Bottom End Rebuild

[mike11743]

I'm planning on rebuilding the bottom end on my blaster in the upcoming couple weeks. It was just done like maybe 2 years ago, but I have a ton of hours on it. Nothings locked up or shattered and it still runs, just has a minor amount of play in the one crank bearing and only like 80 psi.

So I have a couple questions::

What tools do I need. I have a flywheel puller and clutch holder. Crank installer as well as steering wheel puller are on the way. Do I need anything else? besides basic hand tools

Is Yamabond to be used like any regular silicone gasket material? Thghten the bolts till the material begins to squeeze out and then let dry overnight then tighten down the rest of the way.

I have a major oil leak from overtightening the oil drain bolt. The hole is cracked. It's pretty minor. Think I can fix this if I clean it up real good and put jb welb or maybe yamabond in the threads. I have a spare set of cases, but i'd rather fix this one if possible.

Any other tips anyone has would be awesome.

 

[darederek]

if you do use jb weld to fix the crack make sure you thread the bolt in till it hardens a little bit so you dont screw up the threads. you sound knowledgable and probably already thought of that but just watchin out for ya

 

[slickerthanyou]

I'm planning on rebuilding the bottom end on my blaster in the upcoming couple weeks. It was just done like maybe 2 years ago, but I have a ton of hours on it. Nothings locked up or shattered and it still runs, just has a minor amount of play in the one crank bearing and only like 80 psi.

So I have a couple questions::

What tools do I need. I have a flywheel puller and clutch holder. Crank installer as well as steering wheel puller are on the way. Do I need anything else? besides basic hand tools

Is Yamabond to be used like any regular silicone gasket material? Thghten the bolts till the material begins to squeeze out and then let dry overnight then tighten down the rest of the way.

I have a major oil leak from overtightening the oil drain bolt. The hole is cracked. It's pretty minor. Think I can fix this if I clean it up real good and put jb welb or maybe yamabond in the threads. I have a spare set of cases, but i'd rather fix this one if possible.

Any other tips anyone has would be awesome.

Sounds like you have all the tools. One other tool I can think of is a sixpack or two (if your old enough of course) I havent used yamabond, but I know others have they will chime in.

 

[mike11743]

I got these cases apart and let me say with the right tools, It is a lot easier than I thought. I have a couple questions.. first, does anyone on here use yamabond 5 as a case half sealer. I have 2 unopened tubes of it, and after buying it, someone told me to use yamabond 4. The 5 does say for use in areas prone to vibration, so this would make me think it would do good here.

Second question is my oil drain bolt hole is somewhat stripped and has 2 minor cracks on the actual block. I JB Welded the cracks, but cant seem to get the JB weld to stick to the threads. I've cleaned with a wire brush as much as possible and used brake clean to make sure its really clean. Any other options?? Should I only worry about the cracks being that the threads will still allow the bolt to turn in, but it is just a little loose until about the last 1/8 inch. Should I even worry about the threads leaking or would the copper washer at the end of the plug just seal all of the oil that gets past the threads anyways??

 

[Larry's Shee]

Don't know difference between 4-5. Clymers calls for yammy 4 or Threebond 1104, I used 1194 on the banshee with no problems. As to the drain JB the crack and install bolt with silicone allowing it to set at least a day before adding oil.

JMHO, your results may, and will, vary.

 

[1995blaster]

if you have a spare set of cases do it right the first time is my opinion

 

[sicivicdude]

I use yamabond 5 between my case halves. I like that it doesn't dry hard unless it's squeezed between case halves. I don't like how thin it is while trying to apply it... It's a trade off.

Oh, Yamahbond 4 is just ultra grey silicone, and permatex ultra grey is less expensive than yamabond 4.

As for the drain bolt problem, JB weld is a GREAT solution for getting back out of the woods vs. pushing it. It's awesome if you have NOTHING else but no epoxy based material ever really takes to the aluminum, they just "stick" to the outside.

There are a few choices here, however.

You said the threads still work, they're just a bit loose the last bit of thread? You could install a viton o-ring beneath the copper washer so that you don't need to torque the drain bolt nearly as hard to stop any seeping. There is a down side to this, the o-ring doesn't allow you to get the bolt as tight so you must check it's tension every so often. If you ride too long without checking it, it could back out and fall out draining all of your transmission lube without you knowing it.

You could also use an aluminum brazing rod while you have the cases apart. I have a post in the DIY section named "case repair" where I used some of that material to repair some cracked cases. I had mixed results (I went for the big one on my first try and was only able to repair 3/4 of the problems) but for a stripped drain bolt it should work BEAUTIFULLY. As long as you have the case heated properly the material bonds to the aluminum and creates new threads around the steel of the drain bolt.

 

[mike11743]

just wondering what everyone uses to clean up the combustion chamber on the head. I have a hardcore baked on exhaust splooge. Worse than any other ive seen. Probably like 2mm thick. I was thinking a demel with a real soft bit might work. Carb cleaner, brake cleaner, wire brushes are just not cutting it.

 

[Larry's Shee]

Sea Foam will disolve it but takes a while. Dremel is good idea just be carefull. When you get most of it off switch to sea foam and scotch brite. Put plug in head and fill with Sea Foam and let it set.