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Running down a harmonic DT vibe...


flyday58
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So still trying to get this sorted. I've spent so much time trying to figure out the overheating issue that I set aside the vibration problem till that was solved. Now it's sorted I am back on the vibe deal. When I rebulit the 2A7 years ago I put all new bearings in. Except for the clutch basket 'spacer'. I remembered this recently so I am channeling my energies in that direction.

So the vibe comes in all gears at somewhere between 3500-4500 rpm, and again up around 6000. Knowing I replaced all bearings except anything dealing with the clutch I decided to start pulling the clutch side apart. There is a rancid smell coming from the clutch parts and maybe elsewhere, an odor similar to a fridge that has been "accidentally" shut off by a neighbor whilst we were on vacation...don't ask. The oil is fresh, only about 50 miles and 8 month's worth. The bike is an indoor girl when not being ridden.

The question is this: the clutch basket is a two-piece affair, held together by rivets; is there supposed to be any free play between the outer driven gear and the inner basket? I have about 5 or 6 mm rotational play between the two components. I do not feel any shock-absorbing material in the basket so I am thinking there should not be any play. If this is so I would think that would account for my vibration issue. I don't have an extra basket to check against so I am calling on you subject-matter experts for advice.

Hoping all is well across the Atlantic. We have Trump.

Richard

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Hi  ritch "  good to hear from yeh. ,yeh thers rubber cush pucs behind the basket,  a mate just done his RD350,  easy,   buff the rivit heads, seperate the gear half, from fornt half, there is a few round rubber pucks ,  renew and re-rivit the basket together, .

 

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Wow, thanks for the vid. Is it possible then to source the cushions and rivets? I will check around, maybe the NL parts site will have them...

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You can still get the cush rubbers,  my mate got a kit,  the rivits were larger diameter,  he just bored to suit, .. not shure where he got them,, wemoto ,maybe,, 

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Thanks for the link. I will try to get the basket apart tomorrow and see what it looks like in there.

I was discouraged with some crank play I found so I decided to tear the motor apart. Good thing, it looks like whatever case sealant I used 10 years ago failed; it appears that the 2-stroke oil was leaking into the crankcase, causing the foul odor and cruddy-looking case oil. The left main bearing has a ton (tonne) of movement up and down so I'm going to replace it. I've forgotten the history on this motor but I think I swapped the left crankcase out without bothering to renew the bearing. I'm hoping a new one will take care of the vibes issue; if not I will see if I can renew the bushes in the clutch basket. '78 and up clutches are scarce to non-existent right now, although I did locate one on UKbay. Also CMSNL claim to have a new unit in stock, but I cannot justify the price just now.

So renewal parts are on the way, I've got a tube of Yamabond standing by, once more into the breech, as Ghandi used to say...

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yeah Richard a good new bearing might cure the vibes issue, lets hope so. as for the clutch cushions they are so old now and all of em have a bit of backlash but it's not such a big deal, I know that 'you know' about rotating the plain plates around the basket ;)...another vibe culprit!

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7 hours ago, Airhead said:

yeah Richard a good new bearing might cure the vibes issue, lets hope so. as for the clutch cushions they are so old now and all of em have a bit of backlash but it's not such a big deal, I know that 'you know' about rotating the plain plates around the basket ;)...another vibe culprit!

I DO know about rotating those darn plates! Interestingly, the left-hand case I didn't reuse has the original bearing still in place and it has a good bit of wobble with the crank installed also. Right side seems okay, must be a leftie thing!

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  • 4 weeks later...

Um. Update from Mr. Stoopid. Firstly, thanks to all on this site for your valuable {can'tthinkoftheword} through the years. It's great to have a forum with such knowledgeable and nice chaps/chapettes to come to. Unlike many US-based forums. Insight! that's the word!! Your valuable insight!:wacko:

And if I had come back to this thread I would have purchased the correct clutch hub cushions the first time; all I had to do was watch the vid Sir Hat of Black posted. Now I am waiting for the second set to get here from Thailand.

Engine is together and ready to install, sans clutch basket, which is awaiting said cushions. So I was installing an NOS brake lever on the rear wheel to pass the time, and noticed a teeny bit of wobble with everything still tight. Teeny, like a quarter-inch of front-to-back play on the left bearing side.:blush: So Señor Dumbass removed the axle, and there's no way anyone on this forum is savvy enough to guess what I found. Just NOOOO way. What? Did you all say a shot bearing?? Really? Everyone knew to check this but me???

I'm fairly certain where my vibes have been coming from now. I should know better. Additionally I discovered the internal spacer is missing from inside between the bearings. WTH? I know I didn't leave it out, and I've had the bike at least 20 years now. Curiouser and not so much.

So the saga continues this side of the Big Water. "Richard, use The Force! Don't give in to hate, that way lies Harleys..."

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Hee,  great post flybee":D ,,,   is there not 3 bearing in the rear wheel,  [ sprocket carrier,  ]  .  did you shift them   20years ago ,,,

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I swear it wasn't me!! Never had a good look at it though. Guess I should look at the front wheel...

Some ancient history: I went to what we call in the states a junkyard, specifically a motorcycle yard, back around 1997 or 98, as near as I can figure, in search of a project bike. I had been out of touch with scoots for quite a few years, but something gave me the bug and I went looking. I found two 1978 DT175 basket cases in this yard and picked them both up for $125 US. It took quite a few years to get it sorted to one rideable bike, with copious support from a then-budding ebay. About the only thing original from that rust-infested junkyard is the frame and engine. I'm pretty sure the wheels both came from ebay, and they just got bolted on. I think. Lots of water under the bridge of my memory, and I can't find the pics I'm sure I took as I went along. Pre-digital camera days, so not on my computer.

So waiting on parts, the true sign of an avid Yamaboy. At least I have the TW200 to ride whilst I wait. It's a fun little thing, for something with valves, that is. I have 32 miles on it so far; I've been sorting the jetting on it with the help of peeps on its eponymous forum.

IMG_3721.jpg

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Those TWs are proper funky. But of a rarity over here and most are in really rough condition. Yours looks very clean though, nicer climate and all that!

 

Glad you got the DT sorted

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On ‎10‎/‎25‎/‎2017 at 12:19 PM, finnerz89 said:

Those TWs are proper funky. But of a rarity over here and most are in really rough condition. Yours looks very clean though, nicer climate and all that!

 

Plus it's brand new!!

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  • 2 weeks later...

Update: almost there. I replaced the bearings and seals in the rear wheel so it's ready to go. I received the correct internals for the clutch basket, now it's just a matter of getting the rivets bucked and I can install it and put the engine back in the frame. I am anxious now to see how it's going to run and ride. Alas, it will be next week before I can get the basket to a local recommended machine shop to get the rivets set. Stay tuned.

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So everything is on site and ready to be installed, now I just have to find time to get to it. Hopefully Friday or Saturday I can post a ride report.

I had trouble finding someone to set the rivets in the clutch basket for me - Here in the US we are fond of giving up the fine arts of keeping the old stuff running in favour of football (not futbol) and following Trump tweets and the latest mass shooting. Damn, I wish the forum name "Cynic" was still available, cos it's ME!! Regardless of all that, I found an oldster locally who has, for me, a dream shop of old motorcycles and parts. He has a stack of Yokohama tyres for Enduros that he "may" part with some day; He has a Yammy 175 with a head that could be from a WWII Corsair or Hellcat, pre-reeds cylinder, an expansion chamber pipe I don't recognize, and a weird front fork arrangement. I was in Heaven! He didn't even charge me to drive the rivets on the basket as he had never seen one apart before and appreciated the experience!

So keep tuned, we should be riding again shortly...

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Good report  Flybe,, [ thats a budget UKairline :D ]    He sounds like a guy from the Vintage Enduro  forum,   heres thelink    ,it a USA  based site, 

https://yamaha-enduros.com/index.php/forums

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8 hours ago, blackhat250 said:

Good report  Flybe,, [ thats a budget UKairline :D ]    He sounds like a guy from the Vintage Enduro  forum,   heres thelink    ,it a USA  based site, 

https://yamaha-enduros.com/index.php/forums

Thanks for the link. And thanks for clearing up who Flybe is, always wonder about the labels on the side of airliners over yonder!

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