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Asking for opinions, limits, insights, IDEAS re:Dark Child


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darcm10021

 
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Asking for opinions, limits, insights, IDEAS re:Dark Child

Fri May 11, 2007 4:39 am » Post: #1 » Download Post

I have been looking at purchasing what appears to be a well constructed NSR 150 SP. However doing my homework 1st suggests this is not all it appears. That it is a bit of the dark child. Not much support from Japanese companies possibly because they never saw the bike there. The set up now does includ a larger carb, manifold and Tyrga pipe. I haven't seen it or ridden it but I suspect it is still powered closer to a 125cc. I don't think I am gong to spend much time or energy investigating rebuilding, porting, honing if I can't find a larger displacment cylinder kit for it. Is anyone aware of one ? It's charactistics ? How much can the primary cylinder be re- bored out to (saftely) Finally with the great number of other Honda bikes it seems to me that the company would have tried some labor saving techniques and simply adapted this engine to something else any idea of what it might have turned into and if a cylinder from there would easily adapt to the NRS 150. One last question I am under the impression that the 150 and the 125 are different motors not a bigger bore 125 anybody have an opinion on this ? Opinions on hp out put now translated to speed with optimal gear ratio at sea level. Opinion of obtaining streetable 40hp although I did manage to get around NYC, LIE, Hutch, to CT or LI on a way too lean 68cc which stalled at anyless than 7k (ah AH ha ho don't do it if you miss a gear you die.) so I could probably adapt to a spikier powerband but older and wiser now, no just older, and would prefer not javascript:emoticon('Neutral')
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Matt@TYGA
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Fri May 11, 2007 12:04 pm » Post: #2 » Download Post

The NSR150SP is actually an evolution of the NSR150RR, which was an evolution of the NSR125.

It basically started it's life as the 125 and then Thai Honda (well Japan) redesigned the engine to 150cc for the Thai market, and built a frame around this. It was originally manufactured (the engine) in Italy, and the frame parts came from Japan. It was assembled in Thailand.

The cylinder is nikasil plated, so boring out necessitates replating and finding a suitable piston.

40hp is possible, but you'd be looking at some major engine work and it's streetable factor will drop to zero!

If it's got a pipe and carb then you'll be lookijng at around 30hp. Maybe. Getting more requires careful engine work.

As for top speed. A shade over 100mph probably. Ignore the wildly optimistic speedo as it'll probably show about 195kmh, which is tosh. We had a 40hp NSR150SP on the brake that was set up for Shah Alam in Malaysia. Peak rpm in 6th gear showed 110+mph. And this was the fastest NSR150SP in Asia, running HRC parts and burning avgas.

As it is, is should beat most 125's, but may have a bit of trouble against a well set up, fully derestricted Aprilia RS125.

If you want to be a loon, then any cc will do. I've hadgreat fun hooning around on an old AR80 before, but if I need an adrenaline buzz then I'll jump on the 300.
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Andy
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Fri May 11, 2007 2:53 pm » Post: #3 » Download Post

Matt@TYGA wrote:
...As it is, is should beat most 125's, but may have a bit of trouble against a well set up, fully derestricted Aprilia RS125.

I seem to recall your NSR150 didn't struggle much against a quite well set up RS125 a few years back! Mind you, it was Paul on board the RS giving it a bit of a workout! Very Happy

The MC18 was the bike to be on that day though! Doesn't matter how much fun a 125/150 is, it'll never be as much fun as a 250!
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StephenRC45
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Fri May 11, 2007 4:11 pm » Post: #4 » Download Post

Andy, that must be because a 250 is so pure Wink
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darcm10021

 
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Thanks, and remarks

Fri May 11, 2007 9:50 pm » Post: #5 » Download Post

Much of what you offered coorelates well to what the websites offered but I was suprised to hear that it was competative with an Aprilia 125 RS. Unfortunatly I am not familiar with a 150 RR. As I mentioned I have an Aprilia 50ccRS now with the 75cc red head and all the internal mods I guess it puts out about 15hp at sea level; on a cool day it feels more like 17hp and really 70mph is acheviable with quite sane gearing I think its quite fun (from what I recall I haven't been on a cycle in almost two years) My other bike is a MV Agusta with an engine built by Ferracci all done in Mg, Ti ... ah well look up Mototek.com they actually have both bikes. I don't really want the complexity of a 250cc just a simple single cylinder 2 stroke with about 180 - 210 cc displacment, small, light with about 40-42hp and a top speed of 120-130 mph. Because this will drop to 30hp at not much of an elevation change or hot / humid day. But I appreciate your responses.
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1joel1

 
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Sat May 12, 2007 5:15 am » Post: #6 » Download Post

Well, some people drop a 4 stroke 450 Honda into the Aprilia 50 or Honda 125 frames. That's about the only way you're gonna get 40+ rwhp. My Aprilia RSR125 makes 42.5 rwhp, but it is a race bike and not streetable at all. No 125 or 150cc street bike is gonna give you 40hp without spending tens of thousands of dollars in development and parts. I mean, does the NSR150 even have a power jet carb or a power valve cylinder? It's the same problem as trying to get 80+ rwhp from our NSR250s. It isn't likely gonna happen.

My 2 cents,

Joel
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Andy
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Sat May 12, 2007 5:25 am » Post: #7 » Download Post

The NSR150 does have a power valve, and a well sorted one "should" have a power jet carb (if you be bothered to modify it!), but Joel's right... anyone claiming 40+hp out of a street 125 is talking out of their ass.
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darcm10021

 
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I appreciate the help

Sat May 12, 2007 6:33 am » Post: #8 » Download Post

I think that about answers my initial inquiry - If a big bore kit or the like were available to allow the bike to have a energetic (shifted to the left) but not edgy (spiky) power curve. It seems like not resonably. I will look at your classifides to see if someone has a clean 250cc for sale which has been state registered. Any remarks here re: what to look for, work involved in maintence and tuning would be appreciated.
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2-Strokes Rule

 
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Sat May 12, 2007 8:29 am » Post: #9 » Download Post

how much difference would this make to a 125/150cc bike liek he ones talked about above -

1. Machining head down - even to insane levels where octance boost is a MUST.

2. Machining intake of case

3. Tuning ports

4. Mached cases

would it make it any (any thing worth mentioning) closer to 40 hp?
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Andy
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Sat May 12, 2007 8:43 pm » Post: #10 » Download Post

2-Strokes Rule wrote:
how much difference would this make to a 125/150cc bike liek he ones talked about above -

1. Machining head down - even to insane levels where octance boost is a MUST.

2. Machining intake of case

3. Tuning ports

4. Mached cases

would it make it any (any thing worth mentioning) closer to 40 hp?

Yes, for sure, but as Matt has already stated, totally unsuitable for the street.

You'll be needing a better ignition too, as the NSR150 setup isn't really up to the job. I think HRC do an ignition kit for them, but finding one is going to be nigh on impossible. Maybe look for an RS125 ignition (a real RS, not an Aprilia one!!) to modify.

A lot of work when a stock restricted 250 that weighs about the same will give bang on 45hp, and with a wire snip & solder 60+.
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Matt@TYGA
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Mon May 14, 2007 1:40 am » Post: #11 » Download Post

Our NSR150SP that blew the Aprilia125 away wasn't exactly standard, whereas the Aprilia was a stock motor with a pipe and a tickle.

Yeah, the best plan would be a 125 chassis with a big MX motor dropped in it, if you want to stick with a single.

You mention the complexity of a 250 twin.... Confused It's only two 125 motors glued together!
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