Eating pizza , feelin down (82' Maxim 650)

Hey goons and goblins.
I picked up a Yamaha earlier in the year for 200 bucks.key and title,a miracle. It was rusty and coming apart in certain places but towed it home. It even had all original parts and a c cool sissy bar plus chain and toolkit.took it home in a trailer and slowly but surely got it running in a sexy way. After replacing cables x parts,c here and there the only one true bother was it would leak oil/gasoline from the carbs/air box . Drips in various amounts every now and then and it would not like to idle too long. Had to keep choke on medium or do at stops so it wouldn't die. So I got sick this months and after putting it off I decided to do my carbs. Right before I took em off,x it diarrhead oil all over when I turned it on. So they came off rather easily and I replaced the jets main and idle, cleaned the bowls. Replaced that long brass piece that the main jet screws into, replaced the float needles under the butterflys. . .and carb gasketscleaned the spark plugs and put it back together.replaced the fuel line filter. Bike was running fine before. But now if it starts it sounds so weak . I disconnected the hose from the petcock (vacumn for fuel?,? ) and it stayed running very faintly with full choke on.as soon as I give it throttle it bogs down and dies.

I put the battery on trickle and cleaned the sparkplugs after it didn't start and after carb reinstallation. Did I screw on something too loose or tight? Missed a critical poing in the rebuild? Are the carbs not fully locked in with the motor or air box? Any suggestions would truly help

 

Oil from I'm assuming the breather and the gas from leaking in?

Okay so where I'd be starting is with not only cleaning the jets themselves but things like the long brass tubes which happen to be the emulsion tubes and they should have a number of super fine holes along their sides, these are what the main jets screw into from the bottom and are just as critical as the jet itself. These must be clean inside & out along with the little holes otherwise the main mixture will be way off. How is the float level setting? Thru experience I have found this to be by far the most critical of the HSC32 carbs, I use four 1/4 inch chunks of clear plastic tubing and cut them to just over the top of the throat and use a length of wire to keep them vertical then using a pair of discarded intake boots on a plywood slat in the vice I check and make sure everything is square & level then let the fuel flow in from the bike tank I place on a shelf at just the same height over the carbs as if it were in the bike and open the bottom screws to check the levels. Below is a picture of my carb rack with the sight gauges I made. When the book gives the 1MM tolerance they're not kidding, low it runs slightly lean and high its rich and cuts the mpg's down and causes the 5000-6000 RPM full throttle break-up as it's going very rich at that point. I did a YouTube video of my carburetors with a camera in the airbox, do a YouTube search of my member name to see it for yourself.

Idle. Have you removed the pilot screws and physically cleaned the passages? This is well detailed in the Church Of Clean section and as I've found out thru experience far more critical than the main mixtures due to the fact the idle must provide a transition period of fuel to cover the main fuel delay when the throttle is opened slightly say on a 1st gear light take-off. Too rich or lean and the bike will lurch once the mixture settles in after a brief few milliseconds. The mixture and fuel flow is very small for the idle passages and they are very slim inside.
Have you opened the float bowl screws on the bottom and verified a good strong fuel flow? This will confirm if the petcock is actually opening under vacuum provided there's enough on cyl-3 to pull the diaphragm. I'd open all four bowl screws and put a Mity-Vac or other vacuum source on the petcock to see just how much fuel flows from all the drain ports, they should pee like a russian racehorse.

Personally I'd bake up another pizza and grab another 2-Ltr of Mountain Dew and start over again taking my sweet time with the factory book open next to my notebook computer on the In The Church Of Clean section with a second tab on the Secret Life Of Carburetors going thru everything step by step. I often find my faults when I walk backwards and look at what I've done.

Do let us know how it goes.

Brett

 

Yep, same. Clean up those original jets and emulsion tubes. Generally they are going to be better than new stuff unless you are buying original parts from @chacal. Check for vacuum leaks, that petcock vacuum line has to be hooked up or plugged. Bench sync, then vacuum sync (read that Church of Clean link). Out of sync will make you chase your tail forever.

https://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

Well my big WTF is how was it running pretty smooth before I rebuilt it, now I can't get it to stay running. Petcock is fine ,filter let's in gasoline fine. Battery fully charged..now back on it just won't handle a good throttle twist.

Also when I took off the spark plugs I noticed on one the wires inside the rubber hose connecting to the spark plug boot were receding inside the hose. ....maybe not making full contact . Could that be a factor in less engine power?
Looks like I'm taking off the carbs again and switching out from the new parts back to the original ones. Does the emulsion tubes rods with the holes have to face a certain way while putting back in? The carbs were cleaned and passed air nicely when put back together.
I'll read the links you guys provided . I don't have garage space atm, or specific motorcycle tools. I imagined since the bike was running , and if all I did was replace old parts with brand new ones It would be straight forward since I don't know much about synching or have such tools yet

 

Did you remove the pilot screws during your rebuild? That is the very small, fine threaded screw with a tapered point on the top front of each carb. If yours hasn't been messed with ever, they could still have the factory plug in each hole covering the screws. If not, its possible your cleaning efforts in the rest of the carb dislodged some goop and plugged these up. There's also some tiny o-rings in there that generally get dried up and should be replaced. This screw adjusts your fuel flow at idle and through partial throttle.

You don't any special tools to bench synch. There's a few different methods, and all you are doing is trying to get all 4 butterflies to close at the exact same time. Set the gap with a drill bit, paper clip, matchbook cover, or visually by sighting through with a bright light behind. A good bench synch should get you to where things run at least. Being out of synch can act like all kinds of problems though. When you cleaned the carbs, did you have them separated from the rack, or just removed the bowls while the 4 were still together.

The boots on the spark plugs screw into the wires as I'm sure you saw. As long as you can see some wire at the end you should be good. If they are really nasty you could trim a 1/4" off or so.

 

Trim about 1/8 in. or so off the wire and screw the boot back on. Make sure the wire will be long enough to reach the spark plug.

Normally you would not remove the tube. There should not be a specific way the holes need to face.
There is a small jet in the bottom of the well on the side of the float bowl, where the enrichment circuit tube goes when the bowl is back in place. This needs to be completely clear so you can see the light from a flashlight shining into the hole at the bottom of the bowl. Read https://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

When I read this again I think he means the needle jet (I usually call it the emulsion tube also). Some of these have a pin on the side so they are directional. I can't recall right now whether that is the case on the 650.

 

I was confused also.

 

Yes, these 3 parts I replaced with new ones as well as the small needle below the butterflies. The kit came with mini screens,but did not use them as I had bought a new fuel filter. The carbs were filled with seafoam for a couple days before removing them, so everything inside looked very clean , I just used a can of air to clean the passages. Did not separate them individually, kept them on the rack.
I'll put back on the original pieces, diaphragm look great ,boots acceptable ....carbs looked clean on the inside, springs with the needle valves were springy . I just removed the carbs again to see what I may have missed, or what came apart . Not too sure what I did differently when I put it back together

 

No specific direction for the emulsion tubes BUT all the holes must be absolutely clean & clear, if not the power mixture will be off. The aftermarket ones don't work well so clean and use your original ones.

As Roast644 points out the pilot screws must be removed and the passages cleaned not just with a puff of air. These are by far the most important for a good idle and must be clean and clear of anything inside. They're under little brass caps on the top forward of the covers literally over the butterfly. You will need a small wire drill bit and sheetrock screw to grab ahold of and yank out, do not drill down more than the width of the bit itself otherwise it will damage the screw head and make removal difficult.

 

I did not read everything but some of the things you CAN NOT SKIP or should not do IMO is:

Must clean and inspect the fuel enrichment (choke) path in the bowls ( flashlight test, don't know it, find out)
DO NOT replace jets or tubes or any brass when rebuilding carbs unless you have a good reason. MaNY after market jets are wrong (you can trust xj4ever ones though).
MUST wet level carbs to 3mm per the maint manual as noted by brhatweed. Just doing try level is NOT ENOUGH.
MUST verify pilot jet passages to the 3 holes in front top of carb above butterfly are clear and passes gas (LOL).
Set idle mixture on the rich side to start. tune with ears if you can or use colourtune plug
Sync carbs (YICS tool needed for YICS bikes).
Carb rebuilds only really need new needles and bowl gaskets and maybe the butterfly seals. Not all the brass crap that comes with ebay and amazon rebuild kits. Clean up the brass that came with the carbs is your best bet IMO

People will start to mention "oh, check for vacuum leaks" but if you don't do the above steps, forget about vacuum leaks or many other things. Bike will not run well unless your lucky or you do all of the above.

 

So just as a test , I did find one of the butterfly floats was "sticking" when pushed down ,and not spring back up. I found carb 3 butterfly was set higher than the others. Cleaned the pilot screw paths on all 4 carbs. Put back on bike to test. Now finally the bike revved up ,,and stayed on but very high rpm. I adjusted the screws to 2.5 turns, it idled better, and did not die on idle like before when it was running. They were originally set at 1 turn of the screw. Still bafing oil from air box area, I must admit I was ill for the better part of the month and not in the right mind to details and I may have overfilled with oil.
The oil that comes out doesn't smell of gas. Only faintly I would say if any(Maybe I'm smelling gas from carbs) I took off the carbs again to actually put back the original jets. And noticed my kit came with #43 idle jets. Shit I think #40 is the correct one. But I'm glad the thing started up and didn't die with throttle.
I bought a new fuel filter,gasket and spring

 

Just so you aren't confused on bench synching or vacuum synching...the butterflies are the round throttle plates in the front of the carb. The floats in the carb bowls (which probably do look like butterflies more than the throttle plates) are just called the floats.

If you have a high idle, you won't fix that with the pilot screws. If the carbs are truly clean now, and float levels set, then synching is needed before you can reliably set the idle.

If you don't want to invest in a vacuum synch setup yet, you might ask your local parts store or bike shop if you can rent one. The cheapest set of 4 gauges can be had for less than 35 bucks however, and will work fine with a little effort. The Motion Pro synch tool is pretty nice, but you don't have to start with that.

But it sounds like you are figuring it out. These carbs can be confusing little demons when you first start.

 

FYI, ONLY check the oil level after the bike has warmed up fully, then cooled down fully. I feel victim to that when I first changed my oil
#1, at the end of the ride, the oil level will look low and as you let it sit, the oil drops down into the sump as it cools. After it cools, that is when you can look at it.
#2, If you were to start the bike and only run for a short while, the oil may not warm up fully, and when you stop it, the oil will be thick and will not fully drop down to the sump. Again , you will think the oil is low and add more by mistake.
Its often when you overfill that oil pops out of the breather into the air box.

 

More like a pain in the butt if you're not familiar with them. That being said the #43 pilot jet will work well esp with the ethanol laced gasoline, I don't know what the 650 uses for main jets however. My 750 SECA had #120 mains for stock jets but they're far too lean for today, my rebuild kit came with #122's which were okay but I've done some tuning and rework and found the #124 to be a good street jet and #126 for going to battle... I can give an S&S powered Sportster a good run for the money and have more wins than losses under my tank with this.
Just take your time and cook up another pizza, you will feel better.

 

Input gentlemen.
I tested with new parts.....EXTREMELY high RPM.......adjusted screws and still high but not as bad , throttle worked fine, bike didnt die on idle like it used to.

Second time, I reinstalled original main and idle jets ...cleaned. Now it won't start again.
I even aligned all the boots engine and air box side perfect. It start it and it just turns over, engine never comes on and it makes a whirring dying noise before it gives out. Like the sound of a power drill on low speed setting. Would the culprit be the main or idle jet? Battery?
That's the only thing I really changed up.

One other factor,since I'm on medication right now. I left the bike with the key in the bike and drained the battery, in the early morning I put it on the trickle charge so it was fully charged.
If that makes a difference. ..

 

Well it will need a strong battery to get the fires going. Charge it up and give it another whirl, the electronic ignitor needs over 9 volts DC to trigger

 

6th time ,went to church for the gospel and understood the inner workings of fine tuning carbs. The carbs had different part jets, different numbers and sizes. Some washers, spring, rubber seals were missing on idle screws. Washed in water/Seafoam soaked and
Cleaned all passages. so a few local bike mechanics working from home gave me price ranges of 399-500 to bring in my cabs to have them cleaned and synched and all that. One guy said he charged 299 to clean the carbs, but if they were really gunked it was 50 dollars an hour extra. On top of 60 to remove from bike and 60 to reinstall if I dropped off my bike. By the last time I was texting and retesting issues I took off the carbs and put back on in 7 mins or so. Glad I took care of it. Cleaned, all marching parts, new parts boots perfectly fitted and one real important detail. It still idled weird ....just struggling. Then I saw this f***ing knob in the middle of the carbs crack and turned it clockwise and counter clockwise and it resolved the dying on idle unless on gave me choke. I fined tubes that easily so it could idle gently . Beauty was purring and not dying , felt some great difference in power took it for a nice safe ride. Only maybe the change in performance killed my already shitty battery after 1 hour or so. I had to leave it behind and put it battery a trickle for pick up later. At this point after trying to start it, it just picked oil from airbox area. But we'll see what that's all all about

 

Eat more pizza

 

Beats me how a person could strip and rebuild a set of carbs (twice) and not know where the idle speed screw was. More to the point how could they bench synch them? Back to school I think..

 

Everyone has to start learning from somewhere, at least they found this forum.

 

Never messed around with motorcycles, only heard about Idle needles. I was playing with that knob but I thought it was part of the throttle/butterflies to open and shut in the throat haha made sense at the time .Did so much work these past 7 days ive been feeling better, made some diagrams /schemes to remind me of how and why it works. Went for a long ride today after I made some final adjustments ...
cookin up a steak and compound butter, and a nice cheap whiskey. This bike was neglected for over 30 years rotting in a shed, coming back to life in a matter of months slowly. lurking around here since, but glad everyone else knows their shit unlike me

 

You’re doing great. You have earned that steak. I am living proof that you can learn quite a bit, just takes time and experience. Having been in your shoes, I try to help anyone with anything I may be able help with. Im still an idiot, no doubt about that. I just spent 3 weeks trying to get a 750 Seca brake system working. Anyhew, we are all here to play with motorcycles and learn.

 

I'm with Dan, you earned that steak. One thing about the motorcycle world is the everyone who is willing to step up and help mentor and I have found the best mentors are the ones who let you figure things out yourself. I have one of these mentors who gave me the space to learn hands on, when I was 15 he encouraged me to stuff an old Onan CCK opposed twin into a Chapperalle frame and drive it using a jack shaft. It was heavy and sounded like a Harley but man did it go! I had an idea in my head and he gave me the space to make it a reality. That was the spring of 1985 and we're still the best of friends sharing ideas and making things come together. I'm 54 now and passing the torch thru the forums and in person, no judgements only honest opinions and encouragement... you too will walk in those shoes.

Still want to check out Dans SECA

 

I have seen time and time again posts on Fakebook about " professionally rebuilt carbs" or "bring to a professional mechanic".
Sorry, but to really research and do the correct job to rebuild these, it take a lot of time and research if they have not successfully done them before (and maybe recently).
This should be the first thing someone finds out when getting a barn find. #1, if you can't spend the time to do it yourself, it will cost you more than its worth.
I think the first carb set I did I must have spent 10 hours + in total (maybe more). researching, watching vids, reading, ordering parts, getting in crap cheap parts, then ordering better parts, then troubleshooting issues, wet setting carbs over and over again, synching, ordering colortune, color tuning etc.
Result is a bike that has been running SWEET. but I did not get there by dumping in sea foam or dipping the entire carb set into an ultrasonic cleaner.
2nd carb set for a friend was uber easy, did the rebuild in less than 2 hours of labor, wet set got lucky on first try, sync and colortune went fast and he's still happy as a clam.
3rd carb set was a little more of a fight and had to change some jetting/needle settings but got there in a few more hours of work.
4th carb set again about 2hrs rebuilding, gave back to the guy and told him how to do the rest of the work and spent the hours of time himself.

I have 2 more carb sets that I may rebuild and test in my bike just for the winter project (i swore I'd not do any more barn finds this winter, last year I did 2)

 

Brett, I like your wire holding the tubes for the wet level. I'll try that if I remember to order more tubing next time.
I used a #64 rubber band which I have a whole bag of for my wet leveling.

 

Ha! I need to get it back together now!! I should have it done just about in time to put it away for the winter.