I have a 91 883 sporty hugger. I recently got given it off my mum, prior to that my brother owned it and he adjusted the carbie himself. So i took it to a mechanic and had him tune the carbie for me. Since then it wont idle, backfires out of the carbie for about the first 10 mins. And when you are riding it, when you sit on 100ks for awhile it bogs down to 80ks and feels real sluggish and like it will stall. I know i need to take it back to the mechanic but hes off work at the moment.

Any ideas on what it could be?

 

Have drained the fuel from the tank and put good petrol in it. Still does it. So pulled the air filter off and have to get a carby kit and redo the jets, change the gaskets etc. everything is still original.
So hopefully that fixes it up. Thanks for our help. Will let you know how it goes

 flush fuel tank & cock, new inlet manifold seal's  to cly head  a must ,    jets 45 idle , main 190 , mixture screw 3 full turn's  out  . adjust idle speed hot & upright

What size pilot and Main jets are you running?  (as an aside I would ahve though a 190 Main to be too large for an 883 Sporty)

I'm not sure what size jets it has. Everything is still standard, so whatever it came out with.

On a bike that age I would never assume that Anythinh is stock. Your best bet is to pull the float bowl and have a look.

it is all original, the bike was my mums. And they have not done anything to the carbie.
WE have just rebuilt it with all new seals,gaskets,vacuum piston and manifold gaskets. Carbie is fine now. Just wont run. Bike turns over just wont start.

it is all original, the bike was my mums. And they have not done anything to the carbie.
WE have just rebuilt it with all new seals,gaskets,vacuum piston and manifold gaskets. Carbie is fine now. Just wont run. Bike turns over just wont start.

 It has new plugs and the leads are fine. But how do we check the engine module, sensor and the coil?

- The jet sizes will still help us.
- The bogging down at 100km could be the fuel tank vent not working, check the vent in the gas cap
- Take it for a ride at 100km and wait until the bogging down starts; then kill the engine and coast to a stop. Pull the plugs and let us know what they look like. If they look to be full of black carbon then i am interested.

 I'll try and find out he jet sizes. 

The petrol cap is ok. But I have to get the bike going again before I can check the plugs if it bogs down again

thanks for the link. But its no good for us. All these tests need to be done when the bike is going. We cant even get it to start.

thanks for the link. But its no good for us. All these tests need to be done when the bike is going. We cant even get it to start.

 We have a service manual read and did everything it told us. We have spark, we have fuel and there is no air leaks.

in the end we found the old spark plugs and tried them and it started. 

The plugs we had in were only a couple of months old and no problems before. 

Just the old ones worked. So the bike is now going and feels like a new bike again.

Thanks heaps everyone for your help.