New Pipe for the 250R!

[Red Rider]

I finally got a hand-coned pipe for my 250R. I've been wanting to try a different pipe, other than my current FMF Gold Series, to see if there was a little more performance to be had. I was interested in a Paul Turner Hi-Rev, and even bought a new one a few years ago, but then returned it, when it was obvious it wasn't going to clear my modified waterpump. Every pipe I've been interested in, I've run into the same clearance issue. After drooling over others hand-coned pipes, I decided to set my sights on one. I finally managed to get in contact with Kenny Roberts, via a liaison, who agreed to make me a custom pipe for my exact setup. He already had a similar year CR 250R cylinder to mock up from, but needed my R power-valve cover & exhaust flange, to mimic my setup. The routing of this pipe is a little different than Kenny's typical 250R pipes. This one passes close to, but not across the face of the waterpump, and is routed a little closer the engine's bottom end, to keep the pipe tucked in better, while still clearing the R power-valve cover. The routing is very similar to pipes for a 1986-91 CR 250R.

For the exhaust flange, I sent Kenny my old, steel, 2-piece, CR/ATC adapter exhaust flange. Once I had the new pipe, the plan was to make a new, 1-piece, billet, o-ringed, adapter exhaust flange. Once again, this will be made on my router table. Thanks to all involved in making this happen. Your help has been much appreciated, and I couldn't have done it without you all.

[Aulbaugh]

It looks really good Jeff! His work is very impressive!

[yaegerb]

I finally got a hand-coned pipe for my 250R. I've been wanting to try a different pipe, other than my current FMF Gold Series, to see if there was a little more performance to be had. I was interested in a Paul Turner Hi-Rev, and even bought a new one a few years ago, but then returned it, when it was obvious it wasn't going to clear my modified waterpump. Every pipe I've been interested in, I've run into the same clearance issue. After drooling over others hand-coned pipes, I decided to set my sights on one. I finally managed to get in contact with Kenny Roberts, via a liaison, who agreed to make me a custom pipe for my exact setup. He already had a similar year CR 250R cylinder to mock up from, but needed my R power-valve cover & exhaust flange, to mimic my setup. The routing of this pipe is a little different than Kenny's typical 250R pipes. This one passes close to, but not across the face of the waterpump, and is routed a little closer the engine's bottom end, to keep the pipe tucked in better, while still clearing the R power-valve cover. The routing is very similar to pipes for a 1986-91 CR 250R.

For the exhaust flange, I sent Kenny my old, steel, 2-piece, CR/ATC adapter exhaust flange. Once I had the new pipe, the plan was to make a new, 1-piece, billet, o-ringed, adapter exhaust flange. Once again, this will be made on my router table. Thanks to all involved in making this happen. Your help has been much appreciated, and I couldn't have done it without you all.

Always very nice work from ya Jeff!

[Red Rider]

I got a little more work accomplished today on the new flange. The external dimensions are complete, as are the o-ring grooves.

[Red Rider]

I thought the current ID, of my new flange, might be a little too restrictive, so I decided to open it up a bit for better flow. Now that that's done, I'm gonna say the new exhaust flange is officially finished. Tomorrow, if nothing else comes up, it should start going back together.

[Red Rider]

No interruptions today, so I got her all reassembled. Well, mostly reassembled. I'm still waiting on the silencer, which is being polished. While I had it torn apart, I figured I might as well do a power-valve cleaning. They weren't too carboned up, as it doesn't have many hours on it since the last cleaning, but it was an advantageous time to do it, so I said, why not?. Pics of current progress.

[bkm]

Absolutely gorgeous. Did you ever do a build thread or explain the power valve cylinder?

[Red Rider]

Thanks for the nice compliments Joey, Brendon, & bkm.

Absolutely gorgeous. Did you ever do a build thread or explain the power valve cylinder?

No, I never did. That was done before I joined this site, and before I had a digital camera, so I never bothered to. The cylinder is just a standard 1990 CR 250R cylinder. All of the mods, to make the power-valves actuate, were done to the bottom end. A little welding on both center-case halves to build up a flat sealing surface for the cylinder base. Then, the rest of the mods were done to the R side clutch cover. The waterpump was cut off, and extended out to allow room for the CR's centrifugal governor, and some linkages were fabbed up to transfer the governor's motion to the base of the cylinder.

[Red Rider]

Before giving the garage a thorough cleaning, to rid it of all of the aluminum shavings, I decided to bang out another quick project, that would yield more shavings. Years ago, I made 2 aluminum, rear brake levers. For each brake lever's toe pad, I found 2 mangled OEM brake levers (with good toe pads) at a motorcycle salvage yard. I bought them cheap, and cut the toe pads off of the mangled brake levers. These toe pads were then screwed onto the aluminum brake levers. Since aluminum parts are always tricker than steel, I decided to make some aluminum toe pads to replace the OEM steel ones.

[Billy Golightly]

Always super nice work man. I remember when you made the original flange with the drill press and I was impressed how well you made it work. The new one with the router is even better...very cool!

[HairyJR]

Agree you have DIY skills. When first reading that you made the exhaust adapter on a router perked my imagination and wanted to see pics of steps performed. Remember thread where you made front brake disc adapter. Now the toe pads, please share some pic's of the process's used.

"HJ"

[ironchop]

Fantastic work Jeff!

You'd be a great router salesman too

[vegas250rr]

Looks good mang!

[Red Rider]

Thank you Billy, HairyJR, Doug, & Jeremy.

Agree you have DIY skills. When first reading that you made the exhaust adapter on a router perked my imagination and wanted to see pics of steps performed..., please share some pic's of the process's used.

Well, as luck would have it, I only took pics at the end of each day's worth of work, rather than the processes. I will try to explain & illustrate as best that I can. For the exhaust flange, I used the same jig setup, as I did, when I made the brake rotor adapters (pic#1). For the round portion of the flange, where the exhaust pipe slides over it, rotating the 1.5" thick block of 6061 aluminum about the vertical axis of the jig's center pivot bolt, I was able to cut the block down to the desired external dimensions.

For the non-round, flange-to-cylinder, mating surface, I bolted my 1/2" thick MDF pattern to the aluminum block, and then slowly trimmed the aluminum away with a ball-bearing guided, flush-trim router bit (pic#2).

To cut the o-ring grooves, the flange was suspended over the router bit in a jig, which is visible behind the flange in pic #3. The flange was bolted in between the 2 vertical pieces of wood, then rotated about the horizontal axis to cut each groove around the circumference of the flange. At this stage, after the o-ring grooves were cut, the external dimensions are complete.

For the internal dimensions, I once again switched back to the jig in pic#1. Then, I cut a 1/4" deep groove inside the flange with a 31/64" plunge router bit. The OD of this groove is now the proper ID for the inside of the flange. Now, I take the flange to the drill press, and use a hole saw, (which has a slightly smaller OD than the finish ID from the previous step) to bore a hole completely through the flange. After the hole is bored, I remove the jig setup from the router table, and switch to a ball-bearing guided, flush-trim router bit. Now I trim away the rough cut from the hole saw, using that 1/4" deep groove as my guide. Once complete, I've got a uniform ID all the way through the flange (pic#4).

[Red Rider]

Now the toe pads, please share some pic's of the process's used.

For the toe pads, working with something this small, I needed to attach the 1/2" thick 6061 aluminum blocks to a bigger board, as I wasn't too keen on having my fingers that close to the router bit. The first step was to cut the rhythmic serration (pic#1). This is the same guide I used to cut the rhythmic serrations in my footpeg wideners. The block is bolted to the guide, holding it tightly in place, and the 1/4" diameter, ball-bearing guided, flush-trim router bit follows the rhythmic, wood pattern, design and transfers that to the aluminum block.

The next step is to cut the external shape. Again, the block is bolted to a wood pattern, keeping my hands & fingers safely away from the router bit, and the router bit cuts away the aluminum until it is flush with the wood pattern (pic#2).

The final step is to cut the internal shape. Once again, the block is attached to a wood pattern, except this is a 3 piece pattern (pic#3). The center board holds the toe pad in place. The bottom board keeps the toe pad from falling out the bottom, and the top board is the guide for the router bit. Once the 3 boards are aligned, they are screwed together, sandwiching the toe pad in the middle, and holding it tightly in place. This entire setup is then placed over the router bit, with the router bit going through the bolt hole from the previous 2 steps (pic#4). The aluminum is then cut away until it is flush with the top board's internal shape.

Now, who wants to buy some all-in-one wood/aluminum milling machines (routers)? I sell 'em!