[mvorbrodt]

Hi guys!

So I had my '06 Spirit 750 for six months now, and the last 3-4 weeks it starts all funny...

It will start just as quickly as before, but then for the first 10-30 seconds it stutters, and sounds like one of the cylinders isn't firing as often as it should, sometimes it backfires, and then magically after 10-23 seconds it's back to NORMAL.

I figured dirty jets, so I put some cleaner in it last fill up but haven't done many miles since then (I'm off work now, so I don't ride every day).

Any ideas what could cause this? Is this even of concern? The bike runs just fine afterwards. Could it be winter fuel blend? Dirty jets? I'm clueless here :-(

 

[smilie]

Have the temps been cooler? Do you usually start with the choke?

 

[mvorbrodt]

Have the temps been cooler? Do you usually start with the choke?

Yes it has been colder, no I do not start with the choke. One time I did try choke the bike backfired like a cannon so I don't use it :/

 

[smilie]

Not unusual to need to choke it when the temps cool down, but shouldn't be backfiring under ANY conditions. Check your exhaust pipe joint nuts at the cylinders for proper torque. Also check your intake connections from the carb to cylinders to make sure you don't have an air leak.

 

[mvorbrodt]

Not unusual to need to choke it when the temps cool down, but shouldn't be backfiring under ANY conditions. Check your exhaust pipe joint nuts at the cylinders for proper torque. Also check your intake connections from the carb to cylinders to make sure you don't have an air leak.

I'm not sure, but I think this may also coincide with the time I had my resonators welded back in after I got tired of the hole saw mod. Do you think this may be related? After the hole saw mod I did not modify A/F screw or nothing. On choke, it backfired ONCE that I can remember, that's why I don't use choke at all.

 

[Wombatair]

You might want to have your valves checked, could be clearances, burnt valves, carbon crap on valves. But I hope you have change out fuel, plugs, fuel filter , timingetc first.

 

[smilie]

Any other history of changes or mods? Miles? Backfiring is usually a sign of improper fuel delivery or timing.

 

[Eagle7840]

Yes it has been colder, no I do not start with the choke. One time I did try choke the bike backfired like a cannon so I don't use it :/

I use my choke on a cold engine no matter what the outside temp is and then feather the choke as the rpm's increase. Using Gumout or B12 added to the fuel might cure your problem by cleaning out the jets and gum on the float needle and float pins, but the bike needs to be driven for it to work. Like smilie suggested, check all of your exhaust header mounting bolts and muffler clamps and also the carb boot clamps.

 

[Bigboy Al]

I recently had a complete carb job done and on the first attempt at starting her I noticed she was running on one cylinder (#1 rear) and after about 30-60 sec I notices #2 take... Now i attributed this to fuel not getting to the #2carbs becuase she hasn't done it again.

So my question would be are you running the carbs dry every time you park her? If so it may be the fuel isn't getting to that one carb fast enough.

Ps... Mine is also an 06 spirit.

 

[Furball Zen]

You guys are over thinking it, use the choke. Just cause you backfired once...

Thats like saying "i didnt get an erection with ONE girl ONE time and never tried to have sex again".

 

[John Hopkins]

Don't worry about it.. the damp and cold are getting in your engine, probably via the exhaust pipes and the air filter, the spluttering is the engine burning off the water vapour, as soon as the bike warms up it will run smoothly again.. next summer the bike will start and run as sweet as a nut..I would suggest you do nothing..

John.