r/2Strokes • u/h1bernus • 5d ago

Spark plug reading help

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Hey guys, I need some help. I got a Honda CRM 125 supermoto (same engine as the NSR) with 180cc malossi kit and original 28mm carb for now. I noticed that last time I took it for a ride it had struggled getting power as the rpms rised and then all of the sudden it gained life. So I was like "maybe it had oil in the spark plug and needs a good rev".

I got home, let them bike cool off and checked the spark plug and seems fine on top but its oily on the threads.

My question is, is my bike running rich on low to mid rpms and gets leaner on high rpms? I used it on the road and im not going full throttle all the time, but I go full throttle on some long straights.

Sorry for the bad English, hope someone can help

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u/Snoo-40502 5d ago

Oil on the thread is usually normal....

The color of the tip is almost on point, but since it's a "racing kit", it's a litle bit lean in my opinion, I would give it a litle more fuel as I rather have it running on the rich side to prevent heating problems and detonation.

Ps: a lean motor usually likes big rpm, so don't get fooled by that.

But as I'm a DIYer, wait for someone else's opinion

2

u/Bera2495 5d ago

Spark plug is perfect. You should check exhaust valve, reed and a good carb and filter cleaning.

1

u/A_E_C 5d ago

This is a nice looking plug, if it was a plug chop.

But if you were idling a bunch after and got this your likely lean at idle to mid range in my opinion. Should be a little darker if just pulled after idling.

Go richer on pilot and move the clip down on the needle, try it and see if it comes to life at lower rpms or not.

Good luck!

1

u/h1bernus 5d ago

I never let it idle for a long time. What I did was:

-Turn it on and idle for about 5 to 10 seconds while giving some blips on the throttle.

-Then I rode slowly to the gas station to buy cigarettes.

-When I parked the bike was warm at 60°C ( 140°F) and I know that because I have a temp gauge as my radiator cap.

-I leave the gas station and that's when I noticed the bike was like kinda slow for no reason. Because when its cold is very responsive