Guest Posted January 25, 2012 Posted January 25, 2012 hey my bike wont fire up atall now. its a chituma gy 125 05 plate with 3855 miles on it. started playing up last week in the middle of a run started getting boggy and stuttering when hard accellerating so drove straight home (with difficulty) with it losing power so took it straight home to the garage cleaned the carb (jets and float) baught a new NGK R spark plug fitted the carb back in and still wont fire up...im getting a good spark and the spark plug is wet after trying to start it so its getting fuel. had a new coil 2months ago Quote
Guest Posted January 25, 2012 Posted January 25, 2012 it does turn over but wont start ive just been out at it and sprayed about 10ml of petrol into the carb with the throttle open but nothings improving :/even though I know im getting fuel just thaught i'd try that Quote
Fozzie Posted January 25, 2012 Posted January 25, 2012 Sounds chinese so I'm going to guess coil as if you replaced it before because it went id say that...Or it might have packed in the whole CDI Quote
eastanglianbiker Posted January 25, 2012 Posted January 25, 2012 says he is getting a spark so coil and cdi will be ok,be worth checking compression by placing finger over hole for spark plug and turn engine over,it should blow your finger off the hole Quote
Guest Posted January 25, 2012 Posted January 25, 2012 just done a compression test, it has poor compression compared to my nsr. chances are I need a new piston/rings ? Quote
Guest Posted January 25, 2012 Posted January 25, 2012 Sounds chinese so I'm going to guess coil as if you replaced it before because it went id say that...Or it might have packed in the whole CDIyeah its chinese and its getting a good spark Quote
eastanglianbiker Posted January 25, 2012 Posted January 25, 2012 is it 2 stroke or 4 stroke as low compression on a 2 stroke is normally due to worn piston rings or crankshaft seals and 4 strokes can be valves burnt/bent not seating correctly or the piston rings Quote
Guest Posted January 25, 2012 Posted January 25, 2012 is it 2 stroke or 4 stroke as low compression on a 2 stroke is normally due to worn piston rings or crankshaft seals and 4 strokes can be valves burnt/bent not seating correctly or the piston ringsim hoping its piston related, il be taking the head off and checking for any flaws, if there is can I get it bored out and fit an oversized piston on a cbt ? Quote
Boro Jake Posted January 25, 2012 Posted January 25, 2012 What did the spark plug look like when you took it off? Ring could have failed? Bike should have been smoking Quote
Guest Posted January 25, 2012 Posted January 25, 2012 the spark plug WAS getting fouled quite easily, even recently when its been running fine but the brand new spark plug isnt fouled. Quote
Fozzie Posted January 25, 2012 Posted January 25, 2012 I got a spark when my coils went, just the bike couldnt start as it wasnt giving a strong enough spark, so I had to bump it and then it mis-fired badly. But if the compression is right down then it sounds like a worn set of ringsA bit weird to happen on a low mileage 4-stroke. Check your oil levels as worn rings can allow the bike to eat through oil. Do you know what the compression should be to confirm it is that which is the problem? Quote
Guest Posted January 25, 2012 Posted January 25, 2012 il go check my oil level just now if its low what oil do I put in it ? have only had it about 4months hadnt gotten round to considering an oil change...dont know if this informations usefull but it was garaged by my friend (the 1st owner) for 4 years as he passed his car test Quote
Guest Posted January 25, 2012 Posted January 25, 2012 I just done a pressure test by using my finger but I notice its significantly low pressure Quote
Guest Posted January 25, 2012 Posted January 25, 2012 oil level seems fine, before it gave up on the way home it was like I was driving whilst flicking the kill switch on and off, but the electrics are fine and doesnt miss a spark Quote
Tango Posted January 25, 2012 Posted January 25, 2012 With not enough compression you'll not get it to fire.....Is the bike Overhead Cam or Overhead Valve? Either way you could check whether the valves are moving OK.....and the clearances....if the valves are not closing fully you'll lose compression there as someone else has said. Don't know if your engine has tappets....but if the lock nut comes loose the adjuster can work its way in and prevent the valve from seating fully. Quote
Guest Posted January 25, 2012 Posted January 25, 2012 I think its a camshaft il find out tomorrow afternoon when I take the top end off Quote
Guest Posted January 31, 2012 Posted January 31, 2012 after stripping the whole top end down there was a damaged gasket at the bottom end of the head and oil on the piston/barrel new gaskets ordered, couldnt see anything else wrong valves were operating fine etc. Quote
Tango Posted January 31, 2012 Posted January 31, 2012 after stripping the whole top end down there was a damaged gasket at the bottom end of the head and oil on the piston/barrel new gaskets ordered, couldnt see anything else wrong valves were operating fine etc.And were the valve clearances OK?Could just be a blown head gasket..... Quote
Guest Posted January 31, 2012 Posted January 31, 2012 iv got the gaskets ordered, its a full engine gasket set for the bike...im best doing all the gaskets eh ? and give it an oil change to...im.just wondering, could the oil in the bottom end be contaminated with water or anything Quote
Tango Posted January 31, 2012 Posted January 31, 2012 Is the bike water cooled? if so..then water could have mixed with the oil if it's the head gasket that has gone. Does your bike have a dipstick for checking the oil or a sight glass? Either way if water has got into the oil it will start to emulsify....and you'll see an emulsion type substance in the sight glass or on the dipstick.... Quote
Guest Posted January 31, 2012 Posted January 31, 2012 the bike is air cooled and it has both a sight glass and dipstick, no signs of water in the oil so heres hoping the gasket is the issue Quote
Tango Posted January 31, 2012 Posted January 31, 2012 If it's aircooled you shouldn't have any trouble with water in the oil.....unless you ride it through rivers... Quote
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