Buddy of mine posted this on FB.
"Here's one for the experts. Can anyone spot the difference in these? I'll tell you. The lower one has metal molded in around the shift shaft. No room for a seal like the upper one? We also noticed it was molded really roughly leading us to believe it an early R5 side cover?"
Probably a misguided attempt to seal up a leaky shaft :nana:
i own R5 serial number 2000, so its early. that's not a sign of an early cover. its modified. I also own a 72. neither have that. Nor have i ever seen it from the factory.
Pretty much agree with all the answers..
But as I know less than nothing.. I ask.
Lookie here. 1973 RD250 (no letter)
(https://i.ibb.co/PNYvWh9/rdcover.jpg) (https://ibb.co/nb0N1cn)
sooo... why is there an outside seal on the clutch actuator side? makes no sense since the seal is on the motor itself?
Top one may have been modded to take a bushing to support the shift shaft
Yeah, a press in bushing there certainly makes way more sense.
Some DS7 & R5 & earlyTZ engine side covers have the recessed area some don't. Not sure of the years with either. I have some of each. It is not for a rubber seal. It was for a felt 'washer' dust seal. Just like the on in the rear arm for the drum brake.
Felt washer is shown with the shift mechanism.
https://www.cmsnl.com/yamaha-r5b-1971-usa_model8371/partslist/C-03.html#.YdEMES-B1QI
US sites list the part, but CMSL shows pictures of the individual parts.
fuck.. you know, now that you mention it, i do remember seeing the felt washer on some.
interestingly, the part number is the same for all 3 years r5 and the ds7. and the fiche shows the recess. But i have a stak of them and none have it. weird. but drew is right, i have seen that before.
COVER, CRANKCASE L 278-15411-00-00
https://www.shopyamaha.com/parts-catalog/parts/star-mcy?ls=Star&nw=yamaha-motor-company&dealernumber=#/Yamaha/R5_-_1970/CRANKCASE_COVER
I also have some DS7/R5 Clutch side covers which have the 'boss' for the optional Right side shift. Some are not drilled out or machined for the seal, and some are machined but have a solid rubber seal in place (same seal as the shift fork rods use on the left side). Both are original from the factory that way.
that ive seen, have a few actually .
as a follow up, was working on barney today a bit and looked ad the engine covers, they are both original tot he bike and lo and behold has both the pocketed LH one (hard to see in pic but its there) AND the plugged shift shaft RH one. I also know this bike was built in (late) 69
however, the ds7 has neither
(https://www.2strokeworld.net/wp-content/uploads/70-R5/early-r5-sidecovers-engine_3.jpg)
(https://www.2strokeworld.net/wp-content/uploads/70-R5/early-r5-sidecovers-engine_1.jpg)
So I'll assume that we really don't know when or why Yamaha made or installed these different cases.
No rhyme or reason?
id say 1970 and some crept into 71 as leftover parts. neither 72s i have have them, nor did the 71 i had but it was a later 71.
I may be way off base... I seem to recall certain marques making engines that would allow you to switch the shift mechanism from the left to the right, or vice-versa? this was when standardization of controls was on the horizon. Might this be the reason for the differences? I think the YR1 was one of these and we have one at the shop. The next time I'm there I'll see if I can get to it (it's pretty deep in with a bunch of other motorcycles in front of it) and take pictures of the cases to use for comparison.
On a similar (control differences) note, we have a '40's Indian 4 that will be going up for sale. Anyone interested? Black with tan seat.
The Left or Right shifting was an option for a couple of reasons and mostly available on 'race' inspired models. All early Yamaha TZs came with a double ended shift shaft installed (a nifty rubber boot covered the right side splined end). This was so European racers could shift on the right, since early British and European bikes had Right side shift, and that is what they were used to. Sheene and Agostini (and many others) used Right side shift in their GP careers.
Yamaha DT (and other off road singles) engines also have the option of Right side shift. This is because so many were used for flat track racing, and those bikes all shift on the Right side, for obvious reasons. Any why some factory heads have Two 'spark plug' holes. The extra hole was never meant to carry a spare plug, as many think. It is to install a compression release for flat track racing. It was unique sound to hear a bunch of two-stroke singles heading into the first turn of a flat track race and everyone hitting the compression release...
One of my favorite old pics I took as a young teen. This was an AMA sanctioned flat track race in 1970. The guy in the middle has a compression release on his Hodaka 100. Check out the riding attire, gloves?, boots, sweatshirts. Check out the spectators getting their ears blown out by the open chamber bikes getting ready to rip. :eek:
(https://i.ibb.co/0tNhRWj/ecr-b.jpg) (https://ibb.co/k1nQsrg)
lots of bikes from the era had that 'option', or capability. my t500 has the shaft both ways, and the 74 morini 3 1/2 i had restored had a us market only factory series of linkage to move it from the rh to the left for us market only. rare bird that was. as a side note, both these bikes have cable rear brakes and both had the ability to swap the sides of the brake as well. :twocents:
A buddy of mine had a friend that passed. His friends wife sold off his bikes. One was an AMF Harley Sportster in immaculate stock condition. I wanted it bad, as she was selling it for $1500 bucks, but it had right side shift and I knew between the two bikes at some point I'd get confused.
Apparently those AMF's are hard to come by in complete stock condition like that. Whoops.