2nd Gear Issue -> Chain Guide

Hey gents. While investigating a 2nd gear slipping issue (looking at dogs and forks) I saw that the main chain guide is in pieces. Would love some guidance on how to get access to the guide underneath without going into a full on tear down of the rest of the motor, if possible. First time pulling a motor on anything and don't want this to become a case of biting off more than I can chew. Thanks all.

 

Basically, there is no way to get to the primary chain guide w/o splitting the cases. You can get to one (or two) of the retaining bolts thru the oil pan (if I remember correctly) but the forward guide retaining bolt......up by the jugs......it ain't happening with the engine assembled.

Splitting the cases isn't mechanically difficult, but you need to have a shop manual and follow all the steps in the correct order and the correct procedures. You'll also need a tube of sealant for re-assembly, and you must follow the sealant application instructions carefully or you'll block oil flow thru the engine, which will be a Very Bad Thing.........

 

Thanks @chacal - I have Yamabond 4 and all gaskets up to the point I'm at in the photo I attached in the original post. I have the cases split, but not sure how to get under the bottom run of the primary chain to access the guide. Looks like either the crank shaft or the starter clutch has to come out - but the crank shaft has another chain tensioned by the upper assembly. So my initial thought is remove the starter clutch. But when I spin the bolt on the start clutch positioned on the outside of the motor, it spins the entire starter clutch and in turn spins the crank via the primary chain.

 

If it's necessary to get the primary chain out of the way in order to get to any of the guide bolts, then the only choice is to remove starter clutch so you can slacken the primary chain. The starter clutch assembly ride on the same shaft as the alternator rotor, so:

a) remove the rotor
b) remove the rotor shaft bearing housing (note these bolts may be staked in place)
c) pull the shaft out; this will drop the starter clutch and may be a pain in the butt to retrieve depending on where it lands)
d) remove / slacken primary chain from starter clutch
e) now you get to that forward guide mounting bolt...........

In my opinion, the failure of Yamaha to design a chain guide system that was much more accessible and easier to replace (since it's really the only common failure part within the engine) was a gross mistake in an otherwise excellent and durable engine design.

 

Any advice on how to remove the center bolt? The Haynes manual calls this the Central Retaining Bolt. Looks like I can get a longer bolt with a dowel pin the remove the rotor after removing that bolt. But having a ton of trouble getting the central bolt out. Tried impact and strap wrench. Only thing left that I can think of is jamming the gears with softer material to prevent spinning. But nervous to do that because of the possibility of damaging gear teeth.

 

Alternator Rotor Removal Tools:

ap7) Aftermarket alternator ROTOR REMOVAL TOOLS, correct copy of the factory Yamaha tool needed to remove the alternator rotor from its mounting shaft (the rotor is a friction fit onto the tapered end of the alternator shaft). Designed to be used in conjunction with the HCP6495 rotor puller tool Attachment Tool listed below. The use of these two tools allows you to safely and properly remove your rotor without damaging either the rotor or the rotor shaft. For all XJ550, FJ600, XJ600 Seca II, XJ650, XJ700, XJ750, XJ900, and XJ1100 models.

If you find that you need to "lock" the rotor to prevent it from turning while tightening or loosening the retainer bolt, and don’t have the special Yamah “rotor locking tool” (which, honestly, no one has….), as an alternate solution you can put the bike in gear (preferably 5th) to lock the engine and tranny together, put the bike on the centerstand, and then slide a 2 x 4 (or something similar, but it’s preferrable that it’s something “soft” like wood)) thru the rear wheel spokes so that the ends of the 2 x 4 will eventually come to rest on the swingarm after the wheel rotates a distance…….in this way, the engine/transmission (and thus the rotor) are now locked together, and you can proceed to apply torque to the rotor bolt, which will eventually pop free (sometimes with a rather loud “bang!”) once the rear wheel locks itself in place

Or you can carefully employ this creative method of locking the rotor:

"Here's a story: I had to get the rotor off a CB650 thast was lying in a pile of scrap. It's right on the end of the crank, so nothing to wedge against. The guy at the scrap yard was an A$$ - told me I had 30 minutes to get it off or it was going in the crusher. SO the solution, pull a plug and start packing the cylinder with gravel and dirt. filled it up enough to jam the motor, and off pops the rotor."