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]

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]

Carbon

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]

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.

 

[Bryan]

on my old '01, the carb had an internal issue. I never could trace it down, but a friend who I sold the bike to did. When the carb was assembled at the factory, it was not seated properly, and fuel was leaking by internally (as he described it to me).

This is my way of saying it may be more than a jetting issue. If you can test it against a know good carb if you can borrow one. That is how he figured out the problem was in the carb and not jetting.

 

[swazi_matt]

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

so 12-13years old, F5's solution could apply especially on an old bike

 

[ditezz]

I had the same issue on my 08. Could not get to idle consistently, Jetting was a pita , could never get it perfect until I replaced Jet Block O ring.It was leaking and causing all the dramas.You can pick up one on eBay cheap.Youtube is your friend for installation.Not that hard if you watch someone do it .Good luck