17" and 18" rear wheels so the difference is to ensure the correct radius in relation to the circumference of the wheelalanengineer wrote:Im not into lightweights, but have one to put together some day. This is really interesting and now i wonder why they made two different rear mudguards. What is the difference between the two and are they interchangeable
Mudguards
- Ozmadman
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Re: Mudguards
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
- Rob Harknett
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Re: Mudguards
Not on the front wheel as in 1960 parts book both G2 & G5 have the same front guard. the 17" & 18" wheels in the same guard. The rad would not show so much different. As the deep valance will conceal the difference.Ozmadman wrote:17" and 18" rear wheels so the difference is to ensure the correct radius in relation to the circumference of the wheelalanengineer wrote:Im not into lightweights, but have one to put together some day. This is really interesting and now i wonder why they made two different rear mudguards. What is the difference between the two and are they interchangeable
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Re: Mudguards
so, we know that the lightweight mudguard is very similar to the Heavyweight mudguard and now we know their is two versions of an almost identical mudguard. What was Plumstead thinking of.
I think i will go round and tell all of the lightweight owners that they have the wrong rear mudguard and wait for their response.
Or has the club got the drawings so we can find out for sure!
I think i will go round and tell all of the lightweight owners that they have the wrong rear mudguard and wait for their response.
Or has the club got the drawings so we can find out for sure!
- Rob Harknett
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Re: Mudguards
Surely once again the parts lists will tell the story. Also, once again, the drawings question crops up. No matter what the part or the year, prewar, postwar, seems be believed, club have drawing's of everything. Fact is the club probably have very few. Some so faded, just a little more light will destroy them.
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Re: Mudguards
The rear fork & rear frame are the same for the 350 as the 250. The main frame frame/steering head is different. The cradle/frame beneath the engine is the same but the frame/channel (under the gearbox) is longer & different on the 350.The fully extended length eye to eye for Lightweight 250 & 350 rear suspension units is 14 & 3/4 inches and 15 & 1/4 inches respectively, i.e. approx. 1/2" difference. According to the 1960 Spares List the the stands are the same but , notwithstanding what the Spares List says, I have 2 Lightweight stands and one is approx 1/2" taller than the other. Both look original and unmodified. I am going to use the longer one as the 350's 18" wheel must raise the bike approx. 1/2" more than the 250's 17" wheels.
So I can only conclude, Alan, that use of the slightly larger 18" rear Wheel on the 350 with 1/2" more travel in the 350's rear suspension may have required a rear mudguard with more room inside than on the 250. How this is possible using the same rear sub-frame as on the 250 as yet I don't know as I don't have a Lightweight 350 rear mudguard to hand.
I am not an expert on the Lightweights, just been trying to build one 350 machine from a pile of 350 & 250 scrap engines & frame parts. I'm nearly there now but it is much harder than with any of the Heavyweight Twins I've rebuilt due to the absence of a decent, clearly illustrated workshop manual specifically for the Lightweights, in particular the frames, & a poorer spares supply for them than is the case with other AMC models.
Rod
So I can only conclude, Alan, that use of the slightly larger 18" rear Wheel on the 350 with 1/2" more travel in the 350's rear suspension may have required a rear mudguard with more room inside than on the 250. How this is possible using the same rear sub-frame as on the 250 as yet I don't know as I don't have a Lightweight 350 rear mudguard to hand.
I am not an expert on the Lightweights, just been trying to build one 350 machine from a pile of 350 & 250 scrap engines & frame parts. I'm nearly there now but it is much harder than with any of the Heavyweight Twins I've rebuilt due to the absence of a decent, clearly illustrated workshop manual specifically for the Lightweights, in particular the frames, & a poorer spares supply for them than is the case with other AMC models.
Rod
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Re: Mudguards
I sold a rear guard to someone at the last Kempot jumble and he tells me it's off a 350 and not a 250 that he wanted.
Roy
- Rob Harknett
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Re: Mudguards
Could be correct Roy, parts list G2 G5 rear part no's differ so not the same. Front the same pt. no. That guy must had known the difference between 250 and 350 rear guards.
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Re: Mudguards
I have done my homework and checked the parts list and see different numbers.What i want to see is sizes and profiles and what to look out for. Its a bit academic really as im going to fit what i have and enjoy.
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Re: Mudguards
If the 350 mudguard has to fit inside the same rear sub-frame as on the 250, maybe there is no difference in the outside circumference/shape? Maybe the difference lies in the accommodation made on the mudguards for the movement of the chainguard which on the 350 is greater (because more movement in the rear suspension units) than that on the 250?
Rod
Rod
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Re: Mudguards
Hi Rod, i have both front and back G5 guards. I would be happy to show them to you so you could compare. I also have the front mudguard from my 1961 G3 which looks very similar in photos but when put togeather its obvious what the differances are.
If its any help i am working in Leeds on Monday next week (18th) and would be happy to put them in the car, No problem meeting up at a cafe/services at your discretion.
Cheers
Steve
If its any help i am working in Leeds on Monday next week (18th) and would be happy to put them in the car, No problem meeting up at a cafe/services at your discretion.
Cheers
Steve