Hawkeye
Brat Boy
my brothers bike cranks and idle great. However when he excellerates the engine spits and sputters. Any suggestions as to the problem? The carb is cleaned and so is gas.
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Engine sputtering
- Thread starter Hawkeye
- Start date
Carb? These bikes have two. Any mods (pipes and/or pods)? And if so, have the carbs been re-jetted to compensate for them? It's also helpful if you tell us what year the bike is so we know which carb set you're dealing with. Some of the later ones need more changes and fiddling. They came jetted much leaner from the factory to meet E.P.A. specs and any changes to intake and/or exhaust usually affect them more.
Not much to go on, what's been done so far, what carbs, what ignition? Is "your brother's bike" an XS650?
Troubleshooting 101.
Troubleshooting 101.
CoconutPete
1979 XS650 Special
You're awesome Gary.
Hawkeye
Brat Boy
Ok, it’s a 79 with a 81 stock ‘carbs’.
Old Skool rebuilt it about a year ago. And yes it’s an xs650
Old Skool rebuilt it about a year ago. And yes it’s an xs650
Hawkeye
Brat Boy
And yes it’s “my brothers bike”
OK I was poking a bit of fun but it's surprising what "facts" sometimes come out 50 posts into a thread.
It could be;
intake leak
brass vacuum port leaking
stock petcock vacuum diaphragm leaking
charging issues causing ignition problems
poor compression
plugged gas cap
plugged choke orifice in float bowl
leaky float valve o-ring sticky float valve spring.
throttle shaft seals
needs jet needle shim "fix"
choke not sealing
advance sticking, timing off.
dirty points, bad condenser
spark plug plug cap plug wire, coil issue
crappy cheap pod filters.
etc etc.
as above; troubleshooting 101
It could be;
intake leak
brass vacuum port leaking
stock petcock vacuum diaphragm leaking
charging issues causing ignition problems
poor compression
plugged gas cap
plugged choke orifice in float bowl
leaky float valve o-ring sticky float valve spring.
throttle shaft seals
needs jet needle shim "fix"
choke not sealing
advance sticking, timing off.
dirty points, bad condenser
spark plug plug cap plug wire, coil issue
crappy cheap pod filters.
etc etc.
as above; troubleshooting 101
Last edited:
.......needs jet needle shim "fix"
choke not sealing
advance sticking, timing off.
dirty points, bad condenser
spark plug plug cap plug wire, coil issue
crappy cheap pod filters.
incorrect tongue position
waxing crescent moon phase.....
Sorry... couldn't help myself.
choke not sealing
advance sticking, timing off.
dirty points, bad condenser
spark plug plug cap plug wire, coil issue
crappy cheap pod filters.
incorrect tongue position
waxing crescent moon phase.....
Sorry... couldn't help myself.
Do a forum search on "slide drop test"...
Oops forgot;
Pilot jet plugged
pilot jet rubber plug missing
Pilot jet plugged
pilot jet rubber plug missing
pamcopete
Ride.Enjoy.Life is Simple
Some of these might apply to the problem:
1. Low battery / charging system. A low battery will produce a low ignition voltage at the plugs which is most evident at higher RPM's.
2. Timing. Did you use a timing light to set the timing?
3. Stuck or no advance. When checking the timing with the timing light, did you check for maximum advance at 3,000 RPM.
4. Binding advance rod.
5. Fouled plugs. Did you install new plugs? Check them after you got it running?
6. Plug wire not making contact in the coil. Measure the resistance from plug cap to plug cap to ensure that both plug wires are making contact in the coil.
7. Brakes dragging.
8. Speedo out of calibration. You are actually going faster than 60 MPH! Use your GPS to check the speedo.
9. Tire pressure. Pump up to 32 PSI for high speed.
10. Drive chain too tight. That will rob you of power to the rear wheel.
11. Enricher plunger stuck partially on.
12. Enricher (choke) left on or partially on.
13. Weak or loose advance springs. Weak or loose advance springs cause the advance to use up some of the available movement because you have to essentially retard the advance to get it on the idle advance mark, so there is less movement available at higher RPM's.
14. Timing chain needs adjustment.
15. Cheap or bad gas.
16. Low octane gas.
17. Water in the gas.
18. Partially blocked pet cock or fuel filter.
19. Paper filter that has low flow when the tank is not full.
20. Try a run with a full tank of high octane, fresh, expensive gas.
21. Blocked fuel cap vent.
22. Incorrect sprockets. What RPM are you getting at 60 MPH.
23. Rear tire rubbing on brake rod or swing arm.
24. High wind resistance. Are you a large person?
25. Throttle cable not fully opening the throttles.
26. Blockage in the muffler(s)
27. Dirty or blocked air filters
28. High altitude
29. Very hot air, like 95+F
30. Very cold air, like 32F
31. Low oil
32. Really dirty oil
33. Gas in the oil
34. Weak TCI magnet in rotor. Unplug Reg/Rect to test
35. Cracked carb boots.
36. Hole in carb diaphragm(s)
37. Cheap pods covering air hole in carb inlet
1. Low battery / charging system. A low battery will produce a low ignition voltage at the plugs which is most evident at higher RPM's.
2. Timing. Did you use a timing light to set the timing?
3. Stuck or no advance. When checking the timing with the timing light, did you check for maximum advance at 3,000 RPM.
4. Binding advance rod.
5. Fouled plugs. Did you install new plugs? Check them after you got it running?
6. Plug wire not making contact in the coil. Measure the resistance from plug cap to plug cap to ensure that both plug wires are making contact in the coil.
7. Brakes dragging.
8. Speedo out of calibration. You are actually going faster than 60 MPH! Use your GPS to check the speedo.
9. Tire pressure. Pump up to 32 PSI for high speed.
10. Drive chain too tight. That will rob you of power to the rear wheel.
11. Enricher plunger stuck partially on.
12. Enricher (choke) left on or partially on.
13. Weak or loose advance springs. Weak or loose advance springs cause the advance to use up some of the available movement because you have to essentially retard the advance to get it on the idle advance mark, so there is less movement available at higher RPM's.
14. Timing chain needs adjustment.
15. Cheap or bad gas.
16. Low octane gas.
17. Water in the gas.
18. Partially blocked pet cock or fuel filter.
19. Paper filter that has low flow when the tank is not full.
20. Try a run with a full tank of high octane, fresh, expensive gas.
21. Blocked fuel cap vent.
22. Incorrect sprockets. What RPM are you getting at 60 MPH.
23. Rear tire rubbing on brake rod or swing arm.
24. High wind resistance. Are you a large person?
25. Throttle cable not fully opening the throttles.
26. Blockage in the muffler(s)
27. Dirty or blocked air filters
28. High altitude
29. Very hot air, like 95+F
30. Very cold air, like 32F
31. Low oil
32. Really dirty oil
33. Gas in the oil
34. Weak TCI magnet in rotor. Unplug Reg/Rect to test
35. Cracked carb boots.
36. Hole in carb diaphragm(s)
37. Cheap pods covering air hole in carb inlet
yamageddon
XS650 Addict
condenser
(or is it called capacitor?)
(or is it called capacitor?)
