Steve Holzhauser wrote:Well, has the front two down tubes been shortened to raise the engine to gain a little ground clearance. That may account for the bracing ?
Well done Steve. You did well considering you didn't get help from Peter. The frame is just as scrivo described and the "frame gusset" is actually silver tape, to hide the absence of a toolbox. I think it's surprising that other Yamaha TY250 riders didn't notice the engine lift mod on Peter's bike back in 1977.
We were to busy practising our azze off to get up near Peters level to be looking at his bike.
This is what the first series of Majesty 250/320 looked like. This is the series that used a modified Yamaha TY250 frame. The Yellow one is a recent photo of an unrestored 320 and the B&W photo is from a magazine test from the late 1970s. The main benefits of the modifications to the Yamaha frame by John Shirt are that clearance under the motor is greater and rear wheel travel is increased The mods included: Moving the front engine mounts upwards on the front frame tubes Shortening the mid and rear frame uprights at their upper ends Bending the mid uprights forwards to meet with the main backbone Bending the front downtubes rearwards below the toolbox Relocating the exhaust mount bracket lower Relocating the airbox/inner guard mount brackets lower Removing the top shockie mounts Fitting gussets to the front side of the uprights Fitting new top shockie mounts into the uprights Modifying the horizontal frame tube behind the airbox to provide clearance for sparkplug access Bringing the exhaust pipe closer to the head (to provide clearance to the tank)
Here are a couple of photos of modified TY250s showing more detail of some Majesty-type mods. I can't tell if these mods were done in the Majesty workshop, or by someone else. Note the one with the weird exhaust routing required that the tank be reshaped underneath for clearance.
Here is a link to a YouTube video of Mick Andrews riding what I think is the same yellow series 1 Majesty 320 pictured above. It was taken in 2006. The trial is at Larchant in France. [youtube]RVRNZeFCnEM[/youtube]
I was speaking to Peter about the modified bike that this thread started with the other day. Apparently this bike came about through his desire to combine tha best qualities of the 175 and 250 of the time. He and a nearby neighbour known for his modified bike frames for other forms of motorcycle sport discussed his needs.
The objective was to lift the engine by around an inch, soften the rear shocks while lifting the rear end. The geometry of the rear shock changes came about simply by resting the sumpguard of the bike on a stand at the desired level after lifting the engine in the frame. The shocks where then laid forward and new mounts manufactured. This raised the ground clearance somewhat, increased rear travel slightly and as the original springs were used softened the rear shocks.
There was no input from anyone else it was basically driven by the fact that section design had been changing and Peter felt he needed the extra power of the 250 but try and maintain the best qualities of the 175. By all accounts the modificaion where very successful. He indicated that the Yamaha frame was very strong and required little extra bracing.
My comments earlier about Mick Andrews and the design of the Majesty were peotic licence on my part. It certainly took the thread in a new direction. Apparently any similaries between Peter's TY250 and the early MAJESTY development is coincidental. Possibly two experienced riders trying to develop the same bike for the same result have arrived at similiar modifications. If in fact the modifications are similiar.
Sorry I got carried away with the Majesty thing again. I knew that Peter's bike was home grown and wanted to show how John Shirt achieved something similar, later on. The bike I want to build a replica of is Peter's "best TY250"
Scrivo, Thanks for explaining the reason behind the frame modification. I could not understand the reason for raising the bikes center of gravity, thus making it harder to balance, ground clearance - too much compared to these days.
I remember reading a quote from Mick Andrews regarding the TL125 Highboy frame, saying something like he feels right with the footpegs and axle spindles in the same plane, makes some sense that.
I would rather push my twinshock than ride a modern!
Hi SUBANATOR Ground clearance was critical back in the 70 & 80s because if you stopped with the sump guard balanced on a rock it was a 5. Centre of gravity on a Twinshock is not important because they were designed to be leaned over to turn tight. Balance is not the issue for a Twinshock - Counterbalance is !!!!
I must admit i have always been of the opinion that you can have too much ground clearance and get hung up on things that you might otherwise have glided over with a bit of bashplate. I remember riding Kym Powels Whitlock framed Suzuki and thinking this things horrible, it would stop dead if you tried to trickle over a log that on other bikes you could "glance" over. it had excessive clearance. I too did the old shock laying forward trick on ty 175 and 250 i think 2.5 inches on 175 and not very much on 250 but softer rear equated to same ground clearance as before with same rider. We used to drop our forks down flush on the 175 for more ground clearance but with the softer rear you ended up riding a chopper! I remember that rule about taking a 5 if you balanced your bike stationary on the bashplate well as i well recall pointing this out to Dave Pinkerton after he got away with it at a section, later on alone between sections Dave pointed out a few places i could put my opinion to keep them warm, he seemed very persuasive and always scored well .
