RZ/RD 350 & Misc. 2-Stroke Tech BBS

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 Post subject: What Engine is This?
PostPosted: Tue Feb 13, 2018 7:12 am 
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Trying to figure out what engine is in this bike.

Looks like a Honda V-twin. I don't recognize the power valve system on the cylinders. Custom NS or CR?

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 Post subject: Re: What Engine is This?
PostPosted: Tue Feb 13, 2018 9:00 am 
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No clue but someone needs a whoopin'.

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 Post subject: Re: What Engine is This?
PostPosted: Tue Feb 13, 2018 7:03 pm 
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Looks like some sort of v-twin so possibly a NSR250 motor but not a 400.

Another bike built for show and definitely not go. Twin calipers on one disk? Aren't those seat springs supposed to be for hardtail bikes?

RGV rear swinger on it. Looks like a bit of each bike brand all beaten together....


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 Post subject: Re: What Engine is This?
PostPosted: Tue Feb 13, 2018 11:26 pm 
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Reminds me of an old commercial/ PSA: "this is your brain on drugs"

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84 RZ350-Toomeys,SCR milled head, stk 26 carbs,300 M, 35 P, stock regrooved needles AS 2.5 turns out,stk air box,Banshee reeds Zeel non-progr CDI,TSRL Program YPVS,alum rad,R6 shock,GV emulators w/RT springs,fork brace,Shindy steering damper.


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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 3:45 am 
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Thought for sure one of you guys would know what type of engine it is.

If it was a better pic, I could probably figure it out myself.

Do you guys see the power valve cables on the sides of the cylinders? I don't recognize that type. Could be a one-off modified engine.

The engine plumbing, cables, and wires are a mess, but I love the creativity on this little bobber.

Don't know about the dual calipers on the front. Maybe it was a wheel swap going from 2 rotors to one. Depending on that engine, the bike might be a lot faster than it looks, and it might actually need more than one single piston caliper.

Yes. Obviously not purpose built for speed.

Built for fun. :smt003


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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 4:17 am 
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Holy shit.

I was thinking NS250R engine, but doesn't look right.

I was also thinking NSR250 engine, but a factory race engine?

The bike engine looks like a wet clutch, but the power valve system is a match for the NSR250. Probably a hard cover over the dry clutch.

If that's an NSR250 engine, there's your answer for front dual calipers!

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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 6:37 am 
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Good thing they cast kickstarter on the kickstarter so people would know what it is. Are the instructions on the other side?

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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 7:17 am 
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Pretty sure those little engines put out about 91hp at the rear wheel.

Laugh at that. :smt003


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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 7:23 am 
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nsr 250


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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 8:41 am 
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Location: Wolfenbüttel, Germany
waltmil wrote:
Good thing they cast kickstarter on the kickstarter so people would know what it is. Are the instructions on the other side?


Only for the US models.
They say "Caution: Kickin' is harder than it appears"

My guess would be a road going NSR250. Not sure if all of them had a dry clutch.

Dual calipers are a trick from the past to reduce lever effort if other hardware is not available or too expensive.
From the aspect of heat flow you have the same input into the disc volume just the heat flow through the pads is only half the value. That means for road use and medium load it's OK, but in race use the single disc will overheat.
(been there, believe me).

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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 8:58 am 
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Smoker wrote:
Pretty sure those little engines put out about 91hp at the rear wheel.



Uhm......no.

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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 1:00 pm 
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For fun? Maybe the build part. That butchered, whimpy frame? Oooohhhhh! Freaking uncontrolled shivers, up and down my spine.

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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 3:02 pm 
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T.RexRacing wrote:
Smoker wrote:
Pretty sure those little engines put out about 91hp at the rear wheel.



Uhm......no.

Surprised you couldn't identify the engine, then. :smt002

What is the correct rear wheel hp for that engine and how do you know?

Last night I was reading about the history of the factory NSR250s and 91 rwhp was stated. Got the info from the NSR250 forum. Not saying it's a fact - just saying that's the info I found.

"The A kitted RS250 in '98 (was a '97 NSR250 factory engine) put out 91 horse at the wheel. The factory bikes were about 98~100 back then, with the Aprilia the only one over the magic ton, at about 104."


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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 5:43 pm 
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I'm not so sure about those numbers. My '83 TZ250K was claimed buy Yamaha to have 79 hp. That would have been at the crank. It was a power valved engine. The Honda RS250 was a much better bike in the mid '80s. I never had one of my GP bikes on the dyno, so I'n not familiar with their wheel hp.

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 Post subject: Re: What Engine is This?
PostPosted: Wed Feb 14, 2018 8:53 pm 
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Hey Smoker, that would be a NSR250 engine. Only some of the later ones were dry clutch. They were through 3 iterations, 4 I believe if you include NS250R.

Looking at anywhere from 40hp to about 65/70 in the street trim NSR250 depending on the year. Those big HP numbers may have been for the Moto 2 bikes but not likely for the street going minigp bikes.

Aprilia which was on the RGV base was supposed to be the last and greatest and it is showing 73hp.

http://www.motorcyclespecs.co.za/model/ ... 0%2000.htm

Believe a RS250 Honda held the lap record at Race City still when it was demolished (Rory can confirm).


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