boxer54 wrote:Thanks to all for the info.
Here's an update on the bike...the problem persists but with encouragement like: "The mind draws dragons into the blank areas of the chart..." I proceed into the darkness...
I have checked all 4 HT leads and boots and plug caps and all appear in very good order without signs of whitening, rusting, bad contacts. etc. There is also a healthy dose of silicone grease on areas where needed and now WD40 too. The 4 plugs are cross wired as was suggested by PITApan.
There are two ways to cross wire the coils. I have mine set up so each coil feeds the top plug on it's side and the lower plug on the opposite side. The other way is to have one coil feed both tops and the other both bottoms. What I am doing has diagnostic advantages--but it's getting close to spitting hairs on which way you go. But think about what happens if one coil gets weak and what you should observe. Your top plugs are typically the more reliable and stronger ones.
Check the resistance of the wires. You probably have resistor caps at the plug end. Check (post pic). They will be 3000 or 5000 ohms. All can look good but an internal fault will still hurt you. less than 3000 is not the most ideal but it'll run ok. More than 6000 bears further investigation. Ask if you get that.
I have seen bikes where somebody did it wrong and used auto wires with molded on caps. Sure they were cheap, but it isn't the solid core wire you want, the caps were non-resistor and this was not compensated for with resistor plugs. I use non-resistor caps and resistor plugs. Two reasons: I build my own wires and I really like the solder-on caps. They last seemingly forever, even on an open bike. But they happen to be non-resistor. I have lots more choices for my lower plugs in resistor types. So non-resistor caps and resistor plugs it is for me. I use a copper core silicone jackets wire, screw on fitting on the coil end (that has to be maintained), the caps are silicone as well and I stick with black. The yellow and red get dirty and stay that way (very odd ball side story on that one some time, ask me about the dirt getting pounded through ResusciAnnies chest). The overall resistance of the wire+plug combo affects the spark duration in large part and radiated EMI in small part. Too little you can live with (I've run none and it worked fine) , but not too much.
boxer54 wrote:There is NO water in either of the carb bowls, the fuel level is equal on both sides and I found no residue of 'foreign' contaminant i.e. bits of fuel pipe/ enamel from inside fuel tank (as I read someone suggest somewhere was the cause of a scary sudden lack of power mid way through overtaking).
Equal fuel level is nice.
Correct fuel level is critical. I have marked the correct level on the inside of my bowls---permanently. So checking for correct and balanced level takes a minute. You remove the bowls by grabbing the wire bail at the sides and pivoting it. you can remove the bail if it is in your hair by spreading it a bit an popping it off. Data on Snowbums site for the correct fuel height with the freshly removed bowl in your hand.
boxer54 wrote:The spark on all four plugs looks a little weak, i.e. yellow/ orange in colour rather than blue but all apart from top right (dark & oily) were looking okay.
Do not pass go, do not collect $200. Fix this. Tested with a virgin plug strapped to the cylinder head the sparks must be blue white. I have had a couple experiences with dead coils but only one with a weak coil making yellow sparks. I was living at 10,100ft and commuting to my job at 11,360 ft. with an old VW squareback and 4 people. The car was running worse and worse every day. I get some days off (I worked 7 days at a stretch) and I had a look. The oil bath air cleaner was packed solid with sunflower seed hulls. Guy in the back seat was spitting them out the window and they were slip streaming down the body and going in the air intake, packing the filter. I had a mechanical advance distributor so the timing wasn't affected but it ran like crap anyway. With the airfilter cleaned out it ran better but still weak. Next couple days off I checked the sparks. Yellow. Put in a Bosch Blue coil and got nice white sparks. Huge difference. Hauled up the pass every morning with no further issues. I was completely impressed with the change. I didn't expect such a difference in performance.
boxer54 wrote:Yesterday I took a 30 minute ride to remind myself of how the bike felt. It started easily and was soon happy to be off the choke. At start off it was sounding ok though not the best, it was not misfiring. It pulled well though something didn't feel quite right and sounded off, just not as smooth as I've heard it before. I did think that it may be in my mind and the fact that I was EXPECTING a problem. But sure enough, the rough running returned. It seemed to come alongside the bike warming up (is this possible?). It was not misfiring, but it was NOT running smooth. It was lumpy and hesitant when I gently turned the throttle then would suddenly surge (pointing to weak spark and bad timing?).
Don't ride with the chokes on. Unless it is pretty cold out (40-50F) it should be off the chokes in a minute in the driveway. In summer, many people don't need them at all). The big difference between the warm and cold engine is the valve clearances. You should be able to hear the difference as the engine warms up. A mechanics stethoscope is a good investment. listen o the timing chain too. Cold oil is thick and your oil pump is chewing up more HP pushing it. A more minor point.
Do not wonder or theorize about the timing. Just check it. What? 3 - 5 minutes? Something deep in the engine that will take you a day and a half of worka just to get to, and another day and a half to put back together, with $100 worth of gaskets---THATS worth theorizing about. Not your timing.
boxer54 wrote:Could it be an airleak somewhere? How would I check this please?
Good thinking. Another one not worth theorizing about, too easy to just check. The rubber tubes between the carb and the head dry out and leak. Bad--runs the mix lean. Little cracks are a sign of dried out rubber. Look on the ends. test at idle with starter fluid. Spray the fluid around the joints, point blank range. If there is a leak the motor will suck in the ether instead of air and the idle will speed up. Starter fluid is handy for diagnosing other fuel issues. You want some anyway.
You can also try the starter fluid on the throttle butterfly shaft (dried out/ worn out o-ring?) and the enricher shaft (ditto on o-ring). Also check the cover over the enricher assembly. There is a spot (that semicircular bulge) where the cover gasket is very thin and sometimes gets sucked into the compartment.
Another way to check is to seal the joints with grease. Like a thick smear of vaseline on the outside. This can work better at higher RPM on the road.
if leaks are found there are some games to limp some of them. The shaft o-rings are tough---pretty much have to replace with the correct ones. massive leaks (usually carb to head) will stop you. You can run the mix so lean you overheat and burn pistons. But those are the simplest to patch and limp. The throttle shaft will just give you a crappy ride all the way home. Not a stopper.
Air leaks upstream of the carb will let some dirt around the filter but are of no consequence at the moment. Really big ones will affect the mixture at higher speed running. Uncommon. Sometimes a lot plug from a removed clean air system will hurt mix but it's subtle.
boxer54 wrote:I've read about compression tests? Should this be where I should head.
head to the auto parts store to borrow a good (screw in type) compression tester. Then google around on how to do wet and dry tests. Also see the instructions with the tester. I own a good tester but I also maintain 7+ engines--and then I don't use it often. Not worth buying if you can borrow a quality one. You actually do a battery of tests, each revealing a different aspect of engine condition. I would not bother at the moment. If both plugs on one side were oily (not gas, oil) and your inspection with a Streamlight Stylus Reach (buy one--be happy) through the spark plug hole revealed a lot of carbon on the piston crown and valve lips AND a look at the head under the rocker cover (like when setting valves) showed a lot of brown deposits, then maybe break out the compression tester. But not yet. Fix the spark issue and ensure the carbs are up to snuff. When your new flashlight arrives, have a look down the spark plug holes for fun and see what you can see. Did you hear the one about the guy with something rattling in his rear drive but despite the thing having 3 observation holes in it, didn't explore any of them? This is common. There are a number of places you can tell what's going on with various systems just by looking in the hole. You need a good flashlight. You need to remember to look in the hole.
Minor point: Silicone grease gets used sparingly. The stuff migrates and makes a mess. It does not block water by it's mere bulk, as ordinary grease does. It works by making a surface unwettable. The water beads up and the beads don't fit through the crack. If you want the opposite effect use glycol. Water with some glycol in it will go through a crack that plain water can't pass. It's about surface energy if you feel like learning something obscure (not so obscure in some fields and I happen to be in them). Anyway you glob up the grease to keep water out of bearings and in a pinch, very short term, something like the a leaky speedo cable boot (bad news when that leaks water in!). On the electrics, just a film of silicone grease is plenty.
Plain (clear) silicone grease is conductive enough in a very thin film to use on the threads of screw in light bulbs around the house. Good for can lights, sconces, outdoor bulbs, etc. Filled with some graphite powder it becomes very conductive and can be used as an anti-oxidant paste on high power connections---and must be on some aluminum wiring to satisfy building codes. Filled with zinc oxide it becomes very heat conductive and is used as a heat sink paste on auto electronic ignitions, electronic chips in computer, heating rode inserted in various things, etc. I also use the plain stuff inside my heads, just a film. before inserting the exhaust pipes, and also on all exhaust connects. It seems to be better than anti seize. Connections must be kept clean. The exhaust nuts get real high temp (nickel base) anti seize, plenty of it, often.
WD40 can be used for drying wet electrics. it is very good at displacing water on a metal surface. It's the only thing it's good at (maybe getting sticker gum off some things). Poor lubricant, penetrate and anything else. I hose wet tools down with it, wipe them off and put it away. Works well. To keep rust off, lube something, penetrate, etc. everything else is better. I haven't checked the MSDS on it---supposedly it's kerosene and light oil.
boxer54 wrote:With thanks
You're welcome. Now quit granny drivin' the thing like some wanker that lets a marsupial drink his beer. Get it warmed up (maybe 10 miles riding) and do some full throttle passes to blow the carbon out. If you want to be nice to your driveline roll on easy rather than snapping it open--- but open that sucker up already. Your observations of the piston crown will show what it's worth. It helps to have a long and steep grade for these games unless you want to get off the beaten track on some back road or have an autobahn handy. I had one going north on 80 out of Vallejo. I was still pulling a well over a ton over the top but the uphill lanes weren't patrolled. Nobody jumps you going UP the mountain. And the downhill lanes littered with CHPs were well separated. Good place for full throttle plug chops.
