I've finally got my bike back together and a new R/R installed. Unfortunately my rear cylinder gremlin lives on.
Charged battery. Attached a new multimeter. 12.9vdc with key off.
With engine running, volts increase and sit between 13.5 and 13.8v, from idle through rev range.
Bike idles and runs nicely for 10-15 minutes then the rear cylinder begins to cut out. Particularly problematic at low revs, bike refuses to idle. If the throttle is wound open the rear cylinder will occasionally kick in but it takes a while to get home! During this time the bike becomes more difficult to start (starter seems to spin more slowly) and I have also noticed that the digital gauges sometimes reset while start button is pressed. This usually only happens when the gauge is disconnected then reconnected to the battery which suggests to me that voltage is very low. I haven't retested voltage after the rear cylinder has started cutting out.
The tach needle on the digital gauge bounces around quite erratically, this symptom persists regardless of engine performance. I've tried using resistors which didn't work. I'm not sure if this problem is related but I have read that low voltage can influence tach performance.
Rev limiter wire is clipped and taped.
Problem persists with different TCIs.
New R/R has 3 white wires and 1 red and 1 green. Red and green are wired directly to battery.
I've replaced the fuse box. This bike has some creative wiring solutions compliments of the PO and I'm wondering if it could be a wiring problem. Positive battery lead is looking pretty corroded.
I replaced the stator with a spare taken from an engine that was described as "running". The old stator was giving me ridiculously low VAC readings which turned out to be a faulty multimeter.
Since my tach isn't working I haven't measured VAC from stator accurately. Valyes ranged from between 30-70 (from memory) VAC when I plugged the multimeter in to the current stator white wires and rolled through the rev range.
The original R/R had 7 wires total from memory, the new one has 5. The wires that the old R/R originally connected to are unattended. Someone mentioned these were related to lights and signals? Lights and signals seem to work ok at the moment, at least while engine is running properly. The old R/R connecter block at this junction may have been suspect throughout this problem. At this point R/R is wired directly to battery.
In a big nutshell, bike seems to be losing voltage somewhere.
Electrex fault finding chart suggests charging system is not to blame.
I'm getting a bit stumped...
On a positive note the bike looks a lot better.
I will go back through the Electrex Chart again in the next day or 2 to double check figures.
In the meantime any thoughts would be AWESOME!
The tach gets its' input from a gray wire that comes off the spark coil wiring. If you haven't already done so, inspect and clean all spark coil related connections and the ground that is related to the spark coil wiring.
Thanks QBS, I've inspected this coil, cleaned connections and even tried jumping to tach with a new wire. No improvement.
Assuming the problem is electrical, try replacing right side coil and High-Voltage plug wire and spark plug to rear cylinder. If the Y/B Rev Limiter wire is disconnected at tach, disconnect or cut at TCI also in case it's shorting to ground somewhere. BDC
Quote from: Re-Vision on December 17, 2013, 12:27:16 AM
Assuming the problem is electrical, try replacing right side coil and High-Voltage plug wire and spark plug to rear cylinder.
Rather than
replace you could also
swap the coils left to right and see if the problem moves to the front cylinder indicating a bad coil. If the problem persists with the rear cylinder the problem may be in the rear pickup coil. Pickup coils don't seem to be particularly problematic on V's but you can't rule it out. The 4 pin connector (is it clean BTW?) at the TCI holds these B,R, and W wires. Using an R scale capable of +/- 110 ohms check them with the bike at room temperature. If the values are equal and within spec, ride the bike until the rear cylinder drops out, pull over and test them again. Any difference? Resistance may increase slightly on both but a significant difference between the two is problematic.
Also unlikely but not impossible is every TCI you've tried is faulty. ???
Remind me again how you deduce the rear cylinder is cutting out? Spark tester? Y pipe temp?
There are some clues given that can be made to fit a particular diagnosis but don't rule out the possibility there are multiple problems within the arena of "electrical" or even simultaneous fuel
and electrical fault.
QuoteBike idles and runs nicely for 10-15 minutes then the rear cylinder begins to cut out.
Is this from cold where it starts and runs on choke but as the engine warms and choke is removed the problem arises indicating fueling? Or, is this a typical failing electrical component symptom whereby the component comes to operating temp and breaks down?
QuoteCharged battery. Attached a new multimeter. 12.9vdc with key off.
With engine running, volts increase and sit between 13.5 and 13.8v, from idle through rev range.
Depending on the charger used, 12.9 fresh off the charger seems a little low. Nominally 13.5 sounds a bit low while running through the rev range. I'd expect nominally 14.5 right above idle and beyond. Not that this is necessarily contributing to your immediate problem but of some concern to me.
The abandoned wires from your OEM R/R should not be a problem provided they are not shorted. On my US '82 the yellow from the OEM R/R does nothing and the brown senses system voltage. Apparently your new R/R does not use a sensing wire. Are there any wires from the new R/R not in use? Is the R/R one of the inexpensive E-Bay Chinese units that seem to very prevalent now?
Does the tach sense from the rear coil and have you tried disconnecting it?
Thanks for the thoughts guys. I will switch the coils over tomorrow and give it a try. So far I've been diagnosing by a lack of spark and a cool cylinder.
I'm not familiar with the difference in coils and pick-up coils. Coils are bolted to the frame at the end of the spark plug leads, where are pick-up coils? I don't have much experience in that dept.
I can't remember which coil the tach reads from but I'll disconnect. New R/R has all 5 wires in use, 2 to the battery and the 3 white to the stator. New R/R is a cheap one.
I'm wondering if the problem could be a short somewhere? There really is some suspicious wiring in places but not so much around the charging system.
The pickup coils are inside the engine case. The pickup coils are essentially a crank position sensor that tells the ignition box when to fire the ignition coils...
The tack would read from the pickup coils, they're the "source" of the spark timing.
Thanks for that.
I was under the impression the tach got it's signal from the ignition coil rather than the PU coil? Mine is wired that way anyway. I have no idea where the PU coil is inside the cases but I'll do some research. It's not part of the stator unit is it?
I just found another electrex sheet which looks quite useful.
http://www.electrexworld.co.uk/pdfs/Troubleshooting-3P-PMG-&-RR.pdf
I'm not sure if the values etc are bike specific or if I could work through this sheet and use it as a guide?
The tach does get its signal from the right (rear) coil through the gray wire. When tach limits are exceeded it puts a ground on Y/B wire running from tach to TCI Unit.
The pick-up coils are located inside the case near stator, if one of them fails it will cause the same condition as the tach limit circuitry does (one of the cylinders will quit firing).
Something else you might try, when rear cylinder is not firing, try wiggling connectors and harness in an attempt to get rear to fire. In particular the connectors associated with rear coil (right side) and four wire connector from pick-up coils to TCI unit BDC
Thanks.
When I replaced the stator I replaced the whole side cover so I imagine that included the PU coils. This replacement didn't improve situation.
I'll have another look at the HT coils and give things a wiggle. Would a problem in this area account for a drop in voltage? That link I posted looks very useful but I'm not sure if the figures/values/measurements stated are relevant?
Quote from: tig5 on December 17, 2013, 05:24:13 PM
I was under the impression the tach got it's signal from the ignition coil rather than the PU coil? Mine is wired that way anyway. Then try disconnecting to your digital tach and see if conditions improve I have no idea where the PU coil is inside the cases but I'll do some research. It's not part of the stator unit is it? If you replaced the stator with the cover then yes, you changed the PU coils too. These are also called pulse coils and are attached to the inside of the stator cover separate from the stator itself.
I just found another electrex sheet which looks quite useful.
http://www.electrexworld.co.uk/pdfs/Troubleshooting-3P-PMG-&-RR.pdf
I'm not sure if the values etc are bike specific or if I could work through this sheet and use it as a guide?
I think the tests are valid and practical within reason. I don't think you can't use the brake light as a "control" as outlined in Step 1 however flicking the key switch on/off will do the same. The low limit for charge rate (13.6) stated in Step 3 although acceptable is generally higher with MOSFET and OEM Vision R/R's. I can't comment on Step 4. Step 8 basically tricks you into connecting the R/R directly to the battery which I think you've already done. Hopefully with heavy wire and maybe even a 30 A fuse on the red wire? I like that loads are used to further validate what might otherwise be inconclusive results in these tests.
Tig
Quote from: tig5 on December 17, 2013, 06:51:58 PMWould a problem in this area account for a drop in voltage?
Anything that puts a load (shorts)on the battery and/or charging system will try to pull the voltage lower. Voltage changes are more noticeable when charging circuits are not operating. BDC
I appreciate the thoughts, I'll get stuck into it tomorrow and report back
Quote from: tig5 on December 17, 2013, 05:24:13 PM
I was under the impression the tach got it's signal from the ignition coil rather than the PU coil? Mine is wired that way anyway.
So the tach reads from the high voltage output of the secondary winding of the ignition coil?! or it connects to the low voltage input side of the coil and this connection just physically takes place at the ignition coil?
I'm pretty sure the tach is reading the pulses that trigger the spark and not the spark itself... I guess they go through the CDI box first though, so it doesn't technically come STRAIGHT from the pickup coils like I said...
The latter. TCI (Transistor Controlled Ignition) box is controlled by the crankshaft position sensors, and replaces the points in what is basically an ignition points and spark coil system. Like ignition points, the TCI sends timed bursts of 12vdc to both spark coils. One of the coils (not sure which one), sends its signal on to the tach via the tachs' grey wire that branches off of the coils' low voltage harness. This is how the tach is gets its' RPM data.
Short of waiting til spring to remove my gas tank and look... Can someone confirm gray is the rear cylinder circuit color? :-\
I can. BDC
Thank You :)
I charged my battery again and it showed 13.4v off the charger.
With the key (and light) on it dropped to 12.9v.
With the engine running I was getting a slow increase up to 13.9v or 14.1 if I turned the lights off. From what I gather, that's reasonably acceptable?
I swapped the coils over and check the contacts and ground and fired it up. Went for a 15 minute ride with occasional stops to check the charging voltage. Everything seemed ok. If I kill the engine the voltage at battery slowly drops to about 13.2v.
My ride wasn't long enough to say that switching/cleaning the coils solved the problem but I'll take it for another run tomorrow.
My tach is still bouncing all over the place. The right coil has 2 wires including the grey. Am I correct that one wire provides the current, the grey provides the signal for the tach, and the frame provides the earth? The left coil also has 2 wires and the third black wire that grounds between the coil and the frame. I couldn't quite get my head around the differences between left and right.
I have the stock gauge cluster lying around and I'm thinking I might try and hook it up to test whether it also bounces or not. I remember seeing a photo in another post which identified which points on the unit connected with which wires. I'm only looking for +ve, -ve and tach. I'll have a hunt for the photo, if anyone remembers which post it was on a link would be appreciated.
The left and right coils are identical, they just fire at different times so it's important to wire the right one to the right plug wire. They do get their ground connection through the mounting studs. If you ever take them off again, it's a good idea to remove the paint from around those holes so that you can make an even better connection. Some have also reported that the coil housings can crack and stop working well after that. If they're off again, a visual inspection is in order.
Not familiar with which wire colors do what. Hopefully somebody else can chime in on that one.
jetav8r appears to have done considerable research.
Quote from: Jimustanguitar on December 19, 2013, 11:15:13 AMNot familiar with which wire colors do what. Hopefully somebody else can chime in on that one.
http://www.jetav8r.com/Vision/IgnitionFAQ.html#a9p0
Click on 9. Checking TCI module (Power Checks)
Plus I have a bike with the tank off and a harness here at my desk. BDC
jetav8r, who's handle around here was leather, was a sharp fellow . He was also a Warthog pilot in the gulf war. I miss his fellowship around here!
Bike seems to be running well after swapping the coils over, so I'm suspecting a poor ground or a loose connection. Stoked to be riding again. I've noticed a tiny flickering of the oil lamp so I'm going to pull the pump and clean out any debris. It starts easily cold and idles well but the idling and starting ability diminishes a bit once it has warmed up. Could this suggest it's running a tad rich?
Sorry to have to say this, flickering oil light at idle is not good. Suggest you go to 20w50 or even straight 50 oil at your earliest convenience. Will crank with difficulty running straight 50 but might get you down the road for a while longer than otherwise. Checking the pickup screen for debris is a good idea. Maybe it's partially blocked, that would be good news. Of course, the bad news is: Where did such debris come from? All the best.
Take the oil sender unit out of the bike ,,it screws in under the engine ...and stick the air gun in it and blow it out,, that fixed my flickering oil light problem,,it had a build up of sludge in it
Iain
NZ
Thanks guys, I'll try all those measures.
I just dumped the engine oil and there was quite a lot of light brown fluid appearing on top, not quite green but definitely lighter brown than chocolate. I'm wondering if I have coolant leaking into the oil?
This will be my first time removing the right engine cover. Do I remove the thermostat unit from the cover first or can I leave it attached? Do I need to drain coolant before removing the cover?
I see that people recommend replacing the water pump seal, is it #4 on this diagram? http://www.cmsnl.com/yamaha-xz550rk-1983_model8947/partslist/B-03.html
Do I need a genuine Yamaha part or is this something I can take into my local seal specialist and have them replace?
I'm new to this side of the engine. Any opinions appreciated.
Cheers
P.S Engine oil smells a bit gassy...
The bike has been blown over 3 or 4 times since last oil change. Petcock is a cheap replacement, no PRI function, I've a bad habit of leaving it in the ON position.
Bike doesn't blow any smoke that I've noticed.
Check your overflows are clear. If they are blocked then petrol will end up in your cylinder, and sneak past the rings. Makes starting a bugger as well.
Hiya Tig,
Great to meet up the other day. Thanks for the coffee. Did you get your WOF?
I have had a flicker on my oil light as well. I had the bike idling on its side stand parked sideways on a slight downhill incline. Flicker went when the bike was up-right. However, it was also a bit low on oil. As I recall you didn't have a centre stand?
Oil change and a careful top up on level ground sorted my problem.
Is yours a gravity or vacuum activated petcock?
Hey John, likewise!
I failed my WOF on a handfull of things: Steering bearings need tightening, needed a rear reflector, need to reroute my throttle cable and zip-tie a few other cables out of the way. Also need to check for air leaks as my idle wasn't returning properly. This seems to be an intermittent problem and doesn't appear to be related to the cable or the throttle mech as far as I can tell. All up they it shouldn't take me more than a couple of hours to fix so I'm pretty happy.
I figured while the oil was dumped I may as well take off the right engine cover and clean out the pump filter screen. Do I need to remove the thermostat for this and do I need to drain the coolant? It looks like I've had a bit of fuel in my oil. I'm not sure if this was affecting the oil pressure, it did look a little thinner than it should have. I've removed the sender and I'll give it a clean but I thought I should get in and have a look under the right cover while I have the chance.
My bike has a side and a centrestand, I flick between them depending on which way the wind is blowing! Bike has been running like a champ until the oil light came on.
Oh by the way, I had another look at my house on google maps. Carjam.co.nz suggests the bike outside is not a phantom Vision but a humble Yamaha Scorpio. The chain gives it away a little.
Good to see you John! I hope you have a prosperous new year!
Its' been a while, but I seem to recall that the water pump has to come off. Have been in there only once to replace a 72k mile clutch. Also replaced the water pump twice. All of this was a long time ago. My trusty Haynes repair manual was excellent. Every V'nary should have access to one. Sometimes, working on a V can be counter intuitive or just strange. A manual is a good thing.
Likewise, I can't recall what I had to do with the side cover I retrieved off a scrapper for POD. Done in great haste.
I do have a spare Haynes manual if you need one though.
I replaced my steering head bearings with roller bearings in order to put my bike back on the road. Pyramid Parts in Nelson have them in stock. It took me quite a while to get the lock nuts snug - they kept working loose. Some Loctite did the trick.
I have never come across a Yamaha Scorpio, but will look out for them now. You have piqued my interest. Deus Ex Machina in Indonesia do a pretty cool little cafe racer out of them.
I do have a Haynes manual thanks John. It just said to remove the thermostat unit and the side cover, I was just wondering what kind of liquid torrent I was about to run into but I figured that out.
Unfortunately 2 of the allen bolts that hold the thermostat to the engine cover were seized and stripped so I had to remove the coolant tubes from the cylinder heads and remove the cover with the thernostat still in place.
I tried the usual methods for remove the stripped allen bolts but they were well seized in there. Ezy-outs seem to have been well reviewed so I bought one and gave it a go. A quarter of a turn in and it snapped like a twig. So now I have 1 frozen bolt and 1 embedded ezy-out >:(
I think I'll take it to one of the local machine shops and let them have a go...
I located the coolant weep hole and found it blocked up with a sandy clay-like substance. I think this may be insect related. When my bike was in bits I saw a wasp fly into the cylinder weep whole and the next day it was plugged in a similar way.
From the back side of the engine cover there are some prominent ridges that almost look like stress fractures in the metal. Are these normal? Part of the machining process? They look like oil streaks twoard the bottom of the photo but they are actually pretty substantial. I'll be interested to see what the other side looks like when I finally get the thermostat off.
Bummer.
It looks to me as if the cracks have got raised ridges on them which suggests that it is part of the casing cast and not really cracks at all. Best way to find out is to touch it with a grinder to take the ridge off and see what is underneath. Good luck!
I'm pretty sure some of those things are casting marks. Also, hate to say it but some look like cracks. Pins idea should give more data. Just have a really hard time imagining what kind of forces are in this area that generate such cracks.
If you can get the piece of the extractor out of the Allen head screw you can use a 1/4" or 7mm drill to drill the head off the screws and slide the cover off, then you can use a vise grip or other tool to remove the screws. A couple hammer blows on the ends usually loosens them so they come out easily.
QuoteFrom the back side of the engine cover there are some prominent ridges that almost look like stress fractures in the metal. Are these normal? Part of the machining process?
I've seen this on other cases and covers before. As ugly as they look I would not concern myself with them. As stated they are from the casting process. If those marks were on the outside of a cover and oil was weeping from them, then I'd be concerned. :)
To add to fret nut's broken screw suggestions, I'd also apply heat to the aluminum bosses where the screws are prior to your next removal attempt.
Thanks guys,
Heat and drilling the ends completely off are about the only 2 things I haven't tried. I'll give that a whirl and take it to a pro if I don't make any progress.
The ridges definitely are raised, it will be interesting to see what the back looks like. I also couldn't imagine how or what would cause cracking here.
I have mentioned this many times before , but here goes again. Easy outs are miss names . The should be called easy breaks.
They do not work 99 % of the time , instead they cause a worse problem, a piece of hard steel which can not be drilled .
My method of effecting this type of repair is to carefully put a dimple in the centre of the broken off screw and start with as small a drill bit as i can and work my way up , until the there is nothing left with the threads , which can be picked out with a tiny screw driver. In the event that you drill the hole slightly off centre , merely install a helcoil . Every motorcyclist should own a 6mm Hilicoil kit.
Dead right about the impossibility of drilling out hardened steel, though you can slot it with a dremel cut-off wheel.
If I have to drill out a screw I'll usually just tap and go up a bolt size - as long the larger bolt head & hole fits. My bike was a rusty thing - it's got oversize bolts all over it now.
there is the option of annealing the easy out so it can be drilled, but probably a risky operation in alloy. please correct me if I'm wrong. I called myself dingleberry for a good reason.
You could investigate metal disintegration machining. I had this done back in the day to remove a broken RD-250 cylinder exhaust port stud containing a broken EZ-Out. The service was reasonably priced, at least multiple decades previously.
http://en.wikipedia.org/wiki/Electrical_discharge_machining
http://www.sparkeroding.co.uk/
Interesting, I didn't know there was such a method. BDC
Both bolts were too frozen to remove by notching, even with the screwdriver helped along by my biggest hammer. I drilled the head off one, and used a combo of drill and dremel to take the head off the one with the Ezy-Out imbedded in it. Fortunately the Ezy-Out had snapped off quite low in the hole. By the time I got the heads of the bolts off the stems could be unscrewed with my fingertips....
As I mentioned earlier, the weep hole was filled with a sandy sludgy material. I used a drill bit to clean it out . I removed the mechanical seal (4) and will replace it. If I poke the drill bit all the way up the weep hole I can see it appear on the back side of the pump bearing. It looks like there is a piece of partially detached O-ring floating around in there. I'm at work now and didn't get a picture. To get any closer to the bearing I understand it needs to be pressed out and pressed back in by someone with the right gear? Im unable to tell whether or not the weep hole was filling with coolant or not but I'd rather replace parts while I have the cover off. The muck that I pulled out of the hole was stodgy enough that it could have been. There was a bit of gasket sealant floating around but it definitely looks like a bust O-ring.
It sounds like your cooling system could use a good flushing and coolant replacement, after the new parts are in place, of course.
The broken O-ring was actually a munted bearing seal. I got the guys at Boyle Kawasaki to order me a new mech seal and figured I may as well replace the bearing while I was at it. The mechanical seal cost me 55NZD and the bearing was 10 if anyone is curious about prices.
The small factory I work in has 2 EDMs , 2 problems we're in the UK and what ever needs to be eaten out needs to be put on the bed of the machine and sunk in or flushed with fluid.
How much to send the wife to the UK I wonder :P
Quote from: dingleberry on January 10, 2014, 08:22:55 PM
How much to send the wife to the UK I wonder :P
Sorry forgot to mention the object must be electrically conductive. ??? ::) :P