The t pipe connecting my carbs started leaking so I repaired it. While I had the carbs off I cleaned them up and put new carb holders on. The fuel leak is fixed but now when I get up to 5000 rpm the engine loses power. Is there a chance I screwed something up or did something else go wrong at the same time?
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losing power at 5000 rpms
- Thread starter yzwizard
- Start date
That's the most logical suspicion.
For more help, provide the year model of the bike, and pics of the carbs...
Do the carbs pass the "slide drop" test?
What did you use to fix the T fuel fitting? Could of something get pass and partially clog the jets?
I removed the coating back past the two ridges, honed the metal down to fit the inside diameter of some o rings I had. They fit snug into the penetration on the carb body. They are not leaking buy it is possible one may have slipped off and obstructed flow.
Put catch cans under the carbs, open up the bowl drains. Turn on the fuel, check for sufficient flow...
Cool. I can do that without taking them off. I wonder what the rate is?
Look for a steady stream and not drip, drip, drip.
I checked battery voltage at 2500 rpm and it was 12.7
That's not good, sounds like you have charging issues. These bikes require a near full charged battery to run right. If it drops too low, the ignition starts acting up. Start with the simple (cheap) things. Check the brushes, clean the slip rings, and check all related wire connections. The 2 big connection plugs for the TCI and the reg/rec sit right along side the battery box. They can get all corroded from exposure to battery acid or just battery acid fumes.
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5Twins, you may remember a few months back when I had a similar problem where my bike wouldn't rev up or go over 60. I tried tapping the right carb on the side of the bowl with a screw driver handle, while riding, and it cleared up. I suspected that one of the float needles were sticking. During my rebuild I kept the carbs upright and took them apart. No sediment, didn't expect it since I always have those little funnel shaped filters on it.
Well, I replaced the float needles and seats, an inexpensive kit from Mikesxs, and now, after rebuild, no problems.
Hey, I also replaced the float needles and seats when I put it on the road again in 2014 and it ran great for about 20K miles.
With all the vibration that goes on, those little needles, whilst hanging on those little wire holders, I'm sure get knocked around a lot creating micro nicks and dents.
Also, upon removing the head, the intake port and valve on that right side were very wet with gas.
Yes, definitely, 12.7V is not enough.
Well, I replaced the float needles and seats, an inexpensive kit from Mikesxs, and now, after rebuild, no problems.
Hey, I also replaced the float needles and seats when I put it on the road again in 2014 and it ran great for about 20K miles.
With all the vibration that goes on, those little needles, whilst hanging on those little wire holders, I'm sure get knocked around a lot creating micro nicks and dents.
Also, upon removing the head, the intake port and valve on that right side were very wet with gas.
Yes, definitely, 12.7V is not enough.
Last edited:
I know the bike has charging issues because I have to keep it on a tender. Without it the battery will die on a half day ride out. Before the carb work it would run fine right down until the battery tapped out at around 11.5. I will address the charging issue and hopefully find the solution to the power loss at the same time. I appreciate all the great information.
.
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pamcopete
Ride.Enjoy.Life is Simple
Losing power at 5,000 RPM
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 indicated on the speedo. 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. Which PAMCO do you have?
2. If PMA, then battery or capacitor?
3. Was the bike originally a US TCI engine or points?
4. What octane gas are you using?
5. Which carbs do you have installed?
6. Any mods to the exhaust or air filters?
7. What gear and road speed does the problem occur?
8. What was the most recent work done to the engine besides the PAMCO?
9. Have you tried going up one size for the main jets in the carbs?
10. What is the battery / capacitor voltage at 5,000 RPM?
11. Have the ignition switch and kill switch contacts been cleaned? Ever?
12. What is the altitude where you are?
13. New spark plugs?
14. When you say it won't rev past 5,000 RPM, what does it do? Misses? Backfires?
If you installed the PMA at the same time as the PAMCO, then several issues could come into focus:
1. How did you establish the timing marks?
2. Does the rotor of the PMA have a key to the crankshaft?
3. Are you using a battery or a capacitor?
4. What is the battery / capacitor Voltage at 5,000 RPM?
5. If a capacitor, then what is the capacity and brand of capacitor?
There can be issues with the PMA that manifest themselves as ignition problems. One way to split the difference is to temporarily disconnect the PMA regulator and run the ignition from a fully charged battery.
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 indicated on the speedo. 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. Which PAMCO do you have?
2. If PMA, then battery or capacitor?
3. Was the bike originally a US TCI engine or points?
4. What octane gas are you using?
5. Which carbs do you have installed?
6. Any mods to the exhaust or air filters?
7. What gear and road speed does the problem occur?
8. What was the most recent work done to the engine besides the PAMCO?
9. Have you tried going up one size for the main jets in the carbs?
10. What is the battery / capacitor voltage at 5,000 RPM?
11. Have the ignition switch and kill switch contacts been cleaned? Ever?
12. What is the altitude where you are?
13. New spark plugs?
14. When you say it won't rev past 5,000 RPM, what does it do? Misses? Backfires?
If you installed the PMA at the same time as the PAMCO, then several issues could come into focus:
1. How did you establish the timing marks?
2. Does the rotor of the PMA have a key to the crankshaft?
3. Are you using a battery or a capacitor?
4. What is the battery / capacitor Voltage at 5,000 RPM?
5. If a capacitor, then what is the capacity and brand of capacitor?
There can be issues with the PMA that manifest themselves as ignition problems. One way to split the difference is to temporarily disconnect the PMA regulator and run the ignition from a fully charged battery.
Pete, you left out a couple.
- Operating above 12,000 feet MSL.
- Operating upside-down.
- Overdue on bike payment...
- Operating above 12,000 feet MSL.
- Operating upside-down.
- Overdue on bike payment...
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Gremlins?
- Messages
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- Points
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