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Running rich?

4702 Views 8 Replies 5 Participants Last post by  zerogeeR6
Hey guys. I need some assistance from the more experienced wrenchers among us.

My bike: 2001 Yamaha R6 with 7500 miles. Stage 1 Jet Kit and a Micron slipon both installed profesionally last year (previous owner). I de-winterized last week and went through two tanks of fuel since then.

The can has always popped a little at low rpm (1-5krpm), so I figured that the jetting was a little rich for the pipe... a little fuel gets through to the can and burns when it reaches the hot environment... no biggie.

Yesterday I rode 250 miles (mostly highway) without noticing anything strange. Today, after putting about 40 miles on the bike, I stopped off at a Sheetz and filled up on 93. Shortly afterward, the 'popping' graduated to full-on backfiring and she got real jerky and hesitant below 5k (don't laugh... we all have to go down there from time-to-time). It could be coincidence. I haven't got the energy to fill up on my usual brand and ride another 30 or 40 miles to test this theory (just finished 200 miles over the mountains of central PA).

so what do you guys think?
1. Is it really running rich?
2. Can crappy gas amplify the problem, or is it a coincidence?

thanks for any comments :cheers
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it can be hard to decide if you are running rich or lean from just an explanation. Popping is also a sign of lean condition, especially in the lower rpm's upon accleration etc.. so that could be your problem also.

did you use stabil in your gas over the winter, and when was the last time your carbs were cleaned?

I'm wondering if you dont have a pilot jet partially plugged with crap. Riding on the highway you're not going to notice anything weird cause your not really using the pilot circuit. once you started getting in slower traffic in town area etc... it might have started popping more due to you using the mainly pilot circuit. which would be from idle to around 5000.

What happens if you're going really slow in 1st and whack on the throttle?

try that once and see what happens.

Then slip your choke on slightly and see what happens when you do it.
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Yeah, I did use Stabil over the winter. Mixed the prescribed amount into a full tank. Ran the engine for a couple of minutes to get it into the carbs.

It might be a few days before we have weather suitable to do any more test-riding, so I may not be able to answer those quetions right away.

I guess I should also mention that the problem was very pronounced during engine braking, too... especially (as mentioned before) at low rpm. Don't know if that makes a difference... probably doesn't.

thanks for the info!

anyone else care to chime in?
hey all.

Here's the latest. The stammering has almost completely stopped :wtf . I noticed it subsiding near the end of that tank of gas, and I topped off with Sunnoco 94 from my usual station. The bike started running considerably better, save for the usual popping I had heard from the start. I'm thinking it was stupid to buy 93 at a Sheetz. It seemed busy enough, but then again Sheetz is known for cheap gas, so most of those who fill up there aren't lookin' to fill up on premium. Maybe I got some old, cruddy gas

anyway... should I consider running some carb-cleaner through the fuel system? I know that's a point of debate, but I'm thinking maybe a small amount in the tank just before I ride, so that it doesn't sit in the fuel system would be ok.

any opinions? and please don't tell me to take the carbs apart .... I fear them :roll:
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Ok, if it all quit in your opinion, it very well could have been your fuel. Although, in your mind it was bad fuel as a possibility. Run a little while with some what you "think" is good gas and make a possible decision. If not...........clean your carbs sometime. Don't be scared, i'ts really quite simple. If you run into a adjustment area simply COUNT closely how many turns to ALL the way IN.....remember how many turns in you had to make. then screw them all the way out.......clean them then screw them all the way back in.....and then turn them out the exact count you remembered from earlier like i mentioned.

If you notice any previous problems, let us know, come back and be detailed like before. You'd shit at how badly alot of pump fuels (regardless of premium etc) would test out as bad!! Alot of pump fuels will test high for oxygen additives etc..and this is why you don't use pump fuels in races where fuel is subject to inspection...most will fail making you look like a cheater. The oxygen additives i mention that most tests find will make you run lean which will result in hotter combustion temps, common for detonation, pinging, and loss of power on top end.
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What is it with all this about "bad" gas? I understand the psychological phenomenon of attributing higher quality to higher prices, but the FACT of the matter is that gasoline is a COMMODITY of which one can purchase a 50,000 gallon contract trading on the CBOE. The only difference is the attempt to differentiate one vendor's commodity versus another at the marketing level.

Octane is a combustion retardant intended to inhibit premature ignition upon compression within the combustion chamber (i.e. upward stroke of the piston).

Yes, i know what octane is, the effects of it, how it's rated etc...

The bad gas comes with storage and delivery. People would be surprised to see how poor some transportation companies use their tankers! I've seen a fuel sample before that had a shit load of fertilizer in it, turned out the last liquid in the tanker was a liquid fertilizer. And with crap like that or water etc... in the gas, could even turn a good fresh batch of VP c-12 with a motor octane of 108 into shit.
Yes gas is a commodity, but there is a different in different vendor's gas. It is in the detergent they add to the fuels. All common gas has to have detergent added, or your engine would be filled with gunk and by-products left over from the raw fuel. Detergents help burn off the by-products and keep the engine clean. This the Techron Chevron advertises and Texco’s is called Clean System3. They are all proprietary mixtures and that is what differentiates one vendor from another.
One of the guys we ride with works for the state and tests the pumps for accuracy and the gas for quality etc.. you would be surprised at the crap they pull. We've got three stations in a ten mile radius he says check out and pass.. a BP up the road, a Hess (not a franchise) and a 7-11 of all places. The others all use fuel that doesn't pass their testing anywhere from octance rating, fuel quality or even rigging the pumps. We get cheated at every corner. I just stick to the stations he says pass and keep a can of octane boost handy. The bike always runs excellent.
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