flyday58

That was it, big old jets to compensate for cone filters. Runs like it's aspose to now. Something to look for when acquiring an unknown history bike.

Pretty sure I found the problem. Clue was the cone filters installed by the owner prior to the current one, plus the sooty plugs, but I needed to check all the electrical stuff first before yanking the carbs again. As you might expect the jetting has been monkeyed with. Mains are 125s and pilots are 22.5s. We're in the mountains above 8000' (9000 at my house) so super-rich when coming on the mains above about half throttle, the third clue. Just a shame the bank has to be split to get at the float bowl screws. Jets on order from JetsRUs.com. This should do it; I'll follow up once she's all back together.

Made a few test runs trying different things, none of which worked. I jumpered the L/Y and W wires together at the speedo connector, bypassed the faulty side stand switch, checked voltage running (14.1V at idle, 14.08 when revved). So electrical issue looking less likely. Looks like I'm taking the carbs off again!

As a note, this dude had what appears to be an identical problem to mine. No resolution, never been back. I'm leaning strongly toward an electrical gremlin. My speed sensor is failing the test noted above at the speedo, but not sure how to test that theory. Should have continuity between the blue/yellow and white wires on the harness side, I'm showing an open circuit. Ideas?

Señor Puc, how's it hangin?! Figured you'd be along, good to "hear" your voice again! I'm still firmly earthbound since giving up the flying gig in 2018, enjoying running around on two wheels that don't (mostly) leave the ground. How's things in Musky Michigan? Well-taken points you have there in your list. Pipes are open and I bought an OEM airbox to replace the cones the PPO had on it. Diaphragms passed the hold-up-to-the-light test so no tears or pinholes. They seem to return readily to the closed position after opening with my finger. One is a teeny bit sluggish on the return, another has a fairly deep gouge on the upper surface at the base, so exposed most of the time and not riding up in the bore. Metering rods are clean, return springs are in good shape. This baby is largely electronic so didn't see any vacuum advance on it. It won't accelerate uphill and I have to downshift to third then second to keep her going. I'm hoping someone will chime in on the speed sensor question

Yes, checked with my heat sensor. I had pulled the plugs after the first ride, brand new plugs, all were black and sooty. I'm pulling them now... All sooty black again. I remembered one more thing. I did a speed sensor test and it failed. The manual says you should have continuity across the blue/yellow and white wires, I got zilch (open), even at the speedo itself. And the speedo doesn't come apart so I can't look to see what those wires go to. Anyone have a bike open so they can perform this test for me to see what they get? Thanks.

Continuing... Installed the new cap and went for a ride today. Bike now revs a bit more before acting the same way: more throttle results in a bog, with sputtering but no heavy popping, again like it's starving for gas. I could only go up mountain in 2nd gear, otherwise it lost so much power it threatened to stall. If I feathered the throttle it would run smooth, so long as I didn't ask too much of her. Going back down mountain I could get her to do 60 in 5th, no more. When I resurrected the 83 XVZ years back it had similar symptoms; that turned out to be the ignitor/ECU, which was thoroughly corroded inside. This one is acting similarly. At idle it sounds like a Harley, but I've verified spark on all four coils and plugs. New fuel filter and S-hose, fresh non-corn gas. New float bowl gaskets but few other seals available from Yamaha. The float seats were all loose in their receptacles; I found two o-rings in my stash that worked but the other two are original. New intake boots, replaced the cone filters with an OEM unit and filter(maybe I should check the jet sizes since the PO had cones on it?). Fuel pump was clogged with varnish but I got it pretty clean, and it seems to be pumping gas. One other thing, sometimes when I put the side stand down it'll quit, like it's in gear and the SS switch is sensing it. Today it refused to restart until I put the SS up, then it stayed running with multiple swings of the SS. When this happened, it would crank and fire but not run till I put the SS up. Clutch switch is bypassed, fuel indication is bypassed, both at owner's request (lack of funds). That's the story, thanks for any insights. Richard

Hello again everyone, been awhile since I've posted. But I'm back with a problem on a 97 Royal Star Tour Deluxe that I'm attempting to get back roadworthy for a customer/friend. Bike sat at least four years after the PO passed on, not much history except what eyes reveal. Carbs were very clean though not pristine, but cleaned up easily with no petrified varnish to remove. Fuel tank was another story, so bad that I told the owner I wouldn't fool with it. A friend of his took it, pressure washed it and brought it back, along with a can of red goop that can be applied right over rust. I did it but told him no guarantees. Once it all was back together it fired up on the second touch of the starter button and purred like a thing that purrs (right, Half-Pipe?!). First shakedown cruise was when the problem appeared. No tach but it wouldn't rev above 3500 rpm or so except in idle. It doesn't act like a rev limiter, more like running out of gas. I found the #3 plug cap reading infinity; when I took it apart it was corroded inside so ordered a new one from Mother Yam. Everything else seemed okay. TBC...

Great explanation!

Just a thought, but I've seen my Venture do this low-temp/blast off thing after mucking around with hoses and t-stats. Mine was an air pocket that once it burped out, all I had to do was top off the antifreeze and all was good. Fun reading, lots of gained knowledge for you in a short time. Cheers.

Nice looking cap!

Fun thread. I miss the old '83.

Thanks. If the nightmare returns I may have to pick your brain on exactly how to do this. Sounds simple in theory. Still can't believe I couldn't get it to act up at all. So far I haven't heard anything. Fingers crossed...

To quote Major Frank Burns, "nurtz"! Spent all day Saturday and found nothing. The old girl didn't miss a beat and rode like a dream, great acceleration, no hesitation, just kept going and going and going. I found one bad crimp on my fuse panel swap to blades, but it was for the headlight. So I checked all the crimps and redid them while I was at it. I pushed and pulled on every connector and wire I could get at that relates to ignition without unwrapping the wire loom/ bundle, checked all the relay connections, looked for corrosion I might have missed before. The ONLY real smoking gun happened after I first cranked her up. I was able to get two very subjective-sounding stumbles by applying thumb pressure to the Ignitech box, but then couldn't reproduce it the rest of the day. I even put the box in the freezer for a bit because it had gotten fairly toasty sitting in the El Paso sun, but it worked like a champ. I unplugged the fuel pump and let it starve to verify the symptoms. And of course they are different; when it dies it just quits as if the kill switch had been used, but as the fuel runs out it starts to stutter and surge before quitting. Then when you try to start it, she will try to fire off as some remaining gas gets in. I'm quite sure it's not a fuel issue ( petrol for Greg_in_London;)) Took the emergency stop/ kill switch apart and cleaned the contacts ( they already were), verified correct ops of the sidestand switch and relay, pulled each COP plug off in turn to verify all four were firing (ran on three each time, with #2 also killing the tach but the bike still starting up and running), checked the right switch harness plug, wiggled the ignition switch and key, tugged on every plug and wire I could reach, including the pick-up connectors and wires on the left side frame. When I rode it I went fast, I went slow, I hit bumps, I cranked the steering hard over left and right looking for anything but she ran perfect. The NO says it's even running better after we put it back together, but he had added Seafoam to the gas so that may be it, or it could be purely subjective. And for G_I_L, the cutting out of the tacho was when we tried the old 26H TCI last week. NO such issues with the Ignitech. With all that, I had a blast hanging out with the NO. He started me off with a nice steaming cup of mint mocha coffee while I took the old gal's outer garments off ever-so-slowly, like you do with old flames you haven't seen in a while. THE VENTURE COVERS GUYS, JEEZ!! The gentleman really enjoyed seeing the bike apart and seemed impressed with how much I knew about the thing. I tried to show him all my mods and where to look if certain things happened, although he says he's not very mechanically inclined. He's an electrical engineer but tells me it doesn't apply to bikes or cars, at least not for him. We have similar music tastes, so he put on the big-screen in his garage and we watched and listened to videos of Joni Mitchell, The Blasters, Pat Metheny, Crosby Stills and Nash, and Glen Campbell, great guitarists all. Then he gets out an old Stratocaster and plays through an old tube amp while I'm yanking on wires. Our religious values are also the same so we had plenty to chat about there. Finally I put everything back together and we went and had a late lunch before I headed back home. Without having found any real issues I'm not confident I did anything to fix it. He took it out on the highway after I left and said it flew, no issues. I hope they find happiness together (sniff) and many miles of happy trails. On a side note, a buddy of his pulled up on a 1981 CB750 as I was getting ready to leave. It's in pristine unrestored non-bobbered livery, so trying to talk the wife into thinking there's absolutely nothing wrong with having another motorcycle in the garage. 5 scoots, 6 scoots, what's the diff?

Taking all that stuff with me in the morning as I dispatch myself to ELP to work on it. Bringing extra plugs, my spark tester, might even bring the Carb Tune for good measure.I've got an extra right handlebar switch and ignition switch which will be making the trip, too. The way it's acting, from what the NO is telling me, is the bike acts like you hit the kill switch. I'm leaning away from the switch itself as the bike turns over but won't start. The very first thing I'll do is listen for click-click-click from the fuel pump, and if it starts then dies check for spark, then gas in the carbs. NO said yesterday he put the Ignitek back on and now it won't start. Stay tuned...