Redmohawk
30-10-2010, 08:15 AM
Been teaching myself a little about SU carb tuning over the last few months, and had a old fart in seymour poke some ideas/info into my head . Been experamenting on pore old betty to improve the crappy "feel" of her since pulling the air box and going to pod filters. Generally she ran ok but there was always a flat spot some where in the rev range no matter what needle/jet combanations i tried.
Had a wide band OXY sensor for a while to use for tuning, and I noticed something interesting that anyone running pods might want to keep in mind when tuning etc.
I noticed when riding some times a real strong wind into the side of the bike seemed to give it a little more power, only just noticable but a difference for sure, was put down to windbuffering and me just being silly. Then one day I put my feet up on the pillion pegs while riding at 110 and noticed a slight improvement while crusing , motor sounded a little cleaner/smoother. As i didnt have access to the oxy sensor when I first set her up i erred on the side of rich and it seemed that putting my feet up on the pillion pegs was directing air down my body and legs to the pods leaning off the mix a little.
Now with the oxy sensor I have A messured difference and it was quite supprizing , average differerence at 110 kph with legs from my pegs to pillion pegs is 1.4 taking old pod fuel ratio from 13.5 to 14.9 no wonder I could feel a slight difference in the highway and at speeds over 160 it was almost 2.3 different with mixtures going from 11.3 to 13.6 .
All this was with 4 "standard" Ebay pods fitted to a 600cc inline 4 there is a plastic sheet between the rear frame rails (mudgard for pods) Now if your tuning on a real dyno and have your bike setup on the leaner end of the scale and go for a big blat down the road this may be an issue for you depending on the air flow around your legs etc.
Just thought I'd share.
Had a wide band OXY sensor for a while to use for tuning, and I noticed something interesting that anyone running pods might want to keep in mind when tuning etc.
I noticed when riding some times a real strong wind into the side of the bike seemed to give it a little more power, only just noticable but a difference for sure, was put down to windbuffering and me just being silly. Then one day I put my feet up on the pillion pegs while riding at 110 and noticed a slight improvement while crusing , motor sounded a little cleaner/smoother. As i didnt have access to the oxy sensor when I first set her up i erred on the side of rich and it seemed that putting my feet up on the pillion pegs was directing air down my body and legs to the pods leaning off the mix a little.
Now with the oxy sensor I have A messured difference and it was quite supprizing , average differerence at 110 kph with legs from my pegs to pillion pegs is 1.4 taking old pod fuel ratio from 13.5 to 14.9 no wonder I could feel a slight difference in the highway and at speeds over 160 it was almost 2.3 different with mixtures going from 11.3 to 13.6 .
All this was with 4 "standard" Ebay pods fitted to a 600cc inline 4 there is a plastic sheet between the rear frame rails (mudgard for pods) Now if your tuning on a real dyno and have your bike setup on the leaner end of the scale and go for a big blat down the road this may be an issue for you depending on the air flow around your legs etc.
Just thought I'd share.