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Author Topic: CB 200 twin vs. CB 250 Nighthawk  (Read 5543 times)

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Offline Leino

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CB 200 twin vs. CB 250 Nighthawk
« on: February 14, 2010, 05:31:09 AM »
From what I read on the internet, Nighthawk engine is partially based on the old CB 200 twin?
Both have 360 degree cranks etc. and the question is: would a CB 200 cam fit the Nighthawk engine?
Any info highly appreciated.

 
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Offline KB02

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #1 on: February 14, 2010, 05:59:35 AM »
I would imagine that the 200 cam would have smaller lift and duration than the stock 250 cam. If anything, I would imagine about going the other direction - 250 cam in the 200.
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Offline Leino

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #2 on: February 14, 2010, 06:06:39 AM »
Quote from: KB02 on February 14, 2010, 05:59:35 AM
I would imagine that the 200 cam would have smaller lift and duration than the stock 250 cam. If anything, I would imagine about going the other direction - 250 cam in the 200.
My point is that for example Megacycle lists cam profiles for the CB 200 but nothing for the 250.
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Offline KB02

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #3 on: February 14, 2010, 06:49:23 AM »
Ah, gotcha! That makes sense.

In that case, I will be of no help to you. :(

The thing that really stinks is that I know of about a dozen Nighthawk 250's that are for sale right now (or are about to be if the deal has not yet gone through), and I REALLY, REALLY WANT ONE just to play around with. And I don't have the extra cash for one right now.  :(  I teach MSF classes and, despite what people may say, I think they are just neat, fun little bikes. They need a disk brake up front, but other than that, they are great.
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Offline tbpmusic

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #4 on: February 14, 2010, 07:15:14 AM »
The old CB200 (almost identical to CB175 engine) is a completely different engine than the later 200/250 Hawk series.
Though I can't say definitively, it's very unlikely any engine parts would interchange....
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Offline Leino

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #5 on: February 14, 2010, 07:26:06 AM »
Quote from: tbpmusic on February 14, 2010, 07:15:14 AM
The old CB200 (almost identical to CB175 engine) is a completely different engine than the later 200/250 Hawk series.
Though I can't say definitively, it's very unlikely any engine parts would interchange....
Ok, thanks for your input.
I'm building a cafe CB 125 with a 250 Nighthawk engine for my son and I'm trying to find useable engine parts to make some more power.Stock CB 125 produces about 16hp and Nighthawk is around 19-20hp?

More compression and a little headwork would be nice but I really think It needs a bigger cam too.Cam on the Nighthawk is very mild.
Bike sounds good but I'd like it to run a little better too  :D.

 
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Offline cb650

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #6 on: February 14, 2010, 10:09:42 AM »
Have it reground.  I think one of the bike cam places does it.
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Offline Green550F

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #7 on: February 16, 2010, 05:52:28 AM »
I think the closest you'd find for cams is a CM200 Twinstar. ???
But those made even less power I think... At least my uncles Rebel pulled a bit better than my Twinstar...

Should have kept the CM200. I know several kids that'd like it now...
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Offline kenolds

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Re: CB 200 twin vs. CB 250 Nighthawk
« Reply #8 on: April 06, 2010, 05:36:27 PM »
I have been trying to find a cheap and easy way to get a little more power from my CB200.  I was looking through pistons on a British website and noticed that a 1969-1976 CB250 (Available in UK?) piston has similar specs to the CB200 piston.  They are:
(CB200 / CB250)
Bore: 55.5 / 56
compression height: 31.6 / 32.1
piston length: 61 / 62.5
piston pin  15 / 15

Could this fit and have higher compression?  Of course it gives no info on dome shape or anything.  Also, the cb250 pistons are more expensive than the cb200s.

Thoughts?
Kenolds
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