Twist-Throttle.com

Just putting up some pics of the GS750, now that it’s back on the road… this is how it looks currently.

My '77 Suzuki GS750 back on the road

She's ready to go...

Notice my one bar-end mirror

Side view of bike

Those rear turn-signals are huge!!

The front turn-signals aren't nearly as offensive

Well it’s finally happened, I finally have my GS750 on the road! It seems to be running pretty decent to. Of course it could use some more “tuning”, but it’s not to bad.

Last night I finished installing my 2 new throttle cables, the night before that I installed the carbs and the airbox. It took me a little bit to get the throttle to work smoothly last night, it kept sticking & it would not return on it’s own. But in the end last night, I got it freed up & adjusted it the best that I could at that time.

So tonight, after getting my Ignition switch back from my co-worker friend… who repaired the broken connector… I installed the gauges, hooked the wires back up & installed the headlight. After adding some 4-stroke lawnmower gas, bam!, the motor fired up pretty quick, it only took a few revolutions. Actually though, it sure fired up… revving around 4,500 RPMs & holding. I shut the motor down & looked into the culprit. In the end, I ended up putting my one good OEM Throttle Cable backs on the bike. The new aftermarket cable that actually pulls & opens the throttle, well I never was able to get it adjusted to were it had enough slack to let the bike idle down. The new aftermarket throttle cable did seem to be a little longer in length then the OEM throttle cable.

So now that the bike will idle at a decent RPM… well let me repeat that… now my bike will idle. That was my whole problem last fall when I tore into the carbs. Back then, my GS would not idle on its own. So after all my messing around & waiting to get my Idle Adjuster fixed, now that the Idle Adjuster is fixed, my GS will idle on it’s own. This is a big step in getting the bike back on the road & to being a decent commuter bike.

The motor seemed to be running a touch rough, I wasn’t 100% sure that it was running on all 4 cylinders… so I pulled all 4 plugs one at a time, & verified if I saw spark… which I did… I also shocked myself 3 out of the 4 times when holding the spark plugs to the cylinder head looking for that spark (doesn’t that indicate either that I don’t have a wire grounded somewhere, or that my spark plug wires/boots need to be replaced?). So now that I verified that it has spark for all 4 cylinders… I accepted that it was running a little rough, the bike has been sitting for so long, plus my jetting is likely to be off a little & my carbs likely needed to be sync’d as well.

Well the next obvious thing to do was to put some more air in the tires & take the old bike out on the road.

“She’s a runner” I thought to myself as I’m cruising around my neighborhood. It seems to be running ok. It has decent enough torque & actually pulls ok from 4,500RPM - 7,500RPM’s (redline is 9,000 I believe). Of course I didn’t “get on it” right away. Boy, does this thing feel totally different then the ‘08 GSXR600 that I’ve been riding for the last 2 weeks! Everything is different about it; seating position, all controls feel very different then the new GSXR, it has an old feeling to it, it shakes & vibrates more, the brakes work… but surely not very well. But I must say, it was fun to ride it & that it for sure has it’s own character. With it being so old, that makes it cooler, I did notice a few guys & girls definitely watching me ride past.

After riding the GS for a while, I did jump back on the GSXR, now that felt different to me, instead of back to “normal”. I can see that jumping back & forth between bikes will likely need time to get re-acclimated with whatever bike I’m riding at that time… to give it a few minutes of riding to let my brain come to grips with that particular bike.

So yea… I did get the bike up to 65MPH, it seemed just fine at that speed, I do suspect that the brakes will improve a little when the new pads bed into the rotors & that I will look into “dialing in” my carbs better in time… plus just putting some miles on the bike might improve how it runs by itself. I still feel that the GS is a very easy bike to ride & that it would make a great beginner bike, plus it’s way more comfortable then a new sportbike. Oh, and to adjust the Idle Adjuster after you’ve been riding the bike… that thing is a bitch to reach in-between the tank, carbs & the airbox. I tried when stopped, not sure if it’s even possible while riding?

Where from here? Well my wife Brandy, a few days ago, she just received her motorcycle license… so we’ll be battling over who rides which bike of the two… we’ll have to alternate of course. For the GS itself, of course I plan to continue improving it, getting it to run better & stronger, plus to continue improving the looks & condition of it… each year it will only be a cooler bike as it gets older & older. So this is far from the end of The GS Project, it is just the beginning of the next chapter.

Well last night I pulled my GS carbs off of the rack that holds the 4 carbs together, then did the same to my eBay KZ650 carbs… swapping out the racks. So in the end, I now have the KZ rack on my GS carbs. These two sets of carbs do use the same rack, so it was a direct swap. What this did for me was that my busted Idle Adjuster is all attached to the rack… so now the working Idle Adjuster from the KZ carbs is on my GS carbs & I finally have a working Idle Adjuster on my GS carbs.

After I completed the transplant, I went through & swapped out a few fasteners from the GS carbs that were in rough shape, and exchanged them from the non-rusty set of fasteners from the KZ carbs.

I do like the Kawasaki KZ Idle Adjuster better because the Suzuki GS adjuster has a plastic knob on the end, while the KZ’s is all 1-piece metal. This seems like it will be much more durable to me.

This was all pretty straight forward stuff, kind of like a building model as a kid… just disassemble what is needed & reinstall the other equal items. Here is a great set of pdf instructions that I had at my side during this process http://thegsresources.com/files/vm_carb_rebuild.pdf

First I removed the 8 countersunk fasteners on the back of the rack, this is partially what holds the carbs to the rack. Next, I needed to remove the shaft that all 4 carbs hold onto at the top of them. This shaft also is what the throttle linkage grabs a hold of to pull the slides up when you turn the throttle.

After I removed the shaft from all 4 carbs, now the rack is free to be pulled off of the 4 carbs. In this scenario, I was careful not to separate the four carbs from each other, with the rack removed, I believe all that is lightly holding them together is the plastic & rubber fuel lines that go in-between each of them. No harm if they did separate, I just avoided taking the step to put them back together.

Next, I cleaned up my donor rack from the KZ carbs & simple placed it onto my GS carbs, since the rack is the identical Mikuni part #, it just bolted right on. Doing this gives me my working Idle Adjuster since this came along with the transplant as already attached to the KZ rack.

Then I just reversed my steps from un-assemble of the parts. Once the GS carbs were put back together, I did a mechanical sync of the slides… making sure that they both closed & opened the same amount. This is done with the adjuster on the top of each slide. Once that was done, then I installed the 4 carb tops, re-assembled my old rack onto the KZ carbs & now I have my working GS carbs finally!!! I know that I have not explained every step to what I did, but it is all explained in better detail in the pdf link that I listed above.

There were 2 difference that I spotted between the parts that I exchanged. First was the Choke mechanism. On the ‘78 KZ, the arms that actually rotate up & down, that lift the choke plungers up & down… they had a little different shape to them. I do not know if this comes from a Mikuni change in ‘78 from ‘77, or if it is a Kawi Suz difference. Second was on the KZ, where both ends of the Throttle Return Spring attaches, the KZ has a rubber condom over the metal… so that both ends of the springs were attaching to rubber, instead of metal. I guess I’m going to presume that this is a nicer feature that Kawi added, over the basic metal set-up that the Suz has.

I know that there will still need some jetting changes most likely, plus vacuum syncing & possibly more adjustments. Tonight, I hope to install my updated GS carbs onto the GS. At this point, I still do not have my electrical problem resolved, so even if I do complete the carb install tonight, the bike will not even turn over until my Ignition Switch is fixed… which hopefully will only be another day or two.

I’m really excited, yesterday I received my used carbs that I won on eBay. My carbs on my GS 750 have been sitting with a busted Idle Adjuster since I bought the bike.

when I tried to ride the bike that one day last fall, the bike wouldn’t idle, that is when I figured out that I could not adjust the idle on the bike. Since later this spring, my carbs have been at my co-worker friend’s house, while he tries to get the adjuster fixed. He ended up finding out that the threads for the adjuster are a very unique thread, one that he hasn’t been able to find a tap for… since I did buy a Idle Adjuster that was in nice shape from a different co-worker. I just needed the bad adjuster removed & the threads cleaned up.

Well it’s been a long time, so I finally started looking at carbs on eBay to either replace my carbs or to take parts from them & just repair my carbs.

My co-worker friend confirmed that this cheap set of ‘78 Kawasaki KZ 650 carbs uses the same Rack & Idle Adjuster as the carbs on my ‘77 Suzuki GS 750. So yea, now it’s just a matter of replacing the parts that need to be fixed on my GS carbs, getting them sync’d & hopefully firing the bike up for a test ride, finally.

With any luck, in a few days I’ll be posting about my test ride of the GS.

This weekend will hopefully have been a big turning point in getting my GS back on the road. Yesterday I road up to a nearby cycle salvage & was able to buy a used Ignition Switch from a ‘77 Suzuki GS 550. This used switch should be what I need to get my electrical problem resolved.

Actually, my co-worker friend will most likely be the one who repairs my busted connector on my bike. He said that he can just repair the square plastic connector, instead of replacing the entire switch… which I hope to use my original switch, so that my key doesn’t change.

Here are some pics of the used Ignition Switch that I just picked up.

Well Brandy & I just bought a 2nd bike. But it is not exactly like the ‘77 Suzuki GS750 that I’ve been working on. I’m really excited about the new bike, but for sure, the GS Project is still moving forward & I hope within about 2 weeks to have the GS on the road along side the new bike (Currently, I have some carbs & gauges being shipped that will be used to repair my final known issues with the GS).
Actually, Brandy is taking her motorcycle safety class in one week, so then she will have her cycle license & will be riding by herself, instead of passenger. Let the fighting over the bike begin !!

So yes, the new bike, kind of a impulse, but also we’ve been talking about this for a few years, I’ve been doing some casual research for a couple of months, she calls up the bank, tells me what time to show up to sign & all of a sudden we own another bike. You gotta dig a wife that is pushing the purchase of toys

Our new bike is a 2008 Suzuki GSX-R 600. Really, the ‘77 GS750 is the foundation of where the GSX-R’s came from, so it does all tie into the same family, I suppose if we had gotten GSX-R 750, that would of have been even cooler next to our GS750… but o’well close enough. The 600 is still possibly more bike then a beginner should even start with. I hope to start Brandy off on the GS for awhile, but I know that isn’t going to last long, she already wants to ride the GSX-R in a parking lot, the parking lot because she doesn’t have her license yet. I also have to add, that I am nervous about her riding alone… not so much because of her, but the other people on the road.

Well enough babble about the GSX-R…