thunder bolt

randy, pm you the pictures this weekend....:thumbsup:
Hi, we're getting our Thunderbolt up and running and I'm just basically following along with what you and Gumpit have done. Can you send me the decal pics as well? I'm going to cut some out on our vinyl plotter. I'll be sure to post the vector files here once I make them.



Well-Known Member
i did some more up grades to my thunderbolt over the summer and WOW what a big improvement.
first thing i wanted to do was install a 7inch driven so i could help gear the bike down some more and take more advantage of the cam/motor. way the bike was setup it was not taking full potential of the motor. gearing was holding the rpm's back.

here was the Big trick that i had to do. make the factory comet torque converter cover look stock over a 7 inch driven.
first i had to split open the cover to clear the 7inch and then adjust the metal mounting tabs. also use a small metal plate in front of the cover that i drilled into and also through the plastic cover to hold it in the correct position so i could fiberglass in the small voids.

came back and clean up the cover little and now it looks stock again......:thumbsup:

also took a blank aluminum 72 tooth #40 chain sprocket and bored a center hole, bolt pattern and also lighten it up by boring multiple holes.

you can see the different sprockets i had on the bike. first sprocket was a 54tt the second was 58tt and the custom 72tt

after i installed the 7inch and the 72tt sprocket i did notes a difference,but i was still experiencing a small lag when i was going into a corning and trying to accelerate. at that point i new i needed to make the motor rev better and not have the driver lockup. i install a set of white 3100 stall springs. Now the bike just rips out of the corners.
i did start to experience a small problem when the torque converter warms up. i seems like the unit likes to stick little and trys to pull the bike at idle. for some reason one of the springs looks to be damage. might be the problem. i really don't like the comet unit for high performance use. it still works good with the cast iron flywheel and i don't get any unwanted vibrations. cast iron does a good job observing any unwanted vibrations.
one other thing i did to the bike was move the carb behind the block. no reason really , just did it. i had the intake made for my drag bike and now that engine is all apart. so i threw it on...:scooter:
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Are thunderbolts rare?

not sure if they are rare. maybe little harder to find. for me they are easyer to find. i only live hour away from the place where they where made back in the day. so they do pop-up some times. I only enough to make three bikes...:rolleyes:

cdoublejj,are working on any tecumseh stuff lately. i haven't seen you post anything recent.


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here is a picture of the spring that i mentioned about being damage little.

i don't think thats what was causing it to hang up.
couple things didn't look right. the two flywheel assy's surfaces didn't look good.

and the surface of the shaft look little damage.

weird thing was all of it wasn't that old. end up cleaning the surfaces up with 180 grit and respraying it with comet spray.
works good now. just wondering maybe the flywheel weights needed little break in.
also not a big fan running alot power threw theses comet units and getting them hot.
i don't think that helps at all.
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just couple photo's of me drag racing for fun at event that dragracertpp took of me....:thumbsup:
for a bike thats kind of heavy and has just a mild built ohh-motor it seems to pull hard out of the hole.
need to invest in a good video camera someday. without a pictures or video it's kind of hard to believe some of the guys here when they say got my engine/bike running!..right..........sure you did.:rolleyes:

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