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How does this plug look?

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My friend has a foreign model xr400 with some mods. Not sure if the jetting is right. it's very hard to tweak the jetting on the carb. It's a Keihin CV type carb with a blocked fuel screw which we had to drill out. How does this spark plug look? Its all carbon black everywhere except on the center electrode where it's white. Lean?

 

IMG_2924.JPG

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My friend has a foreign model xr400 with some mods. Not sure if the jetting is right. it's very hard to tweak the jetting on the carb. It's a Keihin CV type carb with a blocked fuel screw which we had to drill out. How does this spark plug look? Its all carbon black everywhere except on the center electrode where it's white. Lean?

 

IMG_2924.thumb.JPG.aa758bcf157b8bcbc9e5ad801b6f34f8.JPG

Looks rich to me as well, this is what my plug looks like and from what I could tell while driving it and from visual inspection, the mixture is good (but not great).IMG_3521.thumb.JPG.7cc3eeb760fd08a352341caa2fe5e555.JPG

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6 minutes ago, notoriousE-R-I-C said:

Id look into fixing the fuel screw threads. Helicoil? I know its small. What did you drill out and how did you block it?

 

Sorry maybe to drill out was the wrong terminology. Imagine a screw with no grooves to fit a screw driver. it was just flat to prevent you from adjusting it, and located on the very bottom of the carb facing down towards the starter motor so even if there were grooves there you wouldnt really be able to access it... unless you removed the carb.

That's how much or a PITA this carb is. So we drilled a small hole in the middle of it and fitted a tiny laptop screw in it so it could be removed and adjusted. That's all I meant by drilled out.

 

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I think that sorting out that fuel screw issue is probably the first priority. That will allow you to do some tuning and figure out if your jets are correct also

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Are you sure it wasnt the stock flathead which is basically not poking out at all? This is why theres extended aftermarket pieces. But I agree. Youd just be driving drunk in the dark with no lights if this circuit isnt right. Chasin. Chasin thoughts. 

Like whats the tip look like? How would you know if you cant screw it out? Im picturing just a nail shoved in there. Theres a special tip. An oring a washer and a spring. In is leaner. So to get jetting right you need to know where this is, or even if its tip is doing anything. 

I mean if the pilot you have now feels good, then the screw should go in to lean it a bit

Can you please post a photo of this contraption?

TrailRyder? Thoughts?

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Are you sure it wasnt the stock flathead which is basically not poking out at all? This is why theres extended aftermarket pieces. But I agree. Youd just be driving drunk in the dark with no lights if this circuit isnt right. Chasin. Chasin thoughts. 
Like whats the tip look like? How would you know if you cant screw it out? Im picturing just a nail shoved in there. Theres a special tip. An oring a washer and a spring. In is leaner. So to get jetting right you need to know where this is, or even if its tip is doing anything. 
I mean if the pilot you have now feels good, then the screw should go in to lean it a bit
Can you please post a photo of this contraption?
TrailRyder? Thoughts?


the tip is a normal fuel screw tip with a washer and o ring. his bike (xr400sm) is known in a lot of countries but never made it to the US. the carb and fuel screw issue have actually been discussed in this forum in the past. when my friend popped out tge snorkel (which is TINY in comparison to the regular xr snorkel) and swiched out the air filter and installed fmf pipe and headers, the bike became crazy lean! he got a jetting kit for it with a bunch if jets and has been experimenting to find tge right setting. we thought this was close, but appears to be rich now apparently

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Yup hence e start.

Ok if it has a tip its gotta have some type of slot to screw it in. Its not a thumbtack in a cork board. Sure theres no flathead slot?...take it off, however thats possible, and either dremel slice one in or a few hacksaw strokes so you can get a flathead. 

Or toss it and get one you CAN adjust

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here's the fuel screw that has stirred so much interest, into which we drilled a hole and screwed a crosshead screw from a laptop to be able to adjust it. but the main issue i think is the main jet. originally the bike has a size 122 jet. currently we have in it a 136 after the mods. if it's looking super rich we're thinking of going down to a 130, and then depending on where we're at we'll adjust the fuel screw.

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signal-2017-06-29-125934_zpsnstxfpfj.jpg

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Fudge. At least you can screw it now. 2.5 turns out from full tight is where you want to start. Look into an aftermarket extended fuel screw with numbers on it. Avoid some white hairs with that thing! Also use a new plug to make the next reading. The rich plugs probably still fine to use just not to judge A/F ratio

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