Hey all,

I did a plug check today on my Eiger. I followed instructions I found on HMF's forums. Here's what I did. It was around 70 degrees today. I started the bike and let it idle for about 5-10 minutes and then rode it around for another few minutes. I then shut the bike off and put a brand new spark plug in. I then started the bike back up and immediately got it into 3rd gear and ran it at full throttle for about 100 yards. I then hit the kill switch and pushed the clutch in and let the bike coast to a stop.

Assuming I got all the steps right, I pulled the plug and it looked completely new still. Absolutely clear?! Now, I sorta thought it was running a bit lean, but I didn't think it was that lean.

Does it sound like I did everything right? Should I have left the original plug in instead of swapping the brand new one? I currently have a 128 jet in. I was expecting to go up to a 130, but according to the plug readings, I may have to go further up yet? Any help would be appreciated.

Thanks

 

How did you pull in the clutch?
where on the plug did you check for the smoke ring? Its down deep inside the opening.
Anyway, you found out how difficult it is to do a plug chop. Gas nowadays, is so loaded with solvents and cleaners and alky, that they dont leave many deposits anymore. Your best bet is to go by the drivibility symptoms. If it runs good in all the throttle ranges...its jetted correctly.
Heres a good article on jetting, and the symptoms of lean and rich.jetting

 

hondabuster,

I pushed down on the foot lever and held it down until I rolled to a stop. According to the post I read, I checked the base ring just above the threads. Now, I've also seen diagrams where you can also check deep down inside the opening like your suggesting for proper jetting readings. But, from what I've read you can't really see down there properly with the naked eye.

You're right about today's gas being much cleaner. But, I would think at least if the bike was jetted too rich, I would be able to see that on the plug check?

Thanks for the link. I've seen that one before. But, this time I bookmarked it. Unfortunately, It feels like I have some symptoms that fall into both lean and rich conditions.

 

To narrow it down, whether its lean or rich, you can slowly pull on the choke, as you ride....and if it runs better in those ranges...its lean. You can also remove the air box lid, to see if its too rich.

 

Have you done any mods to the Eiger because if you haven't I really wouldn't worry about it...It may run a little lean from the factory, but that is to meet emissions standards.

 

Yep,

The motor was rebuilt with a .50 over piston. I also made some airbox mods. There was also a long thread on here about how the Eigers are way too lean from the factory. The originator of the thread went from a 122 jet to a 135 jet. Stock jet size is a 122. I've gone from a 122 to a 127.5 to a 130. Each time I've felt it run better. I just keep having trouble figuring the idle mixture screw out. Today, I went to a 132. I'll be riding tomorrow, so I'll find out how it is running now. Since having to rebuild the motor (out of warranty of course), I'd much rather be running too rich than too lean.

 

Yea I hear ya just ride it a little and adjust the adjuster screw a 1/4 of the way until it feels just right and it should prob be around 2 to 3 turns that is if you are right on...Have you tried adjusting the clip for the needle?...let me know how it runs and if you can get a readin on the plug.

 

I rode about 40 miles yesterday. It's the best it has ran since I've owned it. I was able to climb hills in higher gears than before. Had to ride down the road wide open for a couple of miles and it sounded much better. Was hitting 50mph with a little bit of throttle left. I think I can still maybe go up to a 135 main jet.

Now, what I don't understand is...

I checked the plug after riding (I know, not a accurate Plug Chop type test) and it looked plenty rich. Was able to scrape a slight bit of carbon off the top ring. No chunks though, just an even covering (Maybe, I still don't have the idle mixture figured out right.) I guess the important thing is that it ran good!

 

If the plug is black I am sure you already know this that it is running rich which is better then lean, but I would try and get the mixutre just right if you have the time and patience...Try experimenting with other jets and see if you can get the mixture just right and adjust the needle valve clip...Once you have that figure out try and get it to run right with the adj screw and get her in tune...If the jet lower doesn't work out and make it worse try changing the clip positions on both jets and see if you can get the plug to be tannish in color.

 

yeah, it is more on the black side. I don't think the factory needle is adjustable. I'll probably have to get a dynojet kit in order to be able to adjust the needle. I think I'm having the hardest time with the idle mixture. It's a pain because I have to take the side plastic off, wait for the engine to cool, loosen the carb boot clamps, and spin the carb so I can get to the mixture screw. (I haven't found any screw drivers small enough to get in while the engine is running. thinking about making one) Each time I think I got it right (I also don't have a tach), the next time it is idling after several hours of running or maybe the next day after cooling down it sounds like it is hunting to find a smooth idle again.