My winter project

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

Does the dry clutch side cover mount up to the 620 motor? I always counted a different number of bolt holes holding that cover on, and it was my understanding that the primary drive axis and the crank axis were different distances apart between the two motors. Other than that, good luck and keep us posted.

Man, sounds like a cool project. What race sactioning body are you thinking about racing in? Hope to see the bike on the track this spring

I have only slapped the cover on for a few seconds to check fit, but it seems to work fine and mounts flush with the cases just like the wet clutch cover and the clutch cover on the S4. I didn't pay attention to the bolt holes, but I'm pretty sure they are the same (picturing it in my mind). The primary drive axis went in the hole perfect and the crank axis seemed to be in the center of the hole in the clutch cover, but I didn't try sticking the basket on there. I'll find out tonight though.

I really haven't done much research in the racing organization department, so I'm not sure. I know that over at ducat.ms rebelpacket said that 620 are doing good in the production twins class (well I'm out of that class...not production) racing against EX500 and MZs. But like I said I haven't thought about the racing side much yet. Just wanting to go out, have fun at the track for a couple of months and see where that takes me. I hoping to get this project completed towards the end of January and trying to get down to jennings GP in Feb.


Modified by jager at 2:29 PM 12/16/2004

Very intrested in this project!

I am doing something similar except with a 900ss engine. I am avoiding the airbox problem by just installing k&n pods instead of the airbox. The headers are going to require some work because they dont line up exactly. You are going to have to shave some of the engine case off to get the SSS to fit.

Its good to know someone else is doing this project as well. That way hopefully you can make the mistakes before i do!

Keep us posted.

Yup I have to shave the swingarm mount. This can be accomplished a couple of ways, most require the cases to be split. I didn't want to do that, b/c it would open the door for to many additional mods . So I'm using a die grinder with a metal cut off wheel. Works well, just watch out for the rest of the cases. I talked with Norm about this and he told me there are actually markings on the cases showing where to cut to, which there are. He also said that it isn't an exact cut b/c you need some room to shim and align. I have got one side almost down about to where I want it and if I can get the damn needle bearings out of the other side I will be good to good. Of course I can't get the chuck on the grinder to unscrew so I can remove the wheel, so I'm going to have to do something about that.

How are you solving the intake port and frame crossmember problem?

As far as the crossmember, I am going to weld a new one on. The intake port, I am just going to open up the sbk airbox and go with pods directly off of the carbs on the ss engine. I know it wont be the best way, but maybe in the future make a new airbox out of fiberglass or carbon.

OK I may sound dumb, but what is a SBK chasy. Normaly this would mean superbike, so if this is a case I assume 916 and up chassy or 748-9. Am I right ?

Yes

Jager, What are you going to do as far as bodywork?

SBK bodywork, hopefully sharkskins. Looking to get a aluminum subframe and mono tail also.

Jager, what happened to the 620 s rolling Chassis? I have a spare SBK motor

Still got it. Well I have a SS engine in a SBK chassis and a SBK engine in a SS chassis. I pretty much switched the two. Its like I'm Johnny Cash only its a ducati instead of a Cadillac. Hey what year is that ducati...well, its a 96, 98, 2000, 2002, 2003 motobike.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jager &raquo;</TD></TR><TR><TD CLASS="quote">Still got it. Well I have a SS engine in a SBK chassis and a SBK engine in a SS chassis. I pretty much switched the two. Its like I'm Johnny Cash only its a ducati instead of a Cadillac. Hey what year is that ducati...well, its a 96, 98, 2000, 2002, 2003 motobike. </TD></TR></TABLE>

That's some funny shite!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jager &raquo;</TD></TR><TR><TD CLASS="quote">Its like I'm Johnny Cash only its a ducati instead of a Cadillac. Hey what year is that ducati...well, its a 96, 98, 2000, 2002, 2003 motobike. </TD></TR></TABLE>
That is funny! I built it one piece at a time...
Great song.

Cool project!! Definitely need to see pictures...

Just a quick update, things are moving along now that I have most of the parts. I updated a few things on my first post, mainly about the clutch conversion. I haven't had much time to work on it the past week. Still no pics, I'm going to get tons of pics when I start final assembly. Oh wait I do have one pic:

Its a few weeks old. Now the front end is mounted and the clutch is done. I was hoping to be done about now, but I'm not even close, probably another month depending on a few varables. But I'm taking my time and making sure stuff gets done right.

Looks awesome........... I'm wanting to do something just like this so I will keep an eye out for you pictures!

That's so cool! Keep the pic's coming!

Was your 620 originally a 5 or 6 speed?