I've just been given a Sammy miller hi-boy, does anyone know what engines will fit? I have been offered a Tl250 will it fit?

thanks 

Probably need a lot more info, Miller made hi-boys for bultaco, yamaha and honda. 

It’s the Honda frame, currently has an old cg engine in the frame? 

 

12 minutes ago, moi said:

It’s the Honda frame, currently has an old cg engine in the frame? 

The cg is 125cc ? Physically a lot smaller than the 250 I'm sure.

So I’ve seen that there had been a special hi-boy 305, with a big bore tl250 engine, I cant find much information on the conversion etc so wanted to know if there was anyone with any knowledge around the complexities? 

 

The Hi Boy frame sold by Miller was for the TL125

The Hi Boy 305 was a works bike and Miller's own development bike, not available to the public.  The TL250 wasn't on sale in the UK through Honda so there was no market for a Hi Boy frame for the 250

Whether a 250 engine will fit the 125 frame I don't know, you'd have to offer it up and see.

The 305 works bike was a long stroke which retained the 250 bore, it wasn't a big bore 250.

Fraser did a frame for the TL250 which used a big bore for a 305 engine

Edited November 16, 20178 yr by woody
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I  had a Yoshimura 305 kit on my enduro Cheney Honda. The motor was the old 250 single port 250 4v, very similar to the TL250 motor

There was a at least one tl250/305 made.  I saw it for sale on ebay in the USA about 2 years ago.  It was green and nothing like the works bikes.  It was new(ish)!!!! and went for about £3k! You will need new engine plates made, but it can be done.

This might be the same bike.

http://veh-markets.com/motorcycles/honda/312147-honda-tl250.html

1 hour ago, knobbly said:

There was a at least one tl250/305 made.  I saw it for sale on ebay in the USA about 2 years ago.  It was green and nothing like the works bikes.  It was new(ish)!!!! and went for about £3k! You will need new engine plates made, but it can be done.

This might be the same bike.

http://veh-markets.com/motorcycles/honda/312147-honda-tl250.html

That one looks like a Fraser frame with a Bultaco front end (Sherpa T triples, Bultaco Betor forks and Alpina/Frontera front hub)

10 hours ago, feetupfun said:

That one looks like a Fraser frame with a Bultaco front end (Sherpa T triples, Bultaco Betor forks and Alpina/Frontera front hub)

Yes, Fraser frame

 

The CG engine was preferred due to gearing. consult for more info http://www.kaila.net/tl125/

A TLR200 engine will fit where a TL125 engine will fit. The decompressor hump (activated by kick start) on the left side center case will be the determining factor if it will fit your frame. The TLR200 engine has a wider jump in gearing from 1st to 2nd than the CG.

So nearly all single cylinder 2 valve honda motors 100cc to 200cc will fit where a CG was. Maybe some one can speak to the more modern engines like crf230 with electric start.

A 150cc big bore TL motor was common in those frames, a Honda dealership in Raleigh sold them special order back in 1975-1976.

Had this fraser with big bore engine ( 380ccm), now somewere in Belgium....

Miller frame I only know with the TL125 engine, often with 145ccm, maybe the XL185 engine will be suit the frame....

Thanks for your help, two more questions:

1. I’m not sure if I should buy a tlr 200 engine, or build a Tl150? 

2. Is the tlr 250 engine completely different in size to a tlr 200? 

Thanks