[ktm550]

cool and good luck. one question about the rod. all the ktm units i seen used 18mm pin. isnt your piston 20mm ? or am i missing something

 

[HondaATC]

No the piston I'm using is from the Odyssey which still uses the 18mm wristpin. If I can make everything work using a drop-in 4mm stroker crank I will but I think I'm gonna need to use the longer rod to get things right with the deck heights

 

[HondaATC]

Another small update for you guys, working on repairing and leveling out my center cases;

http://www.3wheelerworld.com/showth...50R-Hybrid-Motor-build)?p=1278972#post1278972

Had an .018 gap that I think was from a crank failure in a past life mostly. On that link on 3WW I detail how I covered the case edge with a magic marker and then surfaced them with a flat surface and stand paper to determine where the low places were at, and also briefly went over how I did go ahead and add some weld to the problematic areas and ended up getting it back down to within .003.

 

[John Tice]

Your catchen on Billy. A flat plate, even a thick piece of glass make a good addition to the tool kit.

 

[Morph0906]

wheres the pics???

 

[HondaATC]

Small update, assembled it with dry gaskets and it doesn't hold air quite as long as I want, but definitely did better than I expected given the circumstances and fact I didn't use any gasket dressing on either the center cases or the base gasket. I seem to be getting a small leak either from the base gasket or the main crankshaft drive gear, but i did not have any soap in the shop last night to diagnose. I gotta get back over there with some and see exactly where its coming from. I might end up doing a little bit of sanding/surfacing on the top of the cases at the base gasket area, but from what I could tell last night, I wasn't getting any protrusion through the center cases, which is the most important thing.

 

[John Tice]

Don't forget the soap suds. Simple procedures can solve major problems.

 

[Dangerouspower]

Where's this build at? My big question is how your doing these water necks from bottom end to Cyl..?

 

[HondaATC]

I have been working on this on the weekends but haven't had time to do much for updates, taking pictures here and there. Here is where I am at now, I have to do a little clean up in the transfer tunnels, and then basically the big expenditures such as the new crank, case bearings, etc. will start coming into play for final assembly.

 

[Dangerouspower]

Could you explain what you did for the water spigots? Maybe some pics of the bottom end of how you made the 250r water jackets to the rotax?

 

[HondaATC]

Well, with that picture, your kind of looking at it. The water runs through the rotax cylinder in its original configuration. When I had a spacer plate cut I just made sure the water jackets were not cut through it, so it just doesn't circulate down, it'll go under and around the exhaust port, but it will flow in through the new spigot I welded on the head at the exhaust side of it, go down into the cylinder, and then get pumped out the back elbow right above the intake. It basically stops at the bottom of the cylinder when it meets the spacer plate. Probably not exactly the most efficient way to go about doing this, but should be good enough.

 

[HondaATC]

The one image of the base gasket is before I ever even did any welding, but basically just imagine that front area not cut out on the spacer plate, not allowing the water to go any further down. I also filled the cavities in the case with epoxy as a part of the process since part of the stud holes ended up falling in that area.

 

[Dangerouspower]

I see what ya did now thanks.

 

[HondaATC]

I cannot believe its been over a year since I updated this thread, WOW!!! So much more work has been done, I've had to do this thing just a few hours at a time here and there, but I finally have it in a chassis, RUNNING(!!) and hope to take it for a test ride sometime this week. I have a few fairly minor things to button up.

I ended up making most of the updates on 3WW...I originally was trying to keep both places here up to date, but time got away from me (Obviously...) and I didn't follow through with that. So for that I apologize. If you want to catch up on everything else, here to the end is probably a good place to start;

http://www.3wheelerworld.com/showth...ght-not-to-be-(250R-Hybrid-Motor-build)/page4



By far, one of the most difficult parts of this build was making the pipe for me. I had posted about that elsewhere here on E2S, but a video recap from a few months ago when I was still in the process of making it:

But it did fire off and run! For one reason or another its taken me a few more weeks since then to get the thing into a chassis, and I still have a little more buttoning up to do, but I had it running a few different times today idling and heat cycling. I hope to be taking it for a test ride this week.

 

[bansheekx]

With the tank and plastics on it that motor and pipe look huge in that frame! What's all the bungee cords and zip ties on the swing arm?

 

[HondaATC]

Yes, that pipe is huge, even pictures do not do it justice till you see it in person.

The bungee cords holds my trail clearing machete on.

 

[mgty3whlr]

You have a nice "sleeper" with the tank and plastics on !

Most people won't notice because they just take a quick glance of what you have !

Nice job, even tho the amount of time with design and assembly to get that bad boy going.

How did it run? I know that you'll hafta do some jetting to get it dialed in being the bigger bore, pipe configuration but Sweet job !!

 

[Larry's Shee]

So how many CCs did this end up at?

 

[HondaATC]

You have a nice "sleeper" with the tank and plastics on !

Most people won't notice because they just take a quick glance of what you have !

Nice job, even tho the amount of time with design and assembly to get that bad boy going.

How did it run? I know that you'll hafta do some jetting to get it dialed in being the bigger bore, pipe configuration but Sweet job !!

All of my machines are ugly...:laugh4: Honestly I was even surprised a bit myself how well it ran once I got it fired off. It sat there and idled away with the choke like any other 250R would, just with a much different sound The vibrations were a little bit more than a 250R but not much. Certainly no where near 500 territory. I will heat cycle it a few more times and complete some other issues before I really get to ride it, but it ran really well all things considered actually. I'm gonna have to end up running a big ass pilot jet in it since I had to have the choke on for it to idle, which is okay, just know which direction to start with at least.

I have learned a trick to cranking it, as the pipe was seriously in the way of kicking it, but if you actually go past the pipe and kick it through from say the last 1/2 of the travel, you're actually under the pipe and its all free travel from there uninhibited, so its easier then. It still has a ridiculous amount of compression (Especially considering I clayed the dome and have almost .090 worth of squish clearance!).

Larry, I believe I wound up at about 403'ish. 401 or 403, can't ever remember which it is.

 

[mgty3whlr]

Sweet ! Hold on !