smatta4u

Member
Feb 11, 2002
27
0
i recently purchased a 1996 yamaha pw50 for my four year old. :)
it starts easily and idles good but smokes quite a bit, stumbles at open throttle and there is a little spooge at the end of the silencer. i know running the bike on it's center stand is not the best way to tell but it's all i can do right now plus there is some load from the back wheel spinning. i adjusted the oil pump cable the best i could and the jetting is stock except the needle clip was moved to the top groove. my thinking is that it is rich but i am a novice jetter.
the plug looks pretty clean and brown just a little wet. i don't think that it will bark like carmichael's cr250 but i know it can run better that this. any help is greatly appreciated. thanks.
 

Mr. Clean

~SPONSOR~
Nov 8, 2001
162
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Remove the exhaust pipe from the cylinder and clean the carbon from the port. Clean it with a blunt object until all is cleaned. Then clean the pipe itself. I use a propane torch to do this job. Heat it up until it the carbon burns off. Gently tap and/or blow with compressed air to finish the job. Next I would clean the air filter. Also remember that these bikes are a little rich by design. Hope this helps.

Your ridin' bud Kurt
 

4Tracks

Uhhh...
Feb 20, 2002
2
0
Pipe baffle

A bit more in detail...

The PW50 has a washer-like baffle in the pipe. A lot of buildup occurs here.

Clean that really well, and remember where its at. You can remove it when Juniors riding skills start to be more than the bike can handle, and give him a little bit more power.
 

smatta4u

Member
Feb 11, 2002
27
0
i took the silencer apart and cleaned it already and had the pipe off. i did notice the carbon build up but didn't clean it as well as i should, i will try your technique. the restrictor/washer has already been removed. having the bike run a little rich is okay but i want to cut down on the smoke and have it run
smoother. thanks.
 

smatta4u

Member
Feb 11, 2002
27
0
there is not alot of carbon build up in the exhaust port or the front of the pipe but i did notice some in the expansion chamber. the problem is the chamber is like a box with baffles and a small outlet. i used the propane torch idea and it smoldered for a while so i guess it burned some of it out but it is not easily accessed. i leaned out the airscrew and it got better throttle response and less smoke. the smoke is kind of wierd - blue when on the throttle and black when backing off (from the carbon?) i also realized that i have no idea what oil the previous owner put in it. any idea's?
 

Durt Cycler

Trial Subscriber
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Nov 13, 2001
1,173
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Blue smoke means it's burning tranny oil and black smoke is from a fuel problem right guys? It seems weird hopefully the guy who had the bike before you didn't use motor oil. :think
 

smatta4u

Member
Feb 11, 2002
27
0
i don't think he put motor oil in the injection tank. i mean't the brand and quality (hopefully not from the shelf at the grocery store) i think proper jetting can clear up alot of the smoke. (but then again what do i know:confused: )
 

Durt Cycler

Trial Subscriber
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Nov 13, 2001
1,173
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Heck a weedwhacker turns 10x more RPMs then a PW50 and they run off cheap oil:confused: Hopefully he didn't use a PREMIX only oil...I would think the problem lies in the jetting and carb.:D
 

smatta4u

Member
Feb 11, 2002
27
0
yeah but i think my weedwacker kills more bugs than weeds!:scream: any recomendations on what oil is good an injection type bike? would synthetic oil possibly smoke less?
 

Durt Cycler

Trial Subscriber
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Nov 13, 2001
1,173
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My cousin had a PW80 which I had him run nothing but Bel-Ray Si-7 Synthetic oil. His bike barely smoked (only alittle on cold days when firts started) and it left his topend very clean with little carbon. I got 2 bottles of it sitting in my shed, unfortunely I can't use it and trying to sell them. :(
 
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