My new (used) motorcycle backfires like crazy.

[dentheman]

I just got back from taking my 2007 Shadow 750 that I have had for 2 days for a little practice run around the neighborhood. I need the practice since this is my first motorcycle. All went fine until the engine warmed up fully, then it would backfire very loudly out the exhaust and lose power. Didn't matter if I was accelerating, decelerating, or cruising, and I felt lucky to make it home. I don't know where to start on this problem, any suggestions for a noob?

[blaine]

I just got back from taking my 2007 Shadow 750 that I have had for 2 days for a little practice run around the neighborhood. I need the practice since this is my first motorcycle. All went fine until the engine warmed up fully, then it would backfire very loudly out the exhaust and lose power. Didn't matter if I was accelerating, decelerating, or cruising, and I felt lucky to make it home. I don't know where to start on this problem, any suggestions for a noob?
I would first check the air filter to see if it is clean.Than I would try some Berrymans b-12 or SeaFoam.I'm thinking ,dirty carb .
:) :cool:

[dentheman]

I just got back from taking my 2007 Shadow 750 that I have had for 2 days for a little practice run around the neighborhood. I need the practice since this is my first motorcycle. All went fine until the engine warmed up fully, then it would backfire very loudly out the exhaust and lose power. Didn't matter if I was accelerating, decelerating, or cruising, and I felt lucky to make it home. I don't know where to start on this problem, any suggestions for a noob?
I would first check the air filter to see if it is clean.Than I would try some Berrymans b-12 or SeaFoam.I'm thinking ,dirty carb .
:) :cool:
Thanks Blaine and GZ. I did pull the air filter and it appears to be new. I am on my way to an auto parts store to look for Berryman's or Seafoam. Who knows how long it sat at the dealer, I am thinking that now that I have ran it there probably is some gunk in the carb. I am now noticing that it also 'chuffs' a lot when idling, before it would just occassionally chuff at idle.

[JWR]

What kind of pipes are on the bike???

Stock or straights.

[dentheman]

Stock pipes. I poured about 8 oz. of Seafoam into about 1.5 gals of gas in the tank, ran it for a while to get it into the carb and will let it sit over night.

[blaine]

Stock pipes. I poured about 8 oz. of Seafoam into about 1.5 gals of gas in the tank, ran it for a while to get it into the carb and will let it sit over night.
I think you will see a big difference,the next time you take her out.
:) :2tup:

[mrlmd1]

8 oz of Seafom in 1.5 gal of gas is way too much, and more is not always better. The usual dose, or maintenance dose, of that stuff or Berrymans is one oz/gal. maybe 2 oz/gal if you want to overdose it the first time. With as much as you put in the bike it may run like crap, worse than before, and you may have to drain the tank or add much more gas to dilute it, (like 3 times as much), depending on the size of your tank.

[dentheman]

A BIG THUMBS UP FROM ME TO ALL OF YOU! The Seafoam did the trick! After letting her sit over night, I cranked her up this morning. Lots of pops and sputters at first, but as I revved the throttle a little she started running better. Eventually no pops or sputters. Then I siphoned out the gas/Seafoam mix and put in new gas. Idle seemed slow to the point of nearly stalling, so I increased it a little. I went for another training ride and there was not a single sputter or pop from her. I got up to 55 on the access road, what a blast! I think I got the idle speed about right by ear (the manual states 1200 rpm but I don't have a tach), it sounds right to me and now when I shift from N to 1st it is nearly silent where before it made a definite noise going into gear. THANKS!

[Water Warrior 2]

The extra strength gas drained from the tank might contain a lot of unwanted deposits from the tank. May not be a good idea but I am thinking of a worst case scenario. There could be dissolved solids in the gas that will settle in the carb when it is parked. Then you go back to square one.

[blaine]

A BIG THUMBS UP FROM ME TO ALL OF YOU! The Seafoam did the trick! After letting her sit over night, I cranked her up this morning. Lots of pops and sputters at first, but as I revved the throttle a little she started running better. Eventually no pops or sputters. Then I siphoned out the gas/Seafoam mix and put in new gas. Idle seemed slow to the point of nearly stalling, so I increased it a little. I went for another training ride and there was not a single sputter or pop from her. I got up to 55 on the access road, what a blast! I think I got the idle speed about right by ear (the manual states 1200 rpm but I don't have a tach), it sounds right to me and now when I shift from N to 1st it is nearly silent where before it made a definite noise going into gear. THANKS!
I have always used it,mixed 2 or 3 times stronger than recommended,for cases like your,and get similar results.I get a lot of people than can't believe how good it works in "worse case" scenarios. Glad it worked for you.I always use 2 or 3 oz's a month,and never have carb problems.
:) :cool:

[dentheman]

I'm surprised to see such a quick response from seafoam. Did you dilute it or leave it at the overdose that it was for your overnight results?

Since you already have the stuff, you could consider putting it back in the tank at the 1 oz. per gallon rate- if for no other reason, jsut to get rid of it but it might do some additional cleaning as well.
I left the overdose in overnight, then cranked her up and ran her until she sounded good, then replaced the mix with gas. I will put some Seafoam in at the recommended rate. My next job is to try to get the battery out. It was dead at time of purchase so the dealer put a new one in, but it is jammed tight in the battery box. I did put the maintainer on it right after delivery and it took about 7 hours to show fully charged, so I guess it wasn't fully charged by the dealer. I knew to do that from this forum. I am learning!

Maybe there was some crud that the Seafoam cleaned out, or maybe the gas was old or had water in it. I had added new gas without draining what was already in the tank when I bought it. I probably should have drained that old gas.

I thought about putting the old gas in my car but then decided to take it to an oil change place that disposed of it.

[kmrcstintn]

the gas that I bulk buy & store in gas cans gets 1 oz of seafoam/gal as well as Stabil Marine ethanol stabilizer at maintenance dose & I usually add a few ounces of seafoam or other cleaner occasionally since I do top off at gas stations every week and that gas isn't treated like my stash stuff, which alos gets used each week so it doesn't sit around more than 45 days