Tresette Sprint

Singles built before the Lambertini era
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tremoto
Posts: 22
Joined: 18 Feb 2009 12:53
Location: Londra

Tresette Sprint

Post by tremoto »

Anyone attempted a tresette rebuild lately? I'm midway through a ground up rebuild on a rat sprint that I have spent more time sourcing the right bits for than spannering! Cold out there in the shed I can tell you.

Gearbox is now in place, new top ring, all bearings replaced, new gasket set part used and cases etccleaned & sorted. Reccession or otherwise like to get it MOT'd run it then bust it up again and do it proper like. Any probs you lot encountered?
morinipete
Posts: 166
Joined: 03 Jun 2007 08:45
Location: Rugby, UK

Tresette Sprint rebuild

Post by morinipete »

Hi, if you took it apart yourself you’ve probably discovered the two possible problems on putting it all back together again.

1. The clutch nut is left hand thread and the clutch basket extremely brittle. Hence lots of broken outer baskets ! On doing this up I’d really recommend making a proper clutch holding tool, using one of your plain and one of your bonded plates. If you just drill and bolt them together to do this there’s no reason why you can’t then re-use them for their intended purpose if you make sure there are no burrs, etc. If you try to lock the clutch in any other way there really is a very strong chance you’ll shatter the outer basket.

2. Cam timing. If you have a “Sprintâ€￾ you have the potential for infinitely variable valve timing. Great if you want it, not so great if you just want the standard timing ! On taking the engine apart, if you marked which of the internal ‘notches’ on the pinion which goes on the end of the crank the pin on the crank engages with, you’re laughing. Similarly if this is already marked on the inside of the pinion (from my experience very few are) you are OK (as the gear on this pinion is marked where it engages with the cam gear, so this shouldn’t be a problem). If this pinion on the crank is not marked, or you didn’t mark it yourself you are going to have to time this up by hand, using a gauge, etc, to judge valve opening times. I do have a diagram to indicate which ‘notch’ is correct (I’ve helped two or three people previously on this) but as I’m out of the country at present I couldn’t get a copy of this to you until late June at the earliest unfortunately.

Other than that there is not much I can think of off the top of my head though make sure you’ve kept all the original engine nuts, as things like the barrel base studs are 5 or 7mm fine thread (as may be head nuts ? ‘can’t remember) which are almost impossible to get hold of. Ignition timing can also be a problem, but I can’t really help on this one as I have used the complete electronic kits obtainable from http://www.powerdynamo.biz/eng/systems/ ... 75main.htm which I now note are now not far off £400 ! ‘Struth they’ve gone up, but for this you do get a complete electrical system for the whole bike, 12volt, which replaces the dodgy regulator, stator, etc. It also takes the ignition timing directly off the end of the crank on the right, rather than off the end of the cam (on the Sprint) on the left of the engine, which I reckon has to be a more direct and accurate method.

Anyway, good luck with the rebuild and as a request could you send me any of your sources of spares, as I’m always looking ?

Cheers

Pete
PS. Are you a member of the club ? If not, join ! I regularly put items in the magazine, which will help you with the rebuild.
PPS. I am desperate for some valve collets (i.e. the split ones which are at the top of the valve and hold the spring). ‘Don’t suppose you have one or two spare ?
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Morinijen
Posts: 50
Joined: 01 Dec 2007 14:02
Location: London U.K.

Re: Tresette Sprint rebuild

Post by Morinijen »

Hi Pete. :)
That was a very helpful reply.
morinipete wrote: ...Anyway, good luck with the rebuild and as a request could you send me any of your sources of spares, as I’m always looking ? ...
I dare say you have already heard of Ciabini, but it might be a useful link for someone...

http://www.ciabini.com/

Click on 'Ordine' and 'Moto Morini'.

They have some of those split collets, though they appear to be for the Settebello and I've no idea if they are the same as Tressette ones.

I would have thought that split collets are something that could be made from scratch? No idea how much it would cost.
If they are so hard to obtain perhaps a group of interested parties could club together and get a batch made?

Best Wishes,
Jenny.
morinipete
Posts: 166
Joined: 03 Jun 2007 08:45
Location: Rugby, UK

Collets, etc

Post by morinipete »

Hi Jenny.

Yes I know this lot, and actually got some close ratio gears of him.

They've obviously updated their site recently though as I hadn't seen the split collets ! They should be different, but look suspiciously similar, so when I get back to the UK I'll check.

With getting a batch done just look at the web price ! I did ask around a bit before but concluded it would be easier to get some off the peg collets and valve caps, off something else, then machine the valves to suit.

See you at Cadwell

Pete :D
tremoto
Posts: 22
Joined: 18 Feb 2009 12:53
Location: Londra

Sprint

Post by tremoto »

Thanks Pete,

Useful stuff to know re-the clutch basket and the nuts. I bought a die for an engineer to use to make up clutch nuts because of availability. I am sure he could do more with me twisting his arm.

Being a bitsa, I am in a collet situation myself. One set is not in two halves but in basically quarters. How it ever survived a droped valve I will never know!!! It was originally re-built in Italy with bodges to keep it running. It has been re-bored and the valve gear had been modified to accept a non standard pushrod on the inlet vale side probably due to a seizure, but no work had been attempted on the bottom end. Think crud of the highest magnetude full of swarf coating the oil pump etc. I hope I have put a stop to it by cleaning out the muck and gluing several magnets on the steel sump plate to at least give me a fighting chance in the oil department. On the subject of Ciabiani, I bought a set of new TS bolts off him and cant wait to replace the old cruddy ones that had suffered over the years. He does loads of parts but I will also look at the collets. Settebellos seems to be more vogue in the sales department maybe I'll e-mail him to see if he will up the anti.

Lets keep the post running, I need all the help I can get. Cheers all.
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