oil leak

[His Dudeness]

I seem to have an oil leak behind the magneto. doooh. Is it engine rebuild time to replace that oil seal? If it is what specialist tools would I need to get the engine apart. I'm guessing a puller for the magneto, clutch and starter clutch? Then a valve tool. Might aswell do them if I have to take it apart. Ring compressor, low end torque wrench. Anything else? Parts wise what would I need? Rings, gaskets...anything else? I've done 2 stroke engines but not 4 stroke so I'd be a newb to engine rebuilds. Anyone got any good news for me?

[Gnasher]

Big job this mate are you sure it's leaking I've only known of two to fail and they were high mileage 70k plus?

Yes you will need a puller, gaskets, sealant, loctite and all the normal tools oh and a manual.  Before you strip the motor do a compression check if all cylinders are well within limits you wont need to do the valves/rings, double check the compression rings once the heads off by doing a oil test. 

Take your time read the manual a good few times, oh and don't be tempted to use cheap gaskets/seals you will regret it!  Keep us posted good luck mate.             

[unfazed]

No need to strip the motor, Yamaha supply a special replacement seal without a lip on the end.
I  changed one on my sons fazer 400 about 3 years ago.
Taking off the rotor was my biggest problem I had to heat and it came off eventually with a such a noise that I thought I had broken the crank.
The special seal part number is 93101-29166 and it is about £25, which is over twice the price of the standard seal.
You will need a special sealer, I used RTV 1080 Silicone Rubber Adhesive Sealant.
Carefully drill a small hole in the outer section of the seal sbout 5 mm deep and prise it out with a small screwdriver working bottom to top. It will collapse with supprising ease. Take GREAT care not to scratch the surface of the crank. When the seal is out clean the area with something like thinners, which evaporates without leaving any residue, let it dry well and apply engine oil to the seal lip and the sealant sparingly to the out part of the seal and push it home.
 
 

[Gnasher]

Nice one 

[His Dudeness]

Cheers lads . Not sure how to go about doing this because the bike needs a new cam chain aswell. So I could try a full rebuild with the standard oil seal and an endless cam chain or I could go for the cunning fox method and use a riveted cam chain and the seal with no lip on it that you mentioned unfazed. hmmm decisions. Could either of you give me a rough estimate for the price of the tools and parts needed for a full rebuild, also how many man hours would you think a full rebuild would take taking your time at it? Thanks a lot for the advice

[unfazed]

The cost of the head and base gaskets for the 400 alone would be about £80 plus the chain and oil seal and all that work. If the engine is good and running well why take it apart when you do not need to.
I have replaced the cam chain on the 600 and the seal on the 400 with very little difficulty and very little time compared to a full engine rebuild.
A few important tools required for either job would be:
Rotor holder
Rotor puller
Torque Spanners, at least two, one 0 to 20 Newtons and the othe 15 to 50 Newtons. (A third 30 to 150 would be usefull)
 
 
 
 
 

[Dead Eye]

Gaskets and seals will probably be the largest cost other than time. It will take a while to do if you are anything like me and keep finding other things to do :P

I agree with unfazed that if its running well then it may not be the best idea to take it all apart. If its done a lot of miles and you want to renew several other parts then it makes sense. Mine went through a fire so I'm rebuilding the entire engine.

Tools is basically spanners, sockets, screwdrivers etc. Torque Wrenches are handy but can be expensive. How competent / confident are you and how much do you want to learn? Those will probably be the deciding factors

[His Dudeness]

Think I'll do a compression test and if that looks good I'll go for the cunning fox method I'd love to do a full rebuild but I'll only be able to work on the bike the odd weekend so a full rebuild might end up taking months. Not sure if I could go that long without it

[Dead Eye]

That's basically my situation. I'm working on my engine rebuild when I have some spare days at the weekends but I'm lucky enough to have a spare engine to actually work on so my bike is still mobile

[His Dudeness]

I'm pricing up these parts and the holder and puller are a bit of a rip off. £154 for the puller and £132 for the holder plus delivery  Did you guys use a generic puller and holder or did you go for the yamaha puller and yamaha holder? Any suggestions on other pullers and holders that would work?

[His Dudeness]

think i might just draw up a puller and get it made in a machine shop. couldn't be more than an hours work to make one

[His Dudeness]

Was thinking about this today. I wonder if I got a second magneto and some long bolts could I use it as the puller? It would have the correct hole pattern and I should be able to get one cheap enough. Anyone tried that?

[His Dudeness]

No need to strip the motor, Yamaha supply a special replacement seal without a lip on the end.
I  changed one on my sons fazer 400 about 3 years ago.
Taking off the rotor was my biggest problem I had to heat and it came off eventually with a such a noise that I thought I had broken the crank.
The special seal part number is 93101-29166 and it is about £25, which is over twice the price of the standard seal.
You will need a special sealer, I used RTV 1080 Silicone Rubber Adhesive Sealant.
Carefully drill a small hole in the outer section of the seal sbout 5 mm deep and prise it out with a small screwdriver working bottom to top. It will collapse with supprising ease. Take GREAT care not to scratch the surface of the crank. When the seal is out clean the area with something like thinners, which evaporates without leaving any residue, let it dry well and apply engine oil to the seal lip and the sealant sparingly to the out part of the seal and push it home.

Hey unfazed. I'm trying to find the RTV 1080 Silicone Rubber Adhesive Sealant and I'm not having much luck. Do you know where I could get some or do you know of any other sealants that I could use?

[bandit]

This is the place mate, find a store near you,
http://www.eurocarparts.com/ecp/p/car-accessories/car-maintenance-accessories/car-adhesives-tapes-sealants/quick-gasket/?551770014&0&cc5_139 
or
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_749365_langId_-1_categoryId_255230   

[His Dudeness]

Thanks a lot bandit

[His Dudeness]

Well I've got the new seal in after a load of farting about trying to get the rotor off. Hopefully it seals and I never have to do it again but my question now is I've tighten the centre bolt that holds the rotor on onto the crank to the recommended torque. Can I assume that the rotor is now pressed back far enough onto the crank since the bolt is tightened to the recommended torque?

[Hedgetrimmer]

I'm pricing up these parts and the holder and puller are a bit of a rip off. £154 for the puller and £132 for the holder plus delivery  Did you guys use a generic puller and holder or did you go for the yamaha puller and yamaha holder? Any suggestions on other pullers and holders that would work?

Yamaha genuine tools are always stupid money. You should be able to find something aftermarket out there for a lot cheaper.

[unfazed]

Well I've got the new seal in after a load of farting about trying to get the rotor off. Hopefully it seals and I never have to do it again but my question now is I've tighten the centre bolt that holds the rotor on onto the crank to the recommended torque. Can I assume that the rotor is now pressed back far enough onto the crank since the bolt is tightened to the recommended torque?

I see you had as much fun as I had trying to get the foccing rotor off 
If you torqued it to the recommended setting, all will be well.
Put it all back together and see if the leak is fixed, as there is no other way of testing it.
Let us know if it is fixed. as it may not have been the seal. Mine wasn't

[His Dudeness]

Well I've got the new seal in after a load of farting about trying to get the rotor off. Hopefully it seals and I never have to do it again but my question now is I've tighten the centre bolt that holds the rotor on onto the crank to the recommended torque. Can I assume that the rotor is now pressed back far enough onto the crank since the bolt is tightened to the recommended torque?

I see you had as much fun as I had trying to get the foccing rotor off 
If you torqued it to the recommended setting, all will be well.
Put it all back together and see if the leak is fixed, as there is no other way of testing it.
Let us know if it is fixed. as it may not have been the seal. Mine wasn't

Yeah getting the rotor off was a bit scary. It took a serious amount of force to pop it off. I would have given up on it for fear of breaking the crank if you hadn't said how tight yours was on. I used a 2mm drill bit and drilled into the seal then screwed a screw about one thread into the seal and pulled the seal out evenly with a vice grips on the end of the screw. I'm pretty sure it was the seal that was leaking because there was a small amount of oil on the outside of the seal when I took the rotor off so hopefully the new seal does the trick. I took the bike for a half hour spin last night and checked this morning and there was no oil so hopefully it's sorted. Thanks again for the advice and pictures you sent to me

Nick I bought a generic puller and holder off ebay but they weren't strong enough so I ended up using the ebay puller as a template and making my own puller from some 2" scrap steel.