Need information on old Triumph Cub frame.

[Dakzila]

 

Hello,

I need some help in trying to gather some information on an old Triumph Cub frame that I pickup a few weeks ago.

I bought the frame off of Ebay for the wheels and forks but discovered, when I picked it up, that it had been modified for a different engine.

The frame started out as a Triumph Cub but someone has replaced the swingarm with a solid steel custom unit, lengthen the cradle and replaced the single down tube with double down tubes. The rear wheel has a spacer machined to push out the sprocket and the rear shock mounts are spaced out farther than the stock Cub.

The mods were probably done in Southern California, maybe the Ventura or Oxnard area. The workmanship is very good and it hard to tell with a casual glance that it's not a factory frame.

I'm posting some photos in hopes that someone might know who built the frame or at the very least what engine "might" fit in the motor mounts.

Any information or leads would be greatly appriciated. I have additional photos I can post or send.

Thanks,

Buzz  - 1513 B

[fastman614]

You ARE correct! It IS very good quality work.... It has been a lot of years and I do not consider myself an expert by any means but it looks to have been modified for something other than a larger Triumph engine as there does not seem to be any top mount and, to the best of my knowledge, the front motor mount is too high and too wide for any of the British twins (although, width-wise, spacers could have been used)....

I sort of was hoping to see a (perhaps almost) clone of a frame etc that an old friend of mine had in which he had a Triumph 500 (Daytona -twin carb) engine mounted.

[Dakzila]

Thanks for taking a look fastman.

You never know what going to pop up on the internet or who might be browsing, so I'm just hoping someone like you will stumble on this post and be able to shed some light on who created this conversion.

Thanks again for replying.

Buzz 1513B

[Cereal KLR]

Hi Buzz, I will post up the frame pic on a vintage forum I frequent, maybe someone will have an idea.

[wobblywalrus]

It looks like the chain and brake are on the British side.  Probably not converted to a small Japanese motor.  The mounts look like they are for a unit construction engine.  My guess is a BSA or Triumph 250 single.

[wobblywalrus]

Try a BSA Bantam.  That is the only bike with a lousy enough chassis that a cub frame would be an upgrade.  Vaguely I remember a few of them in the old days.

[Dakzila]

So far the engines of choice are;

*BSA Bantam
*BSA 441 Victor
*Triumph 350 or 500
*Bultaco 250 or 350
*Ossa 250 ( But I believe the Ossa is right hand chain dirve)

No clear winner yet.

Thanks for all the replies.

Buzz1320

[fastman614]

It looks like the chain and brake are on the British side.  Probably not converted to a small Japanese motor.  The mounts look like they are for a unit construction engine.  My guess is a BSA or Triumph 250 single.

W/W - I forgot about the opp side drive on most Japanese bikes.... I do recall though that even the British 250 singles had top mounts ....conventional wisdom said (and to this day says) that the engine will shake sideways without the installation thereof....

... and it had been a very long time since I worked on any of them (close to 40 years).... but I DO have a Triumph 650/750 stashed away and I should just take a look at the layout of the mounts again.

[Dakzila]

Thanks fastman,

I'm really leaning towards the Triumph 350/500.

I think there might be additional hardware involved in mounting it up but so far that seem like a logical choice.  I'll get a set of 500 cases, earlier than 1974, and give it a try.

Thanks again to all of you who gave advice.

Buzz 1513B