BadYamaJama
XS650 Member
Hey all,
Was hoping to get the collective's quick thoughts on something interesting.
I've got a mostly-stock '83 that I've just pulled out of the garage for the first time since last fall, and it's got a rather large issue.
It starts and idles fine, but as soon as I roll on the throttle the engine immediately begins to stutter/stumble and otherwise feels bogged. Like it makes practically zero power.
Here's what I did since then:
1. Disassembled the stock BS34 carbs and thoroughly inspected/cleaned all parts. Diaphragms are in great shape, jets were all clear. Right side carb a bit out of sync but I didn't make/build a sync gauge yet to test. Just bench synced. Replaced o-rings/gaskets.
2. Cleaned air filters, oiled lightly
3. Replaced fuel line & in-line filter
* Fuel is flowing great through the clear filter
4. Checked electrical, meaning:
* Charged battery (Can't test voltage b/c the bike won't rev past 1200 RPM)
* Replaced potentially burnt 20A fuse
* Tested the relatively new regulator/rectifier (Good ol Mikes XS unit)
* Replaces spark plugs (Left side a bit black/rich, Right side more brown) & shortened lines
* Recently replaced alternator brushes / slap tested OK
* Checked timing & cam chain approx. 300 miles ago (Before Winter)
Here's the weird stuff:
1. I think the ignition coil is original - Measuring it's resistance is giving me weird readings.
2. Just found out the TCI box under the frame is missing it's cover and is exposed to all the road grimy goodness
3. Wiring harness looks original. I cleaned up all the contact but it's far from perfect.
Is it possible for the bike to run at idle just fine, but get completely out of whack as soon as it receives gas? I know for a fact the carbs are in pristine condition, plastic floats are at the right heights, new o-rings, etc. so I'm thinking the coil is bad?
Any immediate ideas? I'm already planning on going through the TCI box to check the diodes, etc. and possibly replacing the coil while I'm messing with her.
Thanks!
Was hoping to get the collective's quick thoughts on something interesting.
I've got a mostly-stock '83 that I've just pulled out of the garage for the first time since last fall, and it's got a rather large issue.
It starts and idles fine, but as soon as I roll on the throttle the engine immediately begins to stutter/stumble and otherwise feels bogged. Like it makes practically zero power.
Here's what I did since then:
1. Disassembled the stock BS34 carbs and thoroughly inspected/cleaned all parts. Diaphragms are in great shape, jets were all clear. Right side carb a bit out of sync but I didn't make/build a sync gauge yet to test. Just bench synced. Replaced o-rings/gaskets.
2. Cleaned air filters, oiled lightly
3. Replaced fuel line & in-line filter
* Fuel is flowing great through the clear filter
4. Checked electrical, meaning:
* Charged battery (Can't test voltage b/c the bike won't rev past 1200 RPM)
* Replaced potentially burnt 20A fuse
* Tested the relatively new regulator/rectifier (Good ol Mikes XS unit)
* Replaces spark plugs (Left side a bit black/rich, Right side more brown) & shortened lines
* Recently replaced alternator brushes / slap tested OK
* Checked timing & cam chain approx. 300 miles ago (Before Winter)
Here's the weird stuff:
1. I think the ignition coil is original - Measuring it's resistance is giving me weird readings.
2. Just found out the TCI box under the frame is missing it's cover and is exposed to all the road grimy goodness
3. Wiring harness looks original. I cleaned up all the contact but it's far from perfect.
Is it possible for the bike to run at idle just fine, but get completely out of whack as soon as it receives gas? I know for a fact the carbs are in pristine condition, plastic floats are at the right heights, new o-rings, etc. so I'm thinking the coil is bad?
Any immediate ideas? I'm already planning on going through the TCI box to check the diodes, etc. and possibly replacing the coil while I'm messing with her.
Thanks!