My 1981 GS650G Thread

[Macguyver]

Intake Boot Vacuum Taps

Now I know everyone should do a vacuum sync on their carbs to get our machines to run their best, and me being without a vacuum gauge set, or a manometer, I decided to build one.

Step one in the project is to make the vacuum taps for the carb boots, so I picked up some m5x.8 bolts from the local stealership, and spent some time in front of my favorite tool, my drill press.

In preparation of drilling the center out of the bolts, I first drilled a hole in a piece of 3/4 aluminum plate I had left over from another project, and bevelled the upper edge of the hole so the bolts could thread completely into the hole without binding.

Next I threaded the hole with an m5x.8 tap. Care must be taken when threading holes, make sure you start the tap straight in the hole, or at least have it straight by the end of the first thread cut.

I then threaded in a bolt, and centered the jig on my drill press table, and drilled a small 1/16" hole through the center of the bolt.

The next thing to do is to drill out the allen head indent in the bolt so that I could secure some 3/16" steel brake line in the hole with epoxy.

All done, now I just need some matching diameter hose, and some vacuum gauges, along with a manifold I need to make yet, and I will be able to vacuum sync my carbs whenever I need to.

Overall I would rate this as a moderate skill level job, one must be familiar with the setup and safe operation of a drill press.

If undertaking this project, make sure you are prepared for it. (read: buy a few high quality drill bits, and have some aluminum handy, and a high strength magnet near by for when a drill bit snaps on you and you need to tap the bolt head on a hard surface with the magnet over the hole to pull the shavings and drill fragments out)

I went through 2 drill bits doing this, but I made 8 bolts. The bits broke when drilling through harder chunks of metal inside the center of the bolts.

If the bit sounds like it is making a clicking noise in the bolt, congrats, you've found a bit of metal in the bolt shaft that has more carbon in it than the surrounding metal, thus making it a harder metal, and likely to snap the small bit if not drilled very carefully.

As always, proper safety precautions should be followed including safety glasses and keep loose articles of clothing away from the drill/chuck assembly.

I will update with more pics once my gauges show up and I finish building the gauge set.

[Charlie G]

I am going to try and make it to a rally or two this year, depends on finances. Maybe I should see if there is any interest in having an Ontario rally. First thing to do would be to find a nice long stretch of some twisties. Unfotunately, there really isn't much in my area for twisties. Maybe a rally 'round Algonquin National Park would work? Beautiful area, lots of camping, and it's around 480km's (300 mi) to do a circuit of the park. Sounds like a good long weekend run to me. Unfortunately, it takes around 3-4 hours to get there from here!

Would be a hellacool ride though!

Hi Mac,

I was up in your area 6 years ago visiting my niece in Port Elgin. She's allways bugging me to come and stay at their place for a vacation. The wife sujested I rent a motorcycle and tour the area the next time they twist my arm to come up. Like you said in your post it seamed pretty flat and straight in your area. I may consider the Algonquin N.P. run. Thanks for the idea.

cg

[Macguyver]

Hi Mac,

I was up in your area 6 years ago visiting my niece in Port Elgin. She's allways bugging me to come and stay at their place for a vacation. The wife sujested I rent a motorcycle and tour the area the next time they twist my arm to come up. Like you said in your post it seamed pretty flat and straight in your area. I may consider the Algonquin N.P. run. Thanks for the idea.

cg

No Problem Charlie,
Here's a link to a route suggestion from motowhere.com, quite a bit longer than I originally estimated though. It's do-able in a day, but may be worthwhile to seperate it into two days ride and drag the wife along for a great scenic ride!

http://www.motowhere.com/maps/route/Ride-around-Algonquin-Park

I am still kicking around the idea of setting up a rally run for the summer, we'll see what kind of interest there is. Anyone interested can PM me and we'll see when would work for everyone who would like to attend. I am thinking possibly some time late spring/early summer. If there is enough interest I will crunch some numbers and figure out the details. Any tips/suggestions welcome!

[2BRacing]

Now I know everyone should do a vacuum sync on their carbs to get our machines to run their best, and me being without a vacuum gauge set, or a manometer, I decided to build one.

I will update with more pics once my gauges show up and I finish building the gauge set.

Here is a picture of the vacuum gauge set I built up 35 years ago. It is still going strong today! I bought 4 "identical" vacuum gauges and mounted them on a piece of aluminium plate bent 90°. The gauge supplier also supplied 4 small brass "snubbers" - threaded brass fitting with a hole approximately the size of a pin (or even smaller) through it - to dampen out the oscillations of the needle. These screwed into the gauge fitting. A barbed hose connector for the hose finished the setup.

I found negligible variation between the gauges, as tested by fitting each one in turn to the same cylinder. As the gauges do not have any means of individual calibration, that was one less problem to take care of.

During use, the needles do not oscillate or "pulse" at all, and the gauges are sensitive enough to react to small adjustments at the carbs.

Good luck with your project and looking forward to see pics!

[Macguyver]

The gauge supplier also supplied 4 small brass "snubbers" - threaded brass fitting with a hole approximately the size of a pin (or even smaller) through it - to dampen out the oscillations of the needle. These screwed into the gauge fitting.

That is just the piece of info I have been looking for, wether or not a pin sized hole would help take the bounce out of the gauges. You Sir, just made my project goal much more attainable! I can punch a pin through some copper burst discs from paintball HPA tanks that will fit between the gauges and the barb ends.

Thank you for the info, now as soon as my gauges show up I can proceed with fabrication.
As always, pics will be forthcoming!

[Suzuki_Don]

Thanks MAC. This is a great thread. I will be doing this as a future project as well when I get around to synch. my carbs. So I am following this thread closely.

[Macguyver]

Thanks MAC. This is a great thread. I will be doing this as a future project as well when I get around to synch. my carbs. So I am following this thread closely.

Thanks for saying so Don,
I will make sure when I do the write-up to include each step and any tips/things to be aware of.

[Macguyver]

Accessory Gauges Bracket

Since I am paranoid about power on my GS, I decided to add in a couple gauges which I think should have been stock, or at least available as an option, a voltmeter and an ammeter. In order to do this though, I needed to figure out a place to put them, and since I am unsure what I want to do with the stock gauges, I decided to build an accessory gauge bracket to mount above the handle bar clamp.

I started by tracing out the stock upper clamp half and the bracket that came with the gauges on a piece of cardboard. I then scanned it and mirrored the outline in photoshop to create the full outline needed.

Next I printed out the outline and cut it down to size to affix it on a piece of 1/8" aluminum sheet with some 3M spray mount.

Once mounted, I center punched the holes and sat down for a drill press session and made the necessary holes, then rough cut the shape with the bandsaw.

I then cleaned up the piece with a flat file and a sanding cylinder to get the final shape, and finished it off by cleaning the surface with some adhesive remover and a 3M sanding sponge.

I still need to paint the bezel on the ammeter gauge to match the look of the stock gauges, but that will happen when I paint the bracket and bolts. I think it looks pretty good, and as an added bonus, there is still a healthy clearance between the tank and the gauges at full lock, and the key has plenty of room as well!

I will update with more pics once everything is painted and installed. By then I will hopefully have made my mind up on how many headlights I want up front, and have it/them mounted, as well as have the signal stalk spacers cut down to act as a mount for the electrical bucket, and then tackle the rest of the electrical.

[Suzuki_Don]

Thanks for saying so Don,
I will make sure when I do the write-up to include each step and any tips/things to be aware of.

That would be great. Thanks MAC

[Macguyver]

Gauge Hardware

It happened again, "while I was in there" painting the new accessory gauge mount I made, I decided to freshen up the factory gauge mounting hardware, handlebar clamp, and a few other bits and pieces with a fresh coat of paint. Well, these pieces received my usual treatment of brass wire wheel clean-up, etch prime, gloss black, then flat black to make a satin finish. Then they were baked for 45 minutes at 250 degrees, then allowed to cool over-night to really cement the finish on them. 250 may have been a little warm, they were "steaming" pretty good once they got up to temp.

I think they turned out nice and will compliment the rest of the details nicely. Tonight I plan on giving the top of the triple a similar treatment, and then bolting everything together providing I have a couple LED gauge bulb replacements fabricated by then.

I will also give the factory gauges themselves a good clean and likely polish the plastics up a bit with some orange pledge to return the factory lustre to them. Mind you, I may find a few more things to clean up while I am at it, but that's what the plan is so far.

[low80]

Pretty cool, any pics of the whole bike? I am anxious to see what the projector looks like on it.

[Macguyver]

Pretty cool, any pics of the whole bike? I am anxious to see what the projector looks like on it.

No full pics of the bike yet, the projector is likely going in this weekend when I can get a good stretch of time to futz with the mounts and the front signals.

I will do a BIG update when that gets done since it means I will have a bunch of the other stuff done around the same time. The next couple of weeks should be pretty exciting, a bunch of misc. parts just came in today, so I can get at some of the stuff I have had to put off.

I will update with pics when I can.

[Skateguy50]

You make me feel lazy, I have a few things I need to do to get my 650 on the road this season and so far done none of them.

[1_v8_merc]

yea me too, i also have several things to get ready for this summer....i've done a lot of them, but it seems like every time I fix 1 thing, 2 more problems pop up!

Im just paranoid about getting every single thing 100% fixed and perfect.
But I realized that'll never happen unless I do a complete restoration,.

That's what's fun about these old bikes though, there's always little tricks to get them to start or run correctly, and they are all unique to their riders.

As long as the thing starts up and goes, everything else is easy in comparison i guess.....

[Macguyver]

You make me feel lazy, I have a few things I need to do to get my 650 on the road this season and so far done none of them.

You shouldn't feel that way, under the proper circumstances, I am like the Ferrarri of lazyness. I either have to work on the bike, or go crazy from cabin fever. Not a hard decision.

I promised myself I would have the bike all modded and safetied for spring since I didn't really do much last year other than the paint job, shocks, carb clean and get some ammo tins mounted.

Besides, this year I want to legally ride it!