Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > Question from a Desmo Due would-be racer...

[Iconic944ss]

Hmmmm...the more I look, the less I see (how deep !!!)

The Goodridge hose guide - shows 600SS from 1994-98, listed with only one single front hose, with the 750 and 900 for the same years - also getting two hoses.

http://www.goodridge.net/appguides/UK_sportbike.pdf

The parts fitted all look very original OEM Ducati bits and should satisfy DD rules.

All the stuff I've read so far suggests using a 900ss m/cylinder - one of which I have spare if its not fitted already.

[KeefyB]

Yep 600SS came with a single disc setup as standard.The fork bottoms and disc carriers have probably been painted black as a result of a missmatch,or they were bored!
As for the Legend thing,I think that will be just a decal that some owner has fitted.(Probably the same person that painted the forks!)
As someone else mentioned,check to see if the master cylinder has been uprated to cope with the extra disc.Look at the numbers stamped near the lever pivot.They should end with 16.(16mm bore)
If the numbers end with 15 or 13,budget for a new master cylinder.

[skidlids]

A couple of years ago I purchased a N reg 600SS with a standard twin disc fitment front end (lugs on both forks but only one disc and calliper), but as the forks were very pitted from flood damage I replaced them with a set from P reg bike and these only had brake lugs on one fork.

[uncledunnie]

thanks for that chaps,

I fairly happy with the little bike and the price, but......

I do have one remaining concern and this point is really directed at the rule makers.

The regs state no work to the cyclinder heads, but I can go to the big bore conversion - so if I do buy the bike I know I will want to go big bore so does that mean I'm stuck with the 600 heads?

These things have tiny valves and because of their design I understand that fitting larger valves is virtually impossible / expensive. If I'm correct from the info I have gathered the 600's biggest drawback to performance enhancement is inability to suck air - due to the restrictive valve arrangement, so.......

1. In doing your calcs re performance balancing between the big 600's and the 620's can I change the heads during the conversion? If so what are the regs regarding that?

2. If I cannot change the heads on conversion I assume the figures you have been working to mean a larger bore 600 with stock 600 heads will match a 620 with some simple carburation mods.

Perhaps the powers that be could clarify that one for me.

I'm becoming a bit sceptical that an overbored 600 with stock heads and cams and free exhausts will match a 620 with free exhausts and fettled fueling.

600 approx 50bhp stock Vs 620 63bhp stock, I could see a 620 going to low 70's quite easily but a 50% power gain on a 600 is starting to look a bit optimistic in my eyes.

Any one put my mind at rest, I can't see the point of forking what looks like being the best part of £3k on a 600 with overbore and other mods to find its not competitive (rider ability excluded!) against a much cheaper to modify and easier to sell-on 620.

Any one else had thought along these lines?

[dickieducati]

very simplistic from me but i will be going for a 620.

[uncledunnie]

I wish I had your clarity Dickie!!

the spanners are screaming "sort a 600"

the brain is starting to murmer "just buy a 620"

[dickieducati]

well for me im not a great one for fannying about with bikes, mainly because i havnt got a clue what i'm doing so i want the most easlily available horespower so in my mind that is a 620. it also give you a higher base level to start from if you do want to fettle things a bit. sure it will cost you a bit more initially but there is no such thing as a free lunch.

[skidlids]

Good point uncledunnie, if I was fitting a big bore kit I would certainly like to get the Squish sorted to suit and reduce the risc of detination.

Not sure I would want to go through the hassle of bigger valves but better shaped one piece stainless valves would help both gasflow and reliability and then a camshaft reprofile with different lift and/or duration would again help gasflow.

Still that would be a silly amount of money to spend to try and beat some 620s, be better off trying to beat all the other 583cc bikes out there for a lot less cost.

Then if racing is for you move to a SoT class the following year, for about £3500 I could put a 748R on the track (my 748SP + 748R engine package that Nelly had for sale and sell 748SP engine and injection on)

[Felix]

Kev, you continue to amaze me. Of all the riders I know, both track and race, you fettle the most with lots of bikes. I envy your activities.
Sounds like a dream to me.

[ali]

I'm looking at DD as a two model series. I'll be out to chase the other 583s, and if I pass a 620 or two then all the better.

If things are looking up on the work front later in the season then I might invest in a 675 kit and a cast iron disc (or twin disc set up), as I think a lot of time can be made up into, and coming out of, corners. The big bore should give similar torque to a 620 for the first few yards out of a corner.

Having said all that, if a bashed-about 620 comes my way between now and May then I'll do my best to find the reddies.

Cheers,

ali