What Engine is This?

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T.RexRacing
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Re: What Engine is This?

#16 Post by T.RexRacing » Wed Feb 14, 2018 11:32 pm

Capable? Absolutely. Out of the box? Nope. Mid 50s out of the box and an easy 60+ w/o suffering reliability. Beyond that and they become race bikes and not very suitable for riding. How do I know? For starters dyno tuning has paid my bills since the early '90s. Granted most of my work is with Harley and big I4s but I've tuned everything from Z50 Hondas to Ducati D16RR.

Since we're allowing stuff found online. Click me

Below is what the bike had to get to 60HP. Look at the article and see what it took for him to get 90 HP. Notice the 90HP runs BEGIN @9300RPM. This is a heavily modded motorcycle not close to what Honda supplied.

1) Crankshaft aligned to within 0.01mm tolerance
2) Flowed rear upper crankcase and added material to get TDC crankcase volume equal (593ml).
3) Cleaned up transfer port lip edges on barrels to give better flow.
4) Installed 15% lighter Wossner pistons (for 2003 RM125) with 2 holes for exhaust port bridge cooling/lube.
4a) With deck height of RM125 pistons being 0.6mm less than standard, this effectively lifts all ports by 0.6mm or 2.4 degrees at top of exhaust port.
5) Machined heads for 0.8mm squish and 12.8ml combustion chamber volume. Standard is 1.1mm and 13.3ml
6) Installed Mototassinari V-Force III reed blocks.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
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Smoker
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Re: What Engine is This?

#17 Post by Smoker » Wed Feb 14, 2018 11:51 pm

Wow.

Sounds like that little rat bike might be faster than most RZ350s.

I didn't expect that at all. I just couldn't identify the engine and was curious.

MK
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Re: What Engine is This?

#18 Post by MK » Thu Feb 15, 2018 3:19 pm

Faster? Yeah, if the challenge is "who pukes first" or maybe as long as the road does not have any corners.
Man that pile of crap is a crime qualifying you for death row.

I just imagine the rider as one of those bearded hipsters trying to look like a logger.
(Not that filthy smelly ones but the ones trying to impress other loggers).
Bye
Martin

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JonW
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Re: What Engine is This?

#19 Post by JonW » Thu Feb 15, 2018 6:07 pm

MK wrote: I just imagine the rider as one of those bearded hipsters trying to look like a logger.
(Not that filthy smelly ones but the ones trying to impress other loggers).
:smt005
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Questo vecchio rz
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Re: What Engine is This?

#20 Post by Questo vecchio rz » Thu Feb 15, 2018 6:07 pm

Most average NSR250s fall into the 40 h.p. range, especially versions that were not derestricted. MC16-21s progressively gaining better, then at the end Hondas crown jewel obviously the MC28. Arguably the finest example of any 2 stroke street bike ever produced by any manufacturer.

Wet clutch, is standard on many models then typically SP variants gain a dry clutch.

Alot if work, went into that...Whomever has it likes it, but for me...it's all over the styling map..Po l'il bike has a identity crisis doesn't know what it wants to be.... retro, modern, bobber, cafe.. :smt009
Last edited by Questo vecchio rz on Sat Feb 17, 2018 11:53 am, edited 1 time in total.
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Smoker
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Re: What Engine is This?

#21 Post by Smoker » Thu Feb 15, 2018 6:15 pm

MK wrote:Man that pile of crap is a crime qualifying you for death row.
That's what I love about this place.

You guys keep me from doing stupid shit with my bikes.

Well... at least unsafe shit! :smt003

hondaror
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Re: What Engine is This?

#22 Post by hondaror » Thu Feb 15, 2018 11:02 pm

You're right there. That puppy is extremely dangerous to ride.
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bitzz
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Re: What Engine is This?

#23 Post by bitzz » Sun Feb 18, 2018 2:12 pm

The moment on that second caliper shows who ever built this thing is an idiot.

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busa1300
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Re: What Engine is This?

#24 Post by busa1300 » Sun Feb 18, 2018 8:18 pm

The last (designed) true street based 250 was the Suzuki VJ23.....Not Aprilia....built for 7 months in 1996...
The Aprilia RS used the older Suzuki VJ22 engine as a base....Suzuki did all the head/cylinder casting also...even though the engine had Aprilia written all over it.
Yes, the bike pictured is a NSR engine, never sold outside of Japan new so 45Hp would have been the max originally.

The 250 class GP race bikes were another story all together
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Smoker
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Re: What Engine is This?

#25 Post by Smoker » Mon Feb 19, 2018 1:36 am

Smoker wrote: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!

Image
Pretty sure I said it right. :smt003

Isn't the NSR250 a factory race bike, and the NS250/NS250R are production bikes?

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Questo vecchio rz
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Re: What Engine is This?

#26 Post by Questo vecchio rz » Mon Feb 19, 2018 3:14 am

Honda is a little all over the map, with model designations. RS, NS, NSR, NR etc...
Honda "production race bikes" were RS250s, the street bikes MC 16/18/21 & 28s were known as NSR250s.
Many "Factory Works" race bikes were also labeled NSRs.

A "production race bike" RS250 is significantly faster than a production street bike NSR250, Then you go to the "factory" 250s and there again that Xtra bit of performance
Banshee (Baja) race bike,+ 2 A Arms,L.E.Ds, Toomey, +4 stroker IMS tank, run flats.
96 GSXR SRAD, Future Yoshimura rep.
85 custom Tri-Z
RZ/YZR bike(project)
86 VFR750 RC24 Merkel replica (project)
Royal Enfield Bullet 500

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