Let me start by saying that these bikes were never on my bucket list and the only one I worked on in the past 20 years belonged to my father, who replaced his C70 Passport with the Twinstar 185.
So, just a couple of weeks after sorting out the little burgundy 1979 CM185T (see previous CM185 story) a second one pops up on the Facebook marketplace that apparently had been residing there for a month, unnoticed. I suppose that the seller had relisted it and it popped up in my Marketplace feed.
There wasn’t a lot to go on, apart from his description that the bike had a big oil leak and could not be driven. That and the paperwork was a lien sale, too. This sounded like the typical local auction find, but the paperwork was from 2020 and the tag on the blue CA license plate was from 1987! The bike was showing 7775 miles on the paperwork.
In a meeting with the seller, the first thing to notice was the Harley Sportster gas tank that had been grafted onto the frame. That, plus the turn signals were replaced with little aftermarket items, and a set of some kind of extra lights were added to give the bike some flair, I guess.
The bike was started for just a second and oil gushed out from the left side, right where the oil leak was on the first bike. The tires were old and cracked and the side covers were missing, possibly because the forward tabs for the side covers plug into the back edge of the OEM gas tank. And, of course, the fork seals were leaking, like the other one. After 43 years, I guess they are due for replacement anyway.
The asking price was $500 and was negotiated down to $400, so I decided a rescue was appropriate and we loaded the weepy bike into the back of the Tacoma. With all the paperwork in hand, I swung by the local Chula Vista DMV and lined up in the vehicle inspection lane. There were just two of us in that lane but the drive test line, next to us, was 10 cars long. I guess only one or two employees were trying to wrangle the onslaught, so after getting an unhelpful answer about whether the bike needed the inspection or not, I left and went to the AAA office where the last bike was registered successfully.
It only took a moment for the AAA check-in man looked over the paperwork and said “We don’t do lien sale cars/motorcycles” and off I went to the El Cajon DMV where I have usually had good luck. AAA gave me a paper with a QR code that allows you to “get in line” virtually from your phone and then tracks your place in line as it changes. Very cool feature!
I waited until I got into the inspection line at the EC DMV and then hit the QR code to sign up. After about 10 minutes a man came by and grabbed the paperwork, assessed the situation and whipped out an inspection sheet in a matter of minutes. The lack of a 17-digit serial number threw him off for a bit, but he used his phone to verify that in 1979 they were still using a 12-digit serial number. I rounded the building and found a parking place. Once inside, I watched the registration line shrinking quickly and suddenly I was at the counter after about a 10-minute wait. A woman waited on me, waded through the stack of papers, and said I had to fill in a form and get the name and signature from the man I purchased the bike from. I departed the DMV office and drove home to start the investigation into the big oil leak issue with the bike.
I leaned it up against a fence (these bikes don’t have a centerstand, unfortunately) and removed the countershaft cover. With the countershaft sprocket removed, the seal was sitting neatly all the way outside of the crankcase, just behind the sprocket. I had a spare seal, leftover from the last bike, so cleaned the area up and drove the seal gently into place. I readjusted the chain and put the cover back on. You could see that someone had attempted to work on the bike before as some of the engine side cover screws had nuts added to the outside, where there should have just been threaded holes. I checked the dirty oil level and tapped the starter button which fired up the engine instantly. The battery was over-sized for the battery box and only later after I discovered that the headlight bulb and most of the instrument bulbs were all blown out due to the installation of a 12 volt battery in a 6 volt system!
The engine wasn’t taking throttle very easily and then the throttle seemed to stick causing a high rev idle. So, the next thing to do was to remove the carburetor for inspection. After wrestling it off the studs, the removal of the bowl revealed a combination of older moisture corrosion and a few chunks of old fuel that evaporated into what looked like bee pollen. I wound up gently filling the bowl and the body roof with metal prep (phosphoric acid) and rinsed them both out after about 15 minutes of chemical reaction. Unlike the first Twinstar, this one appeared to have a genuine OEM carburetor, but when I checked the slide needle it was a 5-slot version with no numbers stamped on the edges vs. a single slot OEM needle. Again, the main jet had no markings on it, so I had to compare it against a genuine #105 main jet and found it much smaller, probably a #100 at best.
With everything cleaned up, the carburetor was reinstalled and the engine started up again. It sounded a bit rich off-idle, so the needle needs to be dropped a notch or two. In the meantime, I removed the air filter cover, only to discover that instead of the usual oiled foam filter, there were three men’s socks fitted over the inner filter mesh core! I have heard of “sock filters” before, but never ones like this.
When the breather tube was removed from the air filter core, there was a big WHOOSE sound, as if vacuum was being held in the line. The breather system is different than the first bike, which has to do with the CA emission systems that were imposed on motorcycles. The red bike has a direct fitting from the crankcase to the base of the air filter case. This black one has an intermediate oil separator valve assembly, which can be drained and probably never has been. If that was holding pressure in the crankcase, it may explain the countershaft seal blowout problem.
I had to use an air impact gun to get the spark advancer bolt off the end of the crankshaft for cleaning and service of the advancer. The point’s contact faces on the point plate were coated with corrosion, so it was a wonder that they were making contact at all. After setting the timing, the bike was restarted again and the idle speed screw was more responsive and the engine sounded more refined.
I removed the seat, discarded all the extra lighting wires from the harness plug-ins and rechecked the tail light wiring, which was rewired incorrectly. That’s when I noticed that the headlight wasn’t working and inspection showed the filaments blown apart. The instrument panel had blown bulbs, and was missing the instrument light bulb. I was three hours into the repairs and had enough for the day. That night, I wound up ordering $350 in parts to get the bike in better and safer shape.
The next day, I used the app to get a place in line again at the El Cajon DMV. I left my house at 12:30 when I was 19th in line. When I arrived at the office, my position was 10th. It was a much busier day, though and I waited over a half hour, watching the numbers being called rather slowly. Finally, I was served and after a different agent sifted through the paperwork pile, I was charged $23 for a PNO title- only paper. There was no reason to spend another $140+ for registration for this one, but at least the title will be clear and in my name. This makes reselling them so much easier.
Saturday’s tasks included an oil change, valve adjustment, new spark plugs, dropping the needle down a notch onto the #2 clip slot, removing the 12v battery and putting the old, leftover 6v battery from the first bike in until a fresh one arrives next week. Will do the fork seals and front tire at the same time, of course, and then the rear tire while balanced on the little portable bike lift.
The paper gasket for the gas cap was breaking up, so that was a next buy item and it turned out that the cap gasket needed was for an early H-D model. The local H-D dealer didn’t stock anything for bikes that old, so eBay to the rescue, and a pair there costs $12 including shipping.
The speedometer case, which is plastic, developed a crack down the middle at the front. I have JB-Weld plastic glue to address that problem. I discovered a left-side cover that was already painted black and had a TWINSTAR decal on it for $36. For some reason, the right side covers are less available than the lefts.
I ordered another replacement tail light because the lens screws had been overtightened and broke out the plastic base. There was a bit of re-wiring to do, and the bulb that comes with them is a 12v item, so that was switched out with a correct 6v bulb.
After all of this mechanical work was done, I noticed that the lett side of the handlebars was bent in from a tip-over. I used a MAPP gas torch to heat the handlebar to cherry red and bent it down and out very slightly. The new battery arrived and was serviced and charged up for use. The battery band strap arrived from an eBay seller in great shape for about $15. The new ones online were $25!
I kind of goofed on ordering tires, or at least the front one. I checked online at CMSNL.COM and the microfiche illustrations showed a 2.75x17 front tire listed. Both bikes had 3.00x17 front tires, but one had been replaced. The 2.75 comes as a dual-purpose tread for CT90-110 Trail bikes, so hopefully, it won’t affect the handling or braking significantly. Small bike tires are in short supply these days, so sometimes you just have to get what you can get and be happy. Checking back on eBay, the GS11 tires in 3.00x17 ranged from $75 to $111 each.
The first test drive started with a stuck clutch that released once I rolled it down the driveway and popped it in gear with the clutch lever pulled in until it released. The cable was adjusted almost all the way out as if the clutch was worn out, but of course, there was an underlying issue that you don’t normally encounter… I ordered a set of plates and a gasket from an eBay supplier out of LA and the parts came in quickly.
When I disassembled the clutch spring plate, I discovered that the thick thrust washer had been placed just behind the snap ring instead of behind the inner clutch hub! This allowed the hub to rub up against the inside of the clutch outer. It also set the clutch assembly backwards away from the clutch release arm making the release arm move upward. This caused the clutch cable adjusters to be set at the end of the threads.
Putting the washer back where it belongs pushes the pack forward against the release arm. That puts the arm down further and causes the cable adjusters to be positioned more in the middle of the threaded cable section. The steel plates were lightly rusted. Assembled with a new set of friction discs and corrected assembly, the clutch performs perfectly now. This also explains the tiny aluminum filings in the oil when it was drained.
Both tires arrived on the same day, despite coming from two different sources. The front one was done first, along with the fork seal replacements. The rear went on with no issues and now it has fresh rubber on both ends. The dual-sport front tire kind of goes with the H-D fuel tank and the overall blackout effect.
There are always dozens of little issues with vintage bikes like this, which have not had the best of care during their lives but in the end, they live again to get back into circulation. So, for the moment, I am the father of twin Twinstars! But they are available for adoption now.