XR500 In water R chassis?

[wild200x]

Being back on a trike forum has brought out an interest in me I forgot I have. So I asked a friend an hour away from me if he has a line an a 250R roller and guess what? Says he has one in storage and that we could work out a sweet deal. Also it came to mind that another friend offered had me a 79 XR500he has under the back porch. Thinking I could get it real cheap. SOOOOO, Has this been done? one guy says the xr motor is "to tall". Do any of you know? I am a fabricator so I can change things. But how much? I guess I will be needing to get these things side by side for a looksee. Any real truths will help me decide. Perhaps I will find another better option. I already have 2 decent 85 250Rs. I want to build something different. Or not....My mind is a whirl.

[Minter fab]

do it!! I mean ad long as it can be fitted easily!! dare to be different my friend!!

[Billy Golightly]

Not too familiar with the RFVC later model XR500s, but I messed around with the earlier variant (which was like 1979XL500 through 82XR500, and Also FT500 Ascots were similar enough).

They are big friggen honking beasts. From what I remember on the project I had a zillion years ago even the 350X frame had to be extended like 3 inches in the middle of the back bone and the bottom cradles to make enough room for it. I think the engine weighed like 130lbs or something crazy? It's doable but I'd look hard at the Nicholson and similar frames that housed those engines to get some ideas. The height of the engine alone I think will pose a big challenge for the 250R frame configuration but anything is possible with some heating and beating, haha

[atc300r]

You will need to do alot of frame cradle mods.I started to do a 200x motor in a liquid r frame for mx racing.I cut the cradle in the back by the foot pegs bent it down a few inches just to barely get the 200x motor in.Gas tank would also be a big factor because of the carb position on the four stroke.I started doing a cr 500 liquid r swap that requires way less mods and still alot of fab work.Just my 2 cents.

[jasong_10]

I had heard those XR engines were tall. At one time I thought about trying to build my own TRX 700xx using a 450er chassis and a XR650L engine (love the 450r chassis and wanted the power of the 700 without the IRS, lol), but found out I would have to modify the frame extensively due to the height of the engine. I did hear that a 400ex chassis might work though . . .

[350for350]

Plevid (I think) put an XR500 engine in a second gen 250R frame, so I know that it can be done. It took him a lot of work, but he did ride it some.

[wild200x]

Looking at these comments and also talking to some others I am thinking I may pic up the roller and keep an eye out for something else to put in it. Still contemplating. Thanks for the input. I really do appreciate it.

[legacy51]

It looks like it can be made to fit! I think it would be a really fun trike to have. Better than a 350x in every way. The 500 engines aren't monsters in the power department. I did some research when I was thinking about using one for a build but ended up selling it. They make about 30hp stock, the connecting rods are weak and a lot of people said that you need to get a better one if making much power, you can use an xl250 (I think, I know it was some kind of Honda 250) flywheel as a lightweight flywheel, and the clutch basket is not that strong supposedly. I fully expect to see this at Mosh this year though!

https://www.youtube.com/watch?v=qNuZuzyF6ZQ&feature=emb_logo

[wild200x]

It looks like it can be made to fit! I think it would be a really fun trike to have. Better than a 350x in every way. The 500 engines aren't monsters in the power department. I did some research when I was thinking about using one for a build but ended up selling it. They make about 30hp stock, the connecting rods are weak and a lot of people said that you need to get a better one if making much power, you can use an xl250 (I think, I know it was some kind of Honda 250) flywheel as a lightweight flywheel, and the clutch basket is not that strong supposedly. I fully expect to see this at Mosh this year though!

https://www.youtube.com/watch?v=qNuZuzyF6ZQ&feature=emb_logo

haha, sorry, not sure who you are but apparently you know Mosh.

[BOB MARLIN]

My big bore 250r motor barely fits back in the 250r frame. I can't even run a standard spark plug in it because it hits the frame. So I would think a older 500 4 stroke would have some serious fitment problems.

[Tri-Z 250]

I’d look to a modern 250f CRF for a pound to HP and size aspect. The exhaust port may be a problem, haven’t given it much thought. Electric start models are getting cheaper but it would take deep pockets to pull off. IMO you do you but if I were in your hunt to 4stroke an R I’d consider it.

[wild200x]

I’d look to a modern 250f CRF for a pound to HP and size aspect. The exhaust port may be a problem, haven’t given it much thought. Electric start models are getting cheaper but it would take deep pockets to pull off. IMO you do you but if I were in your hunt to 4stroke an R I’d consider it.

Thanks for the input. I have all but scrapped the idea of the 500. Just was the first option as I can get the bike for nothing. Still can get the roller easily. May just pic up the roller and keep my eyes open for something. This is not about a 4 stroke BTW. Its more about making something different. who know what I will do. I don't. I just need a project at this point. Got to get my head around something new. I have heard KTM 380 is a pretty bad ass motor? can't find one at the moment to look at.

[oldskool83]

It wont fit, youd need to cut frane appart to bad abd gsve custom tank fabbed. Would be better to put in a crf250 motor, smaller lighter more power. If you want big tall motor use the xr frane and mod everything else to fit.

[350for350]

By the way, if the XR500 is free, then by all means pick it up. You can use it for something, some day. Even if it's only for trading material.

[legacy51]

Can't you tell who it is from my picture where I have a helmet on!? This is Carson.