Just me and my GT500B

skids · Post by **skids** » Wed Apr 29, 2009 6:33 am

It's a 1977 GT500B, I also have a 1976 GT500A that I'm making into a cafe racer.

It's working really well (finally) but a little weak on the right hand side, after I get that gremlin sorted it'll all be shiny.

skids · Post by **skids** » Wed Apr 29, 2009 8:08 am

As you can see I've had issues with the right hand side before.

skids · Post by **skids** » Wed Apr 29, 2009 8:32 am

This is how it was when I bought it, as you can see it was in pretty good shape, especially compaired to my other GT500 which I found leaning against a friends barn. The previous owner had dropped it and decided to sell. I still have to pop a dent in the tank, but I wanted to get a chance to just ride it for a while before I did anymore to it.

First thing I did was dump the sissy bar and the luggage rack, then replaced the stock bars with a slightly lower set. I also drilled lower holes in the seat mount tabs and shaved the top off to get rid of the humped apearance of the seat that came with it. I also gave the carbs a quick clean.

During my first long test run I blew a hole in the right piston. So I sourced a new one and rebuilt the top end. I totally rebuilt the carbs, replaced the petcock and the fuel lines, cleaned the tank, added gas line filters, replaced the rear brakes, fixed all the short in the wiring, replaced the blown rectifier and the half dead battery, scrubbed the chain, replaced the clutch cable, cleaned out the pipes... oh and did I mention cleaned the hunks of piston out of the crank case?

rbond · Post by **rbond** » Wed Apr 29, 2009 2:25 pm

Hi, I have a GT500A. It still looks a little rough as the day I bought it, but it runs better. I plan on getting it to look good later, good running is comes first. I rebuilt the carbs, replaced most of the ignition coils on the stator and built a new CDI unit. Any way, you mentioned that you removed the luggage rack, are you going to re-use it or would you be interested in selling it. Mine broke (have fixed it somewhat), and am looking for a replacement. This is unquestionably the best place for info/ help on the web for these old bikes and a great bunch of people too!

skids · Post by **skids** » Thu Apr 30, 2009 5:50 pm

I never thought about selling it, I'll give it a thought.

It is one of the best places to get good info about two stroke Suzuki's, if it wasn't for this place, Muzza and some of the other guys, I don't know what I would have done over the years. They've really made it possible for me to rebuild and repair my bikes.

skids · Post by **skids** » Thu Apr 30, 2009 5:52 pm

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I finally got both sides firing properly

Life is good

rngdng · Post by **rngdng** » Thu Apr 30, 2009 9:49 pm

I finally got both sides firing properly Life is good

What was wrong?

Lane

Barry S. · Post by **Barry S.** » Fri May 01, 2009 6:51 am

Nice bike, I always loved the black B model Suzuki GT's, do you know why it holed the piston?

skids · Post by **skids** » Fri May 01, 2009 7:50 am

I took the right carb off again, disassembled it and soaked the crap out of it with varsol, then cleaned and blew it with air. I found some more crud I missed, then put it back together and very carefully adjusted them according to http://www.gt500.org.uk/manual.htm

When I first got the bike I should have thoroughly cleaned the entire fuel system, tank, petcock and carbs before I rode it. All I did was a quick clean of the carburetors, which is what I believe lead to the holed piston. Another contributing factor might have been the Honda coils and worn out HT leads that were on it. I replaced them with the Suzuki coils off my GT500A.

Just plain, I was too eager to ride.

rbond · Post by **rbond** » Fri May 01, 2009 10:43 am

I had replaced the ignition coil with a Dyna model for a Harley. It had the same resistance ratings as an OEM, but a lot cheaper. Have been running on this setup for almost two years, no problems on ignition......(fingers crossed)

skids · Post by **skids** » Sun May 10, 2009 7:23 am

For future reference, which Dyna coil did you use?

rbond · Post by **rbond** » Mon May 11, 2009 8:22 am

I am not sure which one now. It is green with two HT leads.It might be a DC7-1 or a DC1-1. I do know the resistance ratings were the same for an OEM coil for input and sparkplug side. I was able to build from scratch, a new CDI box with a design from board member Phil C in England. It cost $60.00 for parts, the coil was about $60.00 something, I think from Old Bike Barn.

skids · Post by **skids** » Mon May 11, 2009 10:24 am

Are the plans for the CDI box on here, or did you have to get them from Phil?

rbond · Post by **rbond** » Wed May 13, 2009 8:07 am

OK, the coils is a DC6-1 (green 3ohm) You could make a mounting bracket to use the factory frame mounts, or just zip tie it in place. The gas tank seems to also 'capture' it in place, so I don't think it would wiggle out of place. Phil, myself, and a Dutch website (wiring diagram) reversed engineered the CDI box. Phil provided the electronics brains to figure out the values of the parts needed and I assembled a unit using the connecting wires from a dead OEM box. I posted pictures of the prototype board in use, the pictures for some reason are VERY large. I then rebuilt it in a small plastic box, filled it liquid vinyl (for coating tool handles) for vibration and waterproofing. It has been working like this for over a year,no problems. Just as a backup, I was able to get a used OEM from rngdng. If mine blows, I switch wires and am running again. I need to scan in the schematic of the circuit and make a few adjustments, then I will post it here for everyone. It is so simple, it could probably be adapted to other bikes....?

rngdng · Post by **rngdng** » Wed May 13, 2009 5:33 pm

Yes, it could be adapted to almost any two-cylinder bike......like my RD350. I'll be happy to see the schematic.......

You can also use Honda (and other) CDI dual-output coils which are dirt-cheap.

Lane

Just me and my GT500B

Just me and my GT500B

GT500

coils

coil

coil and CDI