What did you do to your Yamaha today?

Did no riding today instead double checked the integrity of my helmets in light of the recent rash of motorcycle fatalities because they didn't wear their helmets. No they might not save a life that is going well in excess of the prevailing speeds but odds are in ones favor during a true accident.
You won't catch me dead without my bucket on.

 

I got my recent purchase to turn over and spark using the starter button. It's a 1981 550 Maxim. I cleaned up the kill switch and switched out a "fuse" installed by a previous owner, guess which one it was?

 

Think of the time and effort involved in selecting just the right size bolt to fit into those clips so perfectly......instead of just buying "a fuse".

Has anyone else seen the movie Idiocracy?

 

I can’t decide if this is just plain stupid or “it’s not stupid if it works”. I’m thinking just plain stupid. Maybe OK for troubleshooting, but that’s it.

 

Some people are born stupid, some don't really know the difference and there are a select many who try really hard at it.

 

I see it every day!

To stay on the subject of Yamahas, I rode down to Pine Bluff for the Crud Run. Stuck a FOR SALE sign on the windshield. So far nobody’s waving C-notes in my face.



The last 500 miles make me wonder… do I really want to get rid of this bike? It overstuffs my garage, I am constantly fiddling with those fussy carburetors, and I’ve only ridden it 2500 miles this year (of which 1000 so far were to the spring and fall Crud Runs), but… it is a hoot to ride, especially on roads like this one:



So is it OK to keep a bike that’s fussy, high maintenance, only gets ridden a little but is tons of fun? Hmmm…

 

Brawndo, it's what plants want. Also, that movie is responsible for the rise of Croc shoes.

 

In a word.......Yes!

 

Actually, the XJ's are not really high maintenance, once they are "right" they tend to stay that way. At least when we are not fussing with them and trying to "improve" them. Yes, the valves need to be checked once in awhile but don't really change much if one is not trying to ride them like a superbike. Shaft drive means no chain messing about, cleaning, lubing, tensioning and cleaning flung off lube from other parts. Once the carburetors are set they stay well adjusted if not messed with. Take care to get things well adjusted and then just ride and ride and ride and.......

 

And there's the rub. I feel like I'm running into the “90/90 rule,” which says the first 90% of a project takes the first 90% of the work, and the remaining 10% of the project takes the other 90% of the work. The way it's running now, I'd feel pretty comfortable riding it to California and taking along not much more than a tire-plug kit and spare spark plugs. But... it's not yet right. In particular, it doesn't want to idle properly. When I pull in the clutch to shift, the engine is lazy about dropping back to idle. At a stop, it likes to idle fast for a while and then slowly drop... and drop... and eventually stop. This seems to change as the day goes by, and I seem to be constantly fiddling with the idle screw under the carbs... which is hard to reach, just about impossible with gloves on and painfully hot without gloves.

I thought I had this settled a while back, after I adjusted the valves and synchronized the carbs (#1 was far enough off that that cylinder completely shut down when the other three were at a proper idle speed), but maybe a thousand miles later it fouled out the #4 plug. Replacing the plug and leaning out #4 to what I thought I had found when I removed the EPA plug fixed the fouling problem, but caused the idling problem to return, but the carbs still seemed to be in sync. I've tried to find vacuum leaks, with no success thusfar. I think I have the #4 mixture screw set approximately right (according to the spark plug, which is showing neither too lean nor too rich), and so will probably take one more shot at synchronizing, but it's frustrating how the bike is so close to being really good and I kinda feel like I'm chasing my tail on this.

 

The one thing I noticed on my 750 is it only takes just a slight bit of the floats being off to make a really big difference in the idle quality and ease of tuning. I devised a float gauge using 4 short lengths of plastic tubing and secured them upward so they all matched in positions then on a verified level surface opened them all and lets things settle for a minute. It took some time to get the floats exactly right but once I did everything else fell into place. All of my carbs run 2 1/4 turns out using matching (new) fine thread needles backed with new O-rings on the stems. I had one early problem with an O-ring that balled up and after replacement everything was lightly lubed with silicone grease, never had a problem since.

So I have to ask how are the gaskets behind the intake boots to the engine itself? I trust they're verified to seal well and the boot isn't cracked somewhere out of sight? How about the shaft seals and bushings and that all-mighty interface between the lower YICS chamber and cylinder head? When I cleaned out my lower chamber with spray I noticed a little weeping around the #1 feeder port but chose to leave it until I pull the head for a valve job this winter. I can see a leak here causing some big headaches.

Anyway just some suggestions, please let us know how it goes.
Brett

 

Back in April I posted a picture of how I did my float levels. Pretty much the same only I did them one at a time and clamped the rack in a vise, checking with a level. It was an annoying task, but I did get them all to the magic 3 millimeters.

Two of my carbs are at about 1 1/2, the third a bit over 2, and the fourth a bit over 1. These are close to the settings I recorded when I removed the EPA plugs and needles. My carbs are the coarse-thread style.

It's a 1980 model, so no YICS chamber to fool around with . Also no low-end torque .

I inspected the rubber intake manifolds, and while there is some superficial cracking around the vacuum-connection nipples there do not seem to be any leaks. Is there anything I can to to repair these and preserve the rubber from cracking more meaningfully?

Today I took the bike for a little 10-mile warm-up ride, during which I got to see a big mess being cleaned up after a semi loaded with gravel took a corner too fast. They had the truck up on its wheels by the time I got there, and there were a couple end loaders scooping up the gravel from the ditch alongside the road. Interesting...

Anyway, when I got back I tried re-synching the carbs, and here I noticed something odd. A while back I modified the fuel valve to be an OFF-ON-RES style, which involved disconnecting and plugging the vacuum line. When I went to hook up my vacuum gauge on #3, I noticed the hose seemed an awfully loose fit on the little nipple on the manifold. Hmm... I dug around in the garage, found some 1/8" vacuum line I had bought to repair the EVAP system on my Himalayan (wrong size; that thing takes 3/16" or something) and found that was a nice tight fit on the manifold nipple. Could there have been a small leak on this (un-clamped) connection?

So I re-synched the carbs. #4 did require some adjusting to match up to #1; #2 was fine; #1 had to go in a little as well. The differences were about 1 to 1.5" of vacuum, which is actually a lot as the four finally synched at 6.5" vacuum at 1100 rpm. It seemed much better so I took it for a 60-mile ride. Almost immediately noticed I had compression braking when I released the throttle, something that had been sadly lacking before. It also idled well at stoplights; the longest one was about a minute. I did notice that it dropped to about 1500, sat there for a few seconds and then settled in at 1100. Not perfect, but greatly improved. If the bike was 90% of the way to "spot on" a week ago, it is now 95% of the way. It would still benefit from fine-tuning the mixture screws, I suspect.

It did develop a different annoyance: warm starting is now trickier. Could just be that I need to learn the proper technique, but after my ice cream stop (about 15 minutes in the middle of the ride) it caught briefly and then acted like it was flooded, requiring full throttle and a few seconds of cranking to start. No big clouds of smoke, though, so not "flooded" in the traditional sense.

When I got home I noticed there is a bit of oil on top of the engine under the alternator. Not entirely sure where it's coming from, but I cleaned it up and perhaps it will tell me where that leak is...

 

Oh the joys of owning a classic bike... well at least it's not a british leaker, don't get me wrong I grew up on the back of my dads '76 Triumph Bonneville 750 of which he still has and with 27,000 on the clock there's not a drop but we all know how some of those and the American brands like to leave their mark. He takes meticulous care of this machine and it still looks great.

Intake boots.
I recently retired from a plastics injection molding company and have worked with many of the compounds both soft & hard, they made the intake boots for Kawasaki America and Polaris and what I can tell you is there's no way to "preserve" the intake boots long term. The plasticizer itself is ethanol soluble and it also slowly evaporates over time so you get the heating & cooling cycles that bring on the cracking as the lighter compounds evaporate. I forget the name of the base material used for the Kawasaki and Polaris boots but it hardens over time in the presence of hydrocarbons be it gasoline, oil ect so couple that with the high frequency vibration of the inline-4 running 5000 RPM there's a lot of energy being dissipated across them and they're going to stress crack.

Consider just how small the cylinder is and the overall air/fuel volume at each intake stroke running at idle it doesn't take much of a leak to dilute and upset this. Throttle shaft leaks, a slight crack that opens just a hair during the intake stroke itself in the boot plus the tiny little bit that might make its way down the intake valve guide is plenty to throw things off for a cylinder that's slightly larger than a small lawn mower engine.
An issue I had early on was one of the enrichment needles was hanging up slightly causing all kinds of weirdness and I discovered it by accident bumping it on its top while adjusting the balance screws. Somehow one of the lifting fingers got bent when I pulled the rack down and I never gave it a thought, just one of those things.

So my last carb balance brought them all to exactly the same vacuum and turns out on the pilot screws, I double checked my gauges against a real mercury column and everything was dead even so it's achievable but believe me it takes time. I mean a lot of time... like a full case of beer time then it will be off again when sober enough to ride. Okay so I judge the job by the number of 2-liter jugs of Mtn Dew it will take to complete, from starting point benchtop to finished and floats leveled it took me just over 12 hours and this included pushing fine little wires through the passages while wet with carburetor cleaner. A full 2-liter

So don't mind me asking the obvious but how is the compression? How about any leakage passed the valve seats? I used a rubber tipped blow gun in my spark plug holes at compression TDC to check them by ear and found nothing (knock on wood) and only a slight hisssss..... from the little that gets past the ring gaps. My bike came to me in a number of milk jug baskets with the usual disclaimer of "Some Assembly Required" so I did have an opportunity to do some in-depth checking & inspecting, with 36021 miles on the clock when I bought it everything was in grade-8 shape except the carburetors. They looked like a meal I left in the oven too long, like far after the smoke alarm battery went dead. My first attempt despite reading the entire Church Of Clean page got the engine to run but not very well, overall it took me four tries to get everything on the money and now it starts easy hot and cold with only a slight tug of the lever to keep it running on a cold start. A little heat on the jugs and I'm off pulling the lever back to center once I'm moving.

 

What did my Yamaha do to me today, you ask? Well, broke the clutch cable. Needless to say I stalled at the next light, in 1st. Couldn't pull the cable with the tool pouch pliers, so the only way to get going was to start it in 2nd. Wheeeee!

 

Yeah... know this one well so now I keep a spare coiled up under the seat. Sure beats the alternative.

Looking at the possibility of pulling out my motor this winter and doing a valve job & timing chain at the minimum with the possibility of a re-ring or the full-meal-deal rebuild depending on how the funds go. I have a long time friend who is a tool & die maker with some 60+ years of experience of building race car engines who's willing to do the head so once the snow flies things will start to happen.

 

You can take the head off the engine in the frame. But if you fit an endless chain you will be splitting the cases anyway. Change the alternator/starter chain guide too and check your starter clutch. Its not difficult just takes a bit of time.

 

What did I do to my Yamaha today? Rode it 265 miles to the Mississippi River and back. It was a sunny day with temperatures in the low 80s, and in late October I am not going to pass up such an opportunity!



740 miles a couple weeks ago, when I rode to Iowa and Wisconsin. 170 miles on Saturday. 265 miles today. For a bike I was talking about selling, I'm sure riding it a lot...

I have to do something about the kickstand, though... it takes a lot of work to push it down. Comes up easily enough, but getting it down is hard. Doesn't help that my left knee is three weeks from being replaced...

 

I did a 125 mile trip today just up to Moose Lake and back to check out the fall colors... all the trees are bare. Oh well at 76F I wasn't going to sit on my fat... backside and filled the tank. Perfect afternoon for what might be the last nice ride for the year,

 

My last ride of the year will be sometime before November 11, when the knee gets replaced. I still have to stabilize the fuel in three bikes, change the Yam's oil (might do that today, as it's supposed to be 71º and I hear the ice cream shop calling), and possibly trade the 411cc Himalayan for a new 450cc model... assuming the new bikes ever actually arrive here.

 

So today... went for a short (~60-70 mile) round trip to the ice cream shop, came back and changed oil. I am impressed by how easy it is to change oil on this bike, especially compared with my Harley (hard-to-reach drain plug, spin-on filter mounted sideways above the voltage regulator and motor mount) and Himalayan (requires using bent-up license plates to keep oil from dribbling into the bash plate). Somebody at Yamaha apparently gave some thought to changing the oil. Nice.