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bizzare backfires/stumbles, poor running..


Guest dkgross

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Guest dkgross

ok..I went on a 300 mile 'Three Pass' Ride today and just had some weird shit happen.

 

I left Seattle with about 60 miles on my tank of Chevron Premium. It was the first tank I've put in since getting the PCIII and FBF Airbox kit installed.

 

She ran GREAT. Strong..powerful...smooth all the way up to redline...

 

I ran her out to the moutains (Snoqualmie Pass)..elev 4000 or so...NO ISSUES...Ran smooth and powerful all the way. I went about 30 minutes past the pass to get gas... The odo had turned 151 miles!!! AND..the yellow light WAS NOT ON!!! I thought that maybe something didn't get connected...the light always came on around 120...

 

just to be safe, I stopped for gas. I pulled into a Shell station (because the only Chevron in the little town was closed). I put 3.6 gallons in!!!! WOW. 41mpg! That's great for me :)

 

Oh..by now, we're on the dry side of the mountians..no idea of elevation...

 

anyway...I fill up with premium, and take off. Within 10 mintues, it feels like there's NO power...lots of popping and backfiring sounds on throttle release. Sound like it's 'spitting' from under the tank...No gas smell though..WTF????

 

As I'm heading to the next pass (Blewett..eleve 3400) it just gets worse, to the point where I'm really worried that SOMETHING has gone very wrong...

 

Since I'm in the middle of bfe out here, and the bike is running, albeit like a piece of crap, I decide to head through the pass, and try to get home on the north pass route... 75 after the fillup, I start thinking I got a bad tankful, so I pull into a Chevron and put another gallon and a half in.

 

Ride for another 110 miles..the light comes on now...I'm at the top of the third pass (Stevens Pass...elev 4800 or so)....I put 3.7 gallons in and start heading down the pass.

 

She'd been running like CRAP for almost 200 miles...now..as I'm heading down the pass, it starts smoothing out...within 40 miles, it's back to normal (and I'm close to sea level again...)

 

The rest of the trip home, there was an OCCASIONAL pop on decelearation, but none of the other symptoms..

 

SO...

 

BAD GAS???

PCIII not set right for the altitude???

 

should I go to the shop tomorrow am and get a new fuel filter???? Anything else I should check? Plugs???

 

 

argh. I leave sunday am for my trip to Vancouver Island!!!

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Dkgross,

 

Check to see if the insulation under the fuel tank has come loose and fallen on the open air cleaner. I have heard of one case of this happening. Just a thought.

 

Good luck,

Mike

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Sounds like you got the gas from the bottom of the gas station tank. Some water is generally at the bottom. That happened to a car I had one time so bad, I had to have the tank pumped. Twice. Because I used the same station a week later and had it happened again. Since the water can hang around in the tank for a while, you should use up as much of the tank as you can and then drain the rest into your lawn mower or something. Not your Mini.

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Guest dkgross

I thought about the water/gas thing as well...

 

biggest concern is if I screwed up my plugs, or if I need to change my fuel filter...

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That definitely sounds like bad gas. If you can drain it out, do so. It's unlikely you messed up anything if there was just water in the gas. If there was other stuff, like dirt, you should definitely be worried about your filter (but that is what it's there for, and you'd know if it was clogged -- it's probably safe to ride on for the next few hundred miles at least). I doubt your plugs were messed up.

 

Fortunately, just in case it was an elevation problem, most of Vancouver Island is near sea level. Well, except for the middle. :) Where are you going?

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Backfiring generally would be considered a condition of a lean burn. But, at elevation the general condition is of a rich burning situation. So that rules out elevation as a factor.

I agree with the other lads, you got some bad fuel. Water or H2o in the tank can give the same symtoms as a lean fuel mixture.

Burn off as much as you can, try to drain the rest of the crap out, and go on that ride to Vancouver Island, and be aware that we are all very envious.

And also be aware that in Canada, Chevron and some Petro Canada stations have the highest available octane in North America. Your Moto Guzzi will like it very much.

Ciao, Steve G.

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Isn't water heavier than fuel and would be at the bottom of the tank all the time?

 

Yes, if it was bad gas, have the filter replaced. The plugs should be OK, but pulling them and checking them would be a good idea.

 

If you dump the gas from the tank into a can, you will see the water at the bottom of the can (if there was any). The water will look like a flaten out bubble/bubbles (remember oil and vinegar don't mix) at the bottom of the can.

 

The scary thing about water is that it just tears up injectors. Good thing you were able to run a few tank fulls of good fuel through your system.

 

Mike

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Guest dkgross

thanks all.. I'll swing by Moto I and see if they can do the fuel filter, just in case.

 

glad to hear about the high octane gas in Canada :)

 

At this point, I'm heading to Nanimo on Sunday...I had planned to head back to the mainland and to Whistler and points north for a few days, but I'm getting reports of really clogged roads/construction, etc..so..I might do something else...not sure what tho ;)

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The scary thing about water is that it just tears up injectors.

 

Okay Mike, I'll bite. You're the master mechanic here and I would appreciate an explanation.

 

thanks

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Yo Dave,

so i was reading a report in BIKE magazine(best motorcycle mag on the planet) where they were saying we should run the crappiest octance fuel possible with our setups.

 

i think im heading by MI today to pick up my bike. when you going to be there ?

 

robbie

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Guest MotoMessiah
The scary thing about water is that it just tears up injectors.

 

Okay Mike, I'll bite. You're the master mechanic here and I would appreciate an explanation.

 

thanks

The minerals in water can cause pitting in the injectors (one of the reasons disposable razors don't last long). However I've never heard of this happening after one tank of bad gas.

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Guest dkgross

sorry I missed ya Robbie. I was there early this am. If I run anything lower than 92 octane, my bike pings like a beeoch.

 

General concencus...bad gas/water in gas. No need to change fuel filter. Plugs look fine.

 

POSSIBLE issue with the current PCIII map at elevation. If I go to Whistler and it acts up, unplug the thing and see how it runs (of course..I didn't think of THAT...)

 

Run it as close to dry as possible when I leave town tomorrow am, and fill her up with the good stuff on my trip.

 

As Jason said..."You worry too much. It's a Guzzi. RUN IT HARD".

 

:) I love my bike.

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Guest Brian Robson

DK...the altitude will not make a difference...mine ran the same at Whistler as it does at home. The liklihood is the gas. Use PetroCan/Chevron 91 and have a great ride. Any problems I can help you with let me know

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Guest dkgross

Thanks, Brian!

 

Seems like most folks I've talked to said the road to Whislter is a MESS with construction, so I may just have to find a Plan B, and head east or something....feel like playing hookey on monday?

 

:)

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Dk

 

I had a similar experience the other week when I accidentally put in car grade gas... ie. the 87 octane I run in the car vs the 92 I run in the Guzzi.. I filled up and drove 80 miles with lots of pops.. then tooling around town at the destination there were lots of backfires.. I ran the gas out of the tank and got some 92.. problem disappeared. I was amazed at how sensitive the bike was to lower octane gas..

 

Tim

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