner/piston - this will cause problems like piston rock
and gauling on the skirts.
The cool thing about the stock barrel is its stock...
It's not a 750, its not a turbo, its the ultimate middleweight sleeper.
The casting says 652cc.

Believe me when I tell you your not the first guy to try and figure this out...

The pistons are in a box under my work bench.

BTW - that is my red 650 drag bike in your original post.

pretty cool little bike what did you run withit on a regular basis. what were your best times out of it all time. did you ever run into any major problems with it.

You can resleeve the block and have JE make you a set of pistons with 15 mm pins. We have 15mm tool steel pins that will handle any power the motor could make.

I used to do all of the installation machining for Mike Chestnuts 880 kits. It was a nice deal.

I have 71mm pistons with 15 mm pins for the Honda 750 sohc. Wonder how close they would come to fitting a 650?

That has got to be the ugliest motor and frame i've seen. I'm just advising you not to show that thing off too much. It'l cause confusion and possibly a change in meds.

nads.com wrote:

That has got to be the ugliest motor and frame i've seen. I'm just advising you not to show that thing off too much. It'l cause confusion and possibly a change in meds.

lets see yours! :laugh:

APE Jay wrote:

You can resleeve the block and have JE make you a set of pistons with 15 mm pins. We have 15mm tool steel pins that will handle any power the motor could make.

I used to do all of the installation machining for Mike Chestnuts 880 kits. It was a nice deal.

I have 71mm pistons with 15 mm pins for the Honda 750 sohc. Wonder how close they would come to fitting a 650?

www.satanicmechanic.de/board/viewtopic.php?t=355

take a look there folks!

Jay I might have to take a look at those! Are they for the k6 or f2 type honda? I know NOTHING about those honda's but the honda folks seem to think the pistons were CLOSE!

I am thinking if they are the pistons from the honda with the smaller dome they would be great on a decked head; and if the kit is ment for the f2/f3 motors they are talking about it would be awesome as is.

To me, it looks like it would take very little to make these fit. Time for me to get my hands on some 900 liners! Plummen have any spares


::edit:: quick look on APE, the pistons are ment for the K models whatever that honda crap is. They come with a 10.25-1 compression.

I am thinking with the domes being so different compression on a kz would be rather low (turbo??) but I don't know how to calculate the difference. And I have yet to see an actual picture of the wiseco piston (maybe it has some more dome to it).

Anyone want to guess how much the head would need to be decked to get it back to 9.5 to 1?

id have to find a stock block with good sleeves,how much of an overbore is it on stock sleeves? i might have some that need bored depending on how big you can go to clean them up

the wiseco pistons I am looking at (for the Honda ) are 71mm. I don't know what the stock size is on a 900; but I am guessing there is a lot of room for "clean up."

The only thing I worry about would be after machining the OD to fit it to a 650 block the remainder of the liner would be to thin....

But I need to get my hands on at least one liner and bring it to a machine shop.

My dream is getting close, a 860cc motor!