OzVMX Forum

Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: monte34 on July 17, 2010, 02:25:50 pm

Title: Montesa 250 Barrel
Post by: monte34 on July 17, 2010, 02:25:50 pm

I just brought home a bitzer 250 that has a side port exhaust but not the screw on type, it has the two cast lugs so that the pipe bolts on like a VA125. What model 250 used this type of barrel. Btw the rest of the bike is made up of various bits and pieces including an 18" front rim laced to an early VR type hub. Would that be of any interest to anyone for dirt track for example. Rob

Title: Re: Montesa 250 Barrel
Post by: SAABCOMBI on July 17, 2010, 05:39:21 pm

need some photo`s of the bike, barrel.

Title: Re: Montesa 250 Barrel
Post by: Big John on July 17, 2010, 08:10:54 pm

My 1976 250 Enduro has that setup. I don't think it came out of Spain like that. Looks like it has had a makeshift job on it, but it works well so I'll leave it how it is.

Title: Re: Montesa 250 Barrel
Post by: montynut on July 19, 2010, 07:47:07 pm

I have seen a few cylinders that had the thread-in collar nut arrangment stripped completely and people would welded lugs onto the cylinder. They then used either the original threaded collar with corresponding lugs welded on and studs to fix it or a manifilad bolted to the cylinder and a spiggot and spring arrangment to hold the pipe on similiar to Yamaha/Suzuki. Not pretty but if the cyclinder was really badly damaged there was probably little alternative I surpose. Usually appeared on 'H' enduros as they would be ridden for hours without realising the pipe flange was loose.

I saw this mode on at least three 'H' enduros local to Singleton back in the '70's. Surprisingly it seems to work OK but didn't look real flash.

I seem to remember (but could be wrong) that the cylinders may have been sent to Ryan's in Paramatta to have the job done.

Title: Re: Montesa 250 Barrel
Post by: All Things 414 on July 19, 2010, 07:52:35 pm

My VR doesn't have the collar on it. The after-market pipe (the name escapes me at the moment) has some little washers on it bent at right angles which the springs hook onto and they attach to some holes on the fins. Seems to work ok. :)

Title: Re: Montesa 250 Barrel
Post by: monte34 on July 19, 2010, 11:01:20 pm

The barrel on this motor doesn't appear to have been modified in any way. Are you saying that there were no 250 models with a bolt on side exit exhaust. The exhaust is actually held on by springs and the threaded lugs aren't used in any case, I was just wondering if the barrel was a standard item. If it is a modified item it has been done very professionally. ???

Title: Re: Montesa 250 Barrel
Post by: hitatreeonce on July 23, 2010, 08:49:36 pm

All my old girls have the screw in collar not sure about the later models but the threaded bit in the barell is removable, you can buy a replacement from a bloke in the states or any compentent machinist could make one

Title: Re: Montesa 250 Barrel
Post by: JC on July 24, 2010, 08:51:15 am

Monte, can you post a pic of it pls?