Bike "broke down" tonight, good Samaritan helped but........

So I was driving home on about a 20 mile hwy trip and I am about home and the bike starts cutting out and less than a mile after that just dies, not really having any clue whats going on I sit for a minute and try a few times to start it back up. Nothing

I check the gas, seems like there is some in there, not a ton, but not to little that I would think that I am out of gas.........


Then I nice guy stops and asks if I need help, I say yep.

He notices the petcock is on the "ON" and says that I should have it on "PRI" for primary, well sure enough after that it starts right up. He says that "ON" runs both the primary and reserve and is only for after you are completely out of gas the "ON" position feeds gas to the carbs.


Now I thought PRI was for Prime and that I should ride in the "ON" position??

Either way, there seemed like there should be enough gas for it not to die, am I just an idiot or should I have tossed it to reserve??

 

On is for regular riding. Res is for the reserve that is left in your tank after you run out on On. Pri is prime and is for bypassing the vacuum operated diaphragm it will allow you to use all the gas out of the tank.

So in your case you should have just switched to res. You will get so you remember the little stumble feeling that says you are out on "On" and need to switch it to res and start looking for a gas station.

 

You're not the first person to have this happen to, btw *whistles*... The missing on one/two cylinders is a sure sign as Mav pointed out.

Don't forget to update your sig with your bike model/year. On my Max the only way to track gas was to reset the trip meter on each fill up.

 

That would help if the ODO/Speedo worked

 

Anyone know if a speedo cable off an early 80's Yammy 850 triple will fit my bike?

 

A little more on that petcock as it will become something you'll need to understand at some point....

It is vacuum operated, there is a vacuum line from it to the intake boot on one cylinder. Fuel is only allowed to flow to the carbs when sufficient intake vacuum is present (i.e. motor is running).

In ON or RES, flow is controlled by this feature. In PRI fuel flows without vacuum. This is handy for if the bike sits for a long time and the fuel evaporates from the carbs, you have to switch to PRI to fill them again, or it would never start.

Also, if the vacuum circuit for the petcock were to develop a leak, you'd be stranded, as no fuel would flow. PRI gives you some level of redundancy for that scenario.

Also if a carb float or tip were to stick open while parked, fuel would pour through and empty the fuel tank if allowed to go through the petcock unregulated. This way all it could do is empty that carb and the line, and a complete disaster is avoided.

If you ever need to remove the tank, you should be able to do so with the petcock in either ON or RES, and no fuel should come out (once the line drains)...if it does, the petcock is faulty and needs to be rebuilt.

If you ever have a situation where the bike "sags" or dies after getting on the throttle hard for a bit, check that vacuum line...if it's split or swelled and sucking air, that can cause the petcock to shut fuel off completely under sustained hard throttle...intake vacuum levels are low at large throttle openings anyway, if it leaks there will be none to hold the petcock open, and it'll starve for fuel when the carbs start to empty...

 

While we are on the topic of fuel, what octane are you guys running. I have been running mid grade...

 

Re: Bike "broke down" tonight, good Samaritan helped but....

91 octane was the recommend grade for my Seca according to the owners manual. I avoid ethanol blends.

 

a new one can be bought from chacal for like 16 bucks.

I wouldnt mess around buying used since it is such a high wear item.

I cheaped out and bought one from d2 moto, and the cable is kinked a bit, making the speedo tick between 0-20mph. annoying.

See:

http://www.d2moto.com/p-21429-speedomet ... night.aspx

However, the front pads i bought from them have actually been fairly decent! (YES, they DO fit our 83's)

http://www.d2moto.com/p-13895-1982-yama ... -pads.aspx

 

My buddy put a brand new one on his triple and then proceeded to throw a rod a week later, so its pretty much new.


Also my tach seems to be sticky unlit I get up to around 5k rpms? any thoughts?

 

89 is fine for XJ's but if you can avoid ethanol that would be ideal.

If by 'sticky' you mean it isn't operating correctly the cable could just be loose, and about to disconnect-check the threaded sleeve that attaches it to the tach and to the motor to be sure they are both tight. It could also be gunk and build up. Your tach's gears might be worn as well or the driven cable might be getting frayed. It's a really simple setup basically just a driven gear that twists a square wire inside your cable which drives the tach. How many miles on the bike?

 

The fellow that stopped probably either:

1.rides a harley
2.had no clue but was trying to sound important

The ON is for regular riding

The RES is for when the level gets low enough to stutter/stall to let you know that you're gonna run completely out soon, so get to a station

The PRI is for PRIming the carbs when they run empty and you need to get fuel back into the carbs

ON and RES are vacuum operated and hence only allow fuel to flow when the engine is running

PRI is a free-flow setting to allow fuel to run even when the engine is off. That way you can PRIme the carbs before starting if needed, and also allows you to ride if the vacuum tube or petcock vac. side goes bad.

There is no OFF position.

Octane level-- I run the standard 87 in ALL of my bikes, cars, truck, tractor, and sleds.

Dave F