What did you do to your Yamaha today?

They’re supposed to be different.

The one with the washer and split washer is for the vacuum line clip. The short ones with washers are for the screw holes where it’s just a bare hat hole. The longer ones with no washers are for the holes that hold throttle and enricher cable brackets, and the fuel line clip.

most people don’t pay attention to the fact that there are different ones, so the get all mixed up/messed up.

 

This was the starting point on the float bowl drain screws. In order 1, 2, 3, 4. Nothing I have would grab 1, 2 or 3. #4 I got.....and every one of them looked like this when they came out. I’m 99.9% sure the PO ran a bunch of rust through this engine. The questions are for how long? How much? And will it run again? Regardless, I’m learning.

 

Excellent information, Thank You. I’m hoping/guessing that Chacol sells these in complete sets.

 

He sells whatever you need

 

Did some stand tuning, then took it out for some street dyno. The tune seems pretty good. May need to lean it out a bit more in 75MPH cruise range, but, other than that... good. Easy start, good idle, and good return to idle, good throttle response and power pulls.

 

With some help from Dave "Hogfiddles" Fox via the wiring diagram he sent me and a search here that showed me that the Maxim 750's do not have a headlight relay I fixed the intermittently on headlight on Lazarene. It was simply dirty contacts in the start switch. Way, way too simple. She has dedicated relays to supply power directly from the new fuse panel to the bulb via 16 gauge wire so now when the headlight is on, it is ON! Thanks folks.
Also new tires this week. I tried something new when the bead for the front would not catch and pop up. Just a small enough gap to let the air leak by. All the past tricks and cuss words did not work. The old fashioned Barbasol shaving cream is very thick and filled the channel just enough to catch the air in the tire long enough to push the bead up. It hosed right off and left a nice clean scent. Who would have thought?
John

 

And it's why the ladies only go wild over some bikers.....why did you let the secret out?

 

So, my throttle started not returning quickly so I pulled the carbs and found the action acted gummed up even though the springs and shafts were clean. Broke the rack and pulled out the #10 O-rings that were paired with the X-rings on three of the carbs. Throttle shaft movement improved a lot. Reinstalled and the bike started nice and ran good around the block. Today I pulled the tank to check for vacuum leaks where the 2nd O-rings were removed and synced the carbs. Took a nice long ride up to Lake Ontario. Had a scare on the way back when at a stop light the rpms went way down and then the engine stalled. Looking at the fuel filter, it looked empty so I filled it with prime setting and made it home. Upon inspection I noticed the vacuum hose was partially kinked. I'm hoping a lower level of vacuum caused an issue with the fuel supply.

 

That would be fairly nerve racking; I had a little bit of fun on my Harley today; went to Lowe’s for some acid for the 750 tank I bought. Once I got to Lowe’s the bike started surging and I could tell there was a major misfire happening. Felt my secondary ignition and I got zapped by wire number one . Think I found my problem.

 

Getting ready to clean the new tank for my 650, I got a good deal for $125 for a fairly nice 750 tank!!!! Woooohooooo. Then after I clean all the rust out I am going to do a coat/ seal on the inside of the tank. Then I need to put the headlight back together along with my front turn signals. Then I’ll be back to riding my XJ for the season.

 

Some of the new toys arrived.

 

New jet kits, O-rings for the fuel pipes and throttle shaft seals. First shaft seal came out in tiny little pieces. Got smart, soaked the second one in alcohol for about 15 mins. Came out whole. Clearly they’re NOT working anymore.

 

it can never be said enough Replace your throttle shaft seals

 

Did some more street dyno. One of the mods I did to the Microsquirt ECU while the bike was down (since last August) was to add a Bluetooth serial module inside with a switch so I could switch between the stock 2.5mm plug and Bluetooth. This works really nicely. Besides not having to worry about ground loops and such on the RS-232 cable, I don't have to pull a side panel to connect my laptop, and, even better, I can data log to my phone while riding instead of having to strap the laptop to the seat.

So, anyway, today I rode around a bit to get at better idea of where I am on the fuel map when cruising on the highway, so I could see if that part of the table needed to be leaned out (it did).

 

Synced my carbs again to be sure they stay in check and ran compression tests on all cylinders. They’re all right at the standard for a 700 (156 psi). Everything is right about where it should be, just in time to clean and strip everything down to paint the frame/ tank /fenders and put it all back together. That’s the next step (at some point)

 

Where did you find the LED headlight?

 

That clearly can go another 30 years

 

Definitely. I’m currently busy collecting bread ties, plumbing parts, old wires from houses, Elmers glue, baling wire & blue and green duct tape.......so I can get this bike back to original condition.

I’m thinking of using a big candle behind a magnifying glass for a headlight.

 

Hahahahaha

 

As it turns out, the cap arrived but is not a gold cap. The lighting made it look that way. Oh well..... it’ll get a regular chrome cap instead.

 

That might be too bright

 

Good call. I’ve decided to go with fireflies in a jar strapped to the bike with an old belt I don’t use anymore.

My first carb rack. Hats on Friday.

 

Adjusted the injection timing, to what's a first guess of what should be about ideal. Ran some more street dyno and updated most of the fuel table. Also tweaked warm-up and acceleration enrichment a bit. Starting, idle, and driveability are all pretty good right now, as is mid and high end power. Definitely curious to see how fuel efficiency looks on longer trips. Next step, once the weather's a bit more predictable and the lock-down is not as strict, is a ride up to Cripple Creek (10000 feet or so) to check how well dialed in the altitude correction is.

Also hooked up the B/W that used to connect to the TCI to the ECU so I could re-enable the side stand safety circuit. Now it works just like it used to: cut the ignition if the clutch is out, side stand down, and not in neutral.

 

I got a couple stable-mates for (the rest of) my xj’s.....both have good titles
They will both come back to life

 

My bike was manufactured 7/81. Some PO painted the gas tank a heavy metal flake gray. It’s pretty hideous, it also has a large dent in the left side. I’ve had the tank off for a month and it’s marinating in EvapoRust.

The underside of my tank is that ^^^^^ color of red. What’s that called and is there a code for it?

 

It would help to know what model your bike is.

If it's a Seca 750, it's called Yamaha Brilliant Red.

Sounds more like you have a Maxim, though. No idea on that color name.

 

I thought it might be easier to move the whole bike if, by a long shot, I could get it up start... tank smelled ok. I hooked a battery, hit the button——
Slow R-r-r-r, let go of button. Then about a second or two later... GURGLE GURGLE GURGLE.

??????

Starter button again—-


rrrrrrrrr

gurgle gurgle gurgle


Looked around—- hmmm.... oil pouring out of the bottom of the airbox making a big mess.

tried one more time, just to try and clear it a bit...


Rrrr.... click. Hook up aux power... click.

Well, time to push it up to the shop.
Guess it sits there for a bit .

lol

 

1983 XJ750 Maxim models proudly wore the Code 7J "New Ruby Red" color.

 

Today, so far, I am updating this list with what I did yesterday: modified the AFR table and went for a ride with my laptop under the cargo net to apply those changes to the VE table. Also made some manual changes to the VE table outside the typical Auto-tune area. New tune cleans up a couple of spots where I wasn't getting as smooth a response as I wanted when just starting out. Definitely better now for puttering around just off idle. Feels great for mid/upper power, but still might need to be leaner for highway cruise. I also disabled noise filtering, which I'd had on forever on this tune. I don't think it's needed anymore - if it ever really was - and having it on adds to the processing load for the ECU, which can make it a bit glitchy when data logging or auto tuning. Even with it on, though, the 15 minute or so auto-tune run I did was fine.

I do wish my data logging app included speed. It does include latitude and longitude, but no speed. Anyway, net net is I think I'm still around 13.5 or so when cruising at 65MPH. Will probably do some more data logging over the weekend to better isolate where I am on the map at 55 to 75 in fourth and fifth gears, and lean those out to somewhere around 15.

 

Figured it out. It’s Black Red (002J). Gonna change to Frost Silver.

 

Hello all, first post for a new member. This has been a really cool thread to read through. I bought my 1982 Maxim XJ650 about 5 years ago from a young man that "... rode it until it stopped working." Named her Loretta because of her attitude.

To get back on subject; Today I rebuilt the front caliper and master cylinder. I am in the process of an "as is" restoration; make it mechanically sound but not aesthetically perfect. I like to ride and she's just gonna keep getting dirty, lol. Take care and have a good evening.

Toe-Knee

 

Took about a 60 mile ride (first day out of stay at home order in Colorado) up to Woodland Park and back. Woodland Park is about 8500' elevation, whereas I live at about 6000'. I wanted to see what I could learn about the accuracy of my altitude compensation curve. Well... the bike ran really great... just smooth, good throttle response everywhere, good midband power...

So, I got to WP, and pulled into a parking lot, and checked what the ECU had to say at idle... aha! -9% of compensation from the O2 sensor. So, I dropped that part of the curve a bunch, and was still even about 3 to 4 percent rich, but I left it like that and headed back. When I got back home I checked it, and was kind of shocked to see I was running about 12 to 15 percent rich. Shut it down and let it sit for a minute, then restarted, and was initially lean, but shortly balanced back to pretty much right without O2 correction. So, I don't know why that is. I put the old curve back, because it looks like it wasn't terrible, regardless, and I plan to instead head up Pikes Peak this weekend. 14100' at the top there, so I should get a much clearer indication of how much compensation is needed for the low pressure end of the curve.

Plenty of options here for high altitude tuning, but not much for low. There is a spot in NE Colorado that's about 3300'. I'll probably take a drive out there in a few weeks to try to better define the upper half of the curve. I've done a lot of retuning since my trip to Alabama last summer, but during that trip things were far too rich at sea level, and I think that's probably still the case. Half-way to sea level should give me a decent idea of how far off I am, still, I think.

 

Slowly but surely. Waiting on Len’s Fusebox replacement. That’ll be interesting. This bike has no fuse box, the PO apparently threw it away and just twisted all the wires together with zero circuit protection.

Cleaned up the battery ground, didn’t realize it was copper coated until I started cleaning it. It was varying shades of apparently 38 year old rust and dirt.

Does anyone have a good closeup picture of the XJ650J starter relay? My ground wire from the starter relay is a big hairy woven steel cord, its a mess. I’d like to see what it’s supposed to look like.

 

Engine dismantling process going well. Cylinder head moving slightly but two seized broken studs on exhaust side of head. Having a beer then go back tomorrow with blowtorch and have another cautious attempt to remove it. Patience is critical so as not to damage parts.

 

So, it’s interesting what you can learn by tearing apart a parts bike—-

I bought an ‘82 750 maxim a couple summers ago...

a guy bought it to get running, but: no title, no key, engine set up because it’s stopped running for a PO in 1985, and was left outside with one spark plug out. (I doubt I’ll be able to get it to turn, but I’ll try for a bit).

Anyway, I thing I found out why —— when I pulled the kickstand off, apparently a couple of wires had gotten moved, and the front point of the kickstand had cut them. I guess that would do it, and would be tough to locate the issue.



so, now I have a bunch of 750 maxim parts available let me know what you need.

dave fox

 

Rode to the top of Pikes Peak (14110 feet). It was an interesting ride. Definitely going to do it again. Maybe in a bit warmer weather next time. Mainly did it to do high altitude tuning - baro adjustment. Learned a bit... mostly that there's a lot I still don't understand about how MS2/Extra's baro adjustment works.

This photo was not at the top, but a bit down from there. Maybe 13000 feet or so.

 

Interesting.....not much air pressure at 14,000ft. What is it using to read pressure? Is it reading atmospheric pressure or is it reading pressure somewhere in the engine?

 

Interesting......not much air pressure at 14,000 ft. What’s it using to read air pressure? Is it reading atmospheric pressure or is it reading air pressure somewhere within the engine?

 

The setup uses two MPX4100A 1 bar MAP sensors. One senses pressure in the manifold, the other is in free air for ambient baro data.

 

Still trying to remove cylinder head. The two studs on the exhaust side are sheared off and I have tried the blowtorch on them and the blowtorch holding on the fastener securing the cylinders to the crankcase. They probably have not been out since the bike was assembled at the factory. Going to try more heat and penetrating oil. The rest of the disassembly and reassembly should be straightforward once I get these corroded fasteners out. Not surprising really as they are the ones with all the road grime thrown on them. Time for a beer and go back to it tomorrow.

 

Fixed the horn, sort of. Seems that the horn often doesn't work. Today I checked first - turned on the key, pressed the horn button, and nothing. Opened the headlight bucket and grounded one of the pink wires, and the horn sounded. OK. Bad switch then. But, then I pressed the switch, and it worked fine. So I reseated the connectors on both horns, and closed it back up. Tried it a few times during the day, and it worked every time. We'll see...

On the flip side... it looks like I have a slow oil leak from, I think, the top where my spin-on filter adapter plate mates to the crankcase. Hard to see for sure where it's leaking from, but it definitely is leaking with like a drop every 20 seconds or so, only when running. I had machined a flat surface for the adapter plate and used Yamabond 4 for a seal when reassembling. I would have expected that to be sufficient, with the nut of the oil cooler adapter holding it tight against the crankcase... but apparently not. May have to pull this all back apart and add an O-ring slot and O-ring to it instead... ala the original filter cover. :-(

 

Got Cylinder head off had to drill out the two seized studs at the exhaust side of the engine. Holes were damaged when I got the bike. Need to get them welded up and redrilled. Now got a seized crankcase to cylinder bolt, be fun getting that one freed.

 

Yesterday actually. Finally got everything off the frame ready for inspecting and cleaning. Found a ding in the left side lower rail a few inches in front of the kick stand mount. From what I know the bike was dropped in like '83 and the sold to my father because the guy decided he wasn't ready for it. It was ridden on and off until about 2011 where it then sat in a "barn" / tractor shed until last year. I think the ding isn't really a problem but what do you guys think. The Frame over all isn't bad, spots just about everywhere, some of the worst is bottom center connecting rail, as expected. And I got my new helmet.

 

I’d be more concerned about all the writing on your face shield obstructing vision

 

Looks like there is room for more stickers.
I finally nabbed some new Willie and Max saddlebags that are small enough to fit and will ride high enough if routed over the grab handles instead of under.
The guy I got these from said they came on a Rokon he bought and he took them off without ever using them.
https://www.rokon.com/

 

I like a challenge so it would make for an interesting ride.

 

Side cover grommets came in. I thank you and Fujin thanks you. Thanks Len.

 

Replacing pic #1 fuse box (insert laughter here)

with pic #2 fuse box.

Thanks again Len.

 

Did a running synch on my XJ today. I haven’t seen my bike run like that before.... and I do actually mean; run well. That’s awesome for the first time I have some pretty solid hope for the XJ. Gotta straighten out some other small things but she will be rideable very soon.

 

went from runs ok to WOW?