Plug read please (picture)

[95jersey]

I tried to mix some oxygenated VP MS103 50/50 with pump gas and the bike ran very odd. The idle would hang high and it ran hot.

I am assuming this means a lean condition...here is the picture of the plug. This was a new plug and I only used it with the VP fuel mixture. Does this look excessively lean to you guys?

 

[memphis2857]

The plug doesn't look terribly lean. The hanging idle can be fixed with the air screw. How did it run at wot? Did it bog?


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[95jersey]

Here is a different plug using a 50/50 mixture of VP T4 and pump gas.

 

[95jersey]

It did not bog, but the idle hung high after the bike warmed up. I did play around with the idle screw as I was also adjusting a new Rekluse so I was trying to get the idle up a bit so the bike would creep a bit in gear and not stall.

But it ran very hot and I could smell burning, also it made a bad knocking/pinging sound, which I though was strange as I know I had more than enough octane. I unfortunately had a lot of things going on, had a new Rekluse installed and 2 new ebay radiators, but I can't see either of them affecting how the motor would run.

 

[95jersey]

Here is the idle, notice the very strange surging and high idle. The air screw is only turned out 1.5 turns. When it is cold it idles normal and when it warms up after 10 min it starts doing this...

http://vid1269.photobucket.com/albums/jj591/95jersey/race gas idle_zpsu0hjsezt.mp4

 

[Rick]

I think it sounds lean..... that plug looks on the lean side, not seize lean, but lean. The hanging idle and surges pretty much tell the story.


Have you tried lowering a clip on the needle?

VP makes so many different fuels for different applications it is confusing, plus expensive.

Not to start a fuel debate, I like to run 100LL mixed 50/50 with pump 91, both the YZ125 and GG 200 like it.....with no jetting issues.

 

[95jersey]

So I emptied the tank of the race fuel, bought some strait 93 pump gas and took it for a ride. Started up fine, idled ok, but then after 5-10 minutes it started surging. Even with the air screw all the way in the bike is still surging??

I have done absolutely nothing to the jetting and it has been running great for months, then all of a sudden this...

http://vid1269.photobucket.com/albums/jj591/95jersey/pump gas_zpskex2l2v2.mp4

 

[Rick]

I'd start looking for a air leak some place!

Reed valve block

L/S crank seal

 

[Jakobi]

Second that. Definitely sounds like its pulling air from somewhere, or not getting enough fuel.

Did you drain the carb when replacing the fuel? after 10mins will be close to used up whats in the bowl anyway.

 

[95jersey]

I think (or hope) I found my problem. I refuse to think this is a jetting issue, and also think it is pulling air. I was tightening everything down and when I pulled on the choke it just popped out in my hands. Somehow the cheap plastic threads got stripped and would not tighten down, so the whole choke mechanism was just sitting loosely on the carb (see pic).

I am assuming that is my air leak? Unfortunately I can not tighten the choke cable back into the carb, it just spins and doesn't catch.

Can I pick one of these up at any motorcycle dealer that sells bikes with Keihin carbs? I am hoping they are universal.

 

[john r b]

Contact Sudco in Cali.

 

[Jakobi]

Its a generic choke plunger.. Search PWK choke. Ktm/Yamaha/Honda/... etc all use them.. shame on you for still having that cable attached!

 

[rosco]

2nd that! Go to Yamaha and get a choke assy. for a 07 yz250.

 

[95jersey]

Thanks for the replies, none of my local shops have the plungers for even the Jap bikes, so I got one coming from Halls. X fingers that is my problem.

 

[95jersey]

So I had 2 issues. I fixed my choke and then my throttle cable came loose on the carb and was sitting 1/2 cocked in the opening. Fixed both issues and fixed the free play. Turned air screw 1.5 turns out. Now the bike breaks up really bad after 1/4 throttle to redline. Power is good down low but signs off early and runs harsh. Would this be too rich? I had dropped a clip position in the winter as it was running lean from mid to top. Now it just breaks up and never smooths out.

 

[Jakobi]

Sounds rich on the needle. Burble burble. Make sure the new choke is closing properly too.

 

[stian]

The plug doesn't look terribly lean. The hanging idle can be fixed with the air screw. How did it run at wot? Did it bog?


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Plug is white. It IS terrible lean.