TOPIC:

DOHC, thank you for the lead. I found a set of cases. . But with this post revived I'd like to ask about crankshafts. What years will fit in the '76 cases, I'm seeing ones but don't know about the tooth count. I've seen 15t and 17t. Is the cam sprocket on the crank? What affect would a different tooth count do.

You need a 15 tooth. Early 903 cranks look like this.

Early KZ 1000 crank would work but are heavier.

Steve

Thanks Steve. I found one like the first picture but the wrist pin area is rusted. Can that be honed out without causing a problem? What is a good price to pay for the crank

Mikaw wrote: I'm seeing ones but don't know about the tooth count. I've seen 15t and 17t. Is the cam sprocket on the crank? What affect would a different tooth count do.

Here is some crank info.

www.kzrider.com/forum/2-engine/23292-crankshaft-cam-chain-teeth

Mikaw wrote: Thanks Steve. I found one like the first picture but the wrist pin area is rusted. Can that be honed out without causing a problem? What is a good price to pay for the crank

I think I paid $50 plus shipping for the crank. I was watching three. I studied the pics very carefully and knew it was a crap shoot. I figured with what I had and there was a bad bearing I could use parts off the one I had. I got lucky. I washed it really well in diesel before I installed it.
Steve

Mikaw wrote: What affect would a different tooth count do.

If the cam sprockets are not changed to match, the effect would be disastrous. The cam sprockets must have exactly twice the number of teeth as the crank sprocket, otherwise, with every rotation of the crank, the cam timing would get farther and farther off until valves began bagging into pistons, then valve heads breaking off, then BANG!

TexasKZ wrote:

Mikaw wrote: What affect would a different tooth count do.

If the cam sprockets are not changed to match, the effect would be disastrous. BANG!

Thank you Texas KZ.... BANG! is not good.... Are all 900 cranks 15T? At some day in the future I'd like to do a big bore kit. nothing bigger than 1075. I have read that the stock cams are good low end power with the right carbs and a modest piston size increase. Will the lighter "porkchop" 900 Crank be good for a street motor of the design I've purposed? It will not be ridden hard every ride, but want the extra power there on the odd occasion arises...

My next step will be a 1075 with larger cams. Meanwhile with my 903 crank, Wiseco 1015 pistons, Andrews 1X cams and 33mm Mik's I RIDE THE PISS OUT OF IT with no complaints from the bike.
Steve

1.. 1075 cc in a 900 block requires new larger sleeves. OR get a 1000cc block and Just bore it out
2 This alone will give increased power thru out the whole power band using the 10, .5 compression ratio recommended for street use.
3 Depending on budget you can do cams and some head work would be the next level of performance
4 Also while in motor check and replace cam chain and cam related idler wheels and tensioner
5 900 crank is good. I would have it checked and welded since you will be treating it harshly from time to time. ( This is a basic step )
6 900 crank is lighter than the stock 1000 cranks so spins up faster due to less mass rotating .
Happy Holidays now that Christmas is Over
Dave

Steve... Stock 900 crank??? Did changing the shift lever position help with the 1-2 upshift....?

MIKaw
Do some surfing to some performance websites to check whats out there and why.
APE / KZzone is great source of parts. Once you crack these motors open it is a great time to fix some issues that surfaced
since these motors were designed and than raced.
APE makes something as simple as a shift bushing that will help your shifting headaches. Next have the trans backcut so it
no longer risks popping out of 2nd gear
But Hell What do I know
Dave

Dave,

If yours stays together with 200 HP then id say you know a thing or two!!!

I don't have a shift or trans problem. I was asking Swest if he corrected his... I follow most of his posts...

I wasn't having any luck finding a '76 900 in the correct serial number range for my 900 LTD B1 so I ended up buying cases only. Not my first choice but I figure it would be a learning experience for me... I've built several small block chevy's in my day so I should have the talent to pull this off. Of course with the help of the experts here and a FSM. I was planning to use the 1974 Z1900 engine I recently bought for the internal parts I need but I'm second guessing myself. Thinking that would be better to keep complete and rebuild at a later date... maybe wrong but I cant see myself parting out a Z1 motor...

Edit... Dave you mentioned 10.50:1 CR. All the pistons or kits I'm seeing state 10.25:1 CR. Are the 10.5 a thing of the past???