175TS with 125S engine project

[Duccout]

Hi George,

The upper bevel housing always seems to be loose in the head; it would useful to know Nigel's experience with the frequency of this? I think that it is standard practice to loctite the bush.

There is a company called Joy Cams, in Bishops Stortford who reface cams and rockers, who are repairing one of my rockers at the moment.

[Jon Pegler]

I'm fairly certain that the Italian 160 rockers will fit the Spanish 125 or 160.
They both use the 8mm pivot pin rather than the 10mm one of the larger motors.
However, the parts numbers of the rocker is different
Spanish rocker 125.1 TS 1014/2, which is 0251.92.173
Italian rocker 0251.92.174
I doubt that there is much difference between the two.
Without having them next to each other it is hard to tell.

As Colin says, your best option is probably to send them to Phil Joy for re-facing.

Oversize top bevel bearing holders are available if your one is a very slack fit.

Jon

[LaceyDucati]

Hello George

The rockers are interchangeable with Italian rockers, I may have some good used or exchange reconditioned rockers in stock. However you may be best to send the cam and rockers off to Phil Joy for repair, he is by far the best man for the job. I would recommend having the cam at least dressed over to give all the parts the best chance. Running new/reconditioned rockers on a worn cam is less than ideal. Phil will be able to advise if the cam either needs dressing or rebuilding. It looks like there is still an edge of the cam unworn to work to.

The top bevel housing has been spinning due to what I would describe as a flawed design. It is quite a common problem and as with many wear issues the harder material sometimes wears more. There are oversize housings and I have some NOS ones if you need one. If you are a budding machinist you could make one yourself. Using loctite on the top housing is not normal and it is something I certainly would not recommend.

The issue with the housing and top bevel gasket is that there is no provision for shimming and therefore the gasket material thickness is crucial to holding the housing tight and sealing the flange. All gasket material varies in thickness, usually +/- 0.05mm even over the same sheet. You could mess about trying to find the correct thickness material and that "may" hold the housing tight and "may" seal the flange at the same time but that is a tall order. Added to this two hole flanges are particularly poor for sealing as they always tend to bow. Personally I would just chuck the gasket and seal the flange with a good setting sealant. That way the housing will never move and the flange will not leak either. I build up a small bead of sealant well away from the bearing and oilways with a small electrical screwdriver. I do this with the shaft/bevel housing in place and the tunnel pulled away ready to pull down in place with the screws. I wipe the joint very carefully afterwards and I've never had anybody notice or comment. If you want to chat the method through give me a call when you are ready. I've been using the method for 30 years on all the engines I've ever built and never had a problem, leak or spinning housing. Some might disagree with my method, but it's served me and others well over the years.

Regards Nigel

[Duccout]

Sounds good to me!

[George]

Thanks for all prompt replies. Jon thanks for sharing your knowledge.
Nigel have added top bearing housing to ordering list. Will email to you when I have found out what else I need. Its a long list and perhaps have a chat about anything you recommend.
Duccout, sorry don't know your name, will send PM

[George]

There are oversize housings and I have some NOS ones if you need one. If you are a budding machinist you could make one yourself.

Although I served my apprenticeship in machine shop engineering think it will be cheaper to buy bearing housing than lathe
Have read posts about fitting roll pin in end of camshaft. something I will do.
Sorry to be asking simple questions but I have no trust in anything previous owner did. This is my first Ducati and all my Moto Guzzi's are pushrod.
Is it correct that rocker bushes are a sliding fit in rockers. Did 125 /160 have no valve guide oil seals. None showing on parts list none on engine.

[Duccout]

I think, that nominally, when new the rocker bushes were a light press fit in the rockers, but in 45 years of working on Ducatis, I have never found a rocker bush that was not a sliding fit. You'll need more knowledgeable people than me to comment, but I believe that the 125/160 did not have guide seals and there may be a thread on here somewhere about fitting them.

[LaceyDucati]

Hello George

Early bikes often had the bushes tight in the rockers, but the pins and bushes wear badly. If you run the bushes free in the rockers it reduces the wear on the spindles dramatically. Some later bushes (from the parallel twin I think) and some aftermarket bushes have a scroll on the outside so they are intended to be loose. With the bushes tight in the rocker arms you will get more pin wear, so I'd leave them free to turn.

Regards Nigel

[LaceyDucati]

The early 125/160's didn't have guide seals, the late 160 parts book does however show seals. As long as the valves and guides are in reasonable condition it will be fine without seals.

Nigel

[ranton_rambler]

George, my 175 has no seals on the valve stems either. My 2 big block Guzzis are the same. I did consider getting the guides machined for seals on my 1000SP but was advised that they would wear more quickly without a little bit of oil.
Ian