Vintage Dirt Bike Q & A

What if any, is the best way to salvage a pipe from a 1975 CR125. The pipe I have is in great shape but I suspect the packing in the stinger is shot. It's loud as hell and the bike seems to choke out in the upper power band.This is the stubby stock pipe that ends right around the rear shock. I also have a 1978 CR with the same type pipe but it also has the big "BEER CAN" silencer that slips over the end. The 78 runs like crap with the silencer on it and runs great without it.
Should I be running a silencer on these bikes and what do I do about the 1975 pipe? I don't think they're servicable without cutting the end open.

'

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1974 CR250m
1975 MT125,CR125
1978 CR125
1980 CR125
1982 CR250
1979 RM400
1979 IT175
1973 XR75

The '75 CR125M appears to have a small-diameter silencer section with minimal packing. It looks like it would be a real b*tch to repack even after the end cap was cut off; I've never done it and could be wrong, though.



If it were my '75 and I was planning on riding rather than restoring it, and the '75 pipe was in good shape, I would pull that pipe off and replace it with a repackable-silencer pipe. I've got an old LOP 'torque' pipe with minor damage and a new Retro Rocket pipe here, neither of which I'll ever use, and I believe that Jemco and DG both make CR125M pipes; most of these require the larger '76-'78 manifold, though.

I don't know what to tell you about the '78. The 'beer can' slip-on muffler may be a mechanical silencer/spark arrestor unit like the MR250; if it's all clogged up it could be cleaned out with caustic soda or something like that. FMF makes 1.125" and 1.25" universal silencers that work great, SuperTrapp still makes their original line of steel-body disc silencers with a bunch of inlet and core sizes, Jemco makes custom silencers, etc.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric

Hey Ray, Just found your 75 CR125m Elsinore. Wow that really looks great. Im in the process of restoring my 75 Elsinore also. However im at the point of painting the motor. What did you do for yours? Let me know.
My email armstrong21a@aol.com
Thanks Tim

Tim,

That's actually not my bike, just a picture I found on the Web. Mine's a '74, it looks basically the same except for paint.

The Honda CR125M motor paint is really black and seems about halfway between a gloss and semi-gloss finish. The closest off-the-shelf paint I've found is Dupli-Color Low-Gloss Black engine enamel (#DE1634). The color is close to correct, but it's just a bit less shiny than the OEM paint. If you paint the whole motor with it, you probably won't notice the difference.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric