Jetting

So not much to report - I've put a few miles on the bike and been playing with the jetting some more. The main jet I installed at first - 117.5 - seems a bit fat, actually, but the midrange is kinda lean.

I don't want to spend much time with it because I plan to either install K&N "pod" filters or swap a set of VM29 smoothbores onto the motor. Either approach will require some serious jet swapping, so I don't plan to spend a lot of time on this interim setup. I managed to brown the ends of the header pipes while I was tweaking the mixture screws, of course, but most of the color polished out. I've heard it's an inevitable process with aftermarket pipes.

In the meantime, I was annoyed by the top end rattle that I hoped was an exhaust leak. It wasn't. I pulled the valve cover off yet again and measured all of the clearances - I swapped around the shims some more to get them all on the tight side. The clatter seems to have gone away, but I have yet to ride the bike any distance. Hopefully the noise was just a sloppy valve adjustment on my part.

If not, I'm not sure the valve cover gasket will survive another removal, but we'll see, won't we?

Exhaust Time

From the first day I dragged this bike home I dreamed of having an aftermarket exhaust. I just love the way a '70s bike looks with a 4:1 header and megga. While I had hopes of finding a vintage Bassani or Yoshimura pipe, I wasn't able to find a good one for a reasonable price. The occasional Kerker came up, but usually the cheaper one - not the performance-oriented "K-line" header.

Jardine recently stopped making their exhaust, leaving Mac and Vance & Hines the only existing manufacturers of exhausts for the old Suzuki. Mac leaves a lot to be desired in finish and overall quality, so V&H it was for me. Free shipping and a serious discount didn't hurt.

The pipe went on easy and fit well - I used more fancy stainless hardware with plenty of anti-seize. It took about 50 pounds of real weight off the bike, but about 1000 pounds of visual weight. Of course since I didn't buy new exhaust gaskets it leaked a little around one of the flanges - nothing another $10 won't solve.

With new gaskets, it ran great and sounded really good. The stock exhaust was pathetically silent. I screwed the fuel screws out 1/2 a turn (to 1 1/2 out) and the air screws out 1/2 turn to get the idle back into range. It was a little lean at first so I went with V&H's recommendations, replaced the jets with 117.5s and pulled the lid off the airbox. It seems OK, maybe a little lean still but it's hard to tell. I don't plan to spend much time getting the jetting tuned in since it's easier to just get pod filters and a Dynojet kit. Or get some VM29 smoothbores.

New Parts Stash!

Last week I was browsing for motorcycle stuff in the Recycler and I found an ad that read "Suzuki GS1000 Wiseco Pistons, $225, other parts too". I called, and the seller was in Santa Clarita, so I took a trip up there on Saturday. He was a cool guy, and had a lot more stuff than was in the ad, including a set of clean carbs, mirrors, GS1100 aluminum swingarm, GS1100G cylinders and head, the Wiseco Pistons w/Cometic head gasket, and most importantly, an NOS front fender!

I laid down $260 and walked away with the whole pile. Some of this stuff I'll sell on eBay since I don't need it, but the Wiseco Pistons and GS1100G head will eventually find their way onto this motor. He had an amazing GS1000E of his own - bought in the 80s from the original owner who modified it with period parts. I didn't get any pictures, but it has a strengthened frame, 1100cc kit, cams, 33mm smoothbores, Kerker pipe, powder coated GS1100 swingarm, CB750F front fender and a bunch more amazing period mods. A beautilful and fast bike!

The NOS fender went straight on as soon as I got home. Wow, it really makes the front end of the bike look classy! Check back for more as I consider a new engine build to make use of the Wisecos.

Finally Coming Together

With the petcock finished and the engine side covers polished, there isn't much left to do but ride this thing. I gave it a quick once-over, checked the air pressure and hit the road.

I visited a friend from the GS Resources to synchronize the carburetors. Thanks Ed! ON the road the new regulator works great - 13.8v at idle with the lights on, and a fully charged battery after 200 miles and sitting around all weekend.

With the carbs synced, the bike runs really well although I do notice the odd backfire and stumble. I may pull the carbs again soon to check them over, but only after I put some more miles on the bike to make sure it's not just "clearing it's throat". I'll also adjust the idle mixture screws a little too.

Other than that it's running perfectly. Being the perfectionist that I am, I might still play with a couple of small details. I don't have to, but I'd like to tweak the front suspension to perfection. I'm getting 65mm of front sag, which is about 30mm too many. And I'd like to maybe remove the passenger grab handle and plug the holes, but I haven't decided yet. In addition, the clutch cover seems to be oozing oil, but it's hard to tell because of the small amount.

Charging System

The bike seemed to charge OK, but the lights were dim at idle. They brightened up with a rev, which made be think that the stator and regulator were doing their job but the battery was weak.

At idle voltage was just 12 volts, but above 5,000 it climbed lethargically to 13.8. Within specs, but not very impressive. After a few days of charging the battery wouldn't give more than 12.2 volts, which is pretty low.

These bikes are known for having weak charging systems, though, so I wanted to head such problems off before they appear in the future, without spending a fortune. Since it was down for the engine work, I figured I'd do a little creative re-wiring.

The problems are many, but they come down to a marginal-sized stator, over-use (mis-use?) of bullet connectors, one stator phase (of three) that's completely unregulated and a regulator that's not efficiently grounded to the battery.

I formulated a plan to upgrade the weak spots of the stock system:

- Marginal stator: This I couldn't do much about - I measured the resistance of the stock one and it seemed fine. Looked fine too, when I pulled off the cover.

- Sub-optimal bullet connectors: I replaced all connectors with 1/4-inch spade terminals

- One unregulated stator phase: I replaced the separate rectifier and 2-phase regulator with a modern unit (from a Honda CBR929rr) that will control all three phases instead of just two. I wired the third phase directly to the regulator instead of through the lighting switch (and a bunch of bullet connectors).

- Poor rectifier/regulator wiring and design: I wired the regulator directly to battery instead of through the harness. The GS originally has a separate rectifier and regulator, which just adds resistance to the circuit. The 929 combined rectifier/regulator had two positive and two negative outputs - I ran one positive and one negative directly to the battery. The second positive went to the wiring harness like the stock regulator and the second negative was grounded to the starter solenoid along with the harness negative wire.

I took the opportunity to do some more cleaning of the battery box area. I also removed and painted the electrical panel for more bling. And finally, I replaced the weak battery with a nice new 12N14 battery from Wal Mart.

Now, even though the new regulator is about double the size of the old one, you can't tell. Looks good, doesn't it?

That should cure my electrical and charging problems for the forseeable future...

Clutch Rattle

With the covers off, I had access to the clutch. I removed the springs, spring bolts and plates and found the source of my noise - a loose clutch nut. The reason for the loose nut was very clear - the stock setup uses a large lock washer under the nut that is then bent up to lock it in place. The problem with this is that the lock washer is made from soft steel so that it can be bent up. The initial torque of the big nut plus the constant shock of power transfer through the clutch eventually crushes the soft washer until it releases the tension in the tightened shaft. It's a common problem with this kind of arrangement.

After a while of floating free, the shaft splines beat up the aluminum splines in the clutch hub and it gets even more loose. The ultimate solution is getting rid of the lock washer and using a billet clutch nut with red loctite and a brand new clutch hub. I don't have a billet clutch nut or new hub, but I do have red locktite which will hopefully solve the problem. There are available, but I'll see if this works first. It's easy enough to get at the clutch by putting the bike over on it's sidestand, so I'm not too concerned about re-doing it.

I gave the steels and fiber plates a quick measurement to make sure they are OK, and they're within specs. I thought I felt a little clutch slip on one of my rides, so the springs might be getting weak - I'll change them later if it returns. The springs in the clutch were loose and rattly, but just tightening down the hub should cure the worst of the noise.

I knocked the new seal and sight glass into my freshly-polished clutch cover and got ready to bolt it on with new allen bolts. I also changed the oil yet again, and replaced the oil filter and it's o-ring.

Looking good!

Engine Cover refinishing

I removed the clutch actuating shaft, bearing and seal from the clutch housing and knocked out the sight glass. The glass was nice, but I didn't think it (or its rubber seal) would survive the polishing process.

The stator came out with a good hit from the impact driver - the screws showed signs of being replaced before, so maybe this isn't the original stator. I stripped off the remaining factory clearcoat from all three covers to make the polishing easier, and I carefully removed the black circular emblem from the stator cover.

As for the cover refinishing, I'll admit I cheated. While I'd like to say that I spent two days polishing the covers by hand, I can't. I took them to a polishing shop near my work and gave the guy $60. I figure that's a small price to pay for the hours and hours I would spend sanding and polishing if I did it myself. He didn't do the best job on them, but good enough for a rider.

I placed a new order for sidecover gaskets, a starter cover, sight glass, clutch shaft seal, and I scoured ebay for some cam caps that are nicer than my pitted originals. I also ordered a set of stainless allen bolts for all the covers from eBay. Many of the stock Suzuki bolts were rusty and corroded, and some were stripped out from previous attempts at removal. My experience has been that OEM Japanese screws are horribly soft and strip when looked at with a screwdriver.

Allen bolts may not be perfect, but they work really well for low-torque applications like the valve cover and engine case covers. I already had stainless intake bolts from my oring kit, but now I had them for the rest of the motor. At $35 they're not too expensive, either.

Now to tackle that clutch...

Valve Adjustment

Before I yanked off the valve cover and started working inside the engine to replace the tach drive parts I pulled the spark plugs and tested the compression. If it was still low I'd be doing a top end rebuild instead of a valve adjustment so this was the perfect time to check it out. Plugs looked fine, but maybe a little white (lean). I'll do some more plug cuts to verify later.

Compression test came back 145-140-145-145.

Awesome. The bores and rings are still good.

Once the tach seal challenge was overcome, I checked the valves. On the exhaust side, there was one tight valve and one very loose one. The shims were 2.85-2.95-2.85-2.90, with the 2.85 on the loose valve and the 2.95 on the tight valve. I swapped the 2.85 and 2.95 and was rewarded with perfect valve adjustment on all four.

On the intake side, again there was one slightly loose valve and three that were perfect. Shims were 2.75-2.75-2.75-2.70. I ordered the requisite 2.80 shim to replace the loose valve's 2.75. Not bad for an unknown engine that has been sitting for 27 years.

While I had the valve cover off I refinished it with silver engine paint. I also scrubbed the cases and cylinder with solvent to give the motor even more sparkle.

The problem with this was it made the scruffy finish on the sidecovers stand out even more. The bike wasn't going anywhere for a while, so it made sense to pull them off, and there was the issue of the weak charging and rattling clutch, and of course I had to change the engine oil to flush out the dirt from having the valve cover off and my grubby hands inside the motor.

Before I could help myself I had out my impact driver and had drained the oil. I removed the clutch cover and stator cover, disconnecting the stator in the process. I also pulled off the chrome starter cover and sprocket cover.

To be continued...

Petcock Reprise, Tach Seal

Well, I've put about 60 miles on the bike since getting it running, and it's a sweet runner. The carbs required only a little tweaking to get it down to a sweet, smooth idle, and it fires off on the first button push every morning. The brakes are hard as bricks and a delight to use, and the refreshed suspension gives the bike good behavior over bumpy surfaces with no head shake up to the speed I chickened out at - 115 according to the speedo. It got there mighty quick - this thing has tons of power. It's also enough to cruise in comfort at 80 mph on our LA freeways. The transmission shifts nicely after I adjusted the shift lever down one spline on the shaft to match my boot better.

So what's the catch? Well, there are a couple of small issues that I will have to deal with:

- A slight oil leak at the tach drive, and another at the valve cover gasket. Both dripped oil on the exhaust leaving me with a nice oil cloud at long stop lights.
- A gas smell emanating from the bike. Seemed to be coming from the carbs, which were damp on the bottom. This only appeared after parking.
- A couple of cosmetic issues that I want to deal with, including the caps at the end of the cams, the engine side covers and the chrome starter cover.
- The charging system or battery might be a little weak - at stoplights the lights dim slightly until the revs get back above 2000-3000.
- The clutch rattles (another common GS problem) but that might be solved with a carb balance.

Curiosity got the better of me, and a few days ago I decided to deal with the carb issue. A wet drain tube from one of the center carbs pointed to a leaky petcock. I was a little irritated by this because I had just replaced all the seals. One bolt sets the tank free, and with it on the bench I watched the outlet for a few seconds to verify that it was dripping slowly. I tipped the tank over and disassembled the valve portion of the petcock. Everything appeared to be fine, but there was a tiny bit of corrosion on the back of the valve lever. I sanded it on a piece of glass with 800 grit sandpaper until all traces of pitting were gone.

Back together it still leaked, which meant the problem was with the diaphragm. I pulled the back apart and sure enough, the o-ring on the diaphragm valve was cracked. Damn - Suzuki doesn't see fit to sell it separately, and I was starting to regret not just buying a new petcock. I grudgingly placed an order with Z1 enterprises for a new diaphragm. I always regret buying aftermarket parts, and this time was no exception. The diaphragm that arrived had an o-ring that was too small for the recess in the petcock. Why do I bother? I'll live with the seepage for now, but I will be buying a new petcock soon.

While I had the tank off I decided to reseal the tach drive and valve cover too, and do a valve adjustment. I removed the bolt and cable and started to gently pry the drive housing out of the head. Before I knew what happened, the housing broke off flush with the head surface.

Shit.

For better or worse I was tearing into this thing. I pulled the valve cover and tried to pry the stub of remaining tach drive out of the head. It wouldn't budge, obviously stuck in place with 30 years worth of aluminum corrosion. Damn, damn damn.

The next step would be to pull the cam but I was able to avoid it with a pair of vice grips, pick, punch and hammer. The carnage took out the gear, too, so it looked like I'd be buying more parts than I anticipated. With the valve cover off while I wait for parts, I figure it's as good a time as any to take care of all the engine issues that I still had.

IT RUNS!

After I got the tank, forks and exhaust back on the bike, I really didn't have an excuse not to start it up. The day of reckoning had come.

First I drained out the old oil and re-filled the crankcase with 10w40 Valvoline motorcycle oil. This would flush out the remaining ATF that I filled the cylinders with, and remove any contaminants that had managed to find their way into the crankcase over the years.

Next I filled my gas can with a couple of gallons of 91 octane CA gas and threw a bit into the tank. I didn't want the tank to be too heavy if I had to remove it later. I turned the petcock to "prime" and let some fuel trickle into the float bowls, then turned it to "RES".

The battery was one that originally came in my CB450, so it's a little undersized but works pretty well. I had it on a charger while I was working on the bike over the last couple of months, so it was ready to go.

At first the bike simply did not want to start. Repeated cranking didn't do anything, probably because of the stuck rings and low compression. I sprayed some carb cleaner into the intake and was rewarded with some pops and clouds of blue smoke.

After a few minutes of this, the bike started up; snarling and grumbling, but running. I let it warm up, and restarted it a couple of times when it stalled.

With a bit of adjustment on the idle knob, it settled into a high, though unsteady idle. I couldn't resist taking it for a ride like this, and before I knew what was happening I jumped on the seat, dropped it into first and headed around the block.

It ran pretty good, though with some stumbling that I attributed to the carbs not being synced or tuned for the bike. I gladly parked it back in the garage and attended to the final details. It still needs a tuneup, valve and carb adjustment, and I need to check the compression again to see if it's improved, but at least it runs!