yam 22

the yokes are shorter: the under side is to be cut off and rewelded Thanks for the advice. Is the part that you say needs to be 'cut off' / cut down .... the threaded central tube rising vertically up from the bottom yoke ? If so, it's a bit beyond my abilities and I'll need to find a local engineer. As you sound a lot more knowlegable on this framethan me, could I ask you a few more questions: 1) Are there many other modifications that will be required as 'standard' ? 2) Do you know of any way to distinguish between a Hi-boy for a Honda and that for the Bultaco ? 3) Did the design of the Honda Hi-boy change during it's production run (as the few photos on the internet and in the book 'Four Stroke Finale' that claim to be of Honda Hi-boys do vary in detail). Thanks again.

Thanks for your reply Richard and sorry for asking too much. You could be right and maybe mine is for a Bultaco ? I like TLs so jumped at the chance to buy this Hi-boy frame without really knowing much about them. There's so little information on the internet about hi-boys for either Honda or Bultaco. Are there major differences between the two frames which you could suggest ? My standard TL airbox, seat & tank all fit this frame perfectly using lugs and holes which all look original although my fork yokes are not not a good fit. Thanks again.

Just read your comment. Some time back, I bought what I 'believed' to be a Miller Hi-boy frame for a Honda TL125 (and not a Bultaco) but a standard TL engine will not fit the frame's current engine mountings. As the current mountings appear to be not original I just thought a previous owner had cut out the originals to mount a differently sized engine and it never crossed my mind that it might be that the frame is a Bultaco Hi-boy. I also never thought to contact Sammy Miller (as when I spoke to them recently, they said all their records on the TL hi-boy had been lost). I will e-mail a photo to them with a request but if you could e-mail me a photo of your Bultocao hi-boy frame, I would really appreciate it. Thanks.

This is a request for information about the Hi-boy frames produced by Sammy Miller for the TL125. I would really appreciate it if there's anyone out there who owns one, could please contact me? I managed to buy a Hi-boy frame some time ago but it was not in great shape ..... the original chrome coating was poor and the engine mountings have either been adapted or cut out (presumably to accommodate a different engine at some point?). I want to make replica brackets to accommodate a TL125 engine so if anyone can suggest a good web site or any owner could e-mail some close up photos or dimensions of the correct mountings, this would be really appreciated. Also missing from my frame were all the loose accessories (side stand, chain tensioner, etc) so any details on these would also be useful. On a more general note, I have had real difficulty finiding any information about the Hi-boy frames which Sammy Miller produced. I have searched the internet, books and the Sammy Miller shop / musuem. On the internet I've only found about 5 / 6 photos but nothing written. In books, I've only found the single photograph in 'Four stroke finale' but with minimal description. Sammy Miller was good enough to speak to me but said all their information, records, jigs, etc were lost in a fire! From the photos I've found, it appears the Hi-boy design did evolve during it's production run. If anyone knows where written information exists on the subject of Hi-boy design ........ (i.e. when did production start / end, how do you date the frame, what design modifications were made, what was the extent of the specific frame package, how much did it sell for, etc,) ..... then I would appreciate any leads. If this information has not yet been written up but still exists out there then, although I'm no real author, I'd be happy to write this up for inclusion on the internet (Trials Central, TL125 Homepage, etc) if anyone with useful bits of information could forwarded them to me. Thanks again.

Many thanks KCJ for your response. The gearbox oil volume (500ml) is stamped on the casing. The little TY80 is now running but I've been having a problem with the clutch slipping. Probably my fault as although the Haynes manual said 10/30 oil, I followed my local motorcycle dealer's suggestion to put in 10/40 as this would be better for the gearbox. When I looked up 'clutch slip' in Haynes, it says high viscocity oil may cause clutch slip. I've now readjusted the cluch and it's working fine for my 8 year old but has anyone else found this to happen? Would it be best to use 10/30? Thanks.

Many thanks for your response PRW. I just thought Yamaha might have built in some level marker or an over-flow screw hole. It's just a problem at the moment as the bike has an oil leak so it's hard to keep an accurate check (without draining & refilling!!)

I've just bought a TY80 and want to renew the gearbox oil but am unsure how to fill it to the correct level. The Haynes manual says to check the dip stick attached to the underside of oil filler cap but my cap has no dip stick (my TY80 parts catalogue also doesn't show a dip stick on the oil filler cap). Please could anyone advise?