wanted - moto giro bike

vapour (vapor) blasting it is then. Almost pulled the trigger on buying my own vapour blasting cabinet, have wanted one for quite a while, but in my current downsized home/garage my sand blasting cabinet lives outside in an unheated storage shed and there just is no room for another blast cabinet.... Local vapour balsting shop I just talked to quoted a very reasonable estimate, way cheaper than buying my own cabinet, bloody hell.....;);)
 
took the engine, wheels and brakes, cast muffler, carb, and various other bits for vapour blasting. Dropped off late to day.

The vapour blasting palce asked me to take the valves out of the head, so I got out my valve spring compressor. Only two valves obviously, weird things with a sort of mushroom type top on the stems, the pair of collets per valve were actually collet fragments per valve, never seen that before, how the heck does a collet get broken, espcially on both valves? The photo is of the better of the two valves, the collets on the other valves were in 5 pieces. Might be a challenge to source new collets, if I find a pair of valves with collets the head will be gettting new valves, but the only pair of valves I had found so far are stainless steel and almost $400 USD for a pair of valves and guides, seems rather silly and way too much money. One of the valve tip caps also has a piece broken off it.. Strange the things you find in a 65+ year old engine.

the cast muffler is really strange as well. Turns out to be a hollow casting, with the header pipe running full length from the exhaust port in the head all the way through the hollow muffler casting to the end, pipe end cripped mostly closed, and some holes drilled in the pipe. Already planning the hot rod mod of drilling more holes in the pipe....:ROFLMAO::ROFLMAO::sneaky::sneaky:
 

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That muffler looks choked to hell. The both, 2 and 4 stroke dirtbike competition mufflers I have seen and work like that are completely open right through the middle tube with the same diameter and maybe a curve turn down on the end and usually made out of completely perforated mesh. Way more holes than that and not pinched down either. They get wrapped in sound-absorbing material that needs replacing a couple of times a year. Sometimes yellow fibreglass roof insulation or better still a white fluffy fireproof cotton wool-like stuff sold in bike shops.
 
The concave face on the valve shows that it's pretty worn. Hopefully the seat is made from harder stuff and is recoverable.

I'd definitely be replacing the valves if I were you, especially considering that one of them has a bit busted out of the collet retaining lip (dropped valve waiting to happen). Talk to a valve specialist (eg. Kibblewhite). They may have suitable valve blanks (and guide blanks) that can be machined to fit. They also supply collets. You don't necessarily have to stick with the original valve stem diameter if you use custom valves and guides. Valves are made of better stuff now than 60 years ago, so you might be able to go to a thinner stem that'll give you better gas flow and another couple of flea power. I presume there are cylinder head reconditioning specialists in Calgary who will be able to do the machining work on the valves and guides. They may be able to source the blanks for you.

I share Vince's opinion of the exhaust. Open up the crimped end and you'll probably un-leash another 0.2 horsepower!
 
That pipe's a larger version of what Triumph used to sell as a "mute" for trials Cubs.
If your reconditioners say they can K-line the guides and the valves will recut OK, the collets are a reasonably simple lathe exercise.
I've made several sets for valves like that. Mild steel is good enough. Turn them as a solid piece, do the taper first. Bore to the OD of the reduced valve stem. Cut - by hand with a fresh hacksaw blade - most of the way through, longways, then part the machined piece off your blank. Hand finish and job's done.
Nothing against new valves and guides if neccessary - but I tend to look at the cheapest way out.
 
Vince, Cam amd Greg, and all

I need folks like you nearer me. I do not have a head reconditioner specialist or anyone to turn up new collets for me.

The place that is doing the vapour blasting for me, I have known the owner Don Fergin for many years, and "see" him regularly through the local Canadian Vintage Motorcyle Group monthly meetings (by ZOOM these days). http://www.universalcycle.ca/Home/ When I asked Don today about new guides and valves for the Gilera head, he was not keen to tackle it, although he has offered to do the cylinder overbore if I can source a piston. I will have to search around and see if I can find someone willing to tackle the Gilera head. The machine shop I used for years for Laverda stuff got too big and busy and succesful to take small specialty stuff anymore.

I just spent a couple of hours browsing/searching subito, ebay Italy, etc, looking for new valves/guides/collets etc without success. I am also still looking for a new piston with rings, 60.6 mm or bigger. Amazing how many USED gileraa 150 parts there are listed on eBay Italy, lots of used pistons, used cams, etc., etc but nothing that looks any better (and often looks worse) than what I already have.

Also looking for a Veglia speedo cable at least 56 inches long to run from the rear wheel to the speedo, although I am narowing that down to likely something for a Veglia speedo from a period Triumph like a T120 or T 140 maybe.... For brake, clutch, and throttle cables I have sourced generic pattern blanks and will size and assemble them myself.

Deliveries coming to my door fast and furious, left hand drill bits and extractors, a bearing driver set in a multitude of sizes, blind bearing extractor set, new Mitas H 02 19 x 2.50 tires https://www.mitas-moto.com/en/tools-and-resources/tire-selector?mitas-moto-tire-width=2.50&mitas-moto-tire-aspect-ratio=&mitas-moto-tire-rim-size=19 , an engine gasket set, various seals and bits, etc., etc.. Still waiting on lots of other bits and bobs, from Italy, England, Czechia, and the U.S.A.. Have been going back and forth with Hagon shocks, the Gilera shocks are only 9.5 inches center to center and the shortest Hagon makes is 11 inches and fatter, have been trying to sort out a suitable fitment or another brand, any suggestions?

now to get the remaining odds and sods like the handlebars, various closed end nuts, levers etc all ready to drop off at the chromers. Chromer is quoting a one month turn around for small orders.......

Paul LeClair
 
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Re the long speedo cable: Talk to the guys who build choppers with forks a mile-long. They must know where to get long speedo cables when the front wheel is half way down the next block.

I reckon you'd better buy a lathe to machine up your own valve guides and collets. Alternatively, send your cylinder head to Greg in NZ :)

As for finding a piston, I reckon you'd have more luck searching for something other than Gilera. Looking at your existing piston and that head design I reckon you need something with quite a flat top. I recall that the Honda CB750 had 61mm bore with reasonably flat-top pistons. If the gudgeon (aka wrist pin) to crown height is in the ballpark you should be able to do something with it. Any fine CR tuning can be done with a spacer under the cylinder barrel (might have to tweak pushrod lengths if that's the case).

Don't worry about the oil scraper ring below the gudgeon pin. You're better off without that anyway.

There would be a gazillion other engines with 61mm bore, but finding them is the problem.

Here's a piston dimension chart for Honda engines. It lists 13 different models with 61mm bore. If you can find similar lists for other makes, you shouldn't have too much trouble narrowing down the possibilities.

HONDA PISTON SIZE LIST

HONDA PISTON SIZE LIST This is a fairly comprehensive list of Honda Piston Sizes and only apply to 4-stroke engines. In case you need the sizes for 2-stroke en
4-stroke.net 4-stroke.net
 
Paul Marx said:
Paul,
Have you asked Hagon if the can make you your shocks?
They made mine to the length I needed.
Paul
Click to expand...
Hi Paul

I have gone back and forth with a sales guy at Hagon for half a dozen emails, they tell me the shortest they can provide is 11.5 inches center to center which I could probably live with as giving me some extra ground clearance, but the way the measurement works out the shock is then too fat to clear the chain guard. I have asked them if they can supply a non shoruded shock that might work, waiting on a reply. Do you remeber how long your Hagon shocks are the small Laverda?
 
Paul LeClair said:
Hi Paul

I have gone back and forth with a sales guy at Hagon for half a dozen emails, they tell me the shortest they can provide is 11.5 inches center to center which I could probably live with as giving me some extra ground clearance, but the way the measurement works out the shock is then too fat to clear the chain guard. I have asked them if they can supply a non shoruded shock that might work, waiting on a reply. Do you remeber how long your Hagon shocks are the small Laverda?
Click to expand...
They're 26cm eye centre to eye centre.

Paul
 
An old draft I didn't send:
Paul LeClair said:
Hi Steve
yes, I measured everything three times and marked everything. Even then I am resigned to splitting the cases at least once more......;)
Click to expand...
For my interest, what did the lobe centres come out at? To demonstrate my earlier point, I checked the LC's of the Velocette Thruxton I'm presently working on. Totally different kettle of fish to anything Laverda, but yep, 95/105 centres. Laverda F1 is 100/100, 4C's something like 105/112 or so... get the idea. Around a hundred is easy to remember and if no information available it should be close enough to run and not tangle valves. Experimentation one way or the other may yield benefits.
I wonder what the lobe centre numbers are for disparately crazy motors like a Honda step thru vs top fuel motor?

Paul LeClair said:
shorter than Hagon is telling me they can provide, I will go back to them yet again. The set on your bike certianly look perfect for what I need.
Click to expand...

Have you tried Maxton? The T260C twinshocks I use on a few Laverdas are brilliant, as is their service. Not entirely cheap, but good value for what you get.
 
Paul LeClair said:
shorter than Hagon is telling me they can provide, I will go back to them yet again. The set on your bike certianly look perfect for what I need.
Click to expand...
They are pretty porky though.
I at first contacted Hagon UK who refused to deal with me, addressing me to their French distributor. In maybe a week, I received the shocks having given them measurements and weight of the bike and myself.
I haven't tested the bike yet due to the impossibility of registering it in France, it having come from Italy but without the totality of it's documents.
I've got 4 little Laverda like that.
It used to be possible to register them easily in the UK and then import them back to France with UK documents, but Brexit has intervened and there's now a 5.5% import tax. I'm looking into registering them in Belgium, which appears possible.

Paul
 
breganzane said:
An old draft I didn't send:

For my interest, what did the lobe centres come out at? To demonstrate my earlier point, I checked the LC's of the Velocette Thruxton I'm presently working on. Totally different kettle of fish to anything Laverda, but yep, 95/105 centres. Laverda F1 is 100/100, 4C's something like 105/112 or so... get the idea. Around a hundred is easy to remember and if no information available it should be close enough to run and not tangle valves. Experimentation one way or the other may yield benefits.
I wonder what the lobe centre numbers are for disparately crazy motors like a Honda step thru vs top fuel motor?



Have you tried Maxton? The T260C twinshocks I use on a few Laverdas are brilliant, as is their service. Not entirely cheap, but good value for what you get.
Click to expand...
Hi Steve

trying Maxton next, thanks for the suggestion. As for lobe centers, my measurements embarrasingly were not that sophisticated, sorry. I will measure properly once re-assembled from my dis assembly marks, I should be able to get it back together within one gear tooth if not exact, and I am prepared to dry assemble, measure, then split and re adjust if necessary.

No way to tangle the valves, they both open straight down...;)

Talked to Wolfgang to day, the man is a marvel and a fountain of relevant formation. He thinks he might be able to provide old style collets for the 7 mm valves, etc.., maybe even new valves and guides

Paul
 
Dellortoman said:
I reckon you'd better buy a lathe to machine up your own valve guides and collets. Alternatively, send your cylinder head to Greg in NZ :)
Click to expand...
I'd say no probs - except for the transport situation. Before covid it wasn't good from Canada to this part of the world. 3 months for a cylinder head to get here - airmail. We were told that airmail to this part of the world goes into an airfreight container. Which is sent once it's full....
But covid has shot the freight situation to hell. A general lack of freight space from the northern hemisphere means we're getting short of a lot of essentials. I'm told Repco NZ has something like 6000 NGK plugs on back order. Common grades are gone from the shelves.
 
chrisk said:
6,000 spark plugs for NZ?
That’s 1,500 Hillman Hunters and Woolslies awaiting new plugs. Phew.
Click to expand...
The fleet isn't quite that old now, lol. On another forum someone posted a pic of a shipload of Teslas on the wharf in Auckland. Which won't need plugs of course.
What's it like in OZ ? Can you walk in and get common plugs off the shelf still ?
 
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