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Post by Doom on Apr 12, 2007 19:18:17 GMT
My son has a J reg Honda NSR 125F. Recently it has started to run rough at lower revs and it stoically refuses to tick over. This is not good for a lad who is trying to gain confidence on his bike and the road at the same time.
Now, I am not very mechanically minded, particularly when it comes to strokers so if any of you have any ideas of simple, cost effective things to check first then I would be very grateful.
Thanks
Ed
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Post by Tigger on Apr 12, 2007 19:50:38 GMT
Only came across this once on my first bike. Yamaha Fizzer. Turned out to be some shite in the jets in the carb. Strip down blow out and job done. I had run it low on fuel and sucked some crap fom the tank. In-line filter sorted that little problem.
HTH
Matt
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Post by 2old2boogie on Apr 12, 2007 19:55:37 GMT
Fussy things are'nt they!
Right, assuming the compression is ok, and the fuel air mixture has been checked? Then I would look at:
1) Low battery voltage. Sulphated connections. Give the battery a good charge.
2) Spark plug(s) fouled or needing adjustment, also check the HT lead and cap.
3) Ignition coil. Partial failure of the coil internals would give these
symptoms.
4) Intake air leak. Check carb mountings and hose for splitting and security.
5) Pilot jet blocked.
6) Cold start device/choke not freeing up.
And finally (for now) is the exhaust in need of a decoke?
That's enough to keep you busy for a few days!
Good luck
Jim
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Post by high peak fazer on Apr 12, 2007 20:05:45 GMT
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Post by chunk166 on Apr 12, 2007 21:54:42 GMT
failing any of the advice you have been given, there should be a screw on the side of the carb to adjust the slide. i think if you turn it clockwise it should help the revs rise, its just like knob that you would find in the middle of a bank of four carbs, ihope this helps.
ray
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Post by 2old2boogie on Apr 13, 2007 10:46:38 GMT
Reading through my first reply to you regarding the 2 stroke I realise I have given you quite a daunting list, especially considering you are 'not mechanically minded'. I would suggest before you dive into something you do'nt understand to check the obvious first. Like spark plug condition and is it tight in the head (not TOO tight in an alloy head!). The carburettor rubber inlet pipes, are they secure? Good seal around the carb end and into the air-box? No splits visible? And dodgy electrical cable connections. I remember being really stuck on a non-firing kids Yamaha 80 once. That was a dodgy furred up wire connector. Remove them, clean them with emery/wire wool, replace them and WD40 them. Again, good luck. If I was closer I'd pop round and give you a hand!  |
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Post by pebbles on Apr 13, 2007 15:28:24 GMT
i have had many 2 strokes i put it down to
the folly of youth the main problems i had
were plugs forever changing them once they
flooded took ages to right itself, carbs was
the other one, coils had to change two sets
on a gt 250 and a really old bike had to put the
two stroke mix in the tank and put the front brake on
and give it a shake that really was bad news
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Post by CD on Apr 14, 2007 13:42:15 GMT
I've had MZ strokers for years fantastic reliability and longevity, but when they play up (like any stroker) can be a pain. One odd symptom is that they can gradually get faster at tickover so you naturally adjust the tickover speed. Then they refuse to start and when they do start gear changes are nasty (though never nice on a Zed) and wont tick over properly.
Reason? When a stroker revs at tickover but stalls easily its because the fuel mixture is weak. The cause can be an air leak or too much air from the pilot air screw. So, check the intake rubber between engine and carburettor and make sure the air screw setting is as per the manual. There are not many things to adjust but this one is critical.
As others said, always make sure the plug and electrics are all behaving properly.
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Post by Doom on Apr 14, 2007 20:14:32 GMT
Thanks Guys.
I was hoping it might be something simple like the plug. All I need now is a spanner the right size to fit the thing and I will be OK. That is if I can get the spanner into the frame!!
Battery is well charged. Hoping it's not intakr tract orientated.
Keep the suggestions coming.
Ed
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Post by Doom on Apr 14, 2007 20:15:12 GMT
Or event intake tract orientated.
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Post by Doom on Apr 14, 2007 20:15:47 GMT
Aaaagh. I have washed my hands and can't do a thing with them.
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Post by judi on Apr 14, 2007 22:02:58 GMT
Aaaagh. I have washed my hands and can't do a thing with them. try drying them.  |
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