The metralla killer

[Abdelhub]

I got a junky old garelli in a trade i did a while back. Its about a 1960 125 Moto Leggera. Complete except for seat. It has the typical Italian single look from the 60's. After unsticking the piston I found the compression to be about 60....good for a lawnmower but not a motorcycle.

Took the motor apart and the top two piston rings are shot. They are really thick 2mm or so and 54mm. otherwise the piston seems ok (other than the huge pin 16mm) well I'm not having any luck with finding rings or a piston so I thought maybe to stick one of my other motors in there. Lets be honest a 1960 125 would be a serious dog anyway....

I guess my plan is to make it into a nice little street bike with a little more power than the 8hp engine it came with.

heres the bike





here are my engine choices.



short stroke 350 bultaco(326). pursang barrel alpina bottom end.



Longs stroke bul 350 alpina barrel and bottom end



Honda mr250



4 speed Ossa 250. (also have a couple 5 speed motors.)



the lone 4 stroke of the bunch. Bsa b25. Id haft put an oil tank on the bike if I used this as its a dry sump motor.

Whatcha guys think? Its a long term project so I just wanted to put this out there....I realize this is two smokes so most likely I will use a 2 stroke motor. ( I think that B25 will go in a Greeves challenger frame...)


Mike

[Miguel Sanchez]

I vote for the Pursang..! You'll have to reverse the rear wheel (left side drive vs. right side). Of course, there's the Montesa in the background...

[Abdelhub]

if i run a left chain I'll use a triumph tiger cub hub. proably the easiest option is the 4speed ossa. Its narrow and has a right side chain.



mike

[stainlesscycle]

this would make a rocketship : short stroke 350 + pursang top end. add motoplat and pursang right crank counterweight/clutch drive. add a gem reed box, cut piston, 36mm mikuni. zoom.


if you need rings for that garelli , try http://www.thn.nl/EN/index.php - they generally have anything you could possibly need - i found a set of rings for a 175 gilera gina macho there....

[jcf]

.......That depends on what you do to the Metralla as well........

[Abdelhub]

Originally Posted by stainlesscycle

this would make a rocketship : short stroke 350 + pursang top end. add motoplat and pursang right crank counterweight/clutch drive. add a gem reed box, cut piston, 36mm mikuni. zoom.


if you need rings for that garelli , try http://www.thn.nl/EN/index.php - they generally have anything you could possibly need - i found a set of rings for a 175 gilera gina macho there....

Ill check that place for rings....

I will look for the pursing counterweight. did they make them for single row chain?

I don't think a super hot motor is a great idea (for me)....i can see myself breaking off shift dogs...no cush drive in these old bultacos...Ossa was ahead of their time with the crank mounted cush drive...

This will just be a long term fun project. Ive given myself a strict ultimatum not to buy any more projects for a while...

Ive got a round case ducati waiting in the wings and that will drain the kids college fund....

Mike

[stainlesscycle]

Originally Posted by Abdelhub

I will look for the pursing counterweight. did they make them for single row chain?
Mike

no, the double row chain is pursang, etc. . the single row chain is trials and trail bikes.

you need to swap clutch and primary chain and primary gear/weight

i bet the pursang counterweight is 16oz less than the alpina one....


you could sell me the roundcase and you'd have lots of funds to do this bike :)

[nsu max]

Garelli? I don't think thats different enough. Now if you bolt one of those Ossa engines in that would be something.

[Abdelhub]

only ossa that would fit with the chain inside the swing arm is a 4 speed. 5 speed ossa is a bit too wide. I think its going to get a 350 bultaco engine....

On the 21st the state patrol inspects it so I can get the registration/title ball rolling and can start welding on the frame.....just waiting now...

Mike