nsr won't idle

[baldy]

Hi.

Here's what happened....

After 2 days of work reconditioning the rear shock and suspension coupling bearings, i re-fitted it all just the way i removed it. then i noticed that my choke was a bit stiff and oiled it. I put on the choke and fired it up and it run fine until i turned the choke off and it cut out. I fired it up and it backfired very loudly and flames shot out of the exhaust with a few sparks(this was with no choke). So i left it for a while and tried to start it but it didn't want to start without at least 1/4 of the revs on.

The thing is, it will not idle unless you hold the revs on, and when it does start it seems to struggle up to 4000rpm and then it's fine.

I tinkered about with the idle screw but this did nothing.(And yes it was the idle screw not the mixture screw.)

Any help would be appreciated as i need the bike fixed for thursday to go to work on.

Cheers
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One day i will rule the world, just not today.

[alains]

take off your carb , clean it , blow every jet , control that the needle tank do not get stock . my diag is that you got bad mixture & bad timming on the spark . i do not know which bike you own , so i do not know which values on adjustments , but do this after cleaning : tight the pilot screw then undo 2 1/2 turns and tight a bit more the throttle pilot screw . start on ckoke , let it warm 2-3 mn , then choke off . get the idle down to 1500 rpm and screw or unscrew the pilot screw and let it at the best sound you feel . you may change your sparkplug(s) . if you still have flames and trouble , get your ignition timming right (sign of ignition too much advance)
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the worst day fishing is better than the best day working

[baldy]

Hi,

Today i stripped and cleaned the carb, making sure all the jets were clear and put it back on and it still struggled to start.

Also the bike started to spit oil and thick white smoke from the exhaust and cut out very easily. So i checked the oil and water levels and both were very low, especially the oil. when i put my finger into the oil cap hole, all i got was a wet finger with what seemed to be water. I replaced the plug and still it did the same.

I then stripped the barrel apart and found that there was carbon deposits on the inside of the barrel where the water goes.

The main thing that concerns me is that there was what seemed to be a small crack in the barrel on the thin part of the exhaust port and fine scratches and burn marks on the piston. Is this meant to be there or should i replace the lot? I am stumped because i thought it was the head gasket that had gone but there is no traces of oil in the water.

I will try and get some pics posted for tomorrow so you can see the damage.

Cheers
____________________
One day i will rule the world, just not today.

[baldy]

Oh yeah, the smoke is not just a bit of smoke, it fills up the whole street like a oil rig on fire.
____________________
One day i will rule the world, just not today.

[mr jamez]

If the plating on the cylinder wall is cracked/chipped or damaged in anyway then replace the barrel. £85 with a piston from david silver spares. Mine went in exactly the same place, would only run (barely) on full choke. If it is low on oil and water then it has probably overheated causing the plating to crack, or was on the verge of a seize up.

Top end rebuild time!

[baldy]

It wasn't low on oil a day before it happened, that is why i am so confused.

Also it run fine before i did the suspension and then this.
____________________
One day i will rule the world, just not today.

[alains]

i can tell you that i never seen or heard about a barrel cracked . it eventually may happen when you burn a piston or break rings . but i have seen once , the engine carter cracked by a "novice" who try to jump a stone . prior changing top engine , verify if you got cracks under the exhaust exit . in this case better you find a second hand . if you can put photoes of it , we can see better . i hope it's not so serious
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the worst day fishing is better than the best day working

[baldy]

Here's a little drawing i did until i get some pics.
____________________
One day i will rule the world, just not today.

[alains]

well , well , well , does not look good for your purse . before bying a barrel-piston kit (and gasket & seals) inspect very precautionly the engine carter , after taking off the barrel (in case other crack) . when you will have your new barrel , think about grinding the transfert of any roughness and sharp angles , not polish , finish with 180 waterproof sandpaper ( honda is not very good on clean barrel) , this will give a better mixture flooding , but do not touch inside the cylinder , you will damage the nikasil . keep me inform
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the worst day fishing is better than the best day working

[mr jamez]

That is the end of the barrel, mine went in exactly the same place.

[baldy]

Hi.

Finally got a pic but not a very good one.
____________________
One day i will rule the world, just not today.