Tag: RD 350

Screwed

By Joe Gresh

I haven’t been riding the Yamaha RD350 lately and it’s not because I don’t want to. There is a lot of concrete that needs doing at the ranch and I get to do it.  Anyway, the RD350 has a loose screw in the tachometer and the screw dances around inside the gauge beating a tattoo onto the tachometer face. It drives me crazy to see that little screw eating away at the tachometer lettering so I parked the bike. A few days of rainy weather put a stop to my concrete-the-world efforts and I decided to take advantage of the down time and fix the tachometer.

These Yamaha instrument clusters were not really meant to be serviced. The Yamaha factory crimped the bezel onto the gauge body and back in the day it was cheap to buy another gauge. If you have infinite patience like my buddy Deet, it’s possible to unkink the crimp and reassemble the gauge so that it looks to all the world that its never been touched. I am not that patient.

I modified a harbor freight pick (free with purchase!) into a pry bar, which allowed me to get the crimp slightly lifted. Once you have the bezel edge up a bit you can get a more serious pry bar in there.

This bar is also a modified Harbor Freight tool. The rounded face allows you to work the crimp back to a more vertical position.

With the bezel mangled and pried back the lens will separate from the gauge body allowing access to that annoying screw.

Since I had the gauge this far apart I took the mechanism out of the gauge body and gave it a few drops of oil. This turned out to be a bad idea.

Putting the gauge back together is the reverse of the above description. Make sure the lens is perfectly clean or you’ll be looking at that speck of dust forever. To re-crimp I got the bend started with a screwdriver and the used a small hammer and punch to flatten out the waves. It doesn’t look factory but a rubber bumper covers the mess.

After assembly and testing the neutral indicator light looked odd. It was lit all the time and very dim. I assumed I must have screwed up the wiring and rechecked everything. Turns out the rubber bellows that shields the neutral light socket from the bulbs illuminating the gauge did not slip into position correctly. This caused the boot to fold over blocking the neural light photons and allowing random background photons to leak into the green lens area. I had to un-crimp the bezel again, disassemble the gauge and slip the boot on correctly. Perseverance will beat talent every time.

The speedometer screws were also loose, the face was jiggling around and it was only a matter of time before those screws fell out. I took that gauge apart and tightened the screws. Then I did the oil thing and also adjusted the needle 8 miles per hour slower to more closely reflect the speed I was going.

The sun is shining and I can start putting more miles on the Yamaha RD350 without staring at that stupid screw bouncing around inside the gauge. And I will just a soon as I finish up this driveway.

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Yamaha RD350 No. 9: Shocks, It Was Nothing

The RD350’s rear suspension seemed kind of springy to me, like there was no damping or the shock oil had leaked out. In corners the bike would hit a bump and bounce. Nothing frightening or dangerous but in combination with the front forks needing a rebuild anything less than smooth pavement was a ragged, unsophisticated ride. The RD still wore its original shock absorbers from 1974 so I figured it was time for a replacement set.

I found many options online, prices ranged from $500 to $50. I think we all know what option I took. Look, it’s not that I don’t want a really nice set of shocks it’s just that I’ve had some bad luck with expensive shock absorbers. In a nutshell they didn’t last very long. I mean it’s not like a dirt bike where you need good suspension. I’m using the RD350 on the street, an environment where you hardly need rear suspension at all. I found a set of shocks on ebay that looked similar to the original Yamaha shocks. For $47 shipping included I was willing to take a chance. The shocks arrived in about 3 days.

Out of the box the eBay shocks looked really well made. The chrome was beautiful, the top-mounting boss was cast aluminum and the things even have a plastic sleeve between the shock body and the spring to eliminate squeaking. The original shocks did not have this feature and squeaked a lot. They sounded like an old, rusty gate swinging in the wind when you hit a bump.

Fitment was straightforward except that the original Yamaha shocks had no bushings: the rubber inside the mounts fit directly over the shock studs. I had to press out the steel bushings on the new shock, which was fairly easy using a bench vice and a couple appropriately sized sockets. Instead of black rubber like the originals the new shocks used a material that resembled urethane and may in fact be urethane. It is translucent yellow and looks cool.

With the bushing removed the new shocks fit a bit loose on the mounting studs but not loose enough to fit a bushing. I thought about cutting a strip from an aluminum beer can and wrapping it around the stud to take up the slack but instead decided to hope that the now-bushingless urethane would relax a bit over time and swell to suit its environs. I often hope for mechanical things to fix themselves and frequently they do. The washers on either side of the stud sandwich the urethane a bit when the shock bolts are tightened so maybe they will smoosch the fit tighter.

After fitting the shocks I found the first spring preload position was too soft so I stuck a pin punch inside the nifty preload adjuster hole and cranked it up to the second position. That seemed about right. I wheeled the Yamaha out into the daylight and fired up the sweet-running two-stroke twin. It’s a sound that never gets old.

The first thing I noticed while riding was no squeaking, the eBay shocks were quiet. The roads around my place are sort of rough and there was a noticeable improvement in the bounciness department. It seemed like with the rear shocks working better the blown out front forks felt worse or maybe I just paid more attention. Corners were steadier and the rear tire rubbed the fender less than it did before. Still, it wasn’t the dramatic improvement I was shooting for. That might be down to the $47 price point.

Curious about the original shocks I compressed the spring with a long bar clamp and removed the spring collar along with the spring. Now I could test the shocks for damping action. Surprisingly both shocks still had oil in them and offered firm resistance to rebound. The compression action was much less as you would expect. It’s really hard to tell but I think the two Yamaha shocks offer slightly different hydraulic action. Certainly nothing I could feel on the road. I’ll go out on a limb here and say that there was probably nothing wrong with the original shocks. They work like they work I guess.

I’ll clean up the Yamaha shocks and pack them away to rot. In the meantime I’ll be running the eBay shocks to see if they hold up for 47 years like the originals. The new rear suspension has moved fixing the forks to the front burner. The RD350 handles well with clapped out suspension, I can’t wait to get both ends sorted and sample some of that legendary road-racer for the street performance RDs are known for.

More of the Gresh Resurrections!

Yamaha RD350 Part 7: Clutch Without The Cargo

The clutch cable on the RD350 was at max adjustment on the lever perch and the clutch action was a bit stiff so I removed the left side engine cover to clean things up. The cover locating dowel on the bottom was a little corroded so it took some wiggling and wobbling to get it free. Inside I was rewarded with an ignition/alternator assembly that looked nearly new. The screw heads are un-boogered and the cad plating looks like new.

I paid quite a bit for this motorcycle but it’s been worth it as the bike has seen very few ham-fisted sorties into the mechanical aspects of the thing. The sprocket area was well covered in chain grease so I needed to bag up the alternator and clean the area.

Cleaning the clutch release and countershaft sprocket area revealed that the parts were also nearly new. I dismantled the clutch actuator and cleaned up the cover.

I encourage others to leave original finishes alone but the left side cover was missing a lot of paint and had that white corrosion patina that speaks to poor maintenance. A rattle can of Rustoleum satin black matched the original engine color well so I gave it a little squirt. Note I did not polish the bare aluminum parts or touch up the points cover. That stuff wasn’t too bad.

While I had the clutch helix cover apart I decided to install a new chain. I’m not one of those, replace-it-all-or-you’ll-die, type of guys. If the sprockets look unworn I’ll slap a new chain on the old sprockets. I realize this is hearsay in the Big-Sprocket boardrooms but those guys are in the sprocket selling business. The RD sprockets look like new so don’t worry, it will be fine. One glitch was the old tire is a 3.75-18 IRC, the bike calls for a 3.50-18. The narrow swingarm of the RD can barely accommodate the extra ¼ inch. I had to adjust the chain a wee bit tighter than I like to keep the tire from rubbing the front of the gusset. That problem will be solved when I replace the tires.

The RD350 uses a 530-size chain; that’s a pretty heavy chain for a 350’s weight and power. Once these items wear out I plan on going with one of the many 520 chain conversion kits for the RD350. With small displacement engines you don’t want to waste power spinning a heavy chain.

After greasing the clutch release helix and clutch cable, along with the perch pivot the clutch is much smoother and easier to pull in. The RD350 is geared kind of high in first gear so you’ve got to give it some revs and slip the clutch to get it off the line without bogging the thing.

With the new chain and the clutch adjusted I figured I better get the bike legal because there’s no way I’m not going to ride it. I burbled down to DNA title services in Alamogordo with all my paperwork and it was a breeze to swap the title. In New Mexico we have privately run tag agencies in addition to state run agencies. The lines are much shorter at the private places and there’s an incentive to sell you a tag or they make no money. I had my choice of yellow, blue or black tags. I chose yellow because it’s old school New Mexico, like black tags are in California. The transfer, taxes and a two-year sticker cost $265 US dollars.

Arriving home from the title place there was gas leaking from the petcock. Close examination revealed that the hoses were leaking at the petcock barbs. I replaced the leaking fuel hose and added two huge fuel filters along with those springy, compression hose clamps. We will see it the leaks have stopped next ride.

I replaced the funky original Japanese swingarm and brake pedal grease fittings with normal ones that fit the grease gun everybody else on the planet uses. All of the areas were free breathing and took grease ok which makes me think they’re not clogged with hardened old muck.

I still have quite a bit of work to do on the RD350 but it’s rideable as is. I don’t trust the old tires, besides being too big the rear tire is very out of round and who knows how old the tubes are? The front end needs new oil and seals and the steering stem needs greasing. The rear shocks are like pogo sticks. I’ll get to it when I get to it, you know?

More Joe Gresh Resurrections are here!

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Yamaha RD350 Part 4: Stealing Moments

I’ve been on a tear lately. The shed floor is nearly done and I’m laying down some slabs, man. That doesn’t mean I haven’t managed to sneak in a little tinkering on the 1974 Yamaha Rd350. I mean, once the slab is poured and finished you’ve got to let it cure for a day. Green concrete is very fragile.

I wanted to drain the RD 350’s fluids before getting too far along. Which was kind of good because I discovered the oil tank wasn’t slotted into the rubber frame peg correctly. That meant taking out the battery to access the oil tank bolts.

It was no trouble at all to pull the tank, drain it and re-slot it onto the frame peg. The original feed hose drooped underneath the carburetors then rose over the clutch cover forming a trap. I didn’t like the looks of the trap so I shortened the feed hose a bit and routed it without a loop.

When I pulled out the battery to fix the oil tank I noticed the top of the battery had a melted spot. This melted spot corresponded with a melted positive wire to the battery. I suspect the battery is the wrong one. It looks too tall and there was a section of old inner tube covering the battery. I see no evidence of arcing on the seat pan but something melted the positive wire as it has been wrapped with electrical tape.

After refilling the oil tank I needed to bleed out any air in the feed line to the autolube pump. The pump area was shockingly clean. It looked like a new motorcycle inside.

I sent Deet photos of the pump as I was well pleased and wanted to show the thing off. Zooming in on my photo Deet noticed that the autolube pump was not adjusted correctly. The pin and dot are supposed to line up at idle.

The oil pump cable was adjusted as loose as the lock nuts would allow. This RD is near perfect except where mechanics have fouled it up. Resetting the pump was quick and now the pin lines up with the mark at idle.

The chain guard was sort of floppy because the front mount was missing its bolt and the rubber bushing, along with the spacer. I cobbled one together from bits and pieces; it will work until I find the correct parts.

The more I mess with the RD350 the more amazed I am at how unmolested it is. All the case screws look perfect (except for the ignition and pump screws).  Opening things reveals factory fresh assembly. It’s almost too perfect: I’ve got to up my mechanical game to treat this motorcycle with the care it deserves.

More on the RD350 story and other Joe Gresh Resurrections is here!

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