Hi my name is Paul. I have recently registered on the discussion forum as I have recently bought an NRS250 MC18. This is my first Honda after 30 years of riding other makes of 2-strokes.
I have a problem with the new NSR, which is poor starting, and when the engine is up to temperature, the N/S exhaust remains stone cold, while the O/S is hot.
I have not taken the bike on the road yet, in case it does any damage, as I'm not sure if it's a carb fault or a crank shaft seal.
The bike has a very low mileage and is showing just over 4K on the clock.
I bought it from a garage in London, which is 200 miles from where I live in Cheshire so I didn't have chance to road test it myself before buying it.
If anyone has had a similar problem and can help me at all I would appreciate it.

Many thanks, Paul

Sorry to hear that your new toy won't play.

Is the bike a fresh import? It may be a case of cleaning out and setting up the carbs after months sitting full of stale fuel, but you would expect a reputable dealer to take care of all that for you before handover.

If it were me, I'd be going through all the normal steps - Is the non firing plug wet with fuel? Have you changed the plugs? Have you had the carbs off and cleaned them out? Once you've checked and ruled out basic fuel and ignition issues, a compression test and a leakdown test would be next in that order.

Hope you get it sorted quickly.

Hi, many thanks for taking the trouble to reply. I appreciate your comments and I think you're probably right. I was assured by the selling importer that it was fully serviced etc, and I can see that they have fitted new plugs, but I suspect that the carbs haven't even been looked at.

Thanks again

Hi Paul, I also have an MC18 and discovered my bike was doing exactly the same when starting it up.
I found I was leaving the choke on too long so it was flooding the top cylinder.
Now I when I start the bike on full choke I immediately shut it down to half choke (in a matter of seconds) and about 5 seconds later shut the choke off completely. It's just a case of playing around with the choke until you find the set up for your bike without flooding it.
Hope this helps, it definitely stopped my bike from running on just one cylinder.
Cheers & Good Luck.

Hello Paul, and welcome to NSR-WORLD.

It's common on initial start-up, for one silencer to feel a little cooler than the other, but should soon even out. Unfortunately however, poor starting is very often due to crank seals. Is the bike a 1988 R2/4J Mk1, or a 1989 R5/6K Mk2? Use the Specifications section of the main site to quickly identify it.

NSRs can be notoriously difficult to start without a good, solid battery, so make sure it's fully charged, and no dead cells.

As Mark suggests, pull the carbs and check they are clean, and that there are no blockages in the slow jets. The carbs are very simple, and although it's a little tight on the MC18 with its narrow frame rails, are very easy to remove and come off as a complete assembly. If the inlet manifold is a bit tight, just warm it up with a hair drier or [carefully!] with a heat gun, to make the rubber a little more supple.

I'd also suggest popping the exhausts off, and having a look up the ports at the pistons. If you see any bad scoring, then it's possible that cylinder isn't firing.

I'm afraid there are plenty of horror stories about importers these days, and none I would trust personally. Too many trying to jump on the 2-stroke resurgence bandwagon, with little thought other than profit. We've had a number of bikes, motors, and cranks sent to us to make good over the last 12 months, that were from these so-called specialist importers!
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Andy.
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Andy wrote:I'm afraid there are plenty of horror stories about importers these days, and none I would trust personally. Too many trying to jump on the 2-stroke resurgence bandwagon, with little thought other than profit.

Pretty much my thoughts. Hopefully yours is a simple fix, Paul
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If it ain't broke, fix it until it is.

Many thanks to everyone for your helpful comments...
This is the first two-stroke I have bought from an importer - I've had all my others pretty much from new, so these problems are a first for me.
I actually bought the bike with a one month warranty but I have my doubts regarding their ability to sort this one out, as I don't even think they have looked at the carbs before selling it.
It looks like I'll be sorting it myself, so thanks again for your input. I'll let you know how I get on with it.

Hi Andy, many thanks for your reply. You asked me if my bike is a 1988 MK1 or 1989 Mk2.
I'm pretty sure it is a 1989 Mk2 (it was first registered in 1989). If it helps, it is in the black/red and silver paint scheme. Does this enable you to shed any more light on what might be causing the problem? I would appreicate anything else you can add!

Many thanks, Paul

preed wrote:
I'm pretty sure it is a 1989 Mk2 (it was first registered in 1989). If it helps, it is in the black/red and silver paint scheme.

Most likely a 1989 "Seed" R5K, but so much is interchangeable if you know what you're doing (or even if you don't, at times!), that photos are the only real way to tell. It could even be an 89 with an 88 (or 90~97) motor and/or electrics! It wouldn't be the first!

The importers seem to be buying the cheapest bikes they can, to sell on at the maximum profit they can. It wouldn't be so bad if they were honest about it, as after all, maximising profit is what any business is about, but they're not, and often selling bikes as "low mileage" or "rebuilt" when clearly they are not. As I say, we've had motors in that have literally destroyed themselves after even just a few hundred miles.

preed wrote:
Does this enable you to shed any more light on what might be causing the problem?

Unfortunately, yes. I would strongly suspect the centre crank seal if it's 1989.
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Andy.
NSR-WORLD.COM

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