Grime in Valve Cover

[stossboss_gaming_and_news]

So everything back together and it's still failing to start.

Spark - Ignition coils and spark plugs were replaced (I replaced one bad coil last year). Spark is present in all cylinders. Battery was fully charged and measured 12.6
Air/Fuel - Cleaned and bench-synced carbs. One was rebuilt with a k&l kit. Air screws set to 2.5 turns from bottom. All valves adjusted to meet spec. As I had tank removed (cleaned that too), I gravity fed with a water bottle and plugged the vacuum line.
Compression - I did not test this, but it ran last year.

Tried choke open and closed to same result, cranking about average; it isn't sluggish nor quick but engine doesn't start.

My next steps will be recharging battery, testing it while trying to start (under load), reconnecting the tank and using the vacuum on the petcock. I'm unaware if I'm appropriately supplying the fuel or it is flooding in some way and possibly that's why it's not starting, so I will hook the tank up and stand it up nearby. Borrowing a carbtune from a friend and plan to do that as well once I get it running.

My question is, is there anything I'm missing and am I on the right path? I really want to elevate my skills above spamming "cant start" threads.

 

[pdqford]

After trying to start it, I’d pull the spark plugs and see if they are wet with fuel or dry.
If dry you prolly have a fueling issues.
If wet with fuel prolly a spark issues.

Additionally, place the spark plug on the cylinder head with spark plug wire attached and try and start it.
If it throws a blue spark you prolly have a fueling issues.
If no spark you you have an ignition problem.

 

[rphillips]

Just wondering? Did you give it a shot of starting fluid?

 

[stossboss_gaming_and_news]

Just wondering? Did you give it a shot of starting fluid?

I gave that a few tries today along with my other additions, able to start for a couple seconds but battery quickly drained. Cranking at 10.4V which I imagine is low on the acceptable range.

 

[stossboss_gaming_and_news]

After trying to start it, I’d pull the spark plugs and see if they are wet with fuel or dry.
if dry you prolly have a fueling issues.
if wet with fuel prolly a spark issues.

additionally, place the spark plug on the cylinder head with spark plug wire attached and try and start it.
if it throws a blue spark you prolly have a fueling issues.
if no spark you you have an ignition problem.

When i tested spark initially it wasn't very blue, more orange than anything - and it was dusky out. I'll do the plug checks when it gets a little warmer out, the cold returned and i'm working outside :cold::cold:

 

[rphillips]

No, 10.4 V is way below the acceptable range. If eng. starts and tries to run a few sec. on starting fluid, that's a strong indication your carbs are the problem. If carbs supply correct fuel, eng. will run on that fuel same as on starting fluid... As always just my opinion, I don't guarantee anything... keep us updated.

 

[stossboss_gaming_and_news]

Well it may be time for me to throw in the towel. 2 weeks and many a dollar on tools, chemicals, and parts later I'm actually at a worse place than where I started.

New battery, went through the carbs again and made 100% sure float height in spec, moving freely, no clogged passages, o-rings replaced (the only thing not replaced were those rubber caps but I soaked them to swell them up a bit). My non-homemade valve cover gasket and new half moons finally came in, so I replaced the homemade and old.

Primed, starter-fluid, choke engaged, ran for about 40 seconds but when I look at the tachometer it is no longer functioning... The only difference this time is that it idled longer and it "stumbled" and slowly failed instead of an immediate cutoff like previous attempts. But spark plugs appeared dry so most likely still a fuel delivery problem?

My fear is I did not seat the tach gear properly and I can only imagine the damage that can do, the whole valve cover was quite "wobbly" when installing, so I turned the tach gear a tiny bit and that fixed it - was that wrong to do? And suppose that I didn't shred anything more on the camshaft (when installing it was already a bit beat up, but it worked), I still cannot get this bike to idle and probably never will.

My final attempt, I will go through carbs again and check on the tach seating. If there is serious damage I know camshaft repair is far beyond my expertise when I cant do something as simple as getting the bike to idle. I'll either sell it, part it, or bring up to NY where I can work on it in a garage and have some family armchair mechanics to share the blame in further ruining this bike.

 

[Rich82GS750TZ]

You will often have to spin the tach drive worm gear to get gears to mesh, and for the the cover to plop down properly. All that sounds right. Without the tach cable connected, you should witness the flat tab of the drive gear spin when the engine is running. If it does, then you probably just didn't have the cable in properly at either end. But anything's possible, if your gears were chewed up to start with.

You should not need starting fluid to start the bike. I have never used it, even after 2 full top-end tear-downs and rebuilds. Priming the dry carbs for about 20 seconds, then back to ON should be sufficient to fill dry carb bowls. This, and the dry plugs leads me to believe that you do have a fueling problem, IMHO.

 

[stossboss_gaming_and_news]

You will often have to spin the tach drive worm gear to get gears to mesh, and for the the cover to plop down properly. All that sounds right. Without the tach cable connected, you should witness the flat tab of the drive gear spin when the engine is running. If it does, then you probably just didn't have the cable in properly at either end. But anything's possible, if your gears were chewed up to start with.

You should not need starting fluid to start the bike. I have never used it, even after 2 full top-end tear-downs and rebuilds. Priming the dry carbs for about 20 seconds, then back to ON should be sufficient to fill dry carb bowls. This, and the dry plugs leads me to believe that you do have a fueling problem, IMHO.

Thank you, drive tab was checked and spinning so at least it's not worst case scenario!

As for fuel delivery I may have possibly found an issue, my new vent tee o-rings were quite thin and it didn't fit together snugly (incredibly loose) when ganging the carbs, so I'm concerned air is leaking through and consequently the pressure is inadequate. I ordered some different ones to see if there's a difference. As I have never rebuilt carbs before I wasn't exactly sure how it should feel but it's the only thing I can think of at this point.

 

[rphillips]

"The whole valve cover was quite wobbly", that shouldn't happen. There's supposed to be a dowel in the bolt hole in the head for the front, far left and rear far right valve cover bolt. If I remember right those holes in the gasket may be slightly bigger. Wouldn't think damage to tach drive, unless you really over did something when it wasn't lined up, slight adj. to tach drive should let cover drop right on. If runs on fluid but not on carbs, :-k:-k:-k let's see, must be something about carbs... Out here in the shade tree part of the world, we'd try starting fluid, with choke and a little throttle, then with starting fluid and no choke with a little throttle, just to see if it may possibly do something. Also may try with idle adjustment at different places, guessing you have no idea how hi or lo idle is set. Probably won't help, but what you got to lose?.. As he ^^^^^ said if everything is right it should do fine without fluid, but we're pretty sure something isn't fine.

 

[Rich82GS750TZ]

Good. I could be wrong on this but but I don't think there should be any pressure at all in those vent tubes / Ts that gang the carbs together. The tubes are, after all, left open in still air. Someone may have a better idea on that.

Orings: If you bought new orings to rebuild your carbs from anyone other than Nessism, I'd definitely hit him up and get yourself a set.
If you didn't follow the tutorial written by the same when you disantled/rebuilt the carbs, you may want to have a look.
https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

 

[Rob S.]

Well it may be time for me to throw in the towel. 2 weeks and many a dollar on tools, chemicals, and parts later I'm actually at a worse place than where I started.

Hey - we don't allow any towel tossing here!

And you're certainly not in a worse place than when you started. Aside from the lovely new tools, nifty chemicals and new battery, you've got experience. And "it's always darkest just before..." something or other. You get the drift. Hang in there.

I can't type anymore, it's too dark in here. :applouse:

 

[stossboss_gaming_and_news]

Thanks everyone for your help & encouragement. I replaced those o-rings and noticed one of the needle jets wasn't properly seated so I fixed that, double checked all the passages and float heights, the 2.5 turns on the air-mixture screws, changed oil (i was happy to see people deem rotella 15w-40 worthy as thats what my 190d uses too :chuncky, prime -> choke on -> it started right up, not even any need for starter fluid. It even idles well without any choke, which was never possible since I purchased the bike. A lot of smoke coming from the front of the exhaust which I think is from debris after sitting out all year without that part well covered.

I do think what @Rich82GS750TZ​ said was right in suggesting those vent o-rings probably weren't the ultimate factor (although I could have misinterpreted) but that and reseating the one needle jet is all I really changed within the carbs - so most likely it was air-mixture screws?

Next I'll be adjusting air-mixture and tuning as it feels to be revving quite high, although I can't actually investigate without a working tachometer - I dont know what you would call the part, but the sleeve that houses the inner tach cable and connects to the tab in the valve cover appears to have compressed (possibly by me when removing it) which damaged the cable, so gotta get that but all-in-all I'm quite relieved. and also - fork oil, brakes, and fixing my horn button contact and it should be good to ride :triumphant:

And thanks again!

 

[Rich82GS750TZ]

Awesome. Great job!

 

[Rob S.]

That's what we like to hear. Aren't you glad you didn't do anything foolish with that towel?

See if next time it will start without prime. It shouldn't be needed every time (though the choke generally is).

 

[rphillips]

Congrats, doing good