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Need Help Over Here, Please.

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buko0

Veteran
:help:I have this problem with my MX, here's the history. :help:

I changed my stock carb to Keihin Thailand PE 28mm,
open carb, and matched the jettings fit for my set up, no problems.
Used it for a 200+ km ride, smooth-sailing, easily hitting 120kph,
but a noticable increase in fuel consumption. :D

Then maybe after 2 weeks or so, my MX starts to smoke on the exhausts.
I changed oil (Shell Ultra) and oil filter (OEM Yamaha), still smoking. :confused:
I checked the sparkplug because along side this, it was very hard to start the engine,
and sometimes it backfires when running while it never even backfired before, ever.
I have plugged my AIS too, eversince i changed my muffler.
I found out that the sparkplug was black and not brown, and kind of wet too, so i cleaned it.
The engine started easily after that, but then after a day or two, back to hard starting again.
I bought a new spark plug and installed it yesterday, NGK Iridium IX. Engine started easily after that.
I also noticed that the smoke disappeared for a while, so i did a quick test run.
The backfire disappeared. :) But when i checked the spark plug, still its black.
And the smoke out of the exhausts was still there. :eek:
And today i checked it, it is still smoking out of the exhausts. :mad: Why?? :(

I just want to seek help here first before i go to my mechanic, to save money just in case. :p
My Sniper MX is 1 year and 6 months old,
All-stock except for NOB1 Tribold and Keihin Thailand PE 28mm (open carb)

Ride safe everyone. TIA.:thumbsup:
 
Paladin

Paladin

Super Veteran
Your on rich carb setting. Black and moist SP tip is the evidence. Be careful with iridium SPs, it gets busted easily with big carbs specially if in rich air/fuel mixture and in high octane fuel. Backfire can easily eliminated by removing AIS.
 
bosschx

bosschx

Super Veteran
What are the jettings? When my sniper was on the super stock mode my jettings are Pilot Jet 38, Main Jet 110. When I upgraded to Vixion I only changed my Main Jet to 115. aside from changing the jettings as Paladin mentioned. Your Air Fuel ratio is rich. Do some plug reading buddy and experiment on your carb.
 
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buko0

Veteran
Thanks for the inputs T135 friends, i think if the problem is really centered around my carb, then i'ma go to my mechanic as soon as possible. I don't dare to tweak around my carb too much, i'm too scared i'll mess it up. My biggest concern is the smoking exhausts, it gets me uncomfortable thinking about it. :confused:

The jettings? I forgot already because the mechanic was the one who changed it in particular, but as far as i remember and if im correct, it was a jetting that is also used for a car?
 
bosschx

bosschx

Super Veteran
buko0 said:
Thanks for the inputs T135 friends, i think if the problem is really centered around my carb, then i'ma go to my mechanic as soon as possible. I don't dare to tweak around my carb too much, i'm too scared i'll mess it up. My biggest concern is the smoking exhausts, it gets me uncomfortable thinking about it. :confused:

The jettings? I forgot already because the mechanic was the one who changed it in particular, but as far as i remember and if im correct, it was a jetting that is also used for a car?
Click to expand...

First, i assume that the problem is you. You know that there is something wrong with your MC so why you didn't ask your mechanic about it? So now you assume that the problem is on the carb, then what are you waiting for? If you are scared tweaking the carb go to your mechanic and have it fixed right away! your mechanic should have done plug reading first and check everything before on your MC before returning it to you.
 
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buko0

Veteran
bosschx said:
First, i assume that the problem is you. You know that there is something wrong with your MC so why you didn't ask your mechanic about it? So now you assume that the problem is on the carb, then what are you waiting for? If you are scared tweaking the carb go to your mechanic and have it fixed right away! your mechanic should have done plug reading first and check everything before on your MC before returning it to you.
Click to expand...
Thank you sir, I know you are trying to remind me. :D
I'm planning to do go to him sooner or later, when it doesn't rain here. Everyday it is raining. :(
BTW, nothing wrong showed up early. I even used my MX straight up from the mechanic for a 200+km ride and nothing went wrong. I asked him what could be the cause, he said i change my spark plug first. I did so, and the other problems was solved which is SUPER hard starting and the backfire. The problem that is still waiting to be resolved is the smoke from the exhausts, and the spark plug reading (rich).
 
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buko0

Veteran
:thumbsup: Thanks to every input, got it done already. Thank God it was only the jettings of the carb that was causing it, I really thought it was the valve seal. Changed the jettings already, but then another change in my driving style I'm not accustomed to it yet, it sounds like I'm cooking popcorn when I'm playing with the throttle. :D
 
mac kevin

mac kevin

Super Veteran
what du mean ur stock carb is already busted? if ur referring to accel pump, just sealed the holes inside with epoxy..
 
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