Thank you!

Great! No need to ditch it if it’s not broken.

Sweet! I’m glad you found it helpful. Enjoy your amazing machine.

Thanks so much, Johnny!

Thanks, Glenn! Glad it was helpful!

This is a pretty old video at this point, so I’m glad it continues to help people! Thanks for the comment, and good luck on the rebuild b

Thanks for taking the time to say that, Daniel. I'm glad it was helpful and clear! I don't think we ever got the DT200 here in the US, but I'm sure it's like any other Yamaha 2-stroke enduro... reliable, powerful, and fun!

Glad it gave you some confidence, Mike. Thanks for the kind words. Happy riding!

My pleasure!

Thank you! As you’ve now seen from the video, simply cutting the cable doesn’t completely shut off oil flow from the pump. It’ll still pump at “idle” ratios. The 1-into-2 cable isn’t cheap, but it’s worth finding to get your bike back to the way Yamaha intended it. Good luck!

Thanks!

Thanks, William! I actually used to be a teacher. 😉

Glad you found it helpful! From my experience, the DTs will smoke at WOT + low RPM even when properly tuned. It's pumping a lot of oil in at WOT, and if you're lugging the engine, it has a difficult time burning off all that oil. Pop it a gear lower and let it rev, if possible. If you've got a load on the motor (like going up hill or level ground), you will NOT over-rev it. Happy riding!

Thanks, Sanjay! It should give you years of reliable operation.

@@hermetheuscoffee I own a RX135 and the oil pump is flowing oil even when the throttle is fully closed. I have even removed the cable and the story remains the same. I suspect the engine vibes or rather the gravity of the flow is just pushing the oil in which should not be the case, as oil pump is designed to pump oil only when the throttle is opened, im not sure how rpm affects the pump mechanism though. Well, in my case the bike is smoking way too much. How can i fix this problem? Is it something to do with the two seals inside the pump or is it a much bigger problem that im staring at.

@@ragavvijayadev8900 Based on your questions/observations, you might want to re-watch the video again. I cover the operation of the pump and how BOTH throttle position and RPM affect the output of pumped oil. Even with the throttle 100% closed, the pump should pump oil. (I reference this in the video as a way to potentially save your engine if you chop the throttle at high RPM on a downhill.) I would also verify that your adjuster plate (aka the pump pulley in Yamaha terms) is correctly adjusted at 0% throttle. Perhaps your adjuster plate is adjusted too far at 0% throttle and it's pumping in too much oil at idle. Based on the limited clues, this would be my first hunch. But feel free to report back with more findings, clues, and details and I'll try to help out. Good luck!

So glad you found it helpful and took the time to write the kind words. Good luck on the GT80 project! I keep a GT80 gas tank on my shelves as a decorative piece... they're cool little bikes!

@@hermetheuscoffee Indeed! After taking some measurements and doing some research, I have carefully filed the so named adjustment pulley to increase the stroke distance, and did the same to the shaft "lifter". The idea is that within the tolerances, it travels a longer distance and pumps more oil when the gas position is beyond the original carb´s curtain. Not sure if that makes sense in words, but I was enlightened by your explanation. Will share the results when i do the caudal test.

@@gambini_modding I love hearing this! Your description makes sense to me, and it confirms that you not only understand how to adjust the pump per procedure, but also WHY you're doing the things you do! Once you understand how these pumps work, they're less mysterious and fear-inducing. Good work!

@@hermetheuscoffee Thanks man! I come with an update: the modifications did not cause any effect sadly. It seems that despite how much you increase the stroke lenght, there´s a maximul fillrate that the pump can do. I measured both ways and in both cases the readings are on spot with the manual specs (which is a sign of good functioning too) but not enough for the bigger carb, i guess. Luckily i have spare pieces and kept the best ones original to revert the change.

@@hermetheuscoffee and btw, if you happen to have somewhere the output rate of models like the dt100, rx100 or any model inbetween, it would be a good guideline. I currently have the gt 80´s original, which is 4.28 per 200 strokes, and yours which is a very large engine to compare with.

Thanks for the kind words. Next time someone tells you to ditch the pump, point them to this video!

Sweet! Glad it helped, Rodney. Enjoy the bike!

I no longer have my DT, but they're still fantastic bikes. Best of luck on the rebuild!

Thanks for the kind words... glad you enjoyed it!

Thanks, Tyler! Regarding the cable coming off the pulley, you’ve touched on something I completely overlooked in this video! On the pulley, there is a small “protrusion” with a tiny hole in it. You MUST have a pin in this hole to keep the cable from coming out of the pulley! You can use a tiny cotter pin, a small paper clip, or small safety wire… as long as it doesn’t catch on the pump itself, you’ll be good. Regarding not returning to the idle position, are you referring to the pulley on the oil pump? This could be a few things. I would first unhook the throttle cable from the pulley… Does the pulley “snap” back to idle on its own? If so, you just have too much drag in your throttle cable somewhere. (A kink, at the Y junction, or just dry). But if it doesn’t snap back on its own, then you might have a spring that has popped out of the pulley (or has broken). Narrow the problem to either the spring or the cable and then take the next steps from there. Good luck!👍🏻

No, I didn’t create a video for that, but it was fairly straightforward using the instructions from PowerDynamo.

I don't have a video of that, but it really is as simple as taking the nut off and adding/removing shims as necessary. In my experience, this is rarely needed, unless that machined "ramp" has become worn due to a TON of use. Good luck!

Glad it helped!

That sounds like an amazing find! Good luck getting them back to the streets.

Absolutely! Anything the turns the engine over will spin the pump. You could add some premix gas to the tank and run it for a while to make sure it's fully in the carb/engine, then unhook the oil line and let it idle. At idle speed with your finger on the head of the pump (the part the moves in and out), you can very easily feel it and count the strokes.

It's super easy. The cylinder isn't sleeved. Start by pulling the cylinder to find out the extent of your damage. For instance, you MIGHT just have a hole in the top of your piston, but no cylinder wall damage. But find out how extensive the damage is, then I would suggest posting a picture to yamaha-enduros.com. There's a wealth of Yamaha DT knowledge on that site! You can still find original Yamaha pistons pretty easily for these bikes. But before you order, you'll want to pull the cylinder to make sure you don't need to bore it out first. If you have to bore it, figure out how much is required (1 over, 2 over, etc.) then order the right piston for how far it's been bored.

Hey, Spudman, glad you've found the videos helpful! What you describe certainly sounds possible, and the check valve is the first thing I would investigate. Thankfully, it's SUPER easy to get to. The brass outlet port on your pump, where you have a hose that runs to your carb, is just a press-fit port. You can firmly grab it with pliers and twist it off (be sure not to put torque on the barbed nipple part, though, because it can break off). Just put torque on the main brass barrel part. As soon as you get it off, be careful because there's a spring and a 5/32" ball in there and you don't want to lose either. The spring presses the ball against a rubber seal. Just give that all a really good inspection. You might just have some sludge buildup that's preventing the ball from properly seating. You might have a missing or weak spring. You might have a missing or damaged rubber seal. You might have a corroded check valve ball (unlikely, but not impossible). But the bottom line is that if the ball doesn't seal properly, you'll get the EXACT symptoms you describe. The oil will very slowly drain back into the pump (by gravity), and yes, your fuel mixture can 100% go into that same port to "thin" out the oil a bit. That port on the carb is just a straight shot into the main intake, so it's also a straight shot back down the oil line if you're draining oil back into the pump. That's really the only culprit that I can imagine. If that check valve is doing its job, there's no way way for that air bubble to form at the top of the oil line. So HOPEFULLY all you need is a good cleaning and reassembly and you'll be good to go. Good luck!

@@hermetheuscoffee ....thank you very much for the DIY check valve repair info! I'll have a look at the check valve ball, spring and seal and see what I find and let you know. I'm in the process of replacing tubes, tires and brakes now, but the autolube pump will be next on the agenda.

@@spudman1125R sounds like you’re checking all the right boxes on bringing this back to life! If you haven’t done so, I would HIGHLY recommend doing a leak down test. The crank seals tend to dry/crack, and if you’re pulling air in, you have a lean condition that’ll seize an engine quickly!

@@hermetheuscoffee ...thanks for the tip. I have a good friend helping me that owns his own shop and has been a bike mechanic for 40+ years. His knowledge has helped me so much already, and I'll be calling on that knowledge again tomorrow. The 2 Phillips screws holding the pump to the engine case are almost completely destroyed. That's how I found them today. My buddy says not to worry...that we'll get them out...and I hope he's right once again. They wouldn't even budge rapping them with an impact driver...the heads are nothing but round divots.So repairing that check valve will need to wait until we can get the pump removed, as I don't think we can get that outlet nipple removed and reinstalled while the pump is still mounted. I'll keep you posted though! Thanks!

Well, after about an hour of tedious work with a metal chisel on Saturday, my buddy was able to get the destroyed screws to turn and we got them out. Took the pump inlet nipple off and removed the spring and ball and found a somewhat corroded and pitted ball, which we replaced. Reinstalled the pump with Allen screws and started the bike and there is no longer any bleed down of the oil back into the pump! Thanks again for your help and advice Jason!

Yes, it's the same pump design, but the tolerances/output values will be different. But the overall pump design and operation is identical.

Thanks, Tyler! I’m glad it was helpful.

32:1 ratio. Have fun with it!

Are you referring to the silver plate with the hole in it? This is supposed to be aligned so that you can see the pin through the hole. The purpose of it is to actually HELP you find the pin and the dot that it’s pointing to. Maybe your plate is rotated out of position?

​@@hermetheuscoffee Yes, actually have it so that the hole is lined up with the pin pretty closely. But my plate is unlike this one in that it almost completely covers the area where the pin is unless you're looking through the hole. When you're tightening down the nut it's hard to keep it perfectly in line as it wants to move. It's very easy for me to line up the pin without the plate in the way. I'm just wondering if there's another purpose for the plate or if I can just take it off and it will be okay. Thanks!

@@bb8215 I THINK you’d be okay to remove it. I can’t think of any other functional purpose for it.

It's not going to be harmful, but what would be the point of doing it? Adding 50:1 premix as a winterizing step probably isn't as good as using ethanol-free gasoline with StaBil in it. Or better yet, draining the tank and carb dry.

@@hermetheuscoffee thank you for your reply. The question was out of pure laziness. I have a new can of 50:1. Just seeing if I could save a trip to the store. I will drain the tank instead.

@@LastmanLaPan oh, you’re good! Ride and have fun smelling the extra smoke. 😀

The first thing that comes to mind is resistance in the main pump shaft. Remember that the pump shaft is being pushed outward MECHANICALLY, then pulled inward (e.g. pressing down on the pump head) BY A SPRING. if there is resistance in getting smooth pump strokes (or a weak spring), then it won't fully push the pump downward and you'll get exactly what you describe. However, the tolerances at idle are so small, you might also just have a slight adjustment of the cable needed. That is, if you aligned your pin to the dot, the pump pulley will start to move downward to increase the pump stroke (oil output). If there is some play in your pump pulley, then pushing it in by hand more aggressively might just be physically moving the pump pulley. I would take a look at 13:40 in the video. At full throttle (bike not running) can you physically push the pump outward like I'm doing, then see it fully and smoothly retract in? If this motion is very smooth and has no "tight spots" or resistance, then you're still probably just looking at an adjustment that is needed somewhere. If you feel resistance anywhere at all, then you have a different issue. The one thing that I'm curious about is your process of "rebuilding". These typically aren't rebuilt/serviceable (unless you really know what you're doing). What did your rebuild consist of?

Thanks so much for your reply. I just checked the pump and at full throttle, it does pull out and retract with no issue. This morning, as I spun the starter 'gear', it appeared to be moving more oil than what I noticed yesterday. I dont have access to be able to use a drill (as you did in the video) so perhaps I've not spun it up enough at idle to produce enough oil to be noticeable. Also, in response to your questions, yes the stop pin is aligned with the dot. Also, I purchased a gasket and seal kit and disassembled and installed those new components in the pump. (Maybe not necessarily a 'rebuild'). At full throttle, it definitely moves oil!

@@matstang1491 It sounds to me that your pump is probably good to go. The quantity of oil pumped at idle is VERY small. At 33:30 in the video, I've actually sped the video up significantly. If you're spinning it by hand, it might not LOOK like anything is pumping unless you do it for a long time. In addition, although you bled the pump, the line going from the pump to the cylinder could have also had air in it... so until you've purged THAT air, your readings could also be off. If the pump moves freely, quantities look good at full throttle and you're getting SOMETHING at idle, odds are in your favor that you're in the ballpark.

Great news. I have been hesitant to start the bike after the rebuild but feeling confident now. Best video on youtube on these pumps. And thank you, thank you for taking time to help me out!

@@hermetheuscoffee I have a similar issue. At idle, nothing. When I tighten the nut down, it doesn't allow the shaft to move up and down when I turn the wheel. When the nut is loose, it can move up and down. Is that normal?

Thank you! The oil output volumes come directly from the Yamaha DT250A service manual.

I'm not 100% sure on this, but I'm PRETTY sure that plate is nothing more than a circular "window" to draw your eye to the pin that you align with the dot. When the pump is installed on the bike, it can be a bit harder to even find the pin, so this little washer-like plate you talk about helps orient you. You look through the round hole and the pin should be right there in the middle of it. It's not functionally necessary, so if you're lacking that, don't worry about it! Yamaha also did away with the white priming wheel (the one that I spin with the cordless screwdriver) on the "new style" autolube pumps, so if you're missing that as well, don't worry about it! Good luck, and happy riding.

@@hermetheuscoffee Thank you again! You have no idea how much this video has helped me. I had to make my own shims to get the gap correct as the previous owner screwed it all up and there was no movement of the pump at idle (that silly washer thing was mounted UNDER the large washer not above it and no shims in sight). But as of 15 minutes ago I have perfect gaps at idle and FT.

@@rolandwheeler7617 oh yikes! Glad you found the video useful and that it helped get things straightened out!

For the DT250, the quantity @ strokes was in the service manual. For the DT50MX, however, that metric isn't provided. Just aligning the pin with the stamped dot.

I will say that it will NOT be the ballpark of what my DT250 needed in this video! The 50cc engine would require much less oil!

@@hermetheuscoffee okay. thanks!

If you're referring to the wheel to prime the pump, then no, the bike doesn't have to be in neutral. Yamaha wisely engineered a slipper clutch into the oil pump assembly, so you can spin that white priming wheel in gear OR in neutral. It makes no difference.

It’s from the original Yamaha service manual. It has a wealth of detailed information about the bike.

They are not even remotely similar. The pump in this video is an oil INJECTION pump for a 2 stroke engine. It's pumping oil into the crankcase that will then be burned in the combustion cycles. It's nothing like a 4-stroke oil lubrication pump like the Virago.

I briefly touch on shims at the 25:00 mark. If there’s something you feel I’ve missed, please add to the comments to help others. Thanks!

Thanks, Ted. That's a valid and important aspect that I left out of this video.

I can see what you mean. Sorry about that. I tend to talk with my hands a bit. Noted for future videos!