Showroom quality 1973 CR250M

Tokyo_Tiddler wrote:

Another area that I had to figure out because the Honda parts diagram was completely wrong was how the exhaust pipe (or should I say in...

Another area that I had to figure out because the Honda parts diagram was completely wrong was how the exhaust pipe (or should I say in period correct language, the "expansion chamber") mounted to the frame. I believe it is because the original design was failing and people were mounting differently to prevent the failure. Nevertheless, the parts schematic doesn't make much sense.

Here is what I believe is the story.. With the original design, the special attachment bolt (#9 in the schematic) that Honda used had such a long shoulder for mounting of the rubber cushions that it created a lot of leverage and was snapping off the threaded mount that was welded on the frame. A lot of people were welding supports along the sides of the round threaded mount to make it stronger, probably when they welding it back on. My bike has these supports. The parts schematic shows only one washer (#14 in the schematic) and one cushion (#8 in the schematic) used with the original long shouldered special bolt but that can't possibly work since it would leave a huge space for the pipe to float around on the mount as only one rubber cushion and one flat washer uses only have the space on the bolt shoulder. This is because that special bolt was meant to be used with two rubber cushions and two flat washers, one set on each side of the bracket that dangles from that special bolt. I think what a lot of goes were doing, and still incorrectly doing based on some of the other recent builds I have seen, is tossing that long special bolt and instead securing with a shorter regular bolt along with one flat washer and one rubber cushion. While this takes the leverage off the frame mount and seems consistent with the one washer/ one rubber cushion in the schematic, it pulls the exhaust pipe too close to the swingarm.

https://images.cmsnl.com/img/partslists/honda-cr250m-elsinore-1973-k0-u…

Also, unlike the Honda schematic, my NOS pipe had a nut welded on to the mounting bracket from the factory so I did not need to use parts #16 and #13 (the lock washer and nut).

That wasn't the end of the differences in parts either. To mount the silencer to the support arm, the 25mm long bolt (#11 in schematic) is too short to work with the majority of silencers that don't have a nut already welded to the silencer mounting bracket. To remedy this situation, you need to buy a second 35mm long bolt (#12 in the schematic) and add another flat washer (#15), lock washer (#16) and nut (#13) to make it work. This is the correct mounting of the silencer to the support arm. This is just another example where Honda was constantly changing up the parts on these first Elsinores.

Tokyo_Tiddler wrote:

Another area that I had to figure out because the Honda parts diagram was completely wrong was how the exhaust pipe (or should I say in...

Another area that I had to figure out because the Honda parts diagram was completely wrong was how the exhaust pipe (or should I say in period correct language, the "expansion chamber") mounted to the frame. I believe it is because the original design was failing and people were mounting differently to prevent the failure. Nevertheless, the parts schematic doesn't make much sense.

Here is what I believe is the story.. With the original design, the special attachment bolt (#9 in the schematic) that Honda used had such a long shoulder for mounting of the rubber cushions that it created a lot of leverage and was snapping off the threaded mount that was welded on the frame. A lot of people were welding supports along the sides of the round threaded mount to make it stronger, probably when they welding it back on. My bike has these supports. The parts schematic shows only one washer (#14 in the schematic) and one cushion (#8 in the schematic) used with the original long shouldered special bolt but that can't possibly work since it would leave a huge space for the pipe to float around on the mount as only one rubber cushion and one flat washer uses only have the space on the bolt shoulder. This is because that special bolt was meant to be used with two rubber cushions and two flat washers, one set on each side of the bracket that dangles from that special bolt. I think what a lot of goes were doing, and still incorrectly doing based on some of the other recent builds I have seen, is tossing that long special bolt and instead securing with a shorter regular bolt along with one flat washer and one rubber cushion. While this takes the leverage off the frame mount and seems consistent with the one washer/ one rubber cushion in the schematic, it pulls the exhaust pipe too close to the swingarm.

https://images.cmsnl.com/img/partslists/honda-cr250m-elsinore-1973-k0-u…

Also, unlike the Honda schematic, my NOS pipe had a nut welded on to the mounting bracket from the factory so I did not need to use parts #16 and #13 (the lock washer and nut).

That wasn't the end of the differences in parts either. To mount the silencer to the support arm, the 25mm long bolt (#11 in schematic) is too short to work with the majority of silencers that don't have a nut already welded to the silencer mounting bracket. To remedy this situation, you need to buy a second 35mm long bolt (#12 in the schematic) and add another flat washer (#15), lock washer (#16) and nut (#13) to make it work. This is the correct mounting of the silencer to the support arm. This is just another example where Honda was constantly changing up the parts on these first Elsinores.

mxgp250 wrote:

WOW Tokyo this is something else. Bravo at all the nos parts you tracked down. I love your bike.. Tell me my bracket on the bottom...

WOW Tokyo this is something else. Bravo at all the nos parts you tracked down. I love your bike.. Tell me my bracket on the bottom right by the brake pedal is partly missing. Can I ask a BUG favor,can you shoot a few pics of what it should looked like?? I will have to fab something up and weld it. But I want it to look OEM not lousy. If you can help it would mean slot since it's hard to tell what is there?? Beautiful bike Sir. 

Tokyo_Tiddler wrote:

Thanks for the complement. Are you talking about the right side peg bracket that bolts to the frame with one bolt? Here are a couple of...

Thanks for the complement. Are you talking about the right side peg bracket that bolts to the frame with one bolt? Here are a couple of close ups. You should be able to find that peg bracket on eBay or FaceBook.

Tokyo_Tiddler wrote:

Thanks for the complement. Are you talking about the right side peg bracket that bolts to the frame with one bolt? Here are a couple of...

Thanks for the complement. Are you talking about the right side peg bracket that bolts to the frame with one bolt? Here are a couple of close ups. You should be able to find that peg bracket on eBay or FaceBook.

mxgp250 wrote:

Actually very close,the lower exhaust pipe mount that's what is partially missing. So I have no idea what it should look like?? Half way down the...

Actually very close,the lower exhaust pipe mount that's what is partially missing. So I have no idea what it should look like?? Half way down the pipe it has a dog bone that goes from pipe to frame it must be thin so it's missing I would say about half..sorry for not explaining it better..

 

Tokyo_Tiddler wrote:

Do you mean this mount?  Bike is very dusty at the moment.

Do you mean this mount?  Bike is very dusty at the moment.