I was just wondering what was everyones technique for reading a plug. A buddy of mine keeps reading his plug after he is done riding (from a cold start). I dont think he is getting a good reading...what do you guys do?

Eric

 

Here is what I would do:

Checking after riding under all kinds of acceleration and riding will give you a over all idea of how the engine is running, but really won't tell you where a problem is, so you should break it down into three types of riding.

Start with new plug(s) for each test for most accurate readings.

1. Check the idle circuit. Let the engine idle for about 5 minutes, take a reading. Correct if wrong.
2. Check the mid range. Let idle till warm, ride around for about 5 minutes, trying to keep it about mid throttle, not idling or running wide open. Stop and take a reading.
3. Check the wide open circuit. Let idle till warm, ride that baby for a few minutes wide open, stop and take a reading.

When I say stop and take a reading, I mean right there. You don’t want to putt back to the shop, that would make the reading less accurate.

 

i think he means turn the switch off while running wide open and coast to a stop..and check the plug

 

That would be correct. You don't want to run it at idle or midrange after wide open cause it would "cover up" what it looked like after wide open.

 

Thanks for the replys...the reason I ask is because before a MX race this weekend, I was warming up his bike and I noticed his header pipe was GLOWING BRIGHT red. I told him it is running lean. Well, he checks his plug after the race and it looks like it is running rich. Now I can show him at what point it is running too lean. Thanks again!

Eric

 

sorry i can't help you i ride a honda, i have yet to change a plug, i guess i could someday i have only had the machine for 5 years.

 

well he rides a honda as well, we are just working on jetting his quad...he just put on a new filter and exhaust system (plus holes in the airbox lid) so the plug HAS to come out for inspection....

Eric

 

my pipe is glowing with a #50 slow clip one position down on jet needle and #175 main after idleing for a few min also bogs with lid on not with off. what to do?

 

VWVR6,
You might want to read the reply I just made to a post by wicked400ex regarding his glow in the dark pipe. Also, regarding your friend's plug read after a race; he was no doubt running primarily on the main jet circuit when racing & you were probably warming the bike on either the idle or needle jet circuits. Can you say oranges & apples?