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OK y'all, I've got an issue I hope someone else has had and figured it out.
Ever since I've had this 2H7 engine in my bike I've had a small stumble just as the power kicked in, I'm sure some of you might remember me mentioning it on the site before. It has gotten MUCH worse over the last few weeks.
The first real problem I had was in Colorado at elevations over 8000Ft. At those altitudes I could not use full throttle, only 2/3 or 3/4, over that and the engine would just flatten out and start popping through the intake and exhaust. Less throttle and it was normal and below those altitudes it was normal.
Now 3 months later the stumble has become much longer but it will eventually push through it and it takes off. But, now even at near sea level here in Oklahoma full throttle flattens out and there is mild popping from the intake and exhaust.
What I've done since Colorado to try and cure the issue to no avail is 1; replaced the plugs twice 2; swapped out the carbs 3 times with different jetting combos (pilots and mains) including a completely stock setup. Not just gone through them but 3 completely different sets, 3; Changed out the centrifugal advance assembly with a brand new NOS 79 unit. 4; Checked base timing and moved it both ways to test. 5; Replaced the coils with 81 3 ohm and eliminated the ballast resistor. This is suspect to me because it is the first thing (other than plugs) that I did and it seemed to help at first but the issue has become gradually worse since.
Yes Brant, I did check the voltages and they seem normal. 2/10 of a volt loss at the coils and TCI with all other fuses pulled.
I'm fixing to swap out the TCI and see if that makes a difference. I'll check pick up coil resistance at the box at the same time. If that doesn't work I'll try a different set of coils.
Anyone else been here before?
Ever since I've had this 2H7 engine in my bike I've had a small stumble just as the power kicked in, I'm sure some of you might remember me mentioning it on the site before. It has gotten MUCH worse over the last few weeks.
The first real problem I had was in Colorado at elevations over 8000Ft. At those altitudes I could not use full throttle, only 2/3 or 3/4, over that and the engine would just flatten out and start popping through the intake and exhaust. Less throttle and it was normal and below those altitudes it was normal.
Now 3 months later the stumble has become much longer but it will eventually push through it and it takes off. But, now even at near sea level here in Oklahoma full throttle flattens out and there is mild popping from the intake and exhaust.
What I've done since Colorado to try and cure the issue to no avail is 1; replaced the plugs twice 2; swapped out the carbs 3 times with different jetting combos (pilots and mains) including a completely stock setup. Not just gone through them but 3 completely different sets, 3; Changed out the centrifugal advance assembly with a brand new NOS 79 unit. 4; Checked base timing and moved it both ways to test. 5; Replaced the coils with 81 3 ohm and eliminated the ballast resistor. This is suspect to me because it is the first thing (other than plugs) that I did and it seemed to help at first but the issue has become gradually worse since.
Yes Brant, I did check the voltages and they seem normal. 2/10 of a volt loss at the coils and TCI with all other fuses pulled.
I'm fixing to swap out the TCI and see if that makes a difference. I'll check pick up coil resistance at the box at the same time. If that doesn't work I'll try a different set of coils.
Anyone else been here before?
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