What did you do to your Yamaha today?

My record keeping is a little less legible ...

 

Looks good to me

 

So I started thinking about the accuracy of my compression gauge and puffed it with my air compressor... readings were all over the place. Sometimes it would read higher and others were lower but never twice the same so it went in the scrap pile and I took a trip to the local pawn shop where I found an older Kent-Moore gauge set for $100 which I gladly paid, Made in USA.
Screwed it into the #1 jug and puff...puff...puff right away its showing 140 after three passes and all the jugs are within a few pounds. Not quite the book spec given the slight seep of the exhaust valves but good enough where I felt comfortable running it another year and today was the official start of my riding season and I took it out for a shake-down run. A little chilly but with two layers I was good enough for a 30 mile run up & down Hwy 65 going for the redline on the shifts. Feels alright... not great running rich and breaking up on the top end, at first I thought it was lean so I gave it some start lever and it got worse. Floats are at spec but I'm running #124 mains right now so tonight it's swap in a set of #122's and if it's warm enough tomorrow we'll see how it runs.
Overall it was a good run and getting back on the saddle felt great. Been too damn long!


Someday I will put the resistor back in for the BATT warning... maybe.

 

I purchased my resistor from Axe-Man Surplus in St. Paul. I live the of things you can find there.

 

Grew up in that AxMan on University & Fry

 

Long story short & Yamaha related... Most of the "newer" blue cabinets of resistors along the row before the east wall and on the end of that row came from my late Elmer & mentor who got me into motors with two wheels first Rupps then the one year only YZ50 the summer of 1980. He ran a little sideshow called Midwest Recreation and worked with the YMCA, we were neighbors and he got me involved with his program. He was also a brilliant albeit scatter-brained electrical engineer who had numerous patents from his time at Magnetic Peripherals (before becoming Seagate) where he designed the head amplifier used in hard drives that's used today and Cardio-Labs (?) and he worked with Dr. Jarvik designing the brains of the early pace makers. His passion was motorcycles and after the loss of his fiance he focused this to the kids programs. During the 1980's he was a one-third owner of a high end audio/video boutique called Audio Innovations located in the Edina galleria and got me a "job" if you will as a gopher/stockboy/cleaner, I also had the task of cleaning and maintaining the bikes used in the program and in return all of my "wheel time" was free and I had first dibbs on whatever bike I wanted to run. He was a Yamaha man but also had a Honda CR500XL which I managed to tame.
So fast forward to the 2000's. He started having memory problems and eventually succumbed to dementia, two years prior to this he lost his home of over 60 years to a foreclosure as he forgot to pay on an equity loan so before the doors were locked everything was cleared out. He had rows upon rows of those blue parts cabinets full of everything you could imagine and most everything was bought up by AxMan and put out on the floor as it is today. The significance here is most of the labels on the drawers were handwritten by me over time, appropriate they would end up in a retail museum, that particular one in the picture was written by him.

His name was Mike Boot callsign KD0SB with the SB being Super Biker.

 

I'm starting to think a little SECA get-together could happen at the AxMan store this year... thoughts?

 

So back to the topic.
Added two 80s vintage lights to the Atari and a resistor directly to the battery sensor lead. Left red light is a brake light confirmation as my brakes are rather quick to apply and don't always show the rear light right away and the right hand light is for the fog as I don't always see is on say on a cloudy day. I reloaded them with LEDs and tucked everything in the Atari housing.

 

Not perfect, but all within spec now.

 

More like right on the money.

 

I'm in! I would never pass up a chance to hit the Axe Man!!

 

So the latest from my end is a new clutch cable from the folks in Medford Wisconsin. An aftermarket piece that thankfully was NOT made in China but everything feels just as it should. Routed it in this morning and set the relaxed play, now I have to wait for the polar vortex to make its way out so I can take it for a run down the highway. Also got the oil filter element, a WIX 24934 and will be making a trip to the local unfriendly Walmart for a jug of Rotella T4 and some of that zinc fortified STP in the little blue jug.

Last night was doing battle in the headlight bucket with some of the wiring, when I switch the fog over to the alleged high-power Hella I ran a separate power and ground up but not in the vinyl wire sleeves so everything got pulled down, cleaned and checked over before I pulled the high current wires in and terminated them. Power is controlled by a 20A Bosch cube relay fired via the thumb switch on the right side pod which gets supplied thru the headlight relay. Also reworking the little +5 volt DC supply I was using for the Garmin, that has been replaced with a RAM mount for the smartphone and three more USB DC cables are being run for the GoPro cams. Was going to use a smallish USB hub but the cameras have a higher demand for charging. This might change if I can find something suitable.

So how many SECA's could we line up along the side of AxMan? I think a row of them would get some attention.

 

If you ride over to my place I could put it 3 900s, a 750, and a 550 Seca.

 

Maybe it could be a meet at a location who has the most? Dunno but I'm for a SECA meet either way.

 

The most Secas? Looks like you guys might as well go to The Central New York Carburetor Clinic at @hogfiddles.

 

That might impose a question of insanity.

 

So back to the bike, pulled the oil pan off this evening with the intent of cleaning out the level sender of whatever was holding it up and found this... a big fat nothing. Not a flake of metal, no chewed up chain guide just a tiny little of that super fine crud from the 40-some years and 43,850 miles in the back corners. Given the wrestling match I had getting the pan off I'd say this is the first time since the engine was assembled. Starting to believe I have more of a gem than previously thought.
Further inspection using a camera shows the inside of the engine to be Zestfully clean and the pickup screen is completely clear of anything.

 

So I ordered the engine gasket set today as I'm going to at the minimum pull the head and lap the valves, a question I've been battling is how much slack should the starter drive (HiVo) chain have and what the acceptable limits are. Bike has 43,850 miles on the clock with the majority of them on city streets and that chain isn't pulling much more than the alternator or being pulled by the starter so I don't see much stretching it but I'd like to make sure anyway. Factory book has nothing that I can find and I'm not seeing anything in the xjbikes tech section so maybe someone here could give me a better idea? Pushing it up hard from below yields about a half inch of play which to me seems loose but acceptable.

 

12.5mm your chain has, new chain has around 6mm of play so l think it is acceptable. Your chain won't be close to the oil nozzle.

 

Didn't think it was bad or out of spec but I always value a second opinion. Thanks Franz.

So more poking around reveals the real reason for the stuck low oil indicator and occasional ignition miss on coil #2... Wires running along that side of the pan that are secured with the little springy clips are chewed thru and appears to have been intermittently shorting, when I got the bike I noticed the black (ground) for the trigger coils had been cut thru but thought maybe the PO had done this and never gave it a thought but looking closer it was the little clips wore thru the outer jacket and eventually chewed the wires. A few layers of heat shrink are in order.

 

(technically yesterday)

Before


After


Purrs like a kitten.

 

I rode to work for the first time this season. I think I still need to do some more fine tuning on the carbs — she runs okay, but the idle is a little off. It comes down to about 1500 rpm when I let off the throttle, then takes 30 seconds or so to get back to ~1200 where I set it. The idle also sometimes drops to ~1000 rpm after hard braking, which seems like a fuel level issue, but those were all wet set a few months ago.

When I synched the carbs during winter, I was unable to go for a ride and get the bike really warm for the task. I did the best I could, but I imagine doing a sync with the engine warmer would help.

Also, man those brake upgrades make a dramatic difference. New rear shoes, steel braided lines, and high performance brake pads make it feel like I’m stopping a bike that’s 100 pounds lighter. Amazing improvement.

 

Might want to clean the idle passages again after sitting for the winter, it doesn't take much gum or whatever in the passages to lean them down. I've found thru experience the HSC32's really need to be kept Zestfully clean to work right and this matches what the technical section says as well.
Here's what I have found with the XJ750; anyone can make them run, adjust the carbs a little here and there and it's good enough to ride but if one really takes the time to match and balance everything right to the book then go back over their work a few times this can really make the bike sing. Dead smooth idle note, fluid launch be it from a stoplight in heavy traffic to wheel off the ground thru 2nd gear or a long road trip the extra double-double checking really pays off. I'm running #124 mains and #42 pilot jets on the stock emulsion tubes with the floats all set to the book and idle screws matched to make both an even exhaust note and vacuum between the jugs after doing a color tune using 4 clear plugs... yea I'm fanatical with this. The engine is stock except for a 4-into-1 Kerker Pro-Sport exhaust and NGK BP7ES plugs breathing thru the OE airbox. The bike has spanked an FXR and a few modern sport bikes (inexperienced riders) and runs timed mid-12's while doing 35 MPG on the interstate at 80-85, it also has great street manners and I attribute this to setting things up right and not taking any shortcuts.

As for the brake lines... just getting back to work and caught up on the cashflow, there will be a new set on my 750 SECA in the coming weeks and they will be coming from Chacal.

 

For those of us that have to put them away for months at a time, I really recommend the upgraded float bowl drain screws from @chacal - making sure you get the fuel out before storing them helps ensure you don't get any crud in there!!

 

There you go, notice to all newbies: right there is your secret to success.

 

Someone wants to go for a ride...

 

That XJ is purring now .

 

That's little Dorothy, a real sweet kitty. Her hooman is away paying his debt to society for a DUI and won't be back until next October.

 

Here's why they must be Zestfully clean. Look carefully at the pilot jet on the right, just a super small sliver of junk that caused my idle problems. It was smooth enough to ride but I could tell it was slightly OFF by the exhaust tone, just a little "plub-plub-plub" sound.

Rack is getting disassembled for a good biblical cleaning and new shaft seals.

 

Ongoing work on my XJ this evening thanks to the snow keeping me home from work got a new front tire wrestled on the rim, replaced the ancient Metzler with a Kenda Challenger which isn't a bad tire and I'm hoping this will somehow convince the warmer weather to arrive a little earlier... well I tried anyway.

 

Turned over 44,000 miles this evening

 

They cleaned up pretty nice. Pistons look good. One less thing I have to buy.

 

Today I removed the ape hangers, installed Emgo GP sport-touring handlebars, unlocked the brake master cylinder, fixed and adjusted the clutch, removed 15 lbs of accessories, junk lights from tractor supply and 15 feet of garbage wire. I found the missing starter bolt, it was being used to attach a junk tail light. Then while I was removing the stretched right hand control wire harness I noticed that 2 frame bolts are missing... Have no idea where to get replacements, whether or not the frame is supposed to be threaded, or anything else. I'm just going to keep chipping away until it's a bike, but I'm beginning to seriously doubt that it was "running when parked"

 

You say that like it's a problem...........

 

Those frame bolts have rattled out from my 700X before too. I replaced with stainless socket caps with lock nuts on the inside (the kind with the nylon insert). I don't remember the size.

 

Thank's for the info, i thought the motor had been out and some jackwagon lost the bolts, It still appears that the motor has been off the frame, but the numbers match so i'm gonna take a closer look.

lol I find all these "mods" comical. It amazes me the ways people are willing to rig a bike. I mean sure, you need to rig a light or a broken clutch cable just to get home sometimes, but if you do that 50 times and never actually fix anything you wind up with an unrideable bike.

 

You should what happens when I shake my head...

 

Think of the mindset of someone who does that.....

You also end up with a bike that will likely kill you.

 

I know I’ve already made a post about replacing my throttle shaft seals, but man… I can’t get over the difference it has made. The bike ran okay before. I never saw any of the extreme vacuum leak symptoms (runaway idle, overly lean mixture), and I never had any point of comparison to know something was amiss. It’s how the bike came to me, and I assumed that’s just the way XJs work.

But now, my goodness. Synching is easy — before, it was hard to get it dialed in. Its idle is rock solid at ~1050 RPM when warm, whereas before it was difficult to get the idle RPM below 1200. Throttle response is cleaner. Less vibration at around 4500 RPM where it usually gets all buzzy.

I already adored my XJ650. Now it feels hard to imagine wanting any other bike.

 

I bought a 1982 550 Maxim for my son last year for $350. Found out afterwards that a PO had used some kind of putty on the bottom of the gas tank to cover some holes. I bought and tried using a $66 Benzomatic MAP gas/oxygen kit to braze the holes but it was to and used up oxygen cylinders quickly. I used POR 15 to line the tank but didn't wait the full recommended cutting time before putting gas in it so it leaked. I then tried using the low temperature welding "crayons" off of Temu (Do NOT use inside, the funds are horrendous!), that also didn't work well so I sanded it down to bare metal and took it to a local welder who had treated me right in the past. He couldn't give me a ballpark estimate to braze it or weld patches over the problem areas. I then called a gas tank fixing place that wanted $300 to weld it pretty and not line it. The cheapest decent looking eBay tank is $180 and has dents but I can't tell if it has holes....

Then my brain hit on an idea....pop rivet patches/JB Weld, and lining the tank.

I'm letting the JB Weld cure in a warm area for a few days before I use the POR 15 to line the tank and this time I'll let it cure for a few extra days before I add gas to it... I may even make it pretty next winter using some body filler. #redneck engineering

 

☝️I did this pop rivet fix along with a shitload of solder one time on a Suzuki Bandit, and it didn't leak. The trick is to burn out all the flux from the solder so that it's solid, and then don't try to grind it down flat cuz it'll fall out. I told the person for who I fixed their tank this and they stupidly ground it down and then said "oh the solder fell out while I was grinding. why'd that happen? you don't know how to solder"

Somebody has broken my fuel petcock, so today someone gave me a Honda Shadow tank, it looks pretty cool on there, but using that tank causes seat fitment issues.

 

So today I did the "make your own moto battery kit thing, and I got my bike to start and run, but I had to stay on the gas or it would die. It sounds good as long as you're giving it gas. I had a very difficult time trying to get it to start again. I think the fuel mixture is too rich on the pilots. It's got 42.5 pilot jets in it. It had pods on it which I really don't want to run, but there's so much fuel it's coming out of the carb mouths when I'm trying to start the bike. Once I got it to start and idle by leaving it sitting for a while and coming back and pushing the start button and it started right up, I had the mixture screws set to the factory settings. But only ran for a minute. Then it just keep seeming like there's way too much fuel. And now I have the mixture screws set to 1&1/2 turns out, and it still seems like there's too much fuel. I'm aggravated because it's been a long time since I've had to deal with this and I feel like I'm going to be forced to use pod filters because some jack wagon broke the pilot jet screw heads off on two of the pilot Jets. I don't have $100 to sink into 4 vm34 knockoffs and another 75 for a 1 into 4 throttle cable.
Pod filters do not flow more air, they reduce intake velocity and that negatively affects horsepower. I really wish people would stop doing this mod and messing up the carbs while they're at it. It's not that hard to take something apart and put it back together without breaking everything and permanently screwing it up to where it needs to be rigged. Also it's drinking the gas when it's trying to start

 

But they look so cool!

 

Not as cool as a perfectly running motorcycle.
For real though he done all that to the carbs just to have undersized pods that were crushed up against the frame, in clamped into what appears to be chunks of rubber radiator hose hanging off the carbs.
A few minutes ago I finally removed the idiot fuse panel cover to discover that the whole reason why he had all that rigged wiring running around all over the bike was because he had missing and blown fuses he was bypassing by wiring in all this extra wire and switches... Now my temp gauge works again, since I replaced the fuses, so I'm assuming the fan will also work now as it was supposed to from the factory. The guy had actually broken out the lenses from some of the idiot lights in order to get to the bulbs...

This thing must be way too rich because if the carbs are dry it starts really easy with just a very light spray of ether.

So maybe I need to start my mixture tuning at half a turn, and work my way up until it starts. I'm probably going to have to pull the carbs off again and try to get those pilot jets out of there somehow, maybe with an easy out or something but that could be a disaster. Or maybe if I pull the baffles out it'll lean it out enough to start with open carbs and with those oversized jets in there. I'm pretty sure that it's supposed to be like a 37.5 jet, from what I've read, and I'm pretty sure those 2 jets I was able to remove said 42.5 on them.

 

Been down the carburetor road to the church of clean many times, for my seca 750 it used a #40 pilot and #120 main with the OE air box but it runs a 4-into-1 Kerker so I have #124 mains and 42 pilots with the fine thread idle screws out 2 turns. Starts easy and runs well with the floats set to the book. If I run hard it's wheel up thru 2nd and crisp beyond 6500 to the redline.

 

That's good information, I wonder how your bike would run with the stock exhaust on it with those Jets. And I wonder if pulling my baffles out would make this thing easier to tune

 

Those are all good questions and there's a lot of great information in the tech section of the forum. Honestly I don't know how my bike would be with the stock pipes but as I understand they're not a limiting factor. I got my 750 SECA in six milk crates with the standard disclaimer of Some Assembly Required and the Kerker was part of the package. What I do know for sure is the hitachi HSC32 (HSC standing for Horse-S#!t-Carburetor) is not at all tolerant of dirt or poor workmanship, the metering tolerances are matched to each 187.5 CC cylinder... just a few atoms either side of optimal makes a big difference.

Okay so it feels like too much fuel and there's some previous owner damage here. The best advice I can offer based on hard learned experience is to first clean the carbs and set the floats to the factory specs. They must be totally level on both axis using a clear plastic tube. I have found that just a millimeter off is enough to make riding miserable. The height sets the fuel level just below the main metering jet outlet that is the top emulsion tube, the main jet itself meters this fuel once there's a demand made and the needle is lifted by the piston, this is a result of vacuum created by the passing airflow in what amounts to a variable venturi. The standing fuel is sort of like the accelerator pump and this drops down some under demand and is replenished by fuel metered by the main and up to be mixed with bleed air around the emulsion tube, this is supplied by a jet in the carb inlet throat. The height of this standing fuel is critical in that too low it won't pull up enough when the throttle is cracked and that gives it the hesitation and breakup on accel while a too high a level feeds a smidge of fuel during idle and sometimes leaks enough to fill the cylinder or leak down the inlet. One millimeter is all it takes. Honestly if you're using starting fluid to fire the engine cold it's lacking fuel and running lean.

Last year I stuffed a small camera in my airbox to observe the action of the venturi piston under various realtime loads, one thing that was also very clear was the "impulse reversion" or "spitback" of atomized fuel in that critical 4500-6500 RPM running range and most of that accumulated on the camera, normally it's caught in that "log" section of the airbox where the inlet horns are, this as it turns out is a crude resonant chamber or plenum designed to take advantage of the reversion. Air pods effectively eliminate this plenum and consequently throws off the balance of the piston/diaphragm with respect to airflow demands.
Often times people see those air boxes as a detriment to performance not thinking about the engineering that went behind the reasons for it, Yamaha like any other manufacturer is in it for the money and they're not going to spend more than they have to to build the bike, the airbox design being a performance enhancement is an investment in the big picture... that edge over competition sells. If it didn't they would have gone with the pods or a generic air filter box as an OEM being cheaper than the 3-part molding process to make said resonant airbox, I work in plastics and know what goes into making a complex part like that.

So getting back to the problem at hand you clearly need to remove the idle (pilot) needles either way, they must be removed to clean the passages and the only way to make these run right is to zestfully clean the carburetors. Everything apart, soaked in carburetor cleaner not just sprayed and all the passages scrubbed thru then blown with an air gun. From there the emulsion tube holes need to be cleaned with a toothbrush as these are exceedingly sensitive to crud and everything carefully reassembled. Throttle shaft seals are also recommended. I don't know what engine you're running but I've found the #42 pilot jet to be a good match with the 750 and being the bikes were jetted lean from the factory for US emissions in those years moving up by two steps may work to your advantage with today's pump garbage. I believe in running an air cooled motor slightly rich. Pulling the baffles I'm not sure if that will make much of a difference as they're not restrictive to begin with.

Check out the tech section, it's very well written and considered by many including myself to be the authority of the XJ series. He knows what he's talking about and it comes from experience. Click on the upper right icon to see for yourself.


Link to the carb video

 

Today I set my mixture screws to 2&1/4 turns, cleaned out the gas tank, filled up the radiator with water, cleaned out all the brake lines with a guitar string, fixed my petcock, installed the gas tank, and the seat, and rode the bike. Turns out it only needed to be ran a little and now it starts and idles perfect, revs out nicely too. This thing revs quick I'm impressed. I haven't taken it on the road yet I just rode it around my parking lot, but wow! I got up this morning wondering if I would ever get the bike to run right...

 

Yesterday I fired up the 750 Seca for the first time this year. It was a bit reluctant to start at first, but I walked away and left it for 10-15 minutes and when I came back it came right to life. Took a quick run into town to blow the cobwebs out.

I'm reminded of several maintenance items that need some attention that I've neglected while distracted on the 900. Calipers need a rebuild, carbs need some tuning, and the speedo squeals like a pig at low speeds. Also in desperate need of a good wash and detail. But she's still fun to ride.

 

Excellent observation!