update-plugs fouling/rich mixture

A

Assultr

New member
Joined
Jan 25, 2004
Messages
7
Location
Petoskey, MI
Hey Guys, (I originally posted under the scrren name: Rudamin)
I finally found the fix for my problem. First let me recap on the situation: My vmax sx 600 was fouling plugs like crazy, especially when going through powder and having any kind of load on it. So, I ended up pulling the carbs and thoroughly cleaning them. I did find belt dust in there, but there wasn't anything too serious. I put the carbs back on, threw in a new set of plugs, and fouled them due to an overly rich mixture! So then I decided to put a hotter heat range plug in there, BR8ES. These have worked for about a week, but whenever I go through powder, my machine bogs down and the plugs are oily again. Finally, I decided to pull the carb needles and adjust them. On my needles there are three notches, and it WAS on the middle notch. I moved the clip up to the top notch, which drops the needle in deeper, and my problem is fixed! No more dogging, no more wet plugs. I still have those BR8's in there. Im gonna keep an eye on them, I might just leave 'em in if they aren't burning too hot. Let me know if you have any questions, I hope this is helpful.
-Assultr
 

FasterBlaster,
I dont know if it does or not. I just know that it has the stock Mikuni carbs on it. It's a twin.
-Assultr
 
Smart carbs are supposed to compensate for altitude and temp. automatically, so you don't have to re-jet. Can somebody let us know if the 98 Vmax 600 twin had smart carbs or not.
 
LoneViper,
I dont know what you are asking by whether or not the needles sit pretty low when they are adjusted the way that I have them. There are three notches on the needles, and they currently are on the top notch, which lowers the needles the most. My sled has been running flawlessly since I made that adjustment.
-Assultr
 
I was just wondering if maybe the needles where set a little lean being they arre all the way down. Then again if you only have three notches maybe they are ok. Run down the trail at about 45 miles per hour for a mile or so then check your plugs and see what they look like, rich, lean, ect.

I thought there were about 5 notches on the needles.
 
I would agree with LoneViper that you should for the next while keep an eye on piston wash and plugs..... (be sure to do it at different ambient temperatures too)... Normally there are nylon shims which allow you to drop needles one half notch at a time..... I would be careful for a bit.... Midrange burn down hurts the pocket book....

tj
 
I have my 97 Venture VT600 set the same and the plugs are still always
dark brown when I pull them . I have been there for 800 miles and still ok.
I will check plugs again before the weekend .
 
yamahas run rich anyway dont they but i would be leary of the hotter plug if you are leaning it out a tad id go back to the br9es

buzz
 
Okay guys,
I'm still running the BR8's in my sled, and it is still running just fine after rejetting it. I pulled the plugs last night and they are burning brown/dark brown. So I'm just gonna leave the 8's in there, just thought that I would let you know how things turned out.

-Assultr
 
There is an excerpt from the tech pages "Vmax manual", which provides a good grid for carb setups based on altitude. I set my 96' Vmax XT using these settings (pilot, needle, main) and it runs like a top. It's also a good idea to adjust your throttle cable free play (1-2mm) and you can also adjust your oil pump cable a little lean of the calibration mark (the throttle and oil cables work hand in hand and if the free play is out of spec., you could be dumping a lot of oil before the throttle engages). My plugs are light to dark brown depending on outside tempurature.
 
You must log in or register to reply here.


Back
Top