Red Beard
XS650 Addict
Ok y'all, this issue has been getting worse, and I have tried all I can think of so I'm looking for some help or ideas into why this damn thing is running so poorly.
Specs:
1979 XS650
BS 38 carbs
PMA
Pamco
Simplified wiring harness with blade fuses
Problem:
Video link here -
Sorry for the ghetto setup and commentary, you cant really see the volts but when i say there is a voltage drop it was to the point of like 4 volts and at one point 1 volt, but mostly low around 7-9 volts during the bogging and backfiring, as soon as it stopped voltage came back up.
I'm not sure what to test next, the lack of voltage makes me think an electrical issue but she has been running with this setup for a while now with 0 problems, Only thing that has happened out of the blue is this noise
and I cant seem to tell what happened, we were thinking bent valve but the compression says otherwise? IDK I am all out of ideas guys. below is a list of info on what i could think to try.
What I've done:
*Compression test - all good on both 105 and 104 when sitting for a few days, then 145 and 144 with a few drops of oil down the cylinder
*Cleaned carbs - they were spotless and both jets looked great, float levels were on point (I've completely rebuilt them before using the amckay guide including all new rubber, and gaskets, and seals)
*New fuel filters
*Uni air filters cleaned and inspected, they look good to me
*Checked Diaphragms and they pass the "drop down slowly" test
*Sprayed intake boots with WD-40, no increase in idle or smoke out exhaust
*Checked cam chain - was within spec
*Checked valves - had one exhaust valve out of spec by a bit but returned in spec and still issues
*Checked carb sync with homemade manometer- Balanced fluid well
*Voltage at idle is 12.4-13.2 and voltage at 3000rpm is 13.4-14.1
*Checked mechanical advance and springs seem to be in good condition
*Checked timing and it looks good and advance unit kicks in at 2000-3000 rpm and seems to be where it should
*Plugs looked good - they were just slightly rich but that has been tuned out mostly
*All electrical grounds seem to be grounded well and solid.
Specs:
1979 XS650
BS 38 carbs
PMA
Pamco
Simplified wiring harness with blade fuses
Problem:
Video link here -
Sorry for the ghetto setup and commentary, you cant really see the volts but when i say there is a voltage drop it was to the point of like 4 volts and at one point 1 volt, but mostly low around 7-9 volts during the bogging and backfiring, as soon as it stopped voltage came back up.
I'm not sure what to test next, the lack of voltage makes me think an electrical issue but she has been running with this setup for a while now with 0 problems, Only thing that has happened out of the blue is this noise
What I've done:
*Compression test - all good on both 105 and 104 when sitting for a few days, then 145 and 144 with a few drops of oil down the cylinder
*Cleaned carbs - they were spotless and both jets looked great, float levels were on point (I've completely rebuilt them before using the amckay guide including all new rubber, and gaskets, and seals)
*New fuel filters
*Uni air filters cleaned and inspected, they look good to me
*Checked Diaphragms and they pass the "drop down slowly" test
*Sprayed intake boots with WD-40, no increase in idle or smoke out exhaust
*Checked cam chain - was within spec
*Checked valves - had one exhaust valve out of spec by a bit but returned in spec and still issues
*Checked carb sync with homemade manometer- Balanced fluid well
*Voltage at idle is 12.4-13.2 and voltage at 3000rpm is 13.4-14.1
*Checked mechanical advance and springs seem to be in good condition
*Checked timing and it looks good and advance unit kicks in at 2000-3000 rpm and seems to be where it should
*Plugs looked good - they were just slightly rich but that has been tuned out mostly
*All electrical grounds seem to be grounded well and solid.