What did you do to your Yamaha today?

Picked up 10 gals of 100LL AvGas for $85.00, I was filling the bike with KwikTrip 91 ethanol free but the bike seemed "off" so I drained the tank and pumped in the airplane juice for a good run tomorrow, other things took up my afternoon and now I don't feel like dealing with the evening commuters. Bike starts the same, 1/2 in on the enrich lever gets things going with only a couple of puffs of the starter and the idle settles right in like it has so maybe I had a load of bad gas. Weather-wimp is promising us 50F highs so I will get some miles on the clock, at 37F now and a dark shade helmet I'm not up for it this evening.

 

So Monday after work pulled bike out and went for the first official ride , onlt went six miles...the temp was great 74 degrees...but wind guts were 35 miles an hour , hit two gusts that almost put me off the road so called ride short. Today temp is 40 and windy

 

Dropped a set of new plugs in and went for the redline on several plug chops running the 100LL, running a little fat but I think it's dialed in well enough. Clutch held well but still has a grab point on the drop-in that's abrupt, at some point in the near future I will dissect the basket and check the steels replacing the friction along the way.
Had to wipe my @$$ after the runs down the road, not only does the motor sound mean above 7000 it really pulls like stink all the way to 9500... all I can say is WOW! For a shafty this one has some real bite to that bark. It just wants to keep pulling and hard.
So what to b!tch about... Still have to do the fork seals at some point and replace the rear tire, a question for the group: what is the biggest or "best" alternative rear tire size for the 750RJ? I have a line on some 130/80 tires but I'm concerned with the wider tread rubbing than the aspect. Eyeballing with a vernier caliper says the 130 would fit but I'd trust past member experience more. Don't worry about being polite about tires, I'm not politically correct.

 

Today was another hundred miles of just cruising along, I did pull the plugs for a quick check and they're a darker tan but nothing offensive. Got a few complements from fellow riders about the nice survivor and got to thinking about possibly painting things up, I can't find the Yamaha brilliant red in the PPG database so I might jump off the rez and go with the GM 92U which is a dark cherry that's used on my '05 Impala. I have a pint of base now and the mix is 5:1 so this could cover things well, I'm already set up for HVLP. Depends on my ambition level which isn't the same at 54 years of age.

Here are the two side-by-side to get an idea of the color, the Impala needs a wax.

 

Was going to ride today but stuck my nose out the door and said... nope too cold. I keep forgetting we're in early march and normally its in the low-30's. Maybe this weekend as the weather wimp is promising upper-50s. Tomorrow is get a Bosch Day/Night vision camera looking on the bike parking pad with a motion light, small town has some new riff-raff now and they're learnin' the ropes.

 

No from me. original colour is better

 

Have to agree with Minimutly on this one. I played around in GIMP (LinUX Photochop) doing various color fills & overlays over the stock colors and nothing screams 80's Yamaha better than that brilliant red so I'm going to look into a custom match. The only change I made on paper was removing the YAMAHA badge from the tank and going with gold tuning forks and a carbon fiber pattern to the lower edges of the side panels in place of the flat black.
The closest red I can find is what was used on the 1988 Gen-II Mazda RX-7, I had a Turbo-II car long before climate change and found a stray can of touch-up on the shelf, if time allows I may do a mix with some metallic and spray a swatch or two. The color is still available... for $50/pint!

Have to take the carbs to church this weekend, I filled the tank with 100LL AvGas and I think it dissolved some crud in the tank and that has settled into the #4 pilot passage as I get nothing at idle unless I put my hand over the inlet to pull up some raw gas. I religiously turn the fuel valve off a block from home and run the carbs dry before parking, there's also a new automotive style filter down there. Give me something to do this weekend as we're going to warm up for the week and I want to get some miles on. Also threw a new spare clutch cable & bulbs into the rear cubby, not if but when I need them.

 

Went to crank the bike today, and the carbs started flooding out, gas everywhere. Thought the petcock might not be working right, and was letting gas continue to flow in the ON position. Tried a different fuel delivery method, and gas continued to leak out of the carbs. So, pulling the carbs off tomorrow to take a fresh look. Might have a petcock problem, definitely have a carb problem. Seems like a new one as well. I didn't replace the floats when I rebuilt the set, I did replace the float needles.

 

Seems like a weekend for carb work, guess we need some church'n up

Just bought a new Kenda K657 Challenger for the rear, gonna need it sooner'er later.

 

Sudden carb flooding has more to do with rusty bits than carb faults - time to empty and wash out the tank?

 

Spent Saturday in church and followed the factory bible to the letter, what I found was the AvGas I'm using softened the adhesive inside the fuel filter and was dissolving it causing the paper element to break loose. Found the dissolved glue puddled on the bottoms of the bowls and plugging the enrichment passage leading to the air throat. Spent sunday morning cleaning and passing little wires thru all the passages followed by an acetone based cleaning spray to clear everything out then wet set the floats and wrestled everything back on the bike.
First twist of the starter and it was running, throttle is crisp but hot idle has more of a "random" thump exhaust note like a cammed vintage V8 and no amount of fiddling with the pilot screws settles it down. Vacuum is even and balanced and the flame color is a soft blue, I'm at a loss with this one. Before it was much smoother, ideas?

 

Did some test spot cleaning of the engine on the 82 XJ650 this weekend with some of that "totally awesome" dollar store cleaner.
Seems like any other cleaner. Nothing special to me, just cheap. Way too cold to do it outside so waiting for it to warm up.

Weather warming up here in Maryland this week!
And with clock changes, I foresee daily after work rides again in my future.

 

Opinions? Cyls 4-3-2-1 looking almost perfect

 

I was thinking that I needed to drain the tank into a coffee filter and see what's floating around and pull the carbs off and see if anything is clogged up.

 

Today I removed the head from a "spare" 750 engine - the camchain was broken, so I expected to see bent valves, but they were ok?
Anyway, the cam bearings looked dreadful, like the oil was full of metal bits, otherwise I wouldn't have lifted it. one thing I noticed was the bore wear - i could feel it..
One of the bores was oily, one had water ingress, all felt worn, but I haven't measured them yet. I have a strong suspicon that this engine is scrap.

 

one thing I noticed - the head gasket overhangs the bores (by a mm or so) - is this normal or has someone slung on a 650 gasket?

 

Never seen a head gasket intrude into bore space. It wouldn't last long.

 

Worked on the bleeding the front brakes. After removing the bleeder valves and let sit overnight. Then used a body messager on high on the lines to get air pockets out. Still can't get any pressure going on the brake. Just like getting some wrenchen on the bike in at-least.

 

https://www.amazon.com/gp/product/B0BPC5HSXH/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

@Secacsm89
This thing is great for bleeding!

 

That vacuum bleeder is the easiest way. Here's why it is so difficult to build pressure from a dry system that has just been opened, replaced, drained, etc.

The brake fluid exists in a few areas inside the master cylinder. Area "A" is where you dump it in the top. There are two orifices in the bottom of the reservoir bowl. Area "B" is where the high pressure to your caliper is built when the piston moves forward. The high pressure is contained by the front seal. Brake fluid only enters this area through the small orifice. Area "C" is low pressure fluid that is always open to the reservoir and easily exchanges fluid through the large orifice. When the brake lever is release and the piston relaxed, the spring pushes it all the way back until the first seal is parked just behind the small orifice. As soon as the piston moves forward, the small orifice is blocked and the high pressure is contained and pushed further forward. This orifice is intentionally small so that pressure can begin to build as soon as possible during the stroke of the piston, and so the lips of the seal are not "splooshed" out of the hole by the high fluid pressure. Any leakage past the first seal winds up in area "C" which returns it to the reservoir.



When the system is dry, and you fill up the reservoir, this is how it looks. Area "B" is still full of air because the brake fluid doesn't like to flow through the small orifice, even when the orifice is clean. Pumping the brake moves the fluid in area "C" back and forth, but it is not generating any pressure. A couple things will prevent area "A" from ever filling. If your brake lever adjuster is too tight, the piston will be parked too far forward, blocking the small orifice. If the small orifice is dirty or blocked, it will never pass fluid. And it is so small that even left alone with gravity, it just won't fill or will take forever. That is why using the vacuum bleeder helps so much. It will forcefully draw fluid out of the reservoir, through the small orifice, filling area "B". Once you get some fluid in there, pumping the lever can help due to the vacuum of the retracting piston (you can watch tiny air bubbles emerge from the small orifice), but the vacuum bleeder is still a faster way to get there.

 

Roast, nice pics there and explanation and why I never understood the idea of tying your brake lever closed then leaving it all night. I tried that one time and did not work. Got a vacuum bleeder that hooks up to a compressor to use the venturi effect and never looked back.

 

Yes, never a good idea I agree, but of course the head is the same as the 650, so the gasket sits against the head - I've no idea what the clearance is between the piston and the head. Whatever, it's lasted long enough to wear the engine out.

 

Roast that is a great explanation thanks for showing that!

 

That is a really good description of how the brake system works and it highlights the importance of keeping everything clean. Very well done.
I use an old refrigerator compressor as a vacuum pump and a small glass jar with the hoses poked thru the lid to power flush brake systems be it bike or car. Just run the fluid thru until it's clear.

Maybe that explanation and graphics can be added to the catalog?

 

An old timer taught me a cool trick years ago, reverse bleeding. Get one of those big hypodermic needles they use to inject marinade into meat and connect a piece of tubing to the end and put the other end over the brake bleeder fitting. Fill the hypo with brake fluid, crack the bleeder open and force the fluid up through the caliper back into the master cylinder. Works like a snap! On a single disk setup chances are you won't need any additional bleeding.

 

Since the bleed nipple is at the top of the caliper, I have always felt that this method can get air out of the lines, but not out of the caliper cavity. So you want to pump bleed at the end. Vacuum bleeders that hook up to a compressor is the way to go in the long run. I have lots of brakes to periodically bleed so its an investment.

 

If somebody came up with a 3D printed extender cup for the top of the master cylinder that would be slick! Then you could add extra fluid and crank the bars over so the outlet of the master was uphill with no spills. Dump a pint in the top, suck it out the bottom till the level was good. Flushed, bled, ready to go.

 

Why not adapt a top cover to say a small paint reservoir from a gravity feed gun?

 

When bleeding car brakes, I would up-end a pint can of brake fluid over the master cylinder reservoir and it would keep the res topped up automatically without any spills.

 

That was sort of my idea for making the cover with a reservoir

 

Is it a straight or a flush if you collect all the '82s? This bike was actually a two-fer deal with the 1100 that I finally went back to collect. It looked like a scrap pile, but I threw it in the truck and figured there might be some parts to pull, but on second glance...I've seen worse! Complete except for one busted flasher and mirror (side covers came with it). Nothing really seized up, motor turns, just lots of corrosion on the aluminum. Seat cover is crispy. I dunno. This one will just have to sit for a while. But hey, I've been wanting a 650.

 

Well I can't believe it. Was gonna push the 650 into the far corner of the barn this morning, but figured why not throw a battery in it...just to prove it's a basket case. After rolling the fuses in their clips everything worked. Even the horn. So I dumped some fuel in the carbs and the dang thing fired up. Had it running on a bypass tank as the old fuel lines were garbage and petcock seized, but incredibly the tank is rust free. As an added bonus, the frame isn't even bent on this thing! I've never seen something look so decrepit and run.

 

Never judge the book by its cover, a little effort would make that a badass bike

 

Unbelievable. Pulled the carbs and cleaned them out. Not all the way to church, but we stuck our head inside the revival tent. All slides stuck, 3 floats stuck open, half the pilots blocked, 3 choke bowl jets plugged. The ablutions were satisfactory, and the dang bike purrs now. It's a loud purr due to rust holes in both mufflers. Took it for a spin around the pasture. The lack of brakes kept me off the highway, but I'm second guessing that decision. Not bad for a bike that would have just rotted into the ground elsewhere.

 

You should have seen my carbs when I pulled them apart, they had to spend a couple of days in the church of solvent.

 

took my gas tank off in over 20 yrs!
My sidecar bike quit working last September.
I took it to work one day, and when I went to move it into my garage it wouldn't start so I left it over the winter.
It was an old battery anyway so I had planned to replace it.

I put another battery in it today I had on hand.
Its a 3 yr old car battery that was never used but I have it charged and reading 12.9V
When I measure the main fuse I'm already down to 11V and the other 3 fuses lose another V.
I'm going to start by inspecting all the wiring plugs.
There are green custom wires in the harness I don't even remember doing LOL
I bought the Velorex sidecar in 1989 and I have 20,000 kms on it.
that's 35 years. Paid full insurance all those years for 571 kms a year.

 

Nice machine you got there.

 

thanks, its nicer when it works.
I forgot to mention last fall I had tested the starter motor on the bench with direct voltage and also tested the relay with a light bulb.
Just loosing too much voltage to turn it over.

 

oh and I tried boosting it with my car and It got maybe a revolution so there's no break in the wiring.
I redid the main ground wire connections to the motor already.
And lubed the starter button as it was a delayed reaction

 

You will have it fixed in no time, voltage drop somewhere.

 

My son and I got the 550 and 750 out to enjoy this heat wave in the NW. About 100 miles on the backroads. Good warmup for spring. I still need to fix the starter clutch on the 750. It will really bite me one of these days.

 

Unfortunately we're back to our "normal" march weather and it arrived just in time along with my new rear tire. I did manage to get another 150 miles on before the temps took a nosedive and checked the plugs to confirm my suspicions that it's running lean but without a garage things are going to wait. Running #122 mains and #42 pilots and I'm going to swap in #124's and see where that takes things... rather run slightly rich & cool.

 

Rode both '82 and '83 XJ650 on short 30 min rides each. Colder weather coming and not sure I"ll be able to ride them for 2 weeks. I did not winterize them and kept riding them every 3 weeks or less.
I need to hook up a db meter to them cause I swear the '82 is louder. May be my imagination. '83 bike warms up faster in the cold then the '82 does. Both running smooth. But the '82 has this cafe racer/ brat type low profile seat so its not nearly as comfy to ride.

 

@Simmy is that the original Yamaha fuel box you have on your machine? Could that be the culprit?

 

@Simmy is that the original Yamaha fuel box you have on your machine? Could that be the culprit?

 

Weather guessers are threatening us with a large snow event so I rolled another 120-some miles on today despite the winds and this brings me to a question regarding a moderate size windscreen; what is available or recommended for the XJ750 SECA? I don't have a fairing and really don't want one, I've seen a few other 550 members bikes with what looks like a shorty screen but can't seem to locate anything. I had a few gusts this afternoon that about took my helmet off along with my head and while there isn't much inside I do need something to hang my hat on.
Thanks in advance
Brhat

 

it is original but I stand by it.
This bike has rarely seen any rain, still perfect condition

 

"Weather guessers".........ha! That's exactly right..........

 

When they guess bad weather they're almost always on the mark.

 

I finally diagnosed my sidecar starter problem.
Once I had a full battery reading 13+V I measured the voltage at the starter motor post and got 13V.
The starter motor wasn't moving.
I put in a spare starter and it turned over with the button, all good.
It does still delay after pressing the button, I'll have to try another solenoid.
I went through all the plugs on the wiring harness which wasn't time wasted.
The alternator 3-way block was starting to melt on the female side so I salvaged a block from a spare harness.

I put the bike back together.
I started it up and and turned it off prime and let it idle.
The bike stopped, wouldn't start until I tried it on pri again.
Then I noticed it was leaking gas out the petcock body.
When it was in the on position it was sucking air so not opening the gas.
Then on pri it was spitting gas out the leak.
It wasn't that bad so I was able to warm it up and change the oil.
And topped off the coolant.
Once I get new rubbers for the petcock I will be ready for another summer.
I rebuilt this same petcock in 92 I believe. It leaked over a winter and destroyed a side cover.
The original rubbers lasted 10 years, the replacement parts went 32 yrs.