Author Topic: Cool RS 4-stroke conversion (Read 6073 times)

tsflstb · « **on:** August 24, 2007, 10:43:33 AM »

A member of the CMRA board has this up for sale. It looks like a hoot. Probably weighs around 250 lbs. GP handling and brakes with a torquey single cylinder engine...freakin' awesome. I doubt you could ever get it registered for street use, but who cares. Yet another reason to maintain separate checking accounts if you're married.

Quote

its a 1994 Honda RS125 chassis with a 2001 Honda XR250 shoved into the tiny frame.. Custom made frame brackets, custom tank, black powder coating,520 conversion, edelbrock carb, oil cooler/tank, handmade exhaust, 98 inverted forks, mychron2, every part on the bike has been reworked to get the motor in the frame..

The one time the bike was tuned in the middle of winter it put out nearly 30HP.. the motor has been legally built by "XR's only".. they put in a lightweight clutch, lightened crank, dome piston, and about 3 grand work of other engine crap..

To ride it is just indescribable.. Its fun that just cant be beat.. worth every penny of the ~$4,000 I'd like to get for it.. you can actually win with this bike.. not something easy to do in the mini's.. this one will do it.. without all the work of actually building this beast..

S-Dog · « **Reply #1 on:** August 24, 2007, 10:56:19 AM »

Is it good that the chain drags on the exhaust?

tsflstb · « **Reply #2 on:** August 24, 2007, 12:25:08 PM »

It serves as an idler pulley AND a muffler. Brilliant design...

Good eye. Not sure of the story on this bike. It's been raced and thrown down a few times - maybe bent the exhaust tip up. I missed that flaw.

xtalon · « **Reply #3 on:** August 24, 2007, 02:51:41 PM »

Still cool though.

Man, those are some tiny forks!

--xTalon

Caferacingparts · « **Reply #4 on:** August 24, 2007, 08:36:17 PM »

Presumably the chain will no longer contact the muffler when the suspension is compressed from the rider's weight. Here are a couple shots of a similar bike here in the Northwest. It's an RS125 chassis with a CRF450R stuffed into it. The pictures tell the story.
Cheers, Bret @ Glass from the Past

DarkRider · « **Reply #5 on:** August 25, 2007, 01:29:04 AM »

holy crap that looks like fun!

Sam Green Racing · « **Reply #6 on:** August 27, 2007, 10:28:49 AM »

That looks cool Bret

What can one say about the other one though....double the capacity.....loose 10bhp

Sam.

ProTeal55 · « **Reply #7 on:** August 27, 2007, 10:57:56 AM »

I gotta build one of those things

tsflstb · « **Reply #8 on:** August 27, 2007, 01:26:26 PM »

I kind of liked the XR motor idea because it would be simple and reliable. The stock RS 2 stroke is simple, but I'm not sure I'd want to mess with the crankshaft every 5 or 10 hours. Plus you get some torque out of the deal, so you've got a more rideable package for a hack like me.

I've got a deep rooted fear of 2 stroke powerbands since my first (failed) attempt to ride a friend's 250 motocross bike. Probably shouldn't have held it wide open like that.

I think of it like drinking beer vs. hard liquor. With beer you feel the buzz gradually coming on...with liquor it's nothing, nothing, and then *BAM* you're dancing with the overweight cross dresser and your friends are taking pictures.

That monster running the 450 is a different story entirely.

Bob Wessner · « **Reply #9 on:** August 27, 2007, 02:07:40 PM »

Quote

..and then *BAM* you're dancing with the overweight cross dresser and your friends are taking pictures.

Is this a confession?

Sam Green Racing · « **Reply #10 on:** August 27, 2007, 06:16:18 PM »

Sam.

malcolmgb · « **Reply #11 on:** August 29, 2007, 02:53:21 PM »

what 'caferacingparts' has shown there is a Supermono http://www.supermono.co.uk/ a 125 frame with usually a motocross 500cc engine in, I think they have now upped the limit to 600cc+ I recently went to race meeting featuring this class, very exciting too.

c91x · « **Reply #12 on:** August 29, 2007, 03:14:51 PM »

here's mine crf450

ok ok maybe a dream but here's the link

http://www.roadracerx.com/article.php?article_id=454

tsflstb · « **Reply #13 on:** August 29, 2007, 08:39:30 PM »

It's been rumored that these types of bikes may be the future support classes for MotoGP. I think it's only a matter of time before the manufacturers stop putting money into engine technology that isn't marketable now.

I'm surprised that the 125 and 250 2 stroke classes have held on this long. They're fun to watch, but I think we'd benefit as consumers to have the factories developing some screaming small displacement 4 strokes. A 250cc, 450cc and the 800cc class would make for some good racing and some awesome diplays of technology. I'd like to see what Aprilia, Ducati, KTM and the Japanese factories could bring to the table.

Sam Green Racing · « **Reply #14 on:** August 29, 2007, 10:54:27 PM »

That's what Honda did in the early 60s but the FIM changed all the rules and fcuked the job up grand style.

Sam.

c91x · « **Reply #15 on:** August 30, 2007, 11:53:19 AM »

Quote from: SamCR750 on August 29, 2007, 10:54:27 PM

That's what Honda did in the early 60s but the FIM changed all the rules and fcuked the job up grand style.

Sam.

isn't that what the FIM and AMA are for

xtalon · « **Reply #16 on:** August 31, 2007, 05:37:30 AM »

Curious if any one has an approx. HP and weight for these things? Awfully cool!

--xTalon

Caferacingparts · « **Reply #17 on:** August 31, 2007, 07:47:55 AM »

Cedric Smith, the owner holding up his bike, claims 61 HP at the rear wheel at 9500 RPM and that the bike weighs 180 lbs. (82KG)

From the Supermono website:
Specification:Ti everything, stock bore/stroke, bored carb, ported W/cam, reverse meg exhaust, ram air, wide ratio, slipper clutch.
Won #5 overall club plate, OMRRA (Oregon, WA.)

malcolmgb · « **Reply #18 on:** August 31, 2007, 09:49:18 AM »

Quote from: xtalon on August 31, 2007, 05:37:30 AM

Curious if any one has an approx. HP and weight for these things? Awfully cool!

--xTalon

check the link I posted on page1

News:

Author Topic: Cool RS 4-stroke conversion (Read 6073 times)

Caferacingparts

Caferacingparts