350x is smoking on start up and had a topend rebuild 1 month ago

[coleaclark]

alright guys heres my problem i just had the top end rebuilt like a month ago and took it for a ride and next day i start it up it smokes intell its warm and the spark plug is all black and the smoke that comes out is also black please give me some ideas

[firecat]

black smoke sounds like its runnin real rich. as in a carb prblem . if your burning oil im sure the smoke would be white. iwas almost thinking the rings werent put in correctly on mine the oil ring ends had to be installed opposite from each other . when you say the plug is black is it oily or is it dry?

[racerxxx]

How about some more details about the top end overhaul?? Like it was bored out, valve job, new valve seals etc. Or was it just a hone and re-ring? Also does the smoke smell like burnt oil or rich like too much gas, is the plug wet or dry?? The more you can lay out here the more direct of an answer you might get.

[coleaclark]

the plug is wet and the exhaust smells gasy also on the rebuild was new pistion and valve guides and seals and valves and springs

[Erics350x]

clean your air filter

[harryredtrike]

black smoke is fuel [problem,go back to factory settings on the carb

[mudbogger]

Mine has started to smoke at start-up only, smokes for like a minute or 2,once the choke is turned off it stops immedialty.It will not idll till warm as well.The smoke is white-it had sat for some time prior but I have run it for 3-4 hrs and now it is smoking at start up only, valve guides seals the problem?The compression warm is 178-runs great.I just rebuilt the carb-total rebuild and have jetted it up 1 size for the Supertrapp exhaust-could it be too rich, the plug is nice pancake color on plug chops.I was thinking that mabye just the compression ring was seating and the oil wasn't, causing the smoking,will this make it smoke only at start-up?

[4cfed]

on a fresh rebuild it may smoke for a bit untell the rings are seated. white/ grey is oil black is fuel... my 200x has 141 psi of compression, dont leak or burn a drop.. only smoke from mine is a little black at wide open throttle.. stock style filter, lid on 110 main needle to richer than stock, dg rcm exhaust..


a little black is ok... not spot on jettin but its ok.. if your belching black like a diesel truck your way to rich

[mudbogger]

I should have been explicit-I did not get my top end rebuilt as the others did, mine I have no idea on the bore size, amount of hrs on it, etc as I bought it used some years back and it has been sitting around for some time-I always started it every week and ran it, and I fogged the jug as well during long sits.

[4cfed]

I should have been explicit-I did not get my top end rebuilt as the others did, mine I have no idea on the bore size, amount of hrs on it, etc as I bought it used some years back and it has been sitting around for some time-I always started it every week and ran it, and I fogged the jug as well during long sits.

smart man.. i run into way to many machines that ran when parked and now the owner is dumb founded as to why it wont turn over.. well lets see it sat in a ragedy shed or outside for 4 years i wonder why it wont start!!!

i have some good machines that were un known hours on them... had a blaster that was rode hard and had well over 200 hours on it, had a 250r from the original owner and it was never rebuilt! cleaned carb and cleaned out the silencer and she ran like a champ!

[mudbogger]

Thank you-I had a friend big time into snowmobiles and he turned me onto the Amsoil LINE OF PRODUCTS-I love there fog oil psray-it truly helps in the cold weather for sure-now, I think I am going to send this motor out for a complete rebuild, I have PM'D Sandpuppy and are hoping to speak with him in regards to it----I have no idea on the hrs and are pretty sure the oils ring isnt seating at the present time.

[rdlsz24]

on a fresh rebuild it may smoke for a bit untell the rings are seated.

How long is a bit? I rode mine for the first time today after putting in a 20 over Wiseco. It is smoking white pretty good. It has probabably a total of about 10 minutes run time.

Rob