High mileage stuff

You should have a Genuine YAMAHA Workshop Manual as a reference to guide you through Splitting the Cases.

If you decide to do a Split to replace the Primary Chain Guide; replace the Starter Clutch and Timing Chain while you have the opportunity.

Get a Large Cardboard Box.
Cut two large pieces of cardboard to use as "Bolt Organizers"
Use a Magic Marker and draw two Schematics of the Bolt Patterns as shown.
Draw and Number the circles.
As you remove a Bolt, ... jab a hole through the numbered circle where it belongs and store the Bolt where it belongs on the Schematic.


© Yamaha Motors Corp.

 

you did the hard part already, might as well go for it.
case sealer isn't a big deal, squirt your sealer in the corner of a baggie and snip the corner a tiny bit, then you can squeeze a tiny bead right where you want it.
what sealer did you get?

 

I ordered the sealant from chacal, it's Permatex MotoSeal Grey.

I guess my main worry is how easily the case halves will come apart after all the bolts are out. How sticky is case sealant? Any recommended points where I should apply a little "persuasion" to help split the cases?

 

once you get all the bolts out a few bumps with the heel of your hand should do it. remember the one hiding in the oil filter cavity.
sticky? my original stuff was like dried paint, not sticky at all. the new sealer, if it's like yamabond, starts to skin over as soon as it comes out so have everything ready to go and a helper is a good idea to get the shift forks in as you close the case.
go real light with sealer around the oil passages around the crank, you'll see that 99.5% of the sealer will squish out, so it doesn't take a lot. you want the surface dry and clean, no oil. go all the way around the bolt holes.

 

Exactky how and where to apply the sealant as well as a few other "non-intuitive" details are why we're recommending a factory book for this procedure.

 

Get the Genuine Factory Book to guide you through the Splitting.

Since you will be splitting cases, ... you should take this opportunity to do everything that might be a cause for needing to repeat the task.

Starter Clutch (complete)
Primary Chain Guide
Oil Seals
Timing Chain
Examination of Shift Forks

When you prepare to join the cases after completing the repairs and maintenance, ... CLEAN both Mating Surfaces perfectly clean.

Use New Safety Razors to remove any residue of previous sealant.
Cut 2-Inch Squares of a ScotchBrite Pad (Med.-Gray).
Moisten them with Isopropyl Alcohol and scrub Mating Surfaces to bare metal.
Finish Prep by wiping the Mating Surfaces with Cotton Tee-shirt Rags moist with Isopropyl Alcohol and let dry.
This treatment will let the Sealant BOND to the Case insuring an Oil Tight Seal.

http://www.walgreens.com/store/c/walgre ... la&adtype={adtype}&kpid=prod6056577&sst=36c0ba9a-973a-0848-7305-0000040fbafb

http://www.toolup.com/3m_7448_6x9-gray- ... 4AodjioAvA

 

these are the best thing i've found for gasket scraping, they lay flat on the surface and keep it flat, can't gouge the mating surface and they never ware out.
i've tried razor blades Rick, got more blood than gaskets
a machine shop should sell ya one for a few bucks

 

Looks like a great tip!

 

I removed the oil pump and the final drive gear stuff, except for these four screws:



They have been peened, and the manual offers no tips about how to get them out. What can I do to remove these screws?

 

Gotta use an impact driver with the correct-size torx bit........about the only way to get those out.

 

You have to drill out the "peen" first, then they work like normal.

 

Hand-held Impact Driver.
http://www.searscommercial.com/catalog/ ... ical=Tools
Craftsman 1/2 in. to 3/8 in. Impact Socket Adapter
http://www.sears.com/craftsman-1-2-in-t ... 919494000P
Torx Bit Socket

 

I'm back! This semester left me with little time to work on the bike, but I managed to do this:



I pulled out the starter clutch parts and compared them to my new ones. I didn't see a whole lot of wear (by eye), but the new springs did seem stiffer. Either way it's got new parts now, so no more worries about that.

There is also the primary chain guide. It's definitely cracked, which is what prompted me to go all the way, so it's good that I'm replacing it. I'll post some pics of it later.

I completely mangled the oil spray nozzle trying to get it out. It absolutely would not budge. Maybe I'm just impatient. It probably needed a new one anyway.

My goal now is to clean up the cases so I can finally begin reassembly. I plan on taking them to the same machine shop I've taken the other parts to. I'm also going to have them take care of those middle gear bolts, the torx ones. I somehow managed to get the cases apart, but one of those holders is pinching the middle gear assembly in place.

Also, I left the main bearings in. I guess I need to get a hold of some plasti-gauge to make sure everything is still in spec there. The engine ran well (before I took it apart ), so I don't think there is anything seriously out of spec. Should I remove them before sending the cases off to the shop? I guess I should but I would rather leave them alone.

Anyway, that's where I'm at. Hopefully I can begin putting all this back together soon.

 

It's been a while but I'm still working on this project. I've got the cases cleaned up and I am finally beginning to reassemble everything.

I decided to measure the main bearing clearances before proceeding. Most of the bearings are within spec, three close to 0.04mm, one is around 0.05mm, but one of them measured 0.025mm, well below spec. I don't think this is correct; I can't imagine this clearance shrinking over time. Below are some pictures of the measurements and the bad one:

Click to view a larger image:


Like I said I don't think the clearance shrank, so I think I'm safe.

I have the lower crankcase assembled, and I'm going to finish the upper crankcase this weekend.

 

Good luck on your rebuild! You give me the motivation to start working on my topend...

 

Well guys, I've ruined it.

I put the cases back together. I had the bottom end in the bike. I had it all wired up. I was ready to put the studs back in today. The service manual does not list a torque value for them, so I guessed it would be the same as the caps that go on the top to hold down the cylinder head (23.1 ft-lbs).

I guessed wrong.





I'm really bummed, I put a lot of work into this. It's a major setback, but I'm in this too deep to stop now.

I spotted a replacement upper case on ebay. I could tear it all apart again, but I don't really want to think about that right now.

 

I'm weeping for you here bud, don't be tempted to walk away

 

Its winter... RU back into it??

 

Right now I'm taking the engine back apart. It's slow, depressing work . I'm still kind of in shock that I screwed up this badly.

I have a replacement upper case ordered, but the seller messed up and shipped it to the wrong recipient (I got the other guys part too). I shipped him his part, but I'm still waiting for him to ship the crankcase to me.

I have heard (and had people tell me) that mixing cases from different engines won't exactly fit right. It makes sense, but at the same time, are the tolerances on the cases between engines really that far apart? Once again I get burned for not doing my homework.

At least it's nice that people here still care

 

You have ben fed a line of manure. Engine cases are made to be interchangeable. The production line would grind to a screeching halt if workers had to sort through bins to match up a set of cases by hand. You will want to pay attention to the end play of all shafts, but that's why shims come in different thicknesses (and those tolerances are designed into the manufacturing process). It's also why you NEED a copy of the service manual.

Also. Don't throw your old case away. That crack may be able to be fixed. Yo'll need the opinion of a shop that regularly does aluminum repair to know for sure though.