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XS650 Addict
I am trying to diagnose a strange new backfire/stumble issue i have
Specs:
1981 XS650 SH with
Ganzo Box ignition
BP7ES plugs
0.035" gaping
High output coil from Mikes
Carbs are well synced
Stock air boxes
Stock jetting (i believe)
Was running with no issue on a PAMCO before the Ganzo install
Starts first kick
Runs well in low range 70% of the time
No issue above 3000 RPM
All of the issue is between 2000 and 3000 rpm when accelerating
I swapped the plug leads and the issue remained predominantly on the left side
Used carb cleaner to check for vacuum leaks and found none
Description of the issue:
Sometimes, after a sustained high rev run >4000 RPM when i come to a stop the bike idles fine, no issue, maybe a little low rpm... when i come to try and accelerate i get significant backfiring from the left side and a loss of power. After a bit of this the bike seems to clear out (sometimes) after some more popping and then will run fine again and accelerate from a stop no issue and easily climb above 4k. Then SOMETHING will happen and it starts backfiring again after coming to another stop. in the 2000 RPM range. When the issue is happening, you can feel it before it ever backfires. In neutral it will be sluggish to get up to 2500 RPM and hover there for a bit. If you give it a little more throttle then it will backfire a bit and if you get up past ~2500 RPM then it will start to clear up. The problem seems to get worse/more likely the hotter the bike.
I pulled the plugs a couple of days ago and they were very dark and dry (rich?). Cleaned them up and ran em again. Same running issue but when i pulled the today they looked as they had been running lean. So im not sure yet when to take from the plugs. will check them again after another ride. How long is long enough to get a good idea if the engine in running rich or lean from the plugs.
Wondering if this issue is familiar to anyone before i break back into the carbs as they had been running well.
Possible issues:
Pilot jet adjustment?
New plugs?
Weak spark?
bad gas? should run higher octane?
debris somewhere in the carbs?
Specs:
1981 XS650 SH with
Ganzo Box ignition
BP7ES plugs
0.035" gaping
High output coil from Mikes
Carbs are well synced
Stock air boxes
Stock jetting (i believe)
Was running with no issue on a PAMCO before the Ganzo install
Starts first kick
Runs well in low range 70% of the time
No issue above 3000 RPM
All of the issue is between 2000 and 3000 rpm when accelerating
I swapped the plug leads and the issue remained predominantly on the left side
Used carb cleaner to check for vacuum leaks and found none
Description of the issue:
Sometimes, after a sustained high rev run >4000 RPM when i come to a stop the bike idles fine, no issue, maybe a little low rpm... when i come to try and accelerate i get significant backfiring from the left side and a loss of power. After a bit of this the bike seems to clear out (sometimes) after some more popping and then will run fine again and accelerate from a stop no issue and easily climb above 4k. Then SOMETHING will happen and it starts backfiring again after coming to another stop. in the 2000 RPM range. When the issue is happening, you can feel it before it ever backfires. In neutral it will be sluggish to get up to 2500 RPM and hover there for a bit. If you give it a little more throttle then it will backfire a bit and if you get up past ~2500 RPM then it will start to clear up. The problem seems to get worse/more likely the hotter the bike.
I pulled the plugs a couple of days ago and they were very dark and dry (rich?). Cleaned them up and ran em again. Same running issue but when i pulled the today they looked as they had been running lean. So im not sure yet when to take from the plugs. will check them again after another ride. How long is long enough to get a good idea if the engine in running rich or lean from the plugs.
Wondering if this issue is familiar to anyone before i break back into the carbs as they had been running well.
Possible issues:
Pilot jet adjustment?
New plugs?
Weak spark?
bad gas? should run higher octane?
debris somewhere in the carbs?