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]

Originally Posted by 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:

[dentheman]

Originally Posted by blaine

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]

Originally Posted by 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.

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]

Originally Posted by 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!

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: