Plug Fouling

[HurricaneHarry]

New member here, in Newcastle NSW, 08 EC300.

Anyone got any suggestions re jetting, curing plug fouling? I haven't ridden it yet but bought from a mate who tells me it does this sometimes. It has new top end and the old piston had a lot of carbon on the crown.

[swazi_matt]

Originally Posted by HurricaneHarry

New member here, in Newcastle NSW, 08 EC300.

Anyone got any suggestions re jetting, curing plug fouling? I haven't ridden it yet but bought from a mate who tells me it does this sometimes. It has new top end and the old piston had a lot of carbon on the crown.

"does this sometimes" sounds like one of the circuits is rich. i had a kx250 that would foul a plug after long v. slow downhills, where it was just idling so leaned up the pilot jet and problem sorted.

you will need to try and find out which circuit is off - start by checking the jetting database for similar bike and conditions

[(F5)]

Check the carb needle jet. Take carb apart and look down the hole with the slide removed, a good light and a magnifying glass. It should be round and not the least bit oval.

Check gearbox oil level.

I've never fouled a plug.

[HurricaneHarry]

I noticed the piston recently replaced had a lot of carbon build up on the crown. I was also told it doesn't usually idle well. Other threads I've read have given me the impression that unsuitable jetting is a common issue. I would've thought this would be an easy fix - ie these are the carb settings to use. I think I'll just ride it a bit and see how it goes. 50:1 Motul semi-synth?

[swazi_matt]

I agree.
how old is the bike? and what type of riding do you do? I was mostly slow technical stuff, not wfo for any extended periods. Found motul 710 worked best as it had a lower flash point, but oil/fuel mix is not the fix

[Gasser Nate]

What carby is fitted to it? Round top As1 or bolt on As2?
Read the jetting threads. If it has the stock jetting pick anything posted on there and it will be better!

[HurricaneHarry]

Originally Posted by swazi_matt

I agree.
how old is the bike? and what type of riding do you do? I was mostly slow technical stuff, not wfo for any extended periods. Found motul 710 worked best as it had a lower flash point, but oil/fuel mix is not the fix

Same as you. It's an 08. Fresh piston.