82 GS1100E Mr Turbo Rebuild

[oldGSfan]

I'm far from an expert but sharing what I read up on. The original carb with the Mr Turbo or American Turbo Pak (it's confusing) kits was a late 70's HD Keihin 38mm which seems to be universally hated by HD folks, FWIW. The guy that raced mine used a S&S Super B for Bonneville, and I read they are good for all out open throttle but not so street friendly. All signs pointed me to the Mikuni HSR (42 in my case) so I got one since both the Keihin and S&S needed rebuilding and didn't look so good overall with stuck butterfly and hacked up or missing choke, etc. Right now may be too early to judge but it's idling fine and starts right up with a couple twists for the accelerator pump and a bit of choke when cold.

I think the Rajay is a robust turbo but now there are better choices. Plus there is the draw through vs. blow through choice. Gaskets and rebuilding are scarce and expensive. I read that it is slow to spool and will come on with a major bang. Will see. I am too old to go nuts on a turbo bike, it's just a cool thing to have and restore, ride here and there.

I am fascinated with building a turbo setup like the Mr. Turbo kits. I can select a turbo and build all of the parts. The part I know nothing about is the carburetor. What carburetor does this kit use, and does it work well for a street ridden bike that doesn't get whooped on a lot?

[chris]

That seat is a good score. Mine split in the same spot.Two things I never do are body paint and upholstery except dirt bikes that's because everyone will know I did it myself. So I vote professional upholster.

[Rob S.]

So I vote professional upholster.

I concur. Mine was reupholstered, I'm sure, but looks exactly like all the pics I've ever seen from 1982.

[oldGSfan]

Edit/update: Took to a local upholsterer and he said the material is too thin, it will tear again etc. Pretty ornery sort of dude, I appreciated his honesty but he just kept saying the same stuff over and over, and I heard him the first time.

Yeah I will have it done, it's too good to leave to a hack like me. I got it today, it's really good other than that split, like new, made my day opening that box.

That seat is a good score. Mine split in the same spot.Two things I never do are body paint and upholstery except dirt bikes that's because everyone will know I did it myself. So I vote professional upholster.

[Longitudinal]

I'm far from an expert but sharing what I read up on.

Thank you. What have you learned to be the maximum power that can be squeezed from that carb? I would like to build a turbo GS one day, and think around 120-130HP would be more than enough. I'm not trying to threadjack.

[oldGSfan]

Read the posts by Rajay on this link, they are very informative on the HSR and draw-through overall. The numbers are more than double what you are after so the HSR42 is fine. There is a wide variety of main jets. Also this YouTube video of a '74 Z1 with the same setup putting out 120HP is a good watch.

Thank you. What have you learned to be the maximum power that can be squeezed from that carb? I would like to build a turbo GS one day, and think around 120-130HP would be more than enough. I'm not trying to threadjack.

[Longitudinal]

Read the posts by Rajay on this link, they are very informative on the HSR and draw-through overall. The numbers are more than double what you are after so the HSR42 is fine. There is a wide variety of main jets. Also this YouTube video of a '74 Z1 with the same setup putting out 120HP is a good watch.

Thank you very much. I have started a new thread so as not to clutter yours needlessly.

[oldGSfan]

Bike done. 183 HP on the dyno, not sure the boost he was using yet. I told him to go easy . Going to pick it up today, am so amped up to ride it - I better settle down....

[bull958]

Turn it up, don't be a pussy. 183 is hardly enough to get into trouble with. LOL

[steve murdoch]

Bike done. 183 HP on the dyno, not sure the boost he was using yet. I told him to go easy . Going to pick it up today, am so amped up to ride it - I better settle down....

A hundred or so extra hp from stock? Fantastic!

[oldGSfan]

Yeah at least, this is at the wheel not crank, guy said probably has 80 HP at wheel stock. He said it was extremely well built and has hot cams so it idles lumpy at about 1500 RPM (13.5 air-fuel ratio), and he had it up to 11K on a couple runs as there's no rev limiter. There are no charging issues, it was due to not having resistor on plug. 80MPH in 3rd gear is monster wheelie time. I have a couple things to fix, the front springs should be replaced but I may try a spacer just to see how it works. The petcock leaks at the bolts, but I have new sealing washers. The centerstand is coming off, it rubs the chain as there's no stop, and it's too short anyway. Little stuff I can do in a day or two before riding. Here is one of the runs.

A hundred or so extra hp from stock? Fantastic!

[dorkburger]

So cool. .

[steve murdoch]

It will be interesting to know what level the boost was for the recorded runs.
A couple weeks from now when you are bored with the 183 hp you will need to know how much to turn it up. haha.

[93Bandit]

Awesome! It's nice to finally hear some numbers. I'm curious how well mannered it is on the street?

[Longitudinal]

I'm curious how well mannered it is on the street?

So am I! I would also love to know what the jetting is on the carb.