175TS with 125S engine project

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Duccout
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Location: Essex UK

Re: Just Joined 160TS Project

Postby Duccout » Mon Mar 16, 2020 8:56 pm

The later (1970's ) bikes did. It was the same fitting as the Brembo brake pressure switch and was tapped into the camshaft end cap, where I assume there was enough pressure to keep the dash light illuminated. I don't know exactly when Mototrans started fitting the switch, but I have seen it on Road models from the mid Seventies.

Jon Pegler
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Joined: Sun May 16, 2010 6:19 pm

Re: Just Joined 160TS Project

Postby Jon Pegler » Mon Mar 16, 2020 9:13 pm

The oil pressure switch was never a standard fitment to the Road models, either widecase or narrowcase.
It was standard on the Forza, Vento and Strada models from 1977 onwards.
It was also fairly useless.
When first started from cold, there was enough pressure to extinguish the light on the dash panel, but as soon as the oil warmed up, the pressure dropped, or there was sufficient leakage past the camshaft/cam bearing holder and the light usually came on and stayed on.
The standard oil pump is not powerful enough to keep the switch off, thus turning the dash light off.
I've had a number of these machines and none of them have succeeded in working properly, despite changing switches, cam blocks, pumps etc..
Fitting a 2RS bearing in the cam block, with a rollpin restrictor in the camshaft is probably the best way to get it to work at all.
A nice idea, but flawed in it's application.

Jon

George
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Re: Just Joined 160TS Project

Postby George » Mon Mar 16, 2020 9:55 pm

Stripping more parts today. Previous owner(s) were heavy handed I will have to check everything as removed.
This preamble brings me to today's problem.
I require a replacement heel / toe gear change lever.
There is a lever advertised from 175cc engine https://www.ebay.co.uk/itm/Ducati-175-t ... 4118857010
would anyone know if this is a common part with splines same for 125 160 models. Or would anyone have one they no longer need
George Essex UK

George
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Joined: Fri Feb 14, 2020 2:51 am
Location: Essex UK

Re: Just Joined 160TS Project

Postby George » Fri Mar 20, 2020 9:06 pm

Restoration update
Everything points to a 175TS with different engine fitted at some time. Frame and tinware in good condition with surface rust only.
Checked new replica rear light and licence plate holder fitted. All OK, reasonable cost at £50 total for both.
Removed wiring looms and everything in headlamp shell. Lots of bodging, wires twisted together, colour changes, wires fitted in wrong places. I shall have to work out this puzzle at a much later date when assembling.
Engine number indicates early 1960s 125TS with 160 top end.
Valve timing checked:
Inlet Valve closes 60 degrees ABDC opens 48 degrees BTDC
Exhaust valve closes 30 degrees ATDC opens 70 degrees BBDC
Valve clearance inlet 0.15mm exhaust 0.20mm
Static ignition 24 Degrees
These figures are only a guide as top bevel bearing worn, top bevel gears have excessive play and there may be other worn parts,
These figures seem excessive for a touring bike. Never having worked on Ducati before I would appreciate confirmation if this would be correct.
I am having trouble finding information on Mototrans models and can only find details of 160 Monza
Should I check / measure anything before head is removed to measure bore and stroke to establish capacity
All information welcome
Thanks
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George Essex UK

Jon Pegler
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Re: Just Joined 160TS Project

Postby Jon Pegler » Fri Mar 20, 2020 9:40 pm

Your figures for cam timing look about correct for a 125 Sport cam, given that the valve clearances are too great. They should be 2-3 thou ( 0.05-0.07 mm)
125S cam- inlet opens 44 BTDC closes 68 ABDC, exhaust opens 78 BBDC, closes 35 ATDC
Mototrans cams are notorious for being around a certain figure, not exactly as specification, although often quite hot cams for their given application.
Try taking the head off and measure the bore.

Jon

Ventodue
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Location: Montpellier, France

Re: Just Joined 160TS Project

Postby Ventodue » Sat Mar 21, 2020 10:59 am

George wrote: I am having trouble finding information on Mototrans models and can only find details of 160 Monza


The information is out there, but you will struggle to find it in the 'classic' Ducati sources which tend to be rude and dismissive about the Barcelona bikes :roll:

The most widely available published sources are "Ducati Motorans" by Carlos Polo; and "Ducati, mucho más que une licencia de fabricación" by Francesco Herreros. Both are in Spanish. I'm attaching a scan of the technical pages from the first book on the 125 S and the 175 TS.

Otherwise, Jon's 'Your Man'!
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George
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Location: Essex UK

Re: Just Joined 160TS Project

Postby George » Sat Mar 21, 2020 8:18 pm

Thanks for reply's Jon and Ventodue very helpful.
Made the mistake of assuming cam cover marked 160 cc indicated that engine was 160 cc.
Removed head today. Piston is stamped L2 56.50 stroke is 52 mm. 125cc bored to 130 cc
Engine number early 1960s 125TS. Cam 125 Sport, piston not sure if Sport or TS. are Sport and TS valves different sizes?. Is the piston at largest over size.
Carburettor is Amal 375 20, engine chain sprocket 15 teeth. Rear wheel chain sprocket 44 teeth on 18" wheels. 175 cc bike.

I bought what I thought was a 160TS with the idea that with my advancing years my Moto Guzzi 750 would get to heavy and I wanted an Italian lightweight machine to use on VMCC club runs and riding for pleasure. I wanted to be able to keep up with traffic cruising at least 50 MPH with a bit in hand for hills and strong headwinds. I have wanted a Ducati single since the 1960s but could never afford one. Being a little fellow weighing 12 stone the 160cc seemed to fit the bill without getting to expensive.
I would welcome any views or comments knowing that final decision is my responsibility.
1) Are 125 spares available, had a quick look online not many parts showing
2) Before I start spending would this 125 S engine achieve my what I want as above or should I consider looking for 175 cc engine
Thanks in advance
George Essex UK

Jon Pegler
Posts: 459
Joined: Sun May 16, 2010 6:19 pm

Re: Just Joined 160TS Project

Postby Jon Pegler » Sat Mar 21, 2020 8:55 pm

I think that the 125S motor will be every bit as good as a 160TS
As standard, the 125S was a 10Hp motor with an 8:1 compression ratio. This compared favourably with the 160TS.
The 125TS only had a 7:1 piston.
The carburettor is from a 160, the original being a Dellorto UB20BS. A fairly normal replacement in Spain.
The sprocket sizes are probably 175 ones, the 125S having a 16 tooth gearbox sprocket, although that hardly matters.

125 parts are available, not as readily as some of the other capacities, but they are out there.
Many of the Italian 125 parts will fit a Mototrans 125
I might even have a 125 cam bearing block amongst my spares, I'll have to look.

Jon

George
Posts: 385
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Location: Essex UK

Re: Just Joined 160TS Project

Postby George » Sat Mar 21, 2020 10:09 pm

Thanks for prompt reply Jon very reassuring, I would prefer to keep 125 engine and look for new piston if liner will take another rebore.
Silly question, will the bevel tube lift off after removing 2 allen screws. It is preventing the head from coming off. Had a long day and did not want to force it.
Now I know what I am working on will put engine to one side and get on with final stripping / cleaning for painting.
Will look for 125 sport engine workshop manual, sorry to keep asking questions but would Italian manual surfice if I am unable to find Spanish version.
Once again thank for your help
George
George Essex UK

ranton_rambler
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Location: Stafford UK

Re: Just Joined 160TS Project

Postby ranton_rambler » Sun Mar 22, 2020 8:47 am

The bevel tube comes off still attached to the head. If it’s like mine, the bottom end is a push fit into the bottom bevel housing, with an O-ring to seal.
Once the whole lot is off you will be able to wriggle the bevel tube off. I think it interferes with the fins etc so won’t come off in a straight line.
Similarly at the bottom when you get there. Bottom bevel gear can’t come out until the cases are split.


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