Putting things in places they ought not to be (250R Hybrid Motor build)

[Mr. Clean]

It made it!!!!!!

The customs slip says "Sheet metal puzzle - 90 pcs" Thanks Hagen!


Attachment 198824

Billy, After spending some time with Kenny Roberts I have had the chance to get some insight into his pipes. He does not start with flat sections that get rolled. He starts with a straight "sectioned pipe". One piece of the sectioned pipe is in the attached pic from Buster Browns 200r thread. You can see the piece he is cutting is one piece, but picture a 3 or 4 foot piece of pipe that has different diameter sections. Where he gets these pipes I do not know but will ask next time I am in California. He slices off sections as he goes in the diameter and or shape he requires. As Buster Brown also stated he uses oxy/acetylene torch to fuse each section, no filler material. I asked to watch one being built and he said no problem. At some point I will witness and record the process, should be quite the show.

[Mr. Clean]

More pics of the starting pieces, again thanks to Buster Browns 200r build thread.

[Billy Golightly]

You talk him into getting a show, let me know because I wanna fly out and learn myself, Seriously!

Its interesting that is the method he uses, because that is what I started off with actually but I could not ever get the pieces to mate back up right. I ordered those two from Grand River Racing about 3 years ago for a CR500 pipe I tried to build, and I just could not ever get the band saw cuts to match up worth a , and thats why I moved to rolling and making individual sections.

[Mr. Clean]

You talk him into getting a show, let me know because I wanna fly out and learn myself, Seriously!

You bet. When are you available to take time away from work? My next trip is in mid to late April.

[Billy Golightly]

Right now the weekend of the 11th of April is already booked, but other than that, as long as I have about 2 weeks notice, right now I can go whenever. For booking tickets, the further out the better of course, but within 2 weeks I can still make it work.

[Billy Golightly]

I just came back from my first real test ride on it - I am SUPER happy all things considered! Best way to describe the power is like a well tuned 265 motor, but more power EVERYWHERE. It has incredible low RPM lugging torque thanks in part I'm guessing to the RAVE valve. Its like CR500 torque, I can put it in 3rd gear and just lug lug lug it around and then roll onto it. Its like its got a big fat flywheel weight, but it still rings out and spins up like a 250. The power is really broad, and the power range is very similar to what I like to have in a 250R, its almost identical how the power comes on to the 265 motor I pulled out, but it just pulls and pulls and pulls. I have my 10 paddle skat-trak extremes on in the yard and its just blowing them away, no hook up through like 4th gear when I got out of it

I was really afraid I was gonna end up with a high RPM peaky drag racing type motor, but so far, it couldn't be further from that! I have some more carb tuning to do and its cooling down right now so I can pull the plug and put an eyeball on it, but man, for building this thing out of scrap and what it is, it runs pretty damn good for a first ride

[oscarmayer]

Awesome man!! Totally awesome!!


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[RIDE-RED 250r]

So good to hear it's working well Billy!

I would also have thought it would be more of a mid/top loving cylinder. Maybe it is though.. My ESR 350 is ported for mid/top but is still no slouch down low. Sheer displacement is nice for that.

Can't wait to see some vids of fly-bys with the Hond-Ax! ... Or was it Rot-Onda?? I forget....

[onformula1]

HOTAX or RONDA

[Billy Golightly]

I need an education on power valves.

Was checking my plug after richening things up a bit, and saw this little bit of aluminum at the bottom of a dark plug.

Which led me to pull the plug and shine a flashlight down in on the piston, afraid I had some detonation going on. Turned out, everything looked okay from the top, top of the piston looked like brand new all around, still could see the laser etched part # on it, etc. So I pulled the pipe and looked up in the exhaust port.

Which actually didn't look bad! The front exhaust side of the piston looks mint also, and I also ran it all the way down to the bottom so I could look across the top edge. (Excuse the splooge, it happened when I was first running it with the choke on)

What I did notice is the fresh scraping on the corners of the power valve. I guess in talking to afew people, this is somewhat normal, but I wouldn't think that the aluminum from there would make it back to the plug unless pipe is scavenging like a mofo? What do you guys think?

[El Camexican]

Did you bore the cylinder and are you sure that's aluminum in the plug and that it wasn't there from new?

[Billy Golightly]

No it was a fresh replate one with good piston clearance.

And no...I did not check the plug before I put it in, but it does seem very odd it wound up way down in there when the rest of the plug is the color it is...

[onformula1]

The power valve can hit the piston if it is not fitted on many motors, the rotax engines (motorcycle, PWC & snowmobile) are more know for this than the Japanese engines especially if it is bored. If a non stock valve was used in your cylinder it can be worst.

The fix is easy just pull the valve out and clearance it with a dremel with a sand roll or the round end of a belt sander. (I prefer this method)

Clearance should be .016-.020 in. I prefer to run it tight but it should not hit and remember piston expansion when the engine is hot as well.

I use a feeler gauge bent at a approx. 90 degree angle, it will ruin your feeler gauge but buy another one just for this purpose & keep it around as a "special tool" for future rebuilds.

Its a easy fix.

[onformula1]

Billy, After spending some time with Kenny Roberts I have had the chance to get some insight into his pipes. He does not start with flat sections that get rolled. He starts with a straight "sectioned pipe". One piece of the sectioned pipe is in the attached pic from Buster Browns 200r thread. You can see the piece he is cutting is one piece, but picture a 3 or 4 foot piece of pipe that has different diameter sections. Where he gets these pipes I do not know but will ask next time I am in California. He slices off sections as he goes in the diameter and or shape he requires. As Buster Brown also stated he uses oxy/acetylene torch to fuse each section, no filler material. I asked to watch one being built and he said no problem. At some point I will witness and record the process, should be quite the show.

Jerry Hall at- Hall's Precision Racing Glendale, AZ does the same thing he has premade cones and sections stacked up like cord wood and uses a bandsaw or large disc sander to cut them or make tweaks to the angles.

Like Kenny Roberts and a handful of others he makes some beautiful pipes.

[RubberSalt]

This is awesome. I've read through most of the 30 pages now. You've tackled some of this the same way my brother has on his rotunda/hondax build. He's been slacking for some time now. He does plan on using a different rod and the mxz piston. He wasn't aware of the potential case trenching required until tonight. His is for the 89 trx, maybe there is more free space for the crank.

As a heads up, big bore kits are available for the mxz