Ok I'm going to post my progress of the winter project I'm working on here. Hopefully I can get some help and help others at the same time. Pictures to come.

Project:
Dropping a 620 S engine/wiring into a SBK chassis: forks, frame, sssa, etc. Also throw in a dry clutch conversion.

Reason:
This will be my track only bike and most likely a racer. I really love this engine. I just bought a MS4 and would lose a couple grand by selling the 620 right now plus I would hate to part with it since it is my first bike. The SBK chassis in theory should handle better, help the engine breath better(air runners), and generally be a better track package. The process will help reduce the weight of the bike by removing anything that I don't need and help me get to know my duc a lot better. The dry clutch should help in the track/racing aspect I guess, but I just like the noise. But about all, the reason for this is so I can enhance my mechinical knowledge of ducatis and bike building in general.

Progress:
The 620 S has been total stripped down. The engine is on the work table and both of the side covers have been removed. All of the parts have been ordered and most have been received. Here are the steps I have taken or am about to take.

Most of the bike is together at the moment for check the fit of various parts and to make the molds for the airbox and breather box. After the all parts have been assembled and are in working order, the bike will be torn back down and final assembly started.

1 – Strip the 620 S down DONE

ENGINE:
2 – Remove engine side covers, flywheel assembly, clutch assembly DONE
3 – Cut down the swingarm attachment point on the cases to fit SSSA (hopefully without splitting cases) DONE
5 – dry clutch install (yoyodyneti lightweight kit) DONE
6 – put side covers back on DONE
7 - check valves and cam timing
8 – mount engine into frame
9 – mount SSSA onto engine and frame

CHASSIS/MISC
10 – Fab a new airbox to fit the SS TBs based on SBK airbox
11 - Fab a underseat oil breather box
12 – Slice SBK headers off and weld SS headers onto SBK midpipe (should be some work involved getting the headers to line up.
13 – Front end install
14 – custom wiring harness, find place for battery (smaller yusa type), ECU, regulator, etc
15- Fairings, runners, misc stuff

I’m sure some steps are missing b/c I’m just thinking off of the top of my head. So I’m sure I’ll add more.


Problems:
So Far…
1 – Dry clutch driven gear and 620 primary gear don’t quite match up, the teeth on the driven gear are about a .5 mm to long.

2 – The no flywheel thing is a no-go without fab work, since there is nothing to hold the rotor in place.

3 – The Frame cross member is slightly in the way of the vert. intake port. And probably the TB.

4 – The exhaust problem talked about in step 10 above. Need the SS headers on the SBK exhaust.

5 – Find a place to put the battery, regulator, ECU, and misc junk.

6 - The output shaft, I guess is what it is called, that the clutch hooks on to is shorter by a couple of mms on the wet clutch ducs. Also the threads on the end of the shaft are wider on the wet clutch version. So you can't even bolt up the stock dry clutch hub.

Solutions:
1 – Installed a 748 primary and drive gear, so gear ratio might be different from a stock 620's?

2 – Went with OEM flywheel for know.

3 – Chopped the crossmember off and with get a new member welded in that is compatiable with the SS intakes and TB.

4 - Welding job

5 - Got the smaller yuasa battery and I'm fabbing the box now. Hopefully going to put the battery in the space b/w the airbox and the triple. ECU will probably be mount to the front fairing stay and a new wiring harness made.

6 - After looking at the various aftermarket clutch kits I found that I could get one, namely the yoyodyneti lightweight kit, and machine it down a few mms where it mounts to the shaft. The alumium hub would be much easier for me to machine down than the stock steel? one. Then I could mount it up and half of the hub nut wouldn't be hanging off the threads of the shaft. Of course I would need a nut of the correct size which I had off of the old wet clutch. Worked perfect!


Modified by jager at 3:34 PM 2/22/2005