NSR Problem

[jamessmith200...]

Hello there

Ive got a old Nsr125RK

WHen im riding around normally say 30 - 40 mph at no more than 5500 revs,when i suddenly whack the throttle open and give it some stick it goes up to about 7000 revs, starts making this chugging sound and juddering and you can see a cloud of white/blue smoke in the mirror, does that for about 5 seconds then picks up reaqlly quick and flys.

Had a rebuild (top end) 6000kms ago( carb also cleaned, new spark 750kms ago, plug is a bit black.

Cant think what it is, if its slightly running rich can someone tell me what screw it is on the carb and what way to turen it and how much to adjust the mixture screw?

Or whatever you think the problem is just say

cheers

[one1895]

[McJamweasel]

I suggest, that if you are trying to take it over 7k when its cold, you are a moron.

Always let it warm up before you thrash it, if its reluctant to rev because it cold then let it warm up some more.

With the problem being at 7k, which is around where the power valve opens, it could be that there is a problem with that somewhere.
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BCF: Be yourself, just don't be an arse.

[Scotty]

Its true if its not warm and your telling it to go over say 6 to 7 where the power valve opens and closes it won't like it at all.

Least let it warm up.

Mine and i'm sure most / all NSR or 2 strokes for that matter do it.

As colin said if it keeps doing it while its warm i'd check the powervalve operation...
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Regards
Scott

[Racer X]

Let your bike warm up at least 5 min prior to riding, especially in winter conditions. It's not good to thrash the engine when it's cold, as this may lead to cold seizure. The nikasil plated cylinder needs to be at a warm enough temperature to be able to operate without damage the nikasil plated cylinder.
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< Live To Ride & Ride To Live >

[NSR125-Kid-UK]

Where's the blue in the white/blue smoke come from?
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https://www.bikepics.com/members/nsrandy/96rs250/ My Bike!

"I'm either going to teach andy to get his knee down, or I'm going to get him killed. One of the two" - Teaman

[Scotty]

[NSR125-Kid-UK]

On our scoots if you beast the poor thingies, they won't do more than 15 for the first 50 meters or so . I twist the throttle to join traffic, and piss road users and myself off when the scoot craels forwards at less than walking pace for a few seconds.
____________________
https://www.bikepics.com/members/nsrandy/96rs250/ My Bike!

"I'm either going to teach andy to get his knee down, or I'm going to get him killed. One of the two" - Teaman

[Scotty]

[Racer X]

[Racer X]