It has always been that foam air cleaners use a bit of oil. When I oil my 250 filter it seems like it is running rich and fouls the plug.

I down loaded a shop manual and in section 2-4 it states to oil the filter.
Has any one run across this problem or is it just my unit.
Maybe it is my boggered up choke cable causing the enricher to be partially engaged.

 

I've "over-oil'd" my air filter on my '08 TRV and it ran like crap. VERY boggy and loss of top end "oomph".

I never experienced plug fouling from it - re-did the filter asap as soon as I realized what the problem was. But if your choke is partially engaged due to a faully cable.....then you've definately got an over-fueling issue.

I've also got a 250 ('09) and I recently did the "break-in" fluid changes & filter cleaning. I found that the factory IMHP over-oil'd the air filter - IT WAS SOAKED.

I'll share my prefered method:

1. remove filters
2. soak in solvent of choice in pan (I use 2 old bake pans)
3. carefully squeeze out solvent/dirty oil multiple times.
4. move to clean pan w/solvent - rinse/wring out
5. press excess solvent out w/towel(s)
6. let air dry (1hr) preferably outside or blow dry w/air compressor
7. now WASH filters in warm/hot water w/DAWN dishsoap
8. rinse clean - press excess out w/towel - air dry AGAIN.
9. now soak filter(s) in big ZIP-LOC freezer bag w/filter oil - squeeze/scrunch alot
10. lightly wring-out filter(s) then lightly press between 2 towels to remove any additional excess
11. re-install.

The TRV and the 550 share the same filter, so I have an extra one on standby ready-to-go. I've got an extra filter for the 250 on order for the same purpose. I generally clean/swap filters about 3 times a yr.

good luck

my.02¢