Yam RD Crankcase splitting question

2_DONE_THE_TON

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hi!

im currently splitting my RD cases to replace the crank seals on both sides of the crank (generator and primary side).
here are my questions:

1.)Are these two seals enough to replace or are there other seals between the cases that might replacement (i´m doing this only for "safety reasons",i heard that this needs to get done on every RD since the rubber dries out and shrinks)?

2.)do i need to take off the clutch to split the cases?if yes how is the basket fixed?

3.)how do i get the generator off?i got the nut off...manual says there are three screws....cant find any.
 

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There is no rubber seal between the cylinders on the crank, just a aluminum labyrinth seal. You don't need to split the cases to do outer seals, but seeing all the blow by and varnishing on the pistons, I would tear it down and inspect all crank and bottom end bearings.

Clutch- undo the obvious Phillips "X" screws. Remove clutch and springs. Remove soon to be obvious large nut in center of clutch basket, then basket. Done

Flywheel will need a puller as it is on a pressed taper
 
There is a third seal on the output shaft behind the sprocket, but it is pretty easy to replace if it leaks transmission oil with the bike together. There is no concern except for the oil leak, so it is pretty non critical. On the other hand, the seals are cheap, so why not just replace them all since you have come this far. I would not attempt to replace the crank seals with the cases together. They have a pronounced flange that traps them into their bores in the case. I do not believe they could be reinstalled without damage, and no way could you remove them without destroying them and likely damaging the cases.

The clutch must be removed to separate the case halves, because there is a steel ring that reinforces the bearing area behind the clutch that screws into both the case halves. I use an impact to remove (and replace) the big nut that you will find under the pressure plate, but there is a tool to hold the basket and drive hub if you don't want to use an impact and properly torque it during reassembly.

Your flywheel does indeed come off with a special puller. US models have a 3 phase alternator that removes with 3 screws, and then the rotating element is exposed, which also requires a puller (but the right size bolt works fine, but does not apply to you). Your flywheel has permanent magnets and I believe will need a puller with very fine left hand threads that screw into the flywheel with a threaded center that pushes against the crank. The correct thing is pretty much required. The stator is under the flywheel and also has three bolts that screw into both case halves, (actually, the stator mounting plate) so you also have to take this apart to separate the cases.

There is not much else that is tricky on RD's. Be mindful of the washers on the clutch assembly and the kick shaft. There is two on each, and they need to go back the right way. People get them wrong pretty often.

hope this helps.
 
For what it's worth, I did not remove the clutch when I swapped the tranny on my DS7 for a RD350 tranny. In fact the clutch basket is still on the shaft in a box in the attic.
 
You HAVE to remove the generator as the screws holding stator to case are on both halves. You HAVE to use correct puller or flywheel magnets will probably get destroyed. Easiest way I've found to remove rotor is freeze complete bottom end overnight with puller in place (and tight) Next day (after freezing) pour boiling water onto puller and flywheel center. For some reason, the RD350/400 have the tightest fitting flywheels I've ever come across
 
crazypj said:
You HAVE to remove the generator as the screws holding stator to case are on both halves. You HAVE to use correct puller or flywheel magnets will probably get destroyed. Easiest way I've found to remove rotor is freeze complete bottom end overnight with puller in place (and tight) Next day (after freezing) pour boiling water onto puller and flywheel center. For some reason, the RD350/400 have the tightest fitting flywheels I've ever come across

This seems like a lot of work when you just need an impact wrench and one of the front engine mount bolts.......
 
clem said:
For what it's worth, I did not remove the clutch when I swapped the tranny on my DS7 for a RD350 tranny. In fact the clutch basket is still on the shaft in a box in the attic.
Maybe the ds7 is different? The 400 definitely has a connector plate under the clutch, it would be impossible to split the cases without removing it.
 
SONIC. said:
This seems like a lot of work when you just need an impact wrench and one of the front engine mount bolts.......

hey sonic..thanks again for your help!
i seem to be stuck with removing the clutch and the generator.do you mind telling me how i can get these off?


there are noticable points of fixture on the outside of the generator...grrrr
 

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There should be a thread inside that protruding stud on the generator.
One of your front engine mounting bolts should thread into the internal threads.
Put an impact wrench on it and tighten it and it will pop right off.
 
And for the clutch,
remove all 6 of those screws and springs and remove that top plate.
Then remove the clutch assembly (all the plates, you can pull them all out at once)
Then you'll see a large (34mm?) nut holding the clutch basket on.
Bend down the locking flange and remove this nut (again you'll need an impact wrench).
Pull the clutch basket off and you'll see the connecting plate betweenthe cases, pull this and you're good to go.
 
SONIC. said:
There should be a thread inside that protruding stud on the generator.
One of your front engine mounting bolts should thread into the internal threads.
Put an impact wrench on it and tighten it and it will pop right off.

aaah alright!i´ll look that one up tomorrow.will i need to block the crank somehow?my fear is that if i use the impact that the crank and the pistons will yank around like crazy...

SONIC. said:
And for the clutch,
remove all 6 of those screws and springs and remove that top plate.
Then remove the clutch assembly (all the plates, you can pull them all out at once)
Then you'll see a large (34mm?) nut holding the clutch basket on.
Bend down the locking flange and remove this nut (again you'll need an impact wrench).
Pull the clutch basket off and you'll see the connecting plate betweenthe cases, pull this and you're good to go.

same here...do i need to block the crank somehow (like with a piece of wood) that it wont spin...or will the speed of the impact hinder it?
is there something like a loose bearing behind the clutch,saw on some old machines that they have loose bearings and im afraid it will fall to the ground.

where did you your torques for your motor rebuild from for your RD from?

does it run already your sweet little stinker RD??
 
No need to hold the engine with anything more than your hand. The impact does its work really quickly.
There is a needle bearing back there I believe, just pay attention to it and don't drop it in the dirt haha

And no, mines still sitting I haven't had time to mess with it!

As for torque I'm a firm believer in get it tight and call it good.
The only things I torque are the head bolts.
 
ok i just checked it out.THERE IS NO THREAD ON THE STUD.
the stud is has an opening but no thread whatsoever...even not a worn out one :)

what im now thinking that i need to use a wrench to get the "hidden" philipps screws loose?what y`all say?
my rd is the last model maybe they changed the way the generator gets off...
 

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reds said:
................. You don't need to split the cases to do outer seals, ...........................

Early motors had the seals clamped in place and later ones had a lip around them. Either way, it is better to split the cases.

To get the nut off the clutch shaft, I use a clutch tool made from a handle and a couple of steel clutch plates.

That flywheel will be a PIA. They used the same one in the rest of the world on E and F models but not in the US. Is there a female thread in that center hole? That's where the puller should go. If possible, avoid using a 3 leg puller. It will tend to damage the whole flywheel.
 
You can't see the threads.
Just put some bolts in there till one threads in
 
It takes a special puller - something like 20 x 1.25 male thread on puller with a 14mm inner bolt. They retail for 20 bucks or so but you need to know thread size and pitch and left hand or right hand thread.
 
Quote from: reds on Apr 01, 2014, 22:18:31

................. You don't need to split the cases to do outer seals, ...........................

teazer said:
Early motors had the seals clamped in place and later ones had a lip around them. Either way, it is better to split the cases.

Damned if you do and damned if you don't! If I had said "Yes, You Do Have To Split The Cases", then you or someone else would be saying "Well, Technically You Don't...."
I pointed him in the right direction and considering the op didn't know how to remove the clutch tells me they are in over their head. Good thing it's a simple 2stroke and not a 4 stroke with cams, chains, valves...........and clutch!
 
You are exactly right on that. I'm not disagreeing with you, I was expanding on what you said. :) Do you know when the seals changed to a lipped design? My TZs all have them and I don't have an old enough RD set of cases to check when that change occurred. And pressing in seals can be done, but better not to IMHO, and I suspect that you wouldn't press them in on one of your builds.

I do understand your concern that an inexperienced owner might make even more mistakes stripping the motor. Keep the faith. We're all just trying to help.
 
Well somebody needs to fuck off and take their goddamn medicine.
Douchebag.

Sorry for trying to help from memory.
And the bearing retainer CONNECTS the top and bottom cases hence the need to remove it. Please forgive my incorrect terminology your holiness.
 
well FINALLY had the time and ease to split my RD engine..took me again half a day but im still learning so every experience is precious.

gears look fine,after 30.000 km´s i dont see any wear at all.

my next aim will be exchanging all the seals....got em all and will do probably today!the old ones dont lookbad,but i will swap them anyways.

so heres the question:

im a little afraid to lift the crank.how do i get the old seals out and pop the new ones in?since they are pretty rigid i dont think i can pinch them to get them out.
do you guys do anything when you pop new seals in?i would just clean the mating surfaces and maybe put a little 2 stroke oil on the surface before i bring the new seal in.

help aprreciated!!
 

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