GT550 flywheel rotor keeps frying

All to do with wiring, charging or just trying to figure out whats gone wrong.

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NateGT550
Still in the Driveway
Posts: 2
Joined: Thu Oct 30, 2014 1:39 pm
Country: United States
Suzuki 2-Strokes: 1973 GT550

GT550 flywheel rotor keeps frying

Post by NateGT550 »

Hi,
Earlier this summer I bought a 1973 GT550. Barn find, 7,000 miles, had been sitting indoors for the past 30 years. Great compression, clean, (great petina) beautiful. My mechanic and I got rid of the points, and put on the Boyer Bransden (sp?) electronic ignition, got a new voltage regulator, and rectifier. After about 300 miles of riding, I fried my magneto rotor. I purchased one online that tested at 10.4 ohms, which I know is sufficient according to my Suzuki 3 cylinder 2-stroke manual. I popped the new rotor on and the bike was flying! Battery charging fine, running smoothly, and performing great. Again, after a week of riding, the day came where the performance was declining, and I noticed that the battery wasn't charging. I popped off the rotor, and it was fried. 0 ohms. Dead. I need to solve this problem before I purchase another rotor.. Any ideas?
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jabcb
Moto GP
Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: GT550 flywheel rotor keeps frying

Post by jabcb »

Suzuki had a problem with rotors on early GT550s with Nippon Denso alternators.
Check to see if this issue applies to your two rotors.

http://www.ozebook.com/compendium/techb ... mpress.pdf
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
NateGT550
Still in the Driveway
Posts: 2
Joined: Thu Oct 30, 2014 1:39 pm
Country: United States
Suzuki 2-Strokes: 1973 GT550

Re: GT550 flywheel rotor keeps frying

Post by NateGT550 »

Jabcb, I appreciate the help. I just put the bike in storage for the winter months here in Northern Michigan, and flying out tomorrow for the Miami sunshine.. This spring when I get the bike back out, I'll be sure to stay away from the ND rotors. Once again, Cheers.
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