staggs65
Moderator
those mighty vacs are pretty cheap if I remember right. It's been at least 10 years since I bought mine though so ? Any auto parts store should have it right on the shelf
You will want to cut off the oil and fuel supply while you crank it over. Don's input on purging the case via the reed openings using suction is very good advice.
Remember that oil is sent to the engine at 2 basic places . . .
Ways for excessive oil to get in the cases . . .
Changing the oil pump with the engine in the sled can be done but is a bit tricky. I usually pull one engine mount, loosen the others and then tip the engine slightly. Then the hard part becomes replacing the engine mount that was removed.
Remember that oil is sent to the engine at 2 basic places . . .
- Mixed with the fuel at the fuel pump and then sent to the carbs in the fuel supply.
- Sent to fittings in the bottom of the crankcase to oil bearings including the cross shaft (oil pump/water pump).
Ways for excessive oil to get in the cases . . .
- Oil supply lines to ports in bottom of crankcase. If oil tank vent is plugged this can easily happen during warm summer months. Or the oil can simply "siphon" into the case.
- With the fuel from the carbs. When sitting many months the gasoline can evaporate leaving the oil behind.
- Through an internally leaking oil pump ??? I have never heard of this occurring on a Yamaha, but this can happen with the Mikuni oil pumps used on other engines.
Changing the oil pump with the engine in the sled can be done but is a bit tricky. I usually pull one engine mount, loosen the others and then tip the engine slightly. Then the hard part becomes replacing the engine mount that was removed.
More great advice - I'll check the vent on the oil tank and get cracking on getting a siphon - still would love to know where the pump arm is stationed during idle - it's not clear if it's supposed to be at the stop or not - also need to figure precisely where the cable runs from the throttle block to the pump bracket - still can't find a way to get the 22mm that I need.
Yamaha sets the arm swing based on cable play at idle. This effectively is how much cable travel exists from idle to full swing. This is unlike the Rotax (Mikuni) pumps which had a full throttle indicator on the arm itself. While I have placed my own marks (helps adjust aftermarket cables and throttle blocks) I am reluctant to assume yours would be similar. You can look at the Owner's Manual online. The pictures in that manual should clear it up for you.
Ding, if the arm is being held partially open at idle throttle position, will it allow oil to siphon through the lines and effectively flood the cases with oil over time??
Never tried it to know either way. But there is oil flow even at "closed" positions, just a smaller amount. I would think that the "siphoning" could occur regardless of arm position, but that is just an opinion.
It does seem like oil could "siphon" into the case (via the fittings) without going through the oil pump. I don't have a SXr in front of me to double check but I think this sled is plumbed straight from the oil tank to the case fittings like other models.
It does seem like oil could "siphon" into the case (via the fittings) without going through the oil pump. I don't have a SXr in front of me to double check but I think this sled is plumbed straight from the oil tank to the case fittings like other models.
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dsc577
VIP Member
oil cable hangs in holder at end of airbox and goes behind carbs,
oil line goes to the pump then the oil feed lines that go on bottom of case attach to the pump output side. The other output goes to the fuel pump.
same basic set up on all the triples,sx,sxr,viper,srx.
same basic set up on all the triples,sx,sxr,viper,srx.
Yes that is correct, I should have worded that differently.
Do you remember if that port (oil pump to case) is pumped and/or regulated the same as the line to the fuel pump (internally in the oil pump)? Seems like I have a Tech doc on this somewhere that discusses this. I guess I maybe confusing it with the pump (and separate lines) on a Rotax.
Ok - huge help here - thanks for the pic now I know precisely where the cable goes - on less thing to worry about. I've clearly bent the bracket too far in my initial attempt to get the twisted 'wankled' cable bracket in place. I'll tear down asap and also get the reeds off. Need to locate a mityvac or a marine primer bulb to solve the oil in the case issue. While I'm at it - I'll move the pump cable bracket back and reattach and see if I can get the 21mm needed. Still not clear if the pump arm begins its swing from the idle stop when attached to the cable or if it begins at some point later in the swing rotation. Again - you guys are awesome to take the time and help...fingers crossed that I don't break the heart of this redhead.
Update - did as all you have mentioned and tore down past the reeds (looked to be in fine shape too). Sure enough - middle and pto cylinders full of oil. Literally sucked it out with some skinny fuel line attached to a marine primer bulb - worked slick. Great way to clean out a crankcase if you ever need to fyi. Also, rented a high quality compression tester just to see where I'm at - as expected the compression in the oil soaked cylinders was off the chart (like 150 psi) while the mag cylinder was a solid 128 ish. After the oil siphoning of the crank I re-tested. All three are now around 128-130 psi. Adjusted the oil cable bracket on the pump and routed according to the picture. Almost slammed everything back together, but decided not to press my luck - went and tested the compression on the ET340, SS440, and '76 Rupp 440 Nitro instead - I can give you the data on these vintage racers if you're interested...more to follow as I put the readhead back together.
One other thing - how do you guys tackle a first of season cold start? Here are my typical choices:
1. Full choke and yank away until magically starts with plenty of blue smoke
2. Same as above but get angry when nothing happens and then spray a little fuel mix into the cylinder holes to at least get her to pop
3. A couple of shots of ether in the air box - ugh
4. A shot of ether in each cylinder - I know don't start cursing at your computer - just being honest
1. Full choke and yank away until magically starts with plenty of blue smoke
2. Same as above but get angry when nothing happens and then spray a little fuel mix into the cylinder holes to at least get her to pop
3. A couple of shots of ether in the air box - ugh
4. A shot of ether in each cylinder - I know don't start cursing at your computer - just being honest
staggs65
Moderator
premix down the plug holes right before I ever pull the rope
Basically I try to save myself a bunch of pulling on the rope by filling the fuel lines and carb bowls. Just a little (very little mind you) air pressure in the gas tank accomplishes this. A little premix down the plug holes helps make it fire right away which also starts the fuel pumping to the bowls. I usually get it started in 2 - 5 pulls if the bowls are filled without having to pour the premix down the plug holes. Call me lazy I guess.
New Years Day Update: Hell yeah! Re - assembled and took everyone's advice. Fired on first pull with a little pre-mix down the cylinders. Had a couple of hiccups as she purged her summer oil and got fuel back in the bowls. By the third re-start she was tearing up the yard and I was able to get her up to operating temperature. Adjusted the idle a whisker and took the redhead for a little ride around the neighborhood. Checked the plugs but they're hard to read since they're brand new. Need to put a few real miles on her and then re-check. A this point she's running great - I'll keep real close eye on oil consumption and look forward to a great riding season - can't thank everybody enough for their help!