gear box oil dipsticks

[RDryan]

So I thought I would treat my 75' RD250 to a new oil dipstick as the old one always had a chunk of it missing and today the new one arrived in the mail. It looks nice and new but it's shorter the difference measured with a tape measure is 4-3/8" for the original longer one 3-3/4" for the new shorter one. That's just the steel measure in inches from where the bottom of the handle starts to thread into and from there to the steel tip.

The funny thing is the old one always seemed to measure oil a good inch over the upper flat mark and the new one seems to measure just right on the upper flat mark and  that's with the bike on it's center stand, cold engine oil level reading. Not sure what to make of it but I attached an image to post of both the them. Also attaching a link to the Ebay listing where I purchased this oil level dipstick.Regarding the Ebay listing I didn't get a official Yamaha part number
 tag, I think the seller saves that as they seem to have more of the same dipsticks in stock and use that to list it. https://www.ebay.com/itm/177011525512

[m in sc]

I'd be leery of trusting it. years ago I got an aluminum knobbed one from India, same thing,  so I remade the centerpart and I still have it on my hybrid.

[RDnuTZ]

any chance the dipstick that came with your RD250 was a replacement and not the correct original application for the bike?

[RDryan]

any chance the dipstick that came with your RD250 was a replacement and not the correct original application for the bike?

Yep I kinda thought the same thing. I think that's a big possibility but if the oil level reads at the upper part of the flat on this new one when engine is cold and it's reading an inch over the the top of the flat on the old one when cold. Then that tells me when I go to check oil again after I start the engine it probably won't even register a reading on this new shorter dipstick so that kinda makes me leery of it. Of course if I get to know my engine as well the new dipstick and save the old dipstick just to back up a reference point I suppose I'll just get in the habit of reading the oil level as correct when it's a cold engine with the new dipstick in place.

Well what I've been living with is when I start the bike up and really don't even have to run it for more than several seconds, kill the engine. Can let it stand for five minutes maybe a bit longer and go to check the level, at this point its always reading about a 1/4" over the upper mark. Now I leave it this way because in the past I've been changing the oil when it's  hot engine and I just measure what I take out to put back in. Which has been consistent as far as the oil level readings.

I know it all sounds kinda crazy and to add to this neurotic drama it creates in my head is that I learned to like seeing a bit of oil weeping coming from the transmission shift shaft seal/plugs. At least I know the oil makes it from the clutch cover side to the sprocket side because sometimes I have a theory that long ago when I split the cases maybe I did something wrong with the Yamabond and or there's a crankcase venting issue that has more oil on the dipstick when it should be in the gearbox, I dunno just me brainstorming.

I'd be leery of trusting it. years ago I got an aluminum knobbed one from India, same thing,  so I remade the centerpart and I still have it on my hybrid.

yeah, the funny thing is when I go to Google the part number of this new dipstick from the listing I see all kinds of images of RD350 dipsticks that just don't look quite the same with the same part numbers and of course if I reference it to a Yamaha OEM parts diagram that is the correct part number. However like I said it didn't come in official Yamaha labeled parts bag but in a very clean sandwich bag.

[RDryan]

I found this listing for another OEM dipstick.
https://www.ebay.com/itm/256843559358?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=256843559358&targetid=2512152189032&device=c&mktype=pla&googleloc=9001928&poi=&campaignid=21214286338&mkgroupid=161030074701&rlsatarget=aud-1412318123216:pla-2512152189032&abcId=9407521&merchantid=101650987&gad_source=1&gclid=Cj0KCQjwqv2_BhC0ARIsAFb5Ac8O6G2RvCEqSL28v_sd-u8C7HFMngu31KaUDd0h3DYGJvVn2IUjQYYaAvHCEALw_wcB

The seller was kinda enough to include a couple of pics with it alongside a ruler. There is a slight variation in this one compared to the one I have but it's very similar and most important the same length. So I imagine the one that came with my bike probably isn't original.

[sav0r (CL MotoTech)]

Just measure out the volume called out on the case and correlate on the dipstick. Your wife might not like Pyrex being used in the shop, but it's not doing any good sitting in that drawer anyways.

[SoCal250]

Some measurements of OE dipsticks. Approximate length of metal shaft measured from flat surface on cap.

Model      Total      High    Low
RD250B    111.2    107.1    97.6
RD350      110.7    107.8    98.3

Your original dipstick that measures 4.375" (111.1 mm) is the correct length. Never trust part numbers on eBay listings or part # tags unless it came straight from Yamaha. There's a lot of mislabeled and counterfeit stuff out there, especially on eBay and Amazon.
As sav0r said, I use a measuring cup to be sure I'm putting in the specified amount. Then I use the dipstick to verify and fine tune.

[RDnuTZ]

Plastic measuring cups work great for larger volumes like crankcase filling and cheap plastic baby bottles are good for fork oil filling. Keeps the missus off my back too after the hell I caught for using her crockpot for carb cleaning 

[1976RD400C]

I checked a couple of OEM RD400 dipsticks, 4.375" also.

[RDryan]

Thank you good to know. Kinda bummed I bought a fake dipstick.The funny thing is that second link to an Ebay listing for one is a different seller from the one I bought from and they're charging 80$. I got mine for 30$, saved myself 50$ and You know I don't mind getting a fake one but when they can't even make them the same length as the original,that's weird.   

[RDryan]

Well I drained the oil today after a ride and I measured out of the engine 52.5 ounces that I rounded up to 53 ounces which according to Google 53 ounces equates to 1567cc.

This is good for me to know as I was doubting myself and the dipstick readings. Obviously having it slightly overfilled with oil would produce a higher dipstick reading but I still find it odd that the oil level is an inch over the high mark of the dipstick with a cold engine. However I guess after the countless hours and miles of running the bike this way, I haven't had any mechanical issues and the oil always finds it's way where it belongs. Just an oddity to me, I don't get an accurate reading on the original dipstick unless I run the engine for several seconds. Where as I don't know what to call it except shorter Ebay copy dipstick which I find more aesthetic will read accurate with a cold engine and not register at all with anbengine that has been run.

I do like the Ebay copy dipstick so I would like to keep that on the bike but but I will also keep the original as a reference. I find it also interesting that there is what looks like a circular pattern pattern into the clutch cover for where an oil sight window could be, as if it was an idea the engineers at Yamaha had tried but maybe it just wasn't feasible at the time and better to stick with the dipstick?

[RDnuTZ]

good to hear it hasn't caused any problems  I always drain as completely as possible and then add back in exactly recommended amount, let it settle, then check oil level is above minimum and forget about it


I've had many bikes and other small engine powered equipment, and some recommend checking the dipstick level with dipstick screwed & removed- while others say to just touch down then pull and check. I don't know which method Yamaha instructs for RDs off the top of my head, but curious if you are screwing yours in and removing to check level?

[SoCal250]

I've had many bikes and other small engine powered equipment, and some recommend checking the dipstick level with dipstick screwed & removed- while others say to just touch down then pull and check. I don't know which method Yamaha instructs for RDs off the top of my head, but curious if you are screwing yours in and removing to check level?

On Yamaha bikes you unscrew the dipstick and then insert until it bottoms out on the top of the threads, but do not screw it in. Oil should be checked when warm with the bike on both wheels and level.

[RDryan]

Yeah I learned long ago that most of the time I think it's general practice and at least I always do this with even just my log splitter or a lawn mower....I clean the dipstick and just set it there, no screwing it in to check the level. Although with that shorter Ebay copy I tried both methods just to see if some oil was visible after running the bike and just a bit was. Certainly a difference in levels either method.

[RDryan]

Also and wouldn't you know it, after the fact... but I found what is a much nicer deal on EBay for a used clutch cover that included a nice whole as in not dog eared dipstick for less money than I paid for my shorter Ebay copy. I guess that's Murphy's law at work. Tempted to buy it and right my wrongs but I dunno.

Should I? that spare clutch cover could come in handy.