Bultaco "hiboy" 250

[booma]

does any body know much about these bikes I understand that the frames were made by Sammy Miller but was they an improvment in terms of riding position- ground clearance- steering - grip

does any body on here own and use 1

any advice would be good as I have the chance to buy 1 in a very nice condition

Booma

[woody]

Never ridden a Miller framed Bultaco but I would think the main advantages were lighter weight and improved ground clearance through the use of a seperate bashplate instead of the standard Bultaco's frame tubes under the engine.

I'd doubt very much that the steering was any different to the standard bike at the time the Miller frames were introduced as Miller developed the Bultaco with a steering angle that he considered to be the optimum, so it is likely that his own frames were the same. May depend on the year as Bultaco steering angle altered slightly after Miller had left to suit their factory riders of the times and changing sections I guess, so a later, say post 75 bike may have different steering than a Miller frame. Can't honestly see any logical reason why they would grip any better, I think the main reason for producing them (apart from being a nice little earner) was that they were stronger, lighter, more ground clearance and probably looked better with their polished finish. Whether this really gives any noticeable improvement to the handling/performance of the bike is probably down to personal opinion ultimately. Please don't take this as a definitive appraisal of the differences as there may be more and I'm only making an assumption about the steering.

If you aren't interested in buying the bike there is someone who is very keen on buying one who has posted in the Classic forum, so you could always put him in touch with the seller if it's not for you.

[shercomike]

I have a High-Boy that I purchased about seven years ago from a guy in Michigan. It has a Model 49 motor and the one-pice tank/seat with ribbing on the side-panel. It was in OK condition, and I have spiffed it up a bit. I think the geometry is a bit more radical than the stock bike--steeper steering head and shorter swing-arm. Mine had extra plates brazed into the headstock and a local guy that had one in the period said his headstock cracked too. It has better ground clearance but the oil drain sticks below the bash plate.

I was at Samm'y museum a month ago and asked him about the frames. He didn't have a whole lot to say. He said he just wanted something better made than the stock frame, higher quality. He said the oil drain was a compromise thet he had to make. He used to work for Rickman's and I asked if they had made the frame because it looks so Rickman like. I think he was a bit insulted by my question and said that his shop had made the frames. Maybe they used the same material and plate shop.

Finding the one-piece alloy tank/seat would be the hot ticket. I had one in 1974 and Hugh has a HIgh-Boy with the alloy tank/seat in his museum.

I'm a mediocre rider and the frame offers me little advantage in reality. However, it's way cool and Sammy is my hero.

[hounter]

Who is Hugh and where is the museum?

I have just purchased a miller hiboy and am trying to build a replica of Sams 1972 325cc Bike EOR2K.

Anybody have any period miller bits and especially the foot rests I need.

In mean time i will try to use my contacts to put together a potted history on these frames - for the Forum.

I remember they started around 1970. Compared to the stock frame they were lighter and certainly in a better material using Reynolds 531 Tubing and the welding was a craftsmans finish.

More details to come - I have only just joined the forum.

[bultaco49]

Hi Booma

There are more than one version of the Miller Hi-Boy frame. Generally the first models have the frame type similar to the 1970 M80 under seat single post and the later type similar to the later M92 with triangular under seat frame arrangement. All types had the alloy plate connecting downtube to footrest/swing arm which was only introduced on the factory Bultaco frame M198a/199b. The early ones are a lot lighter than their contemporaries as the tubing used is far superior to the tube available in Spain at that time.

The early ones were fabricated by Mick Whitlock I believe and his work is excellent. I'm not sure who fabricated the later ones but the quality of build is not as good.

The early frames were popular and competitive but the later frames are an aquired taste. The riding position is very high as is ground clearance. Not popular with everyone and not considered best for the modern layout of sections.

The weak point of the Miller frame is the gusset joint between the headstock and downtube. It fractures easily and many have had the headstock angle changed badly inreasing problem. Check for cracks on gusset and tube close to gusset. Also check tube under tank as engines did not have head steady (which also braced frame). This tube can bow throwing off fork angle and allowing bash plate retaining bolts to come in contact with crankcase.

None of the frames are competitive against Fantics etc., in twinshock classes in similar hands but having said that I regulary see Miller framed Bultacos giving very good accounts of themselves in Club events.

I own a 1970 Miller Hi-Boy framed Kit Campion based on an M49 Sherpa and have great fun on it at Classic Trials events and shows. Its good enough (as are all Bultaco's) for the Miller Products Championship so my advice is buy it, use it and I'm sure kept in good condition it will be an appreciating asset. There are some photos of my one in the Trials Central Garage.

Tim