My shop is in an over-sized two-car garage attached to my home. My work is a calling, in the theological sense of the word. Ethical and moral questions arise every day – they are hard, sharp, unambiguous and unavoidable.

Float Needles and Blown Fuses

Posted: August 30th, 2013 | Author: Administrator | Filed under: Fuel & Air, Ignition, Timing, & Electrical, Motorcycle Repair | Tags: , | No Comments »

It doesn’t take much at all to cause a float needle to improperly seat and allow fuel to keep flowing. The smallest bit of debris can keep the needle from seating properly and cutting off the fuel flow. Below is an email exchange with a customer regarding such float problems. Also, there are some useful tidbits about diagnosing electrical problems. Enjoy!

Hi Chris, we talked , in past, over phone…I managed to get all plugs in the 83 Venture @ .035 with new OEM(paper element) air filter….I am getting a backfire on deceleration on one cylinder, and idle is just not a consistant solid RPM…vaies, maybe 300 RPM’s at idle…..In your expert opinion, is this a valve adjustment problem and/or carb out of sync? Or, is air filter not breathing as free as it should? Have a great and safe 4th weekend…this is an irratating issue…I drove down to Pickens today and the bike runs smooth enough on the highway….then decelerate and pop goes the weasel….many thanks……need to bring it to an expert….
Respectfully,
W


W,

The symptoms you describe are typical of a cylinder running lean at low rpms. This can be caused by either a carb with clogged up idle/pilot jets or by an air leak. If you can tell which cyl. is the culprit, removal and a thorough cleaning should do the trick. The other possibility is that the rubber intake manifold between the carb and the intake port is cracked and leaking air. Less likely but possible is that the little rubber o-ring sealing the pilot air screw is leaking.

Cheers,
Chris


Hi Chris, I left you a ph message, but here are the symptoms…..1983 Yamaha Venture…one carb is dumping gas and it goes down to ground through short hose….It runs smooth, and strong, but I am wanting to take a trip north (487 mi) to 85 miles SW of Indianapolis camping in KY on way there and back….you can see the gas flow in the carb in question(when air filter is removed), but not other 3 carbs are showing gas flow…Do you think, by adding Sea Foam, to gas line, recently, I could have screwed up the works? Also, I overfilled the tank last saturday, then didn’t drive until yesterday, and noticed gas smell but really had to hunt down leak…..possible vapor lock from heat and expansion yesterday? Anyway, I need to get this fixed….
Many Thanks, Respectfully,
W


Wayne,

My guess is that the problem is that the Sea Foam did its job and dislodged accumulated crud – one little speck of which had lodged in the float needle seat and is preventing it from shutting off the fuel flow to that carb. The overfilling is probably just a coincidence.

An important caveat: I have not worked on a Venture before but a friend of mine has one and there is a lot of stuff to remove before one can put that carb on the bench to work on it. If you have a good shop manual – great – if not, I will need to purchase one – about $30 for a Clymer or Haynes. I can figure out just about anything – given time – and I adjust my hours to reflect what I think it should have taken someone familiar with the bike. But you may prefer to take it to a Yamaha dealer or another mechanic who has experience with this bike. I think, if I were in your shoes, that’s what I would do.

Let me know what you decide.

Cheers,
Chris


Chris,
I traced another caveat: my headlight went out…I took the HL housing apart and cleaned connectors……put it together…still no light….went to fuse box and the head lamp, 10 amp fuse, had burned a hole in plastic fuse housing…I Jerry rigged one annode side of glass fuse with a fashioned connector (what I had available to improvise) and snapped the good side back in…works, but no high beam, so I believe I need a new lamp and a permanent fix for the fuse box defiency…I like working on bikes, but my expertise is limited…Been riding for 42 yrs, and, at 60, still learning new tricks…..my tool kit is my own variety of tools, including cold touch soldering iron, flares, flashlight, night light sticks, electrical & duct tape, fuses, extra plugs, plug gapper, tool to get plugs out and in, Teflon tie sticks, first aid kit, rainsuit, 3 sets of gloves including gaunlet, and misc items for most common fixes…I have running lights, mini-red strobe lights which are motion activated, deer horn alerts(I know they work lol), highway pegs, and a small instrument cluster containing, clock, compass, and thermometer…..these add-ons are for better visability & safety and function…..bike is stock…no mods….Have a great weekend……
Respectfully,
W


Wayne,

The blown fuse means that something in that circuit is drawing more than 10 amps – typically due to either a short or a bad ground. The most likely culprit is inside the light switch module on the handlebar. Less likely is that the headlight itself shorted internally. The fuse exists to protect the electrical components – and from the bike going up in flames – worst case. Juryrigging/bypassing the fuse will – sooner or later – result in much more expensive problems than you have now. If you have a multi-meter you should be able to located the fault and correct it.

Good luck in getting it sorted out.

Cheers,
Chris



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