1981 SD900 Darmah - Restoration Project

Post pictures of your twin cylinder Bevel Drive Ducati (pre-1985) along with a description here.
rwhc80
750 GT
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Location: Melbourne Australia

Post by rwhc80 » Sat Apr 30, 2011 5:35 pm

Pilotg.

Personally, I would not be in a panic about the rotors, unless they are,

A/ Way under the 5.8mm or B/ Already causing problems IE: shuddering.

The replacements certainly are expensive, and if as you say, yours are either just on at 5.8 or just under, I would use them until you absolutely need to replace the items. ( That's assuming they are OK & operational at present ???????? )

With my last pad replacement I simply deglazed the rotors with some garnet paper and it's been absolutely fine, especially, If like me, the bike is only for an occasional ride.

Of course, if it's required for Registration,or the bike is a daily ride, then it's a different matter altogether.

Regards Rick.
I have desmo disease, I just hope they never find a cure !!!

pilotg
Diana
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Location: Christchurch, NZ and Brisbane, Australia

Post by pilotg » Sat Apr 30, 2011 6:13 pm

Hi Rick,

thanks for the encouraging words. When I saw the micrometer reading I checked on the Dept of Trsansport website here in NZ and found that the minimum thickness IS the manufacturers recommended figure, and with it cast into the hub I can't realy do much about it. What I will probably do is present it for it's inspection and see what they say. Hopefully my guage is wrong!

I can't tell if they are causing any grief because I haven't had a chance to ride the bike yet, but I will remember your tip if there's any problems. Any advice on the Loctite front?

Many thanks

George
1981 SD900 Resto project

Vince
750 GT
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Joined: Tue Nov 09, 2004 12:28 am

Post by Vince » Sat Apr 30, 2011 6:42 pm

Mate if measured most would be a bit undersized,mine are as well,if your not racing it best bet is get it going and slowly fix as you go.It will keep you motavated while you burn the cash,have a look at the Loctite website for recommendations,I usualy use the meduim strength when i can be bothered,not much vibration on 90deg V twins.Ozlaverda,never heard of them,wink wink

rwhc80
750 GT
Posts: 174
Joined: Sat May 16, 2009 6:19 am
Location: Melbourne Australia

Post by rwhc80 » Sun May 01, 2011 4:13 pm

Pilotg,

I think your heading in the right direction, if the rotors visually look & operate OK then submit for registration check and see how you go .

If your Dept of Reg is similar to our system, then they tend to rely on the Road worthy check carried out by an Authorised Auto shop who provide a certificate of roadworthiness to supply when applying for new Reg.

When I registered my Darmah, the Vic Roads staff member simply checked the Certificate, then a visual check to see all lights worked. Hey presto, off I went. I was more worried about the Auto shop that checked the bike over. Funnily enough, he was so taken with the old Duc that he hardly checked anything at all. I will add however that the bike was in excellent condition, but I was still surprised how easy it was.
Re Loctite, as Vince suggested, a medium strenth should be fine, perhaps either check the website or chat with the stockist, but they are held with good solid bolts and spring washers to start with anyway. also being the front wheel easy to keep an eye on.
Good luck with your checks.
Rick
I have desmo disease, I just hope they never find a cure !!!

Kickaha
Diana
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Post by Kickaha » Thu May 05, 2011 11:27 pm

Are the discs and carriers one piece or does the disc bolt to the carrier?

If it is seperate and bolts to the carrier I can put you onto a guy who can do you stainless discs for a fraction of that price
Eat Right
Stay fit
Die anyway

pilotg
Diana
Posts: 51
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Location: Christchurch, NZ and Brisbane, Australia

Post by pilotg » Fri May 06, 2011 1:52 am

Hi, the disc are separate from the carrier so any contact you have would be great. Try emailing me on dandieo@yahoo.co.uk.

Many thanks

George
1981 SD900 Resto project

rwhc80
750 GT
Posts: 174
Joined: Sat May 16, 2009 6:19 am
Location: Melbourne Australia

Post by rwhc80 » Fri May 06, 2011 3:52 am

George,

Before you outlay hard earned funds consider a couple of bits of info.

1/ Unlike SS spoked rims, FPS rims have no carriers, the rotor bolts straight to the rim.

2/ Cast iron rotors usually provide better braking than stainless steel in the application of an older bike like a Darmah. Stainless steel contains an element of chrome and requires more pressure from the master cylinder. I'm not an expert, but I would not be confident the SD system would benefit from stainless rotors.

Even Moto gp bikes, used Cast iron rotors up until they changed to carbon Fibre.

Do some research before you buy Stainless Rotors !!!!!!

Regards
Rick
I have desmo disease, I just hope they never find a cure !!!

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BevHevSteve
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Post by BevHevSteve » Fri May 06, 2011 8:33 am

I have stainless full floating brembo rotors on my NCR Replica bike [from an F1] standard F08 calipers with Galfer GREEN pads and the original round reservoir master cylinder with everything tied together with stainless steel brake lines running MOTUL RBF600 brake fluid.

:arrow: I have more than enough braking and have NEVER thought to myself how badly my brakes worked compared to any of my bone stock bevel drives with cast iron rotor[s]. Bottom line is that I do not agree with the above poster in saying that stainless is inferior and 'won't work' etc on bevels.
Last edited by BevHevSteve on Sat May 07, 2011 6:57 am, edited 1 time in total.
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rwhc80
750 GT
Posts: 174
Joined: Sat May 16, 2009 6:19 am
Location: Melbourne Australia

Post by rwhc80 » Fri May 06, 2011 4:41 pm

George,

The great thing about Forums is, they allow differing opinions. I try to clarify in my posts that I am not an expert, and sometimes finish with, do some research. I have however, assumed that your Darmah has the same 4 bolt Rotors as mine, fixing the rotor straight to the wheel. ( apologies if that was incorrect ???? )

Kickaha, suggests having SS rotors made if the rotor is seperate, as in the case of newer style of bikes. IE. semi or fulll floater.

Regardless of what your current rotor system is, I stick by my posting, do some "research" before deciding !!!!!!! ........ In giving you suggestions, my motivation is to save you some dollars, as I'm sure you have plenty of other items you will need to buy for the resto.

If however you are loaded, and want to spend the money, then you should ignore my suggestions, after all, You earned it !!!!!!
Good luck
Rick
I have desmo disease, I just hope they never find a cure !!!

pilotg
Diana
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Location: Christchurch, NZ and Brisbane, Australia

SD900 and PHF 32mm

Post by pilotg » Sat Nov 12, 2011 12:46 am

I managed to find a pair of PHF 32mm carbs, AD and AS. All the documentation I can find says that the SD originally came out with CD and CS carbs. What's the difference?

I need to know as I'm rebuilding them prior to swapping out the current PHM 38s that are fitted to my project SD and I want to buy new slides, jets etc. I don't want to order the wrong bits.

Any advice is very welcome.

Re the project, the bike is now at the electricans being rewired and then it will be on the road. It's been a long tortuous path but I'm nearly there. I'll post pics next week.

Regards

George
1981 SD900 Resto project

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Craig in France
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Re: SD900 and PHF 32mm

Post by Craig in France » Sat Nov 12, 2011 6:00 am

pilotg wrote:I managed to find a pair of PHF 32mm carbs, AD and AS. All the documentation I can find says that the SD originally came out with CD and CS carbs.
Hi George,

Ah, that will because you're reading the wrong documentation :lol: :shock: . Early Dramahs ('77-'78 ) came with AS/AD. Look at, for example:

- Owner's Handbook 2nd issue, July 1977.
- Ist issue Factory Parts Manual
- Falloon's 860, 900, Mille Bible, Appendix.

Standard spec's for the AS/AD were:
Main: 122.
(Note: this is the figure given in the parts book. However, the owner's manual differs, listing 118 for the rear cylinder and 122 for the front only. Me, I run my SSD with 122 in both).
Idle: 60
Slide: 70/2
Needle: K6, middle notch
Needle/atomiser: 265AB
Enricher (aka choke): 75
pilotg wrote: What's the difference?
Simple question, difficult answer. These are the changes given in the parts book:
Slide: 60/3
Needle: K16
Idle: 62
(Note: this is the figure given in the parts book. However, the owner's manual lists 55).

In addition, I believe - and he'll correct me if I'm wrong - that Steve A has worked out that the CD/CS range has a tiny supplementary jet fitted.

The reason for the change is normally reckoned to be to compliance with more stringent emissions control legislation.

HTH

Craig

pilotg
Diana
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Location: Christchurch, NZ and Brisbane, Australia

Post by pilotg » Sat Nov 12, 2011 11:06 am

Thanks Craig,

Looking back at the docs I can see where I've got confused.

My SD is a 1981, which therefore should have come out with CD/S carbs. I'm guessing from what you've written that there should be no problem with setting up the AD/S carbs as per 1978 specs and fitting them to the bike? And before you mention it, yes, I have got new inlet manifolds to fit!! Every time I've bought something I've measured what I've already got!

In hindsight, with what it's cost me for the carb bodies, replacement soft and hard parts it would probably have been smarter and cheaper to buy a pair of Steve's 32's, even though they would be both lefts (or rights, can't remember which). I queried him about the chokes and he reckoned you really only need to use one for starting anyway (re having to take the side cover off on the rear cylinder if you have lever chokes).

One thing that I have noticed in the last week is that the Staintune muffler on the right hand side sits very very close to the lower shock bolt. I checked all the spacers and I've put them all back as per the parts manual. I can't see what I've done wrong.

Thanks for your tips re the carbs. I'll go with your setup unless I hear conflicting advice. If that happens.... I guess I'll just have to play around until I find what works for my particular bike.

V best

George
1981 SD900 Resto project

pilotg
Diana
Posts: 51
Joined: Sat Mar 19, 2011 12:24 am
Location: Christchurch, NZ and Brisbane, Australia

Post by pilotg » Wed Nov 16, 2011 11:22 pm

Ok, here's a stupid question....

I've read Steve's tuning guide. Looks pretty comprehensive except one small detail....


Let's say I've just rebuilt the carbs completely. Therefore they have to be set up ready for the first start. Steve's guide advises to warm up the bike first before tuning. So, assume I've replaced EVERYTHING inside and out. What settings do I need to crank it over and warm it up, with all the fear that comes with blowing the sprag last time out!!

I told you it was a stupid question. :-D

Many thanks
1981 SD900 Resto project

machten
MHR / S2
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Post by machten » Thu Nov 17, 2011 1:02 am

Here's what I do for initial new carb set up. I'm sure their are many variations, but this works for me..

1. Have the slide needles at the second notch.

2. Have 2-3mm of play on your cable outers for both the throttle and the choke. You want to be sure the slides are sitting on the idle screw and the choke plungers are fully seated down with neither being "held up" by the cable.

3. Wind out the idle speed screws until the slides stop moving down, then start moving them in until they just begin to lift the slide. Having done that for both carbs, then you just need to wind the idle screws in the same number of turns. I'd give them 1/2 a turn to a turn, but it isn't that important - just try and give them both about the same. You should be able to check this by comparing the height of the air tunnel arc at the front of the slide. (I have a piece of dowel I use for that).

4. Wind the mixture screws all the way in then back them out 2 full rotations (720 degrees). That's a reasonable starting point for mixture.

5. At this point, I usually do a basic static synch of the two carbies by just working the throttle on and off and listening to when both slides hit the idle screws with the throttle coming off. You adjust the cables to try and acheive them hitting the idle screws simultaneously. This isn't necessary, but I have always found it a pretty good approximation and I find it saves me time when I'm fine tuning with the bike running. (don't let the bike get too hot whilst you are tuning - remember it's expecting to have air running past the engine. I have a cheap domestic pedestal fan I use to help with this.)

At that stage you should be in good shape to start your preferred tuning process. I don't use vacuum gauges to tune, only to diagnose a problem, as I prefer to do it by exhaust note and pressure, so can't offer any thoughts on that.

And btw...I've had plenty of stupid questions and they are all the ones that I didn't ask and would have saved myself a lot of grief if I had! :-D

Good luck!

Kev

pilotg
Diana
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Location: Christchurch, NZ and Brisbane, Australia

Post by pilotg » Thu Nov 17, 2011 1:33 am

Great reply Kev, and just what I was looking for.

The bike is away at the electricians being rewired. Then I'll be looking to flash it up for the first time since the disastrous sprag affair. I've always believed that poorly set up carbs contributed to the problem, hence the nervousness. The other being the stuffed battery. On that front there's a new battery going in and a separate earth lead going direct to the starter motor to maximize the power.

Hopefully I'll be able to come back with a positive result in the next week.

Hope. It seems a good word for bevel owners ;)

Regards

George
1981 SD900 Resto project

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