T
TheWizzerd
Guest
I am doing an MS660 build based on the CDH110 bottom end. I thought I would show you guys how I went about correcting the geometry, as well as share some progress along the way.
This engine will have a special purpose when complete. Not going on a bike, and will have many modifications. Centrifugal clutch, pull start, eliminating the stock manual clutch with a new shaft and modified main gear etc.
The CDH110 cases are meaty with plenty of material for big bore jugs making the use of larger saw jugs easier than using the smaller cases. The transfers are "square" to the sides making them a bit easier to close up too.
I welded the transfers and stock stud holes up, then machined a pocket 5.5mm deep for the jug to sit down in to allow for the same geometry (crank center to jug base) as the MS660 in order to get proper rod angle/port timing/dwell relationship. Then decked the case to clear the shoulder on the jug. I did not machine the jug base down, which IMHO is the wrong way to do it. I machined the pocket large enough to allow the stock MS660 base gasket to fit.
I am using the stock ZMH100 rod. Even if I used a longer rod to get the piston where it needs to be without machining the case, it would still be off so dropping the jug into the cases and using the stock rod is the only way to do it properly and maintain proper geometry.
Don't mind the tape. Just for reference for another mod.
It should be a screamer....hopefully.
This engine will have a special purpose when complete. Not going on a bike, and will have many modifications. Centrifugal clutch, pull start, eliminating the stock manual clutch with a new shaft and modified main gear etc.
The CDH110 cases are meaty with plenty of material for big bore jugs making the use of larger saw jugs easier than using the smaller cases. The transfers are "square" to the sides making them a bit easier to close up too.
I welded the transfers and stock stud holes up, then machined a pocket 5.5mm deep for the jug to sit down in to allow for the same geometry (crank center to jug base) as the MS660 in order to get proper rod angle/port timing/dwell relationship. Then decked the case to clear the shoulder on the jug. I did not machine the jug base down, which IMHO is the wrong way to do it. I machined the pocket large enough to allow the stock MS660 base gasket to fit.
I am using the stock ZMH100 rod. Even if I used a longer rod to get the piston where it needs to be without machining the case, it would still be off so dropping the jug into the cases and using the stock rod is the only way to do it properly and maintain proper geometry.
Don't mind the tape. Just for reference for another mod.
It should be a screamer....hopefully.
