j_aguilar5142 wrote:
Hey everybody,,, I've been lurking here since I bought my bike new 2 years ago and have really benefited from the info here so I wanted to begin by saying thank you for all the great technical tips

The SVS on my roadie began about 6 months after I bought it. Since then I've done Curt's SVS treatment twice, added either ring free or seafoam to every tank (neither seems to really do much), shocked with seafoam before every oil change, replaced spark plugs, and hit the rev limiter as much as possible. I had it dynoed and everything showed to be pretty dead on, a tad bit lean even.

I've had a KN Forcewinder intake and LA Choppers Curved and Stacked exhaust on it since I got it new. The dealer put those on and rejetted it before I ever rode it. So I guess my question is this: is there anything else I can do to prevent SVS in a more long term way? I think it's lame that everytime I get on it I have to endure 2-3 miles of backfiring and dying.

After reading this thread i have a diff take on it and heres why.

He has done all the SVS cleaning proeccedures mult times with no improvement at all and i know 1st hand from using Seafoam etc does a good job at cleaining carbon etc from combustion chambers etc so maybe its not SVS at all & here's why i think that could be the case here.

He made this statement in his 1st original post most people seemd to overlook which is key.

" I think it's lame that everytime I get on it I have to endure 2-3 miles of backfiring and dying."

That problem (eps if worse with a cold or semi cool motor) could simply be too lean of a PMS/pilot crkt fuel calibration along with also maybe too little of a shot from aceel pump too making it spit fart pop untill the motor gets fully warmed up where it can better handle an over lean situation.

That could explain why when he's been doing all the known SVS clean out fixes with no impromevent at all becuase it not an SVS issue in the 1st place.

The R* will spit/fart/pop ect untill it warms up even witn proper jetting if you dont use some enrichement/choke so if it has too lean of a PMS screw adj and or too lean of a pilot jet for a give app esp with pipes & aftermarket airleaner/filter assembly it makes it just that much worse.

Even though the yami dealer supposedly installed a jet kit still doesnt mean the did it right and could have clip on jet neeld set to higi up/to close to blunt end for over lean alosn with not oepning up pms screw for some more fuel and or maybe installing larger pilot jet too thats often needed when running the better breathing aftermarket aifcleanr assembly.

It could also be a dirty carb slid from backfiring making the situation worse too becasue tha will makemit stick at times not allowng the slide to move up/rise enough to allow neelde to come up for more enrichment until carb body heats up a little making it expand a few .001 letting the dirty/sticky carb slide move better esp going up for more enrichment.

Another remote possibity could be a weak valve spring/s but i doubt it,as far as i know R* doesnt have a tendency for valve sprngs get weak enough in stock setup to cause sticking valve/s & then go away when motor warms up espcially since he did the seafoam cleanout in fuel tank/ex ports/carb mult times ensuring the carb was cleaned out enough to at least not be sticiking valves anymore or at least not for a while untill it carboned up again due to too much oil in crankcase and or over rich .

If his carb is in fact over rich the seafoam should have cleaned out enough caron off the valve stems with all the mult seafoam treatments to run ok for a little while untill enough miles are run on to re-carbon the valve stems again due to an over rich carb making the valve/s stick again.

Again,its just a diff take on it since all the std SVS fixes are not getting it done at all.

Scott

hey everybody,,,

the reply function doesn't seem to be working for me so I'm gonna try this quick reply option and see what happens.

Just an update: I took my bike to yamaha and they put it on the dyno and hooked up an auxiliary tank with a fuel/additive mixture. The additive is unavailable for sale as far as I know, but I gather that they use it on some of their personal watercrafts and stuff. They let the bike idle for an hour with the mixture going directly into the carb. After the hour was up they ran it with the RPM's higher.

After I got it home I changed the oil. Just like a couple of previous replies, Yamaha suggested that I only put in 3.8 quarts of oil,,, which makes sense because before I drained the oil I checked the level and it was right at the top of the acceptable level, and I only ever put in 4 quarts. It seems to me that just blindly putting in 4 quarts of oil (which is what I've been doing) actually puts you close to overfilling. So far the bike's been running like a dream, no backfiring or sputtering or dying. The idle seems alot smoother and the power is back like new. If you're having SVS and can't seem to get rid of it I'd definitely put this on your list of things to do.

Yup,thats why i feel running some seafoam and or Cevrons Techtron in fuel every 4-6 tankfulls should keep things clean enough like combustion chambers /valves/etc to keep SVS away unless maybe is the is running pig rich ,thats a dif story.

Doing so doesnt cost that much and i did notice a diff in my bike when running a fairly healthy 7oz does of seafoam every 4-6 tank even though its not running rich & plugs look good,i'd rather take the safe apporoach then get the dreded SVS/LOL???

Oh,another thing you can do if still running stock aircleaner assembly is remove the crankcase vent from it and install a samll filter from Barons/Phat perf .

Doing that significantly extends the srv'c life of the airfilet and more importatnt ly keep oil from being sucked into the intake of carb to be digested by the motor which can also collectively add to carboning up/gumming up vthe alves & combustion chamber to.

Scott

Thanks for the heads up Scott,,, I'm running a K and N Forcewinder intake. I haven't heard of those having the oil to carb problem you described, is there any way to check for that?

I've actually been running either Ringfree or Seafoam in every tank of gas. At one point when the SVS was really bad I was mixing both to try and get some results. I think it was so far gone and that didn't seem to work. Now I'm back to just running one. I've seen guys on here talking about one or the other but is either preferable to the other?