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Discussion Starter #1
I have a 2000 magnum 500 it sometimes will go 75-80km on gravel road but most of the time barly reaches 65km. and it has now developed a HUGE backfire when i coast to a stop. I got the bike used and dont realy know the service history on it. i changed the spark plug and also the belt. clutches look ok as well. it has about 2500 miles on it according to the speedo.when crusing on the road it seems to slowly lose speed and power.but on the trail at slower speeds seems to be working fine. when it is acting up on the road(wont go over 65k) it seems to be making a throaty bogging sound like it is working hard. any ideas?
thanx
 

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Welcome to the board! And happy 4th!
 

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Is it backfire through the carb or is it lean popping out the exhaust? Inspect the intake boot for tears and proper sealing to the motor and carb also inspect boot from the carb to airbox. If there is a lean pop from the exhaust check to make sure the manifold is tight on the motor and make sure the joints are tight around the grafoil gaskets where the pipes join together.
 

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Discussion Starter #4
thanx for the advice. :)
checked the intake and carb boot. cant find any leaks or cracks.
it seems to be the same every time even when crusing at a slwer speed.
it kinda boggs suddnley. you have to add more throttle to keep the same speed. it happens all of a sudden like you flipped a switch.hard to explain but im at a loss. im a class A mechanic i have a fair bit of troubble shooting experence. this one has got me beat so far..lol
 

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Discussion Starter #5
oh for got it is back fireing from the exhaust. i put in a new needle seat and float.
I also bought a jetkit for it but looks like i would be jetting it down from what is in it now. the kit said to put in a 55 but it had a 57.5 in it.
but i changed it aneyway just to see. diddnt seem to make a diffrence still axactly the same.
 
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