Advice on starting after valve shim adjust. She's proving tough

[londonboards]

Fiddling with the mix screws won't stop it starting. You are not getting any fuel into the combustion chambers.

Take out the air filter and start the motor with some carb cleaner. Then you'll know for sure:

 

[Guest]

Did you get the plug wires back on correctly?

 

[cp___32]

Yeah, plug wires are on correctly.

I got it running once I backed the mix screws out about 8 full turns (close to the top). Tried lowering them down and the bike would stall out and not start again. The rightmost cylinder won't run until I've got the mix screw right at the top. Back to this problem again. It'll start and idle ok with the mix screws way up. Ok fine, doesn't seem right but whatever. Try to do a sync and get that dialed in. Shut the bike off and then back on and it struggles to start. Give it a little choke and then the revs climb like crazy. Let off the choke and the revs come down a bit and stabilize but are too high for idle. I back the idle screw down, nothing, nothing, nothing then the bike idle drops way low and almost dies. Turn the screw back to a normal idle and it sits for a second, then races again.

So now what? Main jets? But why would a stock bike need larger than stock mains? I can't figure out why this bike is so friggin hard to dial in. Been through the carbs twice this year. probed every orifice I could find. Sprayed carb cleaner everywhere. Ultrasonically cleaned them. (We don't have carb dip here in Canada so that's the best I can do). They look squeaky clean inside and out. Swapped out all OEM parts for a K&L kit just in case something in the carbs was screwy. No difference. Checked the markings on the kit vs OEM and they're all the same sizes. Put OEM stuff back in after cleaning again, still no luck.

 

[MechMessiah]

I'm having a very similar problem to you. Just did a top end rebuild, got it to start and took it for a test ride and now nothing. No fuel seems to be getting to the chamber. Best of luck man! Hope you figure it out and if you're interested here's my post on the issue.

 

[gearhead13]

I was looking at your video and seemed strange to see the slides moving that much if its not under load. How high are you revving it? Hard to tell with no audio. Are the springs in place on top of the slides?

 

[Steve]

Poor running at low throttle openings is a sign of clogged pilot passages.

Buy new pilot jets.
Check the starter jet.

If it is not firing at all, and the plugs are not wet after a decent attempt to start, then you are not getting any fuel into those chambers.

Just because you have fuel in the bowls does not mean it's getting into the cylinders.'

No fuel to the plugs, they're dry.

If the plugs are not wet, fuel is not getting through the carbs.

So now what? Main jets?

You can lead a horse to water, ... but most people would rather ride it there. :-\\\

.

 

[cp___32]

I get it Steve, but considering with my no spark issue a few years ago I was told replace this, then that, then something else, now it's the same deal with the fuel flow. Everyone says if I change the air intake or exhaust I need to rejet. That totally makes sense. What does not is why an absolutely stock bike with 18K miles on it would need larger jets. I have yet to hear someone say that it's common to need new jets for stock bikes just because.

If it's a matter of needing the same size, but the old ones are worn somehow, I've covered that with a K&L kit which made zero difference. I can't imagine the K&L stuff being THAT bad that it's as bad as screwed up OEM stuff.

So if I get new jets, what am I looking for? One size up (whatever that means), a drastic change? Just keep ordering parts till it works?

As for the video it was about 1/4 to 1/2 throttle steady and as the revs climb to about 1800 rpm the sputtering starts. That's when you see the fluttering and the backflow of fuel into the airbox (toward the camera lens).

 

[londonboards]

OK so you checked the float bowl starter circuit passageways?

Now this was my other mistake once when I first rebuilt the carbs: I put the spring for the needle in the throttle slide on the wrong side of the red washer:

This has the effect of keeping the main jet closed so it would stall as soon as you opened the throttle more than a smidgen, like this:

Is this what's happening to yours?

Don't get too phased about jets right now. We just need to get fuel in the combustion chambers (assuming your jets have some kind of hole in them!).

Post up some photos of your carbs if you can and the whole bike.

 

[bwringer]

A couple of observations gleaned from the above:

1) When discussing the valve clearances, you appear to be mixing units between hundredths of a mm and thousandths of an inch. You imply that you had to make drastic moves in the valve clearances, which is one sign of unit confusion. That said, it may or may not keep the bike from starting, but it certainly won't run very well. This is worth at least a few moments of honest introspection.

2) Yes, the K&L carb rebuild kits are in fact complete crap. I don't know why otherwise reputable places sell these, and I don't know why anyone in the age of Google buys them. The float bowl gaskets are usually OK (but compare them to the originals carefully to make sure all the holes got punched out correctly), but for the sake of all that's good and holy, don't use any of the other bits in these little sacks of random junk.

3) You've most likely made some sort of minor error in assembling and/or cleaning the carbs. A few common errors are detailed just above. There are many other potential errors. Without the bike in front of us, all we have is guesswork.

4) Yes, it is entirely possible for the idle circuits to clog over just a few weeks of inactivity, especially in warm weather. These passages are TINY.

5) Main jets are irrelevant to the immediate problem, and you shouldn't need to change them unless there have been drastic exhaust/intake changes. Mains only come into play at throttle openings at and near WOT. OEM main jets don't wear out.

6) Canada's a big place. You might mention approximately where you are -- perhaps there's a GSR member with relevant experience nearby. Sometimes another set of eyes on the problem can be very helpful.

7) Apologies in advance if this gives offense, but... check your attitude. You're obviously frustrated and angry, and this inevitably leads to narrowness of thought and vision. We've all been there. Much of this discussion is already starting to go in circles as you angrily cut off certain lines of discussion. Do whatever is necessary to get back into the right frame of mind. Walk away for a while, accomplish some other task, go for a ride if you've got another bike around, or do whatever you need to do to get back into the correct frame of mind. Motorcycles are fun, dammit!

 

[JTGS850GL]

OK so you checked the float bowl starter circuit passageways?

Now this was my other mistake once when I first rebuilt the carbs: I put the spring for the needle in the throttle slide on the wrong side of the red washer:

This has the effect of keeping the main jet closed so it would stall as soon as you opened the throttle more than a smidgen, like this:

Is this what's happening to yours?

Don't get too phased about jets right now. We just need to get fuel in the combustion chambers (assuming your jets have some kind of hole in them!).

Post up some photos of your carbs if you can and the whole bike.

The assembly on the left side is correct.

 

[alke46]

In post #29 by Mr bwringer, take #6 and run with it. Another set of eyes on the problem will be worthwhile to say the least. There must be another GSR member close enough to provide that 2nd set of eyes. Good luck and when this problem gets squared away, you will be more appreciative of the bike.

 

[cp___32]

A couple of observations gleaned from the above:

1) When discussing the valve clearances, you appear to be mixing units between hundredths of a mm and thousandths of an inch. You imply that you had to make drastic moves in the valve clearances, which is one sign of unit confusion. That said, it may or may not keep the bike from starting, but it certainly won't run very well. This is worth at least a few moments of honest introspection.

2) Yes, the K&L carb rebuild kits are in fact complete crap. I don't know why otherwise reputable places sell these, and I don't know why anyone in the age of Google buys them. The float bowl gaskets are usually OK (but compare them to the originals carefully to make sure all the holes got punched out correctly), but for the sake of all that's good and holy, don't use any of the other bits in these little sacks of random junk.

3) You've most likely made some sort of minor error in assembling and/or cleaning the carbs. A few common errors are detailed just above. There are many other potential errors. Without the bike in front of us, all we have is guesswork.

4) Yes, it is entirely possible for the idle circuits to clog over just a few weeks of inactivity, especially in warm weather. These passages are TINY.

5) Main jets are irrelevant to the immediate problem, and you shouldn't need to change them unless there have been drastic exhaust/intake changes. Mains only come into play at throttle openings at and near WOT. OEM main jets don't wear out.

6) Canada's a big place. You might mention approximately where you are -- perhaps there's a GSR member with relevant experience nearby. Sometimes another set of eyes on the problem can be very helpful.

7) Apologies in advance if this gives offense, but... check your attitude. You're obviously frustrated and angry, and this inevitably leads to narrowness of thought and vision. We've all been there. Much of this discussion is already starting to go in circles as you angrily cut off certain lines of discussion. Do whatever is necessary to get back into the right frame of mind. Walk away for a while, accomplish some other task, go for a ride if you've got another bike around, or do whatever you need to do to get back into the correct frame of mind. Motorcycles are fun, dammit!

Thanks for the reply bwringer.

To address what you have said, here goes.

1) My feelers have both metric and imperial measurements on there. I have read posts where some people feel more comfortable talking in thousandths of an inch and other people prefer to deal in metric. I had many valves that had less clearance than my feeler gauge would go so I had to shuffle around a 2.45 mm shim in order to get a reading and then went from there. The shim procedure wasn't too difficult to figure out and I do understand it. What I wasn't sure about was when people in other posts said it's not a bad idea to go above the top range for clearance on the exhaust valves, but nobody really said how much above is too much. Some on here might see 0.102 as the top end, and 0.127 as WAY too big, but in imperial see 0.004" and 0.005" as not a big deal. I went back and sorted out the valves that had clearances that would allow a 0.127mm feeler in (meaning it's a larger opening than 0.127mm, and backed them down so that all valves I can fit the 0.0508 feeler in at the least, and a couple where the 0.102 goes in, but not the 0.127mm. Yes I did rotate the engine to squeeze out the oil from between the shim and the bucket before checking the clearances and went back around and double checked them after rotating the engine a few times just to make sure things were well seated.

2 & 3 & 4) I'll pull the carbs again and make sure all the passages are clean. I already switched back to the original Mikuni components, but made sure to compare the two parts to make sure the original parts had just as many holes visible as the new ones. I picked up a carb kit for my old Toro snowblower last year and had I not, I would not have known that there was a vent hole in one of the jets that was caked and corroded. But I'll pull them again, clean everything and make sure I'm getting carb cleaner spraying out of the appropriate orifice when sprayed through the carb to make sure it's all good. Then make sure it's all back together as per the walkthroughs on BikeCliff's site.

6) I'm in London, Ontario. If there's anyone in town that wants to lend their knowledge and experience I am more than happy to learn.

7) I'm sorry if my responses come across as harsh sometimes. Yes I have been frustrated with the bike but I have tried not to let that influence my receptiveness to what to do to get the bike running properly. I appreciate everyone who takes the time to read my posts and certainly everyone who offers advice. Part of my writing is tone. It tends to come across more harsh than intended and for that I apologize.

I'm not trying to shoot down anyone's ideas and if there are tests/checks I can do with the bike in the state it's I'll gladly do them. About the only one I can't do readily is the leak down test. I've got some people saying I need mains, replace the mains and that will fix my problem, but then I've got you saying unless there's a drastic change to the intake/exhaust there should be no reason to do so, hence my reluctance to do that. And I haven't read anything on the forums here to indicate a bone stock bike needs larger/smaller mains as the OEM setup is pretty good. Plus without any knowledge about what to buy I'd basically be blindly throwing jets in and hoping something works if I did decide to replace them.

Starting procedure has been as Steve suggested. I can (and do) use choke, but don't touch the throttle. I'll double check compression results with WOT sometime this week provided I can get the bike warmed up to operating temp.

Other than that I guess I'll tear the carbs down again and make sure everything is correct and report back.

Thanks for all the help so far.