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post carb cleaning, trouble
- Thread starter emzdogz
- Start date
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- Tags
- carbs enrichener firing
put the carbs back on yesterday after having had them pulled and on the bench for several days, where they mostly just sat.
However I did re-set the float height to 23 mm. (plastic floats)
I'd been really encouraged by good compression readings several days ago, and thought oh well I guess the valves are ok and rings, since I did get the good readings.
So I put the carbs back on and, no joy.....still the same freakin' thing. Right side doesn't get hot and spews an oily gas mixture out the tailpipe and smokes white when revved. Doesn't make the smoke at idle.
So after I saw this was going to still be the case, I pulled the bowl of the right carb (bad side) with the carbs still on the bike. I then put a 2nd gasket in the bowl, thinking that would effectively lean that carb out more and be equivalent to having set the float that much higher even. But when I started it - same sh_t.
And really the left side is running rich, too. At one point I got highest idle with right mixture screw all the way in and left one almost all the way in, too.
I guess I could buy a pair of tiny pilot jets in, and try that. I think if any part of the pilot circuit could still be clogged it would be some part that has to do with air.
In the carb guide it says that the BS 38 type of pilot jets would "probably work" in the 34's. I have a bunch of BS38 pilot jets. I'm almost thinking of sticking a pair in there.
The numbers on pilot jets - do those refer to the amount of fuel they flow through their holes? or is does the numbering not refer to that?
I guess I will check valve adjustment yet again. Have done it twice. Cam chain tensioner adjustment is normal. Maybe I will leave the cap off the cam chain tensioner while the bike runs and try adjusting it a little while it's running.
I wish this could be simple. I'm getting fuel, spark and air and yet I have very little combustion on a right cyl which, however, has a decent compression reading.
Then I thought, well could it be the coil. Switched the plugs from side to side. Bad side remained bad side. Since it's an elec ignition bike and runs and charges, can I rule out timing issues? When an ignitor box goes bad, does it send "wrong" timing signals to the coil?
As I mentioned earlier in the thread, I'm using (for now) "clear" spark plug caps and can easily see that I have spark. The spark, as seen by my eyes, appears equal on both sides. It's not like it's intermittent on the bad side.
I'm trying to rule out certain things.
It comes down to fuel not being burned in right combustion chamber.
Maybe exhaust valve not opening?
sheesh.......
Do the fairly decent compression readings rule out bad valves?
Anyway, tomorrow, the carbs will come off again. Not sure what else to try, except go through pilot circuit yet again. Check the 3 tiny holes in throat of carbs....
Sure wish I had a known good pair of carbs on hand.
I lost the battle to a pair of carbs once before, when I had my 79. I just could not get one side to run right. At the time I gave those away, I would have sworn up and down they had some kind of crack or defect in the castings.
As soon as I put the carbs which had been in THIS bike on it, it ran perfectly. I then bought this set of carbs and saved them for when I got around to this bike again.
So now I'm faced with very nearly the same issue - a very rich running right side. On those 38's, I even replaced all the parts in the choke, too, thinking maybe the choke wasn't ever closing completely off. Still had the prob.
I'm really trying to think this through with my brain and the basic rules I understand about simple engines.
This has me pretty frustrated.
On the bright side though, the battery I'd thought dead works great now. Cranks and cranks!
And the bike runs and runs! just not on the right side cylinder.
However I did re-set the float height to 23 mm. (plastic floats)
I'd been really encouraged by good compression readings several days ago, and thought oh well I guess the valves are ok and rings, since I did get the good readings.
So I put the carbs back on and, no joy.....still the same freakin' thing. Right side doesn't get hot and spews an oily gas mixture out the tailpipe and smokes white when revved. Doesn't make the smoke at idle.
So after I saw this was going to still be the case, I pulled the bowl of the right carb (bad side) with the carbs still on the bike. I then put a 2nd gasket in the bowl, thinking that would effectively lean that carb out more and be equivalent to having set the float that much higher even. But when I started it - same sh_t.
And really the left side is running rich, too. At one point I got highest idle with right mixture screw all the way in and left one almost all the way in, too.
I guess I could buy a pair of tiny pilot jets in, and try that. I think if any part of the pilot circuit could still be clogged it would be some part that has to do with air.
In the carb guide it says that the BS 38 type of pilot jets would "probably work" in the 34's. I have a bunch of BS38 pilot jets. I'm almost thinking of sticking a pair in there.
The numbers on pilot jets - do those refer to the amount of fuel they flow through their holes? or is does the numbering not refer to that?
I guess I will check valve adjustment yet again. Have done it twice. Cam chain tensioner adjustment is normal. Maybe I will leave the cap off the cam chain tensioner while the bike runs and try adjusting it a little while it's running.
I wish this could be simple. I'm getting fuel, spark and air and yet I have very little combustion on a right cyl which, however, has a decent compression reading.
Then I thought, well could it be the coil. Switched the plugs from side to side. Bad side remained bad side. Since it's an elec ignition bike and runs and charges, can I rule out timing issues? When an ignitor box goes bad, does it send "wrong" timing signals to the coil?
As I mentioned earlier in the thread, I'm using (for now) "clear" spark plug caps and can easily see that I have spark. The spark, as seen by my eyes, appears equal on both sides. It's not like it's intermittent on the bad side.
I'm trying to rule out certain things.
It comes down to fuel not being burned in right combustion chamber.
Maybe exhaust valve not opening?
sheesh.......
Do the fairly decent compression readings rule out bad valves?
Anyway, tomorrow, the carbs will come off again. Not sure what else to try, except go through pilot circuit yet again. Check the 3 tiny holes in throat of carbs....
Sure wish I had a known good pair of carbs on hand.
I lost the battle to a pair of carbs once before, when I had my 79. I just could not get one side to run right. At the time I gave those away, I would have sworn up and down they had some kind of crack or defect in the castings.
As soon as I put the carbs which had been in THIS bike on it, it ran perfectly. I then bought this set of carbs and saved them for when I got around to this bike again.
So now I'm faced with very nearly the same issue - a very rich running right side. On those 38's, I even replaced all the parts in the choke, too, thinking maybe the choke wasn't ever closing completely off. Still had the prob.
I'm really trying to think this through with my brain and the basic rules I understand about simple engines.
This has me pretty frustrated.
On the bright side though, the battery I'd thought dead works great now. Cranks and cranks!
And the bike runs and runs! just not on the right side cylinder.
Make sure the pilots you have in your BS34s now are the proper type, the BS30/96 style. If the BS38 pilots you have are this same type then they can be used. If they're the VM22/210 style, I don't think they'll work. Here's how to tell the 2 apart .....
Maybe the floats are the problem. Some of the ones sold by Mike's are junk.
Maybe the floats are the problem. Some of the ones sold by Mike's are junk.
kvanderploeg
The Dutch Terror
Emz, all I can say is, I'm sorry. I did the plug wire swap the other day with a fresh set of plugs too. Same crap. The other thought I had was to plug everything up in that pilot circuit and load it up with carb cleaner, cap it off, and let it sit. Maybe even overnight.
Kent
Kent
TurboFarviknugn
XS650 Addict
MANY are eagerly following your trials and tribulations, this is WAY over my head to be commenting. BUT MANY are reading and following, awaiting the next development in the saga.
GOOD LUCK BROTHER !!!!!
Swap your floats and float valves (needles) from left to right and see if the problem switches sides. That will tell you if floats and/or needles are the problem. Too bad you can't switch entire carbs from left to right.
I don't know if Mike's plastic floats are hollow or not as I've never used them.
I don't know if Mike's plastic floats are hollow or not as I've never used them.
the thing is, I just put these floats, needles and needle seats in, brand new - and the problem I'm having is still on the same side as before I replaced all those things.
But I will do that (swap) when I take them apart next.
It seems like the 2 floats don't move exactly the same, when I move them manually on the bench.
As if one has a little more friction working against it. I guess the bore where the pin goes through is maybe a little tighter or deformed on one. The pins are brand new too.
When I had the carbs upside down on the bench I blew compressed air into the fuel inlet T (between the carbs) and noticed the floats "fluttered" up a little differently from each other. Not sure what I was trying to test with this, however.
"and how do YOUR floats flutter? "
Also the good side carb, when first filling frmo empty, doesn't seal off right away - it gushes gas. If I tap the bowl it goes ahead and seals and keeps sealing until it has to fill up from empty again. So if I just leave it sitting with a full bowl of gas and gas visible in the clear line, it doesn't leak - I can see that the fuel isn't being lost and stays at the same level in the tube. But when filling up from empty the good side doesn't shut off right away.
Maybe I can go through the bores of the floats (where pins go through) with a tiny drill bit. Or maybe it is bent, making the pin hang up ever so slightly.
Is there any point to checking the timing on an electronic ignition bike?
I don't think the ignition is the problem. With the flashy plug caps if they flash the same brightness left to right I doubt you have a problem there.
With the carbs off have you checked the carb sync with a piece of paper. I use a strip of paper about 1/4 inch wide and use it like a feeler gauge to bench sync carbs.
Set the left carb to get a slip fit with the paper with the idle speed screw, set the right side for the same slip fit with the sync screw.
That's about it until some one close by can loan you a known good set of carbs.
Leo
With the carbs off have you checked the carb sync with a piece of paper. I use a strip of paper about 1/4 inch wide and use it like a feeler gauge to bench sync carbs.
Set the left carb to get a slip fit with the paper with the idle speed screw, set the right side for the same slip fit with the sync screw.
That's about it until some one close by can loan you a known good set of carbs.
Leo
kvanderploeg
The Dutch Terror
Just to clarify, you're referring to slipping that piece of paper in between the throttle butterfly plate and the throat of the carb, correct? Fairly similar to how I've bench synched my V-Star carbs.
Kent
yep have done the test with a slip of paper and a rougher way too, with wooden popsicle sticks that I'd read of before.
There's GOT to be something clogging an air passage.
What if I stand by with rubber tipped air gun on compressor and while running blew some air in the intake?
There's GOT to be something clogging an air passage.
What if I stand by with rubber tipped air gun on compressor and while running blew some air in the intake?
Yes, this gets the carb mechanically synced and will get the bike running till you can sync them on the bike.
Leo
Leo
kvanderploeg
The Dutch Terror
One more thing has occurred to me, while doing some reading on MikesXS website. I've now ordered some new tiny o-rings for the needle jet. The one the slide needle goes down into, and the main jet is under. I noticed one was a little loose. Then when I screwed the main jet in that held it in place, but otherwise one was kind of wobbly. Rubber didn't look bad, but my eyes aren't that great....so maybe they are allowing extra gas to travel up into carb throat.
Also ordered a smaller pair of pilot jets.
Funny, the shipping and state tax on this order made it very close to double the price. Oh well, at least I get my Mike's parts extremely quickly.
Also ordered a smaller pair of pilot jets.
Funny, the shipping and state tax on this order made it very close to double the price. Oh well, at least I get my Mike's parts extremely quickly.
Em, it's been noted many times that the float pivots on the Mike's XS knockoff floats are badly made and cause trouble and that knockoff float valves are also chronic sources of grief. OEM Mikuni parts are still available; for floats, check Top Dog Yamaha and a few of the other NOS vendors. Shop around, prices vary pretty widely.
I've said this before, but some things bear repeating: You can't get something for nothing, but if you buy low enough, it's easy to get nothing for something. I'd strongly advise you to bite the bullet, spring for the OEM parts, and stop driving yourself crazy trying to make that junk work!
I've said this before, but some things bear repeating: You can't get something for nothing, but if you buy low enough, it's easy to get nothing for something. I'd strongly advise you to bite the bullet, spring for the OEM parts, and stop driving yourself crazy trying to make that junk work!
So you're dealing with 1980 BS34s that originally had brass floats? My buddy went through the same song and dance. His bike ran rich, puked gas from the carbs one day, not the next, puffed black smoke, and on and on. He swore to me that he cleaned and replaced everything he could in the carbs. Turns out not so much. He had those crap MikesXS plastic floats but set them to the brass float spec. That combined with their loose, sloppy fit on the pivot was half his problem. The other was he never pulled or cleaned his needle jets. They were totally black and gummed up. I looked at his carbs during a top end rebuild we were doing on the bike. His cylinders were so badly scored he needed a 2nd oversize rebore. I think his "stupid carb tricks" and running waaaaaaay too rich for two years caused that. His topend rebuild cost him near $300 more than it might have if the cylinders weren't destroyed.
If you do have BS34s, there are no o-rings on your needle jets, that's a BS38 thing.
If you do have BS34s, there are no o-rings on your needle jets, that's a BS38 thing.
well I definitely wouldn't ride the bike as it is now, so I hope nothing's getting ruined. Thanks for pointing that out about the no o-rings on the needle jets. My needle jets didn't look black, and I did clean them, but again one didn't sit all that tightly once the main jet was removed. Nothing to be done, I suppose, but try try again. So did your friend end up using that very same set of carbs once he had the top end re-build? Did they eventually work ok?
thx 5twins, for everything.
thx 5twins, for everything.
Yes, he bit the bullet and bought brand new original brass floats from Yamaha, cost him about $60, but the bike is fixed fuel-wise now. Same carbs except now they work correctly. No more rich running or gas leaking. Now he's chasing electrical gremlins. I should mention his electrical skills are right on par with his carb skills, lol. When I checked his MikesXS replacement fuse box, one of the wires pulled right out of the crimp. When you ride behind him, you can watch his brake light come on and off at random - and he's not applying the brakes, lol. And he wonders why the bike intermittently cuts out. And I left the best for last - him fixing oil leaks - he's got more now than he started with, lol.
am looking now for original fixed position slide needles - the non-clip type. Looks like Mikes now only sells the clip type and the clip conversion ones.
Have checked a couple more places and they seem to be not widely available.
Will keep looking.
Bike running wicked rich = must be getting extra gas from somewhere. The next suspect is the needle jet (emulsions tube) possibly being distorted and out of round (from wear) at the throat end, where the needle jabs down into it. Maybe the needle itself slightly broke. One time, (when I first started this journey of troubleshooting these carbs) it revved way high by accident (my fault) and on that side the needle actually hung up in the throat of the carb. Like the tip of it got stuck at an angle at the very beginning of emulsion tube. It ascended so high up that the tip of it cleared the very top of the emulsion tube where it sticks into carb throat and hung up there.
I guess I'm surprised that the original type are not widely available.
Later I will pull carbs again and see if I can visually detect damage or wear to needles or needle jets.
Just thinking out loud here, feel free to chime in.
Just don't call me a slut.
Have checked a couple more places and they seem to be not widely available.
Will keep looking.
Bike running wicked rich = must be getting extra gas from somewhere. The next suspect is the needle jet (emulsions tube) possibly being distorted and out of round (from wear) at the throat end, where the needle jabs down into it. Maybe the needle itself slightly broke. One time, (when I first started this journey of troubleshooting these carbs) it revved way high by accident (my fault) and on that side the needle actually hung up in the throat of the carb. Like the tip of it got stuck at an angle at the very beginning of emulsion tube. It ascended so high up that the tip of it cleared the very top of the emulsion tube where it sticks into carb throat and hung up there.
I guess I'm surprised that the original type are not widely available.
Later I will pull carbs again and see if I can visually detect damage or wear to needles or needle jets.
Just thinking out loud here, feel free to chime in.
Just don't call me a slut.
