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Revcounter drive ratio
http://www.ducatittandf1.com/viewtopic.php?f=10&t=1560
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Author:  geo7863 [ Fri Dec 16, 2011 3:04 pm ]
Post subject:  Revcounter drive ratio

Hi all, a quick technical question for you.

My bike has a 1993 900SS engine..gasp shock horror..Ok I know the heads are the wrong way around, but I had a couple of spare engines so it seemed silly not to waste them!

I have currently fitted a replica competition Veglia rev counter from 2 to 12 Thou' RPM with I think a 4:1 ratio (but don't quote me on that!), the 1993 SS speedometer drive cable fits the rev counter but does anyone know if the Pantah engine and the later SS engine have the same rev drive gearing? (I havent run the engine yet so I haven't seen this replica rev counter in operation!)

My original cables from the 93 SS had the old style Ducati graphics stamped on the side so I would hazard a guess that Ducati didnt change the drive gearing for the sake of it when they probably had lots of pantah bits and bobs still in stock, I mean lets face it the F1 instument panel was carried over to the SS (and 851/888) model range so I am hoping I can use any Pantah Instrument with my SS engine. (I am thinking of using a standard Pantah rev counter instead of the competition rev counter!)

Thanks in advance for any help

George

Author:  f1inabox [ Fri Dec 16, 2011 4:44 pm ]
Post subject:  Re: Revcounter drive ratio

Hi George

Sorry to be of no actual help but I broke the cable drive gear (the one that drives the cable) on my F1 when I forgot to remove it when removing the cam from the head! (The comment at the time was a lot less than polite!) I had a bit of a job trying to get a replacement, mine had 13 teeth and is used with the white veglia instruments. I came across two other teeth numbers whilst looking for another. Now don't quote me on this but: 19 teeth for an earlier pantah? and I think the other was 17 teeth but it was awhile ago now and I might have that wrong. Sorry I can't be more specific.
The 13 tooth replacement came from a 90's ss900 I think in the end...

regards Hamish

Author:  618F1 [ Fri Dec 16, 2011 5:12 pm ]
Post subject:  Re: Revcounter drive ratio

I tried to get definitive answers to this last year (and tried to get some owners of genuine TT1s and TT2s [Lou] to pull their engines apart to answer this), before the board crashed and we started all over again. I will tell you what little I have seen, or think I know: The worm gears in the Ducati Pantahs, the Paso, and some Elefants have fine worm gears, 19/9, in the front head, and work with the original street NDs, some odd instruments, and Veglia race tachs (I think). Makes sense that the Pantah ratio fits the Veglia race tach. I have the 19/9 and ND combo on the No. 8 Pantah replica, and it seems right to me. Still, some in OZ say this is all wrong, and that there is another ratio, but I never get an answer as to what that is and where it is. The Veglia race tach (vintage and replica) is marked 4:1 ratio (RADD, I think, on the stickers), although I believe that there is also something different for Hondas. The later F1Bs and 750/900 SS with the modern Veglia tachs have coarse 13/4 worm gears and those tachs are marked 6.5:1 ratio. So I would not mix the coarse worm gears from the "wrong" heads (sorry) with the Veglia race tachs. Now, please, someone who really knows chime in. MikeV

Author:  geo7863 [ Fri Dec 16, 2011 5:23 pm ]
Post subject:  Re: Revcounter drive ratio

Cheers for that chaps... I didnt think life would be so easy even if I had hoped it to be!...so next question (if I manage to find one) will the Pantah/early F1 Rev counter drive fit into the drive housing on the later SS (wrong way around) head?

Author:  geo7863 [ Fri Dec 16, 2011 6:28 pm ]
Post subject:  Re: Revcounter drive ratio

In fact thinking about it (and I am not that clued up on engines... I have built a '95 900SS and a highly modified '92 900SL from scratch...but sent the engines away to be rebuilt!) I guess the gear on the camshaft which drives the rev counter worm gear drive will be different for each model too!

I guess the easiest approach would be to use a standard 900SS rev counter with a modified instrument face and pointer to 'look like' the original TT1 F1 endurance rev counter...that way would mean no messing around with gearing!

Author:  618F1 [ Sat Dec 17, 2011 9:48 am ]
Post subject:  Re: Revcounter drive ratio

All the front heads fit the "right" way, and the worm gears are interchangable. So, just pick your poison and match the parts (gears/tach). Ian Gowanlich (Italspares) has matching sets of the gears, and they are not expensive.

Author:  corsa [ Sat Dec 17, 2011 6:50 pm ]
Post subject:  Re: Revcounter drive ratio

I'm just about to try one of the Veglia Replica Rev Counters on my TT2 racebike, I'll let everyone know what they're like when it turns up.
Corsa.

Author:  geo7863 [ Sun Dec 18, 2011 5:12 am ]
Post subject:  Re: Revcounter drive ratio

618F1 wrote:
All the front heads fit the "right" way, and the worm gears are interchangable. So, just pick your poison and match the parts (gears/tach). Ian Gowanlich (Italspares) has matching sets of the gears, and they are not expensive.


Cheers for that :D

Like I said I am not that 'clued up' on engine matters... I pay someone to do all that malarky for me! I am 100% sure I can strip an engine successfully without too many problems...putting the blighter back together properly is a totally different story!

I take it the front head camshaft has a gear ring which slips over it somewhere and the worm gear spindly type thing (do you like the technical terms here? :P ) just slides down in and meshes with the aforementioned gear ring on the camshaft?

Before I bought the replica Veglia (arent they a lot cheaper on ebay now!!!!) I bought another similar looking rev counter..cant remember the make now but I have it in a box somewhere... I also cant remember what drive ratio that has on it...but if it fits the standard SS 13/4 ratio then I will use it and just put a new face on it to resemble the black rev counters that I have seen in every pic of a TT1 F1 Endurance racer! a la photo attached!

Attachments:
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Author:  loudbike [ Sun Dec 18, 2011 11:30 am ]
Post subject:  Re: Revcounter drive ratio

The 1:4 is for bevels and singles.. From the parts books, I was able to figure out (by tach drive) what was going on..
1 : 6.5 066092160 750 F1 Later
?????? 066792160 750 Paso
1 : 6.5 066092160 900SS
1 : 6.5 066092160 750S
1 : 6.5 066092160 F1A
1 : 6.5 066092160 Alazurra
1 : 5 066092155 600 Pantah
1 : 5 066092155 500 Pantah

F1 / Supersport Tacho: 067038640 = 402.4.003.1a

Clear as mud?

Author:  geo7863 [ Sun Dec 18, 2011 11:55 am ]
Post subject:  Re: Revcounter drive ratio

loudbike wrote:
The 1:4 is for bevels and singles.. From the parts books, I was able to figure out (by tach drive) what was going on..
1 : 6.5 066092160 750 F1 Later
?????? 066792160 750 Paso
1 : 6.5 066092160 900SS
1 : 6.5 066092160 750S
1 : 6.5 066092160 F1A
1 : 6.5 066092160 Alazurra
1 : 5 066092155 600 Pantah
1 : 5 066092155 500 Pantah

F1 / Supersport Tacho: 067038640 = 402.4.003.1a

Clear as mud?



Er.... yes....quite! ...and happy birthday by the way Steve!

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