Hello,

Appreciative new member here.  And I have hit a snag with my Ryca cafe conversion of a 2003 ls650 with 4500 miles.  

I completed the Ryca cafe racer conversion about 3 weeks ago and have taken about 6 or 7 ten-mile rides on the bike for the purpose of (1) fun obviously and (2) tuning the carb.  Bike has a fresh oil change and oil level is proper judging by the window on the engine while bike is level.

I removed the brass cover to the mixture screw and adjusted that screw to get a smooth idle and to minimize afterfiring.  Before this adjustment, the bike would die at idle occassionally and the throttle would be lurchy and not totally responsive.

After the mixture screw adjustment everything was all very smooth and dependable for several short rides (50 miles total)

Yesterday, I rode to the YMCA (about 5 miles away). I followed my standard start procedure: 1. Petcock to on position 2. Pulled out choke  fully 3. Pressed decompression lever (the ryca part that replaces the stock decompression solenoid) 4. Pressed ignition and released decompression lever.  

The bike started right up as has been typical.  I let it warm up with the choke out for 30 sec or so and then pushed choke back in and idle settled in between 1000 and 1500 rpm.

I ride to the YMCA with no problems.  Engine is smooth, throttle is responsive, and idle is dependable during 2 or 3 stop lights on the way there.  I don't push the bike past 55 to 60mph during the short ride.

I park the bike at the YMCA for about 1 hour during my kid's soccer game.  The weather is warm, about 75f, but not hot.  I get back on bike and it starts right up without the need of using the choke.  Stock petcock has been set to on position this whole time.

I ride about a mile or two, and the bike dies as I am downshifting during approach of stop light.  I coast to the side of the road.  The bike starts back up after 3 or 4 tries.  I am pretty sure I smell gas.  

I ride another mile or so and notice that the idle is no longer dependable.  I have to keep the rpms up to keep it from dying, like 2k to 3k rpms.

The bike dies on me again.  It takes me several cranks to get it going again.  Pretty sure I smell gas again, and I thought I even saw light puff of smoke somewhere near the engine, but I couldn't tell where it came from.

I get it back home, but it is not running right, and it dies as soon as I let off the throttle.  

The Ryca conversion removes the airbox and just puts an air filter on the intake of the carb.  I notice a bit of smoke coming off that air filter.  Its not as much smoke as a lit cigarette makes but looks kinda similar.

I let the bike cool for an hour so I can take a closer look without getting burnt.

My first hunch was that my header pipe screws had vibrated loose and that there was not a good seal at the engine.  The fact that I had seen smoke near engine earlier contributed to this hunch.  But my header pipe screws were tight.  I also confirmed secure connections between my filter/carb and carb/engine.

I reluctanty tried starting up again.  It did start again after a few cranks but I noticed several things.  1. I saw the same faint mist of smoke near left side of engine. 2. Pretty sure I smelled gas again. 3. A very slight bit of gas was spit out from somewhere near the top left part of the engine because I felt it and the top left side of the engine had a slight residue of gas on it.  The bike did not run long or right.  I let it die within 20 seconds by letting the rpms down.

For the life of me, I can't find the source of the gas on the engine.  I detected no leakage/wetness where petcock enters gas tank.  Fuel hose appears intact.  I just can't figure out where this gas could be misting from.

Evidence of gas on the engine is enough to keep me from trying to start again until I get some guidance and a gameplan.  

I have explored this forum and suspect that a bad petcock may be the problem.  But could that explain the puff of smoke near engine, the cigarrette-like smoke from air filter, and the residue of gas on the top left front of the engine?

Thanks in advance for any help!

What does the level in the crankcase look like - do you have more oil than you did when you started the ride?

Does your oil smell like gasoline?

Do you have the stock vacuum operated petcock.....or the Yamaha Raptor replacement?

caferacer,
Another thing. How much oil is in the engine? With the engine tipped forward like that how are you determining the proper oil level?

Perhaps somebody who has done the RYKA conversion will chime in on this proper oil level thing.

caferacer,
If you have a stuck float in the carb. fuel can overflow and drain into the crankcase. Very bad. Too much "oil" and the gas in there  doesn't help at all.

There are several different scenarios that can occur when the stock petcock decides to be a problem.

1)  The diaphragm in the petcock can get stiff, and fail to provide enough fuel flow to keep the engine running.  During periods of low vacuum, the diaphragm can fail to flow fuel...and the engine runs out of fuel and stops.  After some cranking a bit of fuel may flow into the carb and help the bike to start again.  (As a temporary solution/fix/bypass to the problem, you can turn the petcock to PRI and see if the bike runs).

2)  The diaphragm can also leak fuel down the vacuum line when it goes bad.  This can cause the bike to get too much fuel to the intake port, and as the same time can cause the fuel flow to the float bowl to be erratic.  It can also allow fuel to flow into the intake and flood the crankcase with gasoline....and this causes very poor running as the crankshaft is embedded in too much oil/fuel, and the spray can come out the breather hose....which may be the smoke you are seeing.  (As a temporary cure you can disconnect the vacuum line to the carb, plug both the carb and petcock ends of the vacuum hose, and set the petcock to PRI.  If the crankcase has too much fuel/oil - you need to dump the contaminated oil and filter and start again).

3)  The petcock can also be very elusive about failure.  You can ride along without issue, then a strong headwind or some freeway riding can result in the bike stopping like it is out of fuel - even though you have lots of fuel.  The low intake vacuum that occur when you have the throttle cracked open can result in low intake vacuum - and that can result in the petcock shutting off the fuel flow.  There have been several forum members trying to chase down electrical or carb problems that are related to a fuzzy stock petcock.

I have a Cafe' conversion where I have used some RYCA parts and modeled my bike based on their conversion.  I have 10,000 miles on the bike and you can keep your oil level between the 2 marks on the oil window without issue - but do this with the bike level and not leaned over on the sidestand.

You should also consider jetting the carb properly, and doing a white spacer mod.....and actually setting your idle fuel mixture with the engine running and your ears listening - not by just cracking the screw open a bit more.

I can't see in  the photo where you are running the engine breather hose to.....do you have a filter on the end - or is it open?  I would not be surprised to see some smoke come out of this hose when the engine stops.....it likely will emit some water vapor and oil goo out of this tube.

Whatever you do don't leave the engine breather open. To the air- box or to a filter on the end.

caferacer wrote on 05/01/18 at 16:49:47:


Since this engine is a single....the crankcase gains volume when the piston goes up, and loses volume when the piston goes down.  At low speeds air goes in/out of the vent tube....this evens out as the rpm increases as the air cannot flow in/out of the small tube as quickly as the volume changes.....so a sort of partial vacuum/pressure exchange occurs constantly in the crankcase.  Having a filter on the end will prevent dirt from entering through the tube when it is in a vacuum condition in the crankcase.

However - the rings don't seal perfectly well and some combustion gases to get past the rings...especially at high throttle settings.  Those gases will vent out the tube, and carry some oil and water vapor with it.

You want to look for a genuine Raptor petcock.  If they don't show the white Yamaha box, and claim it is genuine and include the part number and want about $25 or more...it is not the real deal.

LkAAOSwmfhX4r09&vxp=mtr" target="_blank">https://www.ebay.com/itm/NEW-YAMAHA-RAPTOR-660-YFM-660R-OEM-FUEL-VALVE-SHUTOFF-PETCOCK-5LP-24500-01-00/273176937668?fits=Make%3AYamaha%7CModel%3ARaptor+660R&epid=1023314198&hash=item3f9a9d44c4:gLkAAOSwmfhX4r09&vxp=mtr

Thanks ohiomoto.  Will check the float valve too.  

Is there anything I need to do, in addition to getting the Raptor petcock, to keep the float valve from sticking in the future?  I cleaned the entire carb very well (with carb cleaner) when I changed the pilot jet during the recent RYCA conversion/rebuild.

I ordered the Raptor last night. I plan to install that, change the oil/filter, and look into the float valve.

Will report back here on the outcome of those efforts.