Riders Of Vision

I've had the '82 XZ550 off the road for a couple of months while I tinkered, de-rusted the tank, cleaned the carbs, dropped the exhaust etc. She now starts nicely (half a twist on the throttle and then choke, no throttle) and sounds pretty sweet. But there are a couple of quirks and would appreciate your wisdom

1. After going for a run, she doesn't want to restart when she's hot - especially if I stall. The starter really struggles to turn the engine over. It comes up to compression and then stops. If I was starting a Ford Model A I'd say the timing was too advanced. If I leave it for 5 minutes, she cranks over and starts fine. Any ideas what the problem is?

2.  Under load, the engine hesitates when I open up the throttle. The accelerator pump is working OK but I suspect that it isn't activating quickly enough? If that is the cause, what's the fix for that?

3. While checking the alignment of the accelerator pump nozzle, I noticed that the petrol squirts as a stream into the carbs. The Haynes manual talks about checking for a spray pattern. What is the norm? A jet of petrol or a spray?

Many thanks, John M

The normal spray pattern is a jet. The accelerator nozzles don't shoot a mist or anything. I'd suspect that you need to tweak the volume being sprayed, and its aim to inprove your acceleration problem. carb sync can also have a lot to do with this. I believe you're supposed to shoot 1/4cc of gas, and it's supposed to shoot straight down the carb's throat without hitting the sidewall or the butterfly.

I cut down an insulin syringe to make a little graduated vial for measuring the spray volume. Twisted a bit of wire around it to hold it in place, and it works pretty well for taking a measurement.

As for the aim, just bend 'em with needle nosers ever so slightly.

I have some good links for this kind of stuff (past posts) that I'll dig up when I get back to my office.



As far as hard starting goes, lots of things may be going on. Voltage is the main culprit that everybody looks at first. Mixture is second. Some have gone as far as modifying the enricher circuit with different sized air openings. I don't have any experience with that.

These are the links that I've found helpful with carb questions.

Accel pump adjustment
http://ridersofvision.net/rovforum/index.php?PHPSESSID=n61oqpo40rvnpbndf74vrc3dv7&topic=5336.0

carb tuning
http://ridersofvision.net/rovforum/index.php?topic=11128.0
http://ridersofvision.net/rovforum/index.php?topic=13106.0
http://ridersofvision.net/rovforum/index.php?topic=3410.0
http://ridersofvision.net/rovforum/index.php?topic=4279.0

Quote from: pinholenz on October 02, 2012, 04:41:47 AM
1. After going for a run, she doesn't want to restart when she's hot - especially if I stall. The starter really struggles to turn the engine over.
Just out of curiosity, where is the temp gage when you shut it off? The Vison is especially dependent on a good battery, starter wires & ground, and all associated connections to start properly. I suppose it's possible the starter is simply on the way out too.

2.  Under load, the engine hesitates when I open up the throttle. The accelerator pump is working OK but I suspect that it isn't activating quickly enough? If that is the cause, what's the fix for that?
shorten the accel pump adjuster rod a bit

3. While checking the alignment of the accelerator pump nozzle, I noticed that the petrol squirts as a stream into the carbs. The Haynes manual talks about checking for a spray pattern. What is the norm? A jet of petrol or a spray?
I've always been puzzled by this. They want the fuel to hit in a very specific place - that changes BTW depending on throttle position, and yet it's depicted as a syray rather than an easily aimed stream. In reality it is a stream but does become a bit more atomized when the engine is running. Try to aim the stream where the throttle plate and venturi meet just as the plate begins to open. Be carefull bending the nozzles. They can become loose in the carb body or be deformed and the "spray" pattern will be impacted.

Many thanks, John M

Thanks for the library of links Jimustanguitar. That's great. Looks like I could either have too much gas and she's running rich on the accelerator pump and choking, or not enough gas. I will measure the accelerator pump volume  check to see what is coming through. If I am reading this right it should be  2.5mls output on each  front and back carbs. And and if there is a difference in volume then it is likely to be a sticking balance ball in the throat of the accelerator jet feed. From the links it suggests that early models pumped too much gas and choked cos it was too rich. Right?

Rikugun, my first worry about the hot starting problem was that the engine might be seizing or binding when at temperature.   The temp guage (or "gage" on your side of the ditch) is in the lower quarter of the temp dial when this happens.

I flushed and checked the cooling system, all burped OK (was very clean)

Then ran the bike on its stand till it was hot to check whether the radiator fan came on and whether the bike would seize up of its own accord!. The fan was working OK. It came on when guage reached about 3/4 into the green and the engine didn't seize. I don't think it is an overheating issue - although this looks very suspicious when she turns over and starts fine after a stall by just letting it stand for a few minutes.

Its all very "Zen and the Art of Motorcycle Maintenance" I'd like to spend more time riding though....

I think you need to check your battery for charge, charging rate, and ability to hold a charge.  How old is your battery?   Before you turn the key on read the voltage of the battery, than after you get it started read the charging rate (voltage).  As previously mentioned make sure ALL the connections between the battery and starter are clean and tight, also the ground cable.  If you don't have new cables for the battery and starting system you might do well to check the cable ends for corrosion under the insulation.

Thanks Fret Nut. Battery side seems good. The R/R was fried when I got the bike and the previous owner had put a new battery on thinking that the battery must have been dead. Its less than a year old and holds a good charge. I bypassed the loom when I wired in the new R/R via a new fuse. Last time I checked, (from memory) Static voltage was about 12.6, dropped down to 11.8v while cranking and charged at about 13.8v at 3000 rpm.

I have never had the starter out. She cranks over and starts fine. (IMO) But I am stumped as to why she wont turn over when I have stalled her unless I let it stand for 5  minutes. Then its fine. Maybe it takes that long for oil to drain away from the brushes? Cheers

   Nice to meet you, these bikes will teach you patience, or drive you away entirely!!  Have the valves been checked?  One of the symptoms of a tight valve is hard starting hot. 

Quote from: pinholenz on October 02, 2012, 07:04:29 PM
If I am reading this right it should be  2.5mls output on each  front and back carbs.

.25 cc, not 2.5

Not sure about an imbalance, I'd suspect dirty passages and nozzles before I'd dig into the metering weight and ball.

The one thing I've learned over and over again on the vision is, if you think something is mechanically broken, clean it one or two more times and it will work :)

Yep, that makes sense, a sticking valve not opening. Valves have not been checked.

I recall some posts on other forums talking about the negative effects of modern lead free and ethanol added fuels - one of which was sticking valves. 10 years ago the answer would have been a shot of Redex in each tankful. Any recommendations for today's upper cylinder cleaner and lube snake oils?

Everybody around here swears by SeaFoam. I also use Marvel Mystery Oil from time to time. SeaFoam is petroleum based, and MMO is peppermint oil, so my thought is that whatever isn't soluble in one, will dissolve in the other. (there's a lot of placebo in that, mostly it just makes me feel better to alternate :) )

That's only preventative though, and only for petroleum sludge. A lot of the crud that gets into these carbs is oxidation and sediment that a chemical won't be able to remove. There is a physical element to the cleaning that's important on these. Install an inline fuel filter when you're done, and it will last longer.

The hard starting when hot could be a combination of vapor lock in the carbs and oil in the starter. If you haven't had the starter apart then take it apart, clean it and replace the nose seal. As to the vapor lock, my '83 has that problem but only if I park it on the sidestand. I always put it on the centerstand and no problem.

This situation makes me curious to know the real reason the starter doesn't turn well when hot.  Seems to me the starter would have difficulty whether hot or cold if oil inside the starter was the problem.  This happens when hot but not when cold.  It's a simple process to remove the starter and take it apart, but if there is no oil inside then the problem likely lies elsewhere.

The charging rate is not as high as expected, could be a contributing factor.  Do all 3 leads produce the same current from the stator?

Rechecked the battery voltages this evening. 12.65v static, 9.8v cranking and 13.3v @3000 rpm. Guess I will have to drop that starter out after all.

Also went and got some snake oil for the upper cylinder lubricant. (Local stuff is known as Moreys) I'll see if it makes a difference after a tankful or two. Hopefully if its a valve that is sticking when hot starting, that will loosen it up.

I'm not sure what the symptoms of vapor lock would look like?. (Turning over OK but not starting because of vaporized gas in  the feed lines or bowls?) I'm more inclined to think it was "hydro lock" the way that the starter doesn't want to go past compression. Cheers

QuoteI'm not sure what the symptoms of vapor lock would look like?. (Turning over OK but not starting because of vaporized gas in  the feed lines or bowls?)

Yup, but since you report the temp gauge was in the lower part of the range I tend to doubt vapor lock is the culprit. Hydro lock would be much worse in that bending a connecting rod would be a concern. You haven't mentioned overflowing carbs so I tend to doubt that is the problem.

Quote from: fret nut on October 03, 2012, 11:28:38 PM
This situation makes me curious to know the real reason the starter doesn't turn well when hot.  Seems to me the starter would have difficulty whether hot or cold if oil inside the starter was the problem. 

Not necessarily. The engine is harder to turn over when it's hot due to increased compression. The starter motor has to overcome increased electrical resistance when it gets heat soaked. Oil fouled brushes may only become an issue when this happens but still pass sufficient amps for the first start of the day. Also if the commutator windings are marginal from years of cranking, they can lose effectiveness when hot. You can check their resistance when it's apart but a starter repair facility has specialized equipment that may be more thorough. It may be the commutator segment undercut simply needs to be reestablished. Corroded wires and connections will also pass less current hot or cold but the "fail" threshold is more easily met when hot.

I'd look carefully for corrosion at the crimped ends of the heavy wires and connections to the starter motor from the solenoid and the shorter lead to the battery as well as the ground wire to the engine. You can isolate the wires and check resistance although the results may be inconclusive.  :( If the starter has not been rebuilt it may make sense to pull it apart and see what's going on in there. Of course all this is for naught without a sound and fully charged battery. I share fret nut's concern over a seemingly marginal charge rate you've got goin' on there.

One final thought, bring a sacrificial screwdriver with you and short the solenoid when it's hot and not turning over. If it then turns over, the problem isn't the battery, starter, or wires.  :)

As always, excellent advice. Thank you all. Now down to some tracking and tracing. Cheers.

I spent a 119 deg.F. day in 2008 in Lake Havisu  , enjoying my vapor lock. The temp gauge never went over half way. There is no relation ship between vapor lock  and engine temp. The engine may be over heated and not produce vapor lock and conversely the carbs can vapor lock with out engine over heat.  My vapor lock was caused by the fairing , which directs a lot of hot air into the carb area on top of the engine. Don minor and I speculated that a scoop in front of the fairing and some aluminum flex tubing, such as used in automotive emissions systems , would ventilate the area and prevent  t he problem , Except when there were extended periods of idling.

Wow! What are the symptoms of vapor lock when you are cranking? I'd be interested to know, although I don't think this is the problem in this case - (I am running a naked XZ550 and its still a very chilly spring here in New Zealand). I am however dreaming that it might be a long, glorious hot summer with lots of touring. Vapor lock would be a good sign!!

At this stage it looks to me as if my charging circuit is starting to fail (again) and the battery isn't up to turning her over when its hot. I have slipped some upper cylinder lubricant in to the gas in case there is a sticky valve and will do a thorough check of the starter motor and connections including a short of the solenoid when she next has an "episode". A starter specialist here has a used XZ400 starter which I might buy as a backup. Cheers.

Get a starter rebuild kit from e bay they are cheap , then you know your starter is good, I got re-vision to send it over to keep the freight cost down

Iain
NZ

Doesn't the TCI box cease functioning below 11 volts?

The TCI stops functioning below 10 to 10.5 volts. Most electronic systems do this. When the starter is cranking the engine, voltage will drop below the thresh hold of function , the starter will still crank the engine however.

Quote from: pinholenz on October 04, 2012, 06:35:58 AM
Rechecked the battery voltages this evening. 9.8v cranking  

This is not enough for the coils to fire up a Vision!!!

                 

QuoteWow! What are the symptoms of vapor lock when you are cranking?

I've always understood it to mean the engine cranks over fine but won't start and acts as if it's not getting gas.  It seems that in your case the starter may not be turning over the engine properly when hot. I'd investigate battery/charging and starter health first. If hot starting problems persists move on possible vapor lock causes.

I've always understood vapor lock to be when fuel gets hot enough that bubbles form and cause blockages in the tiny carburetor circuits. Is this the same understanding of vapor lock that you guys are referring to?

If so, I don't think that vapor lock is to blame either. I still think that you have a cranking speed, or voltage problem. Could also be idle mixture or carb sync.

Quote from: Jimustanguitar on October 07, 2012, 10:09:51 PM
I've always understood vapor lock to be when fuel gets hot enough that bubbles form and cause blockages in the tiny carburetor circuits. Is this the same understanding of vapor lock that you guys are referring to?

Yup, more or less. Liguid turns to gas due to high temps. Sometimes it's associated with mechanical fuel pumps bolted to the block of older cars when there is too much under hood heat. They are designed to pump liquid not bubbly liquid on it's way to a gaseous state.  :( I'd think the V's pulse pump is located in a prime position to suffer the same problems when the conditions are just right.

Iain, I am most offended by your avtar! It has no place here. Take it down before its is taken down for you!

Sorry Rick G didn't mean to offend more of the riders of vision, of course I will remove my avatar.
As we all know soft porn is a no no and now lets add religion to the list, so my new picture is of a cute wee baby ,
Iain
NZ

That's better Iain.  Who wouldn't like a picture of a cute wee baby.  I particularly like the fact that it has a moustache - not unlike Magnum PI

You guys crack me up. All this down under Kiwi humour really must look distinctly below the belt to all the upright folk on the other side of the planet - but I am glad you changed your avatar Iain. I was sad to see Roro's bottom go though, - it was truly a mesmerising work of art.

Back to the topic at hand. Has anyone had a go at soda blasting their carbs? Results OK?

Quote from: roro on October 12, 2012, 09:11:23 PM
That's better Iain.  Who wouldn't like a picture of a cute wee baby.  I particularly like the fact that it has a moustache - not unlike Magnum PI

What!?  :o That's just crazy talk...Magnum PI's mustache laughs at that baby's mustache.   ;D   ;D It does look somewhat familiar though. Charlie Chaplan perhaps?  No, that's not it. Oh well, it'll come to me....

It seems to me that I have seen  a picture of a fellow  , who looks a lot like that baby , only a lot older . I seem to have seen it in a history book or maybe on the history channel. It will come to me , I'm sure.

Rick ,I know who your thinking about , when he got older he was one of the village people .Not sure which one though, my money goes on the Cowboy or the Contruction worker or the biker, and at long odds the black guys at the back

Thanks for the advice and tips on dealing with my problems when I started this thread. Here's an update:

1. After going for a run, she doesn't want to restart when she's hot - especially if I stall. The starter really struggles to turn the engine over. It comes up to compression and then stops. If I was starting a Ford Model A I'd say the timing was too advanced. If I leave it for 5 minutes, she cranks over and starts fine. Any ideas what the problem is?

After rebuilding the starter, I installed a digital voltage meter on the horn circuit. The readout was 14.2 at idle but the charge dropped when the engine got warm. I was running on battery only. When the engine was hot, the additional compression/weaker battery meant that she wouldn't turn over under compression. Leaving it five minutes, the battery recovered and the engine turned over OK.

Solution: Replaced the stator with a used Suzuki XS600 G7 stator, and the Regulator/Rectifier from a Suzuki as well. We now have a good charge and battery. Starts easily under all conditions.

2.  Under load, the engine hesitates when I open up the throttle. The accelerator pump is working OK but I suspect that it isn't activating quickly enough? If that is the cause, what's the fix for that?

Over the months I have had the carbs off 4 or 5 times to clean them, replace "o"rings etc. Last time was to clean the idle jet to the rear carb because that cylinder got lazy and  cut out at idle. I was distressed to find that the same thing happened after my last clean. Went away for 10 days on holiday and magically, problem was gone when I came back. Yay. I had read that this sometimes happens with the XZ carbs. I am now a believer.

I thought that my throttle-on hesitation problem was because the accelerator pump wasn't reacting quickly enough when I opened up and it needed adjusting/stronger springs. Then I read in an old post that one member had solved his problem by putting in a WEAKER spring, (from a Biro) on the accelerator pump rod. I.e, the opposite of what I had done. So I have reduced the amount of spring on the pump rod and that has indeed reduced the hesitation. Still not good enough though. Next time the carbs are out I will replace the spring with a weaker one. 

It seems that  the hesitaion is caused by an overly rich "shot" down the carbs and that the weaker spring helps to regulate the rate at which the accelerator pump delivers its petrol.

There's been some great weather here this summer and at last I am beginning to get to know my XZ a bit better.

John, thanks for the update. It's really nice when an open thread is revisited and some closure given.  :D Glad to hear some problems have bee resloved and hey, what a surprise - a weak charging system was part of the problem!>  :laugh:  :P Sounds like you experienced some Vision carb magic too which is nice. All bonding moments for sure and how enjoyable the Vision can be when reliability/driveability issues are resolved.  8)

Your theory of overabundant accell pump output is a new one on me.  ??? Almost seems counterintuitive but can't argue with results! ;)  When you change the spring out again do let us know your results. Thanks.  :)

Excellent!  +1

The accelerator fuel stream is barely atomised, and there's a lot of it.  The Yamaha Intake and Carburetor mod kit manual specified backing off the accelerator pump by 5mm.  I think 50mm-60mm from the bend to the nut is the recommended setting.

There are lots of combined causes for stumble:
Check your accelerator stream is a spray, not a jet and that it doesn't hit sides of carb or butterfly
Check float level, and emulsion tubes / jets for blockages
Check round grey air filter and tube for blockages
Check for air leaks in YICS and manifolds
Check carb sync
Check you have a good strong spark
Check your mixtures

If you are getting a cut-out, suspect electrical. 
Is your rev-limiter playing up (can be disconnected), or could be as simple as a loose connector on the crank pickup.

Thanks Roro, that's a pretty comprehensive checklist and I think I have most of them covered thanks to advice and previous posts to the forum. I am not getting cutout at any point, she is just gagging when I am aggressive on the throttle, but comfortably redlines in those gears that take me up around the legal open road speed limit.

The two niggles not yet fully ticked off are my accelerator pump settings (strength of spring and length of the accelerator link rod) and  a small butterfly shaft seal leak on my rear carb. This will affect the mixture on that carb, but I am noticing that the more mileage the bike does, the smoother the idle becomes. (Probably improved compression from rings and valves getting comfortable after sitting for years.)

I will work through these two issues then tweak the mixtures and  re-sync.  In the meantime I will try not to beat the traffic at the lights or accelerate to overtake anything faster than tractor on a straight road. I sure feel stupid when it gags for a second like its going to die and then streaks away like a scared cat.

Update: Tonight I adjusted the accelerator rod length. It was easier to do on the bike than I expected. Is the standard measurement from the bend in the rod to the far end, or from the bend in the rod to  the point where the spring begins?

I shortened the rod as far as it would go. Still some hesitation when I open the throttle under power, but it is now more of a gasp rather than a gag. I will keep tweaking it and try a weaker spring than the replacement for the rusty one.

For me, installing a new accell pump diaphragm and shortening the rod adjustment made the biggest difference in curing the lag you describe. I'd hasten to add this was after installing new throttle shaft seals which finally allowed for a proper idle mixture adjustment.  :)