yamaha dt175cc enduro

Discussion in '2 smokers' started by clicheche, Apr 11, 2013.

  1. clicheche

    clicheche Adventurer

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    i have a pretty bad gearbox oil leak. probably the crank seals?
    is there a decent tutorial on the site as to replacing these?

    i've tried searching.
    #1
  2. baloneyskin daddy

    baloneyskin daddy bikaholic

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    Theres only one crank seal that could leak trans oil and it would leak into the crankcase and smoke like hell when running. If its leaking onto the ground its probably the shift shaft seal ,countershaft seal or gasket on the drainplug .
    #2
  3. clicheche

    clicheche Adventurer

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    what is, and where is the countershaft and seal?

    i reckon i know the shift shaft seal.
    #3
  4. stainlesscycle

    stainlesscycle Long timer

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    countershaft seal is behind the sprocket.

    both the shift shaft and countershaft seals are easy to fix.

    there is also a shifter cover on the early dt175 (1974-1976) (held on with four bolts behind shifter) - it has a rubber o-ring around it that could leak, but that's doubtful.. what year is your dt175?


    it could also leak between the crankcase halves. or a cracked case could leak... or even the clutch cover could leak.
    #4
  5. lrutt

    lrutt SILENCE.....i kill you

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    CS seal would not have pooled oil behind it, little higher than the level. It would leak while running. Likely shifter seal, or clutch push rod as well.

    As stated, easy to replace in situ. Just did it on my RT1 plus the crank seals as well.

    Do you go to the Yamahaenduro.com website. Dedicated forum for these old bikes there.
    #5
  6. clicheche

    clicheche Adventurer

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    thanks for the responses.
    i have joined the yahamaenduro site as well.
    this one is phenomenal though!

    i am going to replace both the shift shaft and crankshaft seals.
    the year of my bike is a 1980 dt175cc
    so i don't know if it will have the o-ring you speak of, though i will look.
    (ps:i really hope this bike runs better now that i've got por15 all over my hands from lining the incredibly rusted gas tank. looks to have done a pretty good job. thousands upon thousands of times better shape than it was prior.)

    on the other side of the bike, is there a gasket for the gearbox cover or anything? that looks like it could potentially be leaking as well.

    thanks a ton for the replies folks!
    #6
  7. stainlesscycle

    stainlesscycle Long timer

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    you do not have a separate shifter cover, so no o-ring.

    clean the motor, and look for where it's weeping..
    #7
  8. clicheche

    clicheche Adventurer

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    pretty sure its leaking from the shift shaft. though i'll be replacing the crank shaft seal as well. is there a particular tool to loosen the crank gear?
    and you're right, i don't see a separate cover... just one.
    #8
  9. clicheche

    clicheche Adventurer

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    hi ya.

    so i'm wondering if i have to remove a philips bolt right next to the shift shaft to remove it or not...

    also, do i have to disconnect the chain in order to loosen the crankshaft?
    or just loosen the crankshaft?

    1980 yamaha enduro 175cc
    #9
  10. clicheche

    clicheche Adventurer

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    looks like i don't remove the shaft... duh. just a ring and washer around it? to gain access to the seal?
    #10
  11. stainlesscycle

    stainlesscycle Long timer

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    do not need to remove shaft. if you want to remove shaft, you need to pull clutch cover, remove clutch basket, etc, because selector end of shaft is behind it.

    to replace shift shaft seal, just pull the shifter lever off and remove replace seal. i do not believe the later models had the snap ring/washer/rubber boot external to the seal. the early ones did.
    #11
  12. stainlesscycle

    stainlesscycle Long timer

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    huh? loosen the crankshaft? i'm assuming this is a typo/misspoke/etc...

    you mean countershaft seal? remove rear wheel, move chain off front sprocket. bend lock tab on frt sprocket. remove nut. remove sprocket. remove/replace seal. you may want to bend locktab and loosen frt sprocket nut before you remove wheel/chain so you have something to hold the frt sprocket from spinning..

    there is a bushing the countershaft seal rides on. you may want to replace, or at least flip it around if the seal has worn a big groove in it.
    #12
  13. clicheche

    clicheche Adventurer

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    well damn it. so its the countershaft seal that is on the same side as the shift shaft seal? that's brutal. i ordered a crankshaft seal and a shift shaft seal. thought to be on the same (left) side of the bike.

    would i have to drain the gear oil when changing either seal? maybe just for the shift shaft seal? not the 'countershaft' seal?
    #13
  14. clicheche

    clicheche Adventurer

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    well here's hoping. the dude at blackfoot motosports here in calgary said, 'so the left hand side of the bike? those two seals?' so hopefully he just ignored my blunder of calling it the crankshaft seal... is there a crankshaft seal on the bike? or am i just spouting weird words?
    #14
  15. mtothef

    mtothef Been here awhile

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    please don't take this as me being a dick, but...

    maybe you should get a repair manual for the bike? that would, at the very least, help you identify the parts you are talking about, and give you some reference points as to what all is going on with the bike and what people on this site giving you advice are speaking about. seriously, every single bike i ever tear into at some point or another has some moment where i am elbow deep in engine parts saying to myself "what the hell is this?" moments like those, a shop manual can be worth its weight in gold. other times, shop manuals can also be just obscure enough to frustrate the hell out of you, but most of the time they are a very solid investment.

    re the seals you are talking about, the shop guy was right - "the two seals on the left side of the bike." both of them can be replaced pretty easily, as has already been mentioned. if you are careful, you don't even have to drain the oil, just lay the bike on the right hand side and work on it there. there are also crankshaft seals, one on either side of the engine, they serve to keep the engine oil OUT of the crankcase, which is itself lubricated by the premix or autolube oil. they do need periodic replacement, and usually this involves tearing the engine almost all the way apart. they are in no way related to why your gearbox oil is appearing outside the engine instead of inside where it belongs.
    #15
  16. clicheche

    clicheche Adventurer

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    no offense taken. you're right.

    i think i have the manual somewhere.
    as these maintenance parameters are so elementary, (aside from knowing the names, i've seen youtube vids, and read some threads that have given me the info i should need.

    i've used a manual or 7 before. just being lazy i 'spose.

    thanks for the replies.

    how does one load pics up? through a third party site or server? not directly to the website correct?
    #16
  17. clicheche

    clicheche Adventurer

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  18. DoctorRoboto

    DoctorRoboto Destroyer of Things

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    DT175 owners,

    I have read through this whole thread, which is incredibly helpful, and went out to line things up on my new 1975 DT175B, as it is mysteriously leaking oil from around the same area. The first thing I found is that the shift shaft cover, part 437-15419-01, is cracked around the oil seal, with JB weld trying to hide the sins of the previous owner. So that's getting replaced immediately.

    [​IMG]

    I was able to wiggle that shift lever shaft (shift shaft asy 2 / 'B', or part #401-18155, the one that goes to the foot lever) quite a bit, and oil started oozing out around the shaft as I did so. This shaft:

    [​IMG]

    Before I cracked that shift shaft cover open to see what seals might be leaking oil, I drained the oil from the bike by opening the drain plug (which has a new fiber crush washer I put on as my first attempt at fixing the oil leak). But instead of seeing oil all in the shift shaft compartment, I found hi-temp (red) lithium grease covering up the shift shaft connection mechanism. I'm very confused by this. So, questions:

    1. Where is oil even coming from, if this compartment is packed with grease? From the look of things, oil can't get in here - there's a cavity for the shifter lever in the crankcase (the bottom right hole in the below image), but I can't quite tell where the oil flows relative to this area.
    2. Does the cavity for the foot lever shift shaft go all the way through to the other side of the crankcase wall, where the transmission oil sits, or is this a 'sealed' hole? It seems packed with crud and I don't have a good tool to clean that out.
    3. Should lithium grease be in the shift shaft compartment, on those two shift shafts and their linkages, or is this an oil bathed compartment?
    4. Probably the same as #1, but if no oil is supposed to be in this compartment (see below pic), how the heck is it getting in here, and why would wiggling that shaft - the one that is in no way touching an area where there should be transmission oil - release oil, as opposed to grease, to the outside of the bike? The other shift shaft that goes into the clutch area seems like it might be more exposed to oil, but that one seems pretty clean, causing a good deal of confusion.

    [​IMG]

    I'm planning to replace both oil seals on the two shafts in there, as well as the cover plate and its o-ring. But I'm still very confused where the oil could be coming from. Any help is welcomed.
    #18
  19. MathewC

    MathewC All adders are puffs

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    Is it possible that because of the age of the bike, seals, gaskets were removed by the previous dipshit owner and could not be properly replaced?
    #19
  20. DoctorRoboto

    DoctorRoboto Destroyer of Things

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    I don't think so in this case. The seals were all in there, and look to be in decent shape. Except for the broken housing that had enough flex around the seal to make the seal meaningless, and likely an old o-ring that was no good (there was RTV around the edge of the shifter cover plate), both oil seals I could see were properly installed. There was a missing washer in front of shift shaft A, but that one didn't seem to be leaking oil - it was shift shaft B that seemed to be the leaky one, although still a mystery as to how.
    #20