197x BGW Tri-Rod STR-381 in progress

#1
Hey all,

I just wanted to share this pic I took of my two boys helping work on this old Tri-Rod I last weekend. I think it is a STR-381, but the motor was gone when I got it. The 212 is a temporary solution, as I would like to get it street-able for an in-town runabout/short commuter. I would like to make it electric start and in order to street it here, I need lights, so I have my eyes out for a better motor that I can add a CVT to. IMG_20190313_180531.jpg
 
#2
They are saying DAD when are you getting it done ?
I have done it 4 times the last one a Tri-Sport RTS 440 and I rode it on Portland, Oregon freeways but I had to get approved tires and it was covered with State Farm Insurance . But I got stupid and sold it.
 

Cuda54

Active Member
#3
Nice! Is the body metal flake and did you get the ski for it? I did mine is metal flake blue and it has the same shock set up. I have a 10hp electric start on mine with charging. How are you getting it street legal?
 

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Cuda54

Active Member
#4
Nice! Is the body metal flake and did you get the ski for it? I did mine is metal flake blue and it has the same shock set up. I have a 10hp electric start on mine with charging. How are you getting it street legal? Mine had the secondary on the jack shaft it had the wrong primary. So I bought a new clutch and secondary and belt too. I had thought about a snowmobile engine but did not want to mix the gas. I then saw a 18hp electric start and liked that better. I am putting in new brakes on it now. I should take more pictures of it as we do it and a picture of the ski too.
 

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#6
It's not done, per se, but it is rideable. I have the 212 Predator motor and a 30-series torque converter on it and have been tearing up the back yard with it. I can get it up to 33MPH as it is with the stock motor.

The next step is either a bigger/faster motor or upgrading the Predator 212 to get a top speed between 60 - 70mph. Given the current rear sprocket, I need to get the 212 up to 6500 RPM. I think a slightly larger motor with electric start will be the way to go, since I also want to add lights to make it road legal. Once the drive train is sorted, I'll make it pretty.
 
#7
Nice! Is the body metal flake and did you get the ski for it? I did mine is metal flake blue and it has the same shock set up. I have a 10hp electric start on mine with charging. How are you getting it street legal? Mine had the secondary on the jack shaft it had the wrong primary. So I bought a new clutch and secondary and belt too. I had thought about a snowmobile engine but did not want to mix the gas. I then saw a 18hp electric start and liked that better. I am putting in new brakes on it now. I should take more pictures of it as we do it and a picture of the ski too.
The body is a red metal flake, but it probably won't stay that way. There are a couple of big chunks out of the fiberglass and once those are patched, repainting the flake will probably be too costly for my budget. I'm also a pretty big guy (6'3") and I want to stretch the frame and the fiberglass about 8" to make it more comfortable.

I don't have the ski, but I've already started designing one that actually fits in place without taking the wheel off. I'm thinking about essentially building a support "cage" around the sides of the wheel with the tire sitting on the ski. Think a steel ski that is wide enough for the tire to sit on with two hinged struts on each side. One strut will attach to the axle and the second would attach to the trailing part of the fork. I think it will work, but I'm still working on the drive train and winter is over.

This picture is the previous version of the drive train. I tried to run a short chain between the jack shaft and the driven pulley. I never could get the two chains to line up properly so I have since eliminated the backplate on the TAV2 and put the driven pulley directly on the jack shaft and running a slightly longer belt. That seems to work perfectly.

As for the road legality, here in Indiana, according to the BMV branch manager here, I just need to add head/tail/brake lights and turn signals, and then get a police inspection in order to title it as a custom built motorcycle.
 

Cuda54

Active Member
#8
The stock jack shaft sides to adjust the chain if it is not straight it will jump. You will like it that way on the jack shaft to up grade to a bigger motor you just need the driver with the 1" bore. And I do not think a 212 will get to 60 I was going to put a 18hp electric start on mine and I was shooting for 70 to 75. I have a 10hp on now and looking for the right sprocket to see how fast it will go. Plus you will need to put different tires on too. They have 18.5 trailer tire that will fit perfectly and you might want to put on new brake bands. I was even looking to add a front brake too. That is my son in the picture he is 6'4" 370ld with the old setup he could spin the tires. I have a new primary and secondary and 2 new belts they do not have them local here. But I think you might need more motor I am 5'11" and close to 280ld and I would like to get mine street legal in Iowa. I will have to dig he ski out and add a picture with it on to my rides. It is not that hard to repaint the metal flake use a two part clear coat mix in the metal flake. Use a big nozzle gun with some marbles or nut inside the paint cup to help keep the flake mixed up. Then just add more clear coat to get the shine you want. The more you put on the more you can buff it out.
 
#9
A 212 will not do 60MPH with the governor on it, but with the governor removed and a billet cam, flywheel, and rod, it will get pretty close. I'm not sure it is worth the money though. Given the 20" tire diameter and the gearing I have, the motor needs to turn around 6000-6500 RPM to hit 60MPH. Tillotson just came out with a 10HP 212cc race engine for about $250 that has electric start and 10k RPM flywheel out of the box. I'm thinking about using one of those.
 

Cuda54

Active Member
#12
Mine has a tire and rim more like a trailer tire. But I did get the ski for the front that is cool looking. And it works great on sidewalks and the street too.
 
#15
i really like the front tire. did it come on the bike or did you add it. mine has a much smaller , wider wheel
It was on there when I got it, but I don't think it is original. These did not originally have front brakes, just two rear brakes. I think that front wheel is off of a small dirt bike or scooter. It has the speedometer sending unit and a drum brake in it.
 
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