Engine Rephase Rebuild Thread

[alfredo]

good to hear man! Yes, the installation is very, very simple. Just make sure you have some circlip pliers. I got a set from a local auto shop for like $8! totally worth it.

So, I've been keeping an eye on my bike in terms of vibes, speed, and RPMs and here is the verdict. With a 277 rephase, 5th overdrive, and 17-32 gearing my highest sustainable cruising speed where vibrations are minimal is about 75mph/4kRPM. I can comfortably cruise at this speed for at least an hour before my legs start cramping, but that's an unrelated problem. Going up to 80mph/4800-5000 RPM the vibes get more noticeable. I can sustain this for about 10min before vibes numb my hand. From 80-85mph/5k-5300RPM, I can resist the vibes for about 2 minutes but they're pretty intense at this point. my right (throttle hand) in particular really feels the vibes, I'm starting to wonder if a better throttle could solve this problem.

Keep in mind that my carbs are set up pretty good, but I havn't confirmed that they are perfectly in sync. Synced carbs are essential for reduced vibrations, incase you didn't know.

Hopefully this will give you an idea of changes you could make to your gearing if you would like a higher comfortable cruise than me. I went with this gearing because I still wanted to have the off-the-line acceleration for city riding. this may not be an important factor for the riding you do...

When you say circlips, are these the same as 'hog rings'? Also, go sync those carbs . . . . TODAY !!!. That will make a massive difference in vibes if they are out of sync even a little. I learned that the hard way.

Thanks for taking time out to check this. I appreciate it as it will help myself and others set some sort of baseline of what to expect and what not to.

 

[KentMoney]

HAHA, OK. Im convinced. Im gonna whip up a manometer today and git 'er done!

 

[alfredo]

HAHA, OK. Im convinced. Im gonna whip up a manometer today and git 'er done!

Mine were out of sync once by about a half a millimeter. I rode the bike for two days like that and couldn't get it above 45mph without it feeling like the whole thing was going to explode. Made the yard stick manometer, synced them and it would run up to 60 before vibrating to death. So, long story short: even the smallest sync problem will be felt in large effect.

 

[Simple Bob]

That Engine is looking great. Keep up the hard work and cant wait to hear this thing.......

 

[alfredo]

Just got the case back together. Went with a light smidge of Yamabond all around the case halves. Got it together and torqued all around to 15'lbs. Flipped the motor over. Spun the sprocket and shifted gears again. All good.

Then I went to spin the crank and it spins about halfway before it starts to hit something and its really hard to push it past the point of being free again. Weird right? Anyone have any tips or tricks to find out what is going on before I have to split the case again and see what the deal is?

I am certain that the bearing races are in the right place and that everything worked great before putting the halves together.

I am stumped and obviously can't go any further before I figure this out.

 

[KentMoney]

is it like a blunt hit? or is it like a binding of the bearings if you're sure that you lined up the oil feed holes etc, that's weird.

also, I synched my carbs and I did notice some top-end power gains. cool!

 

[alfredo]

is it like a blunt hit? or is it like a binding of the bearings if you're sure that you lined up the oil feed holes etc, that's weird.

also, I synched my carbs and I did notice some top-end power gains. cool!

I just put a flash light down the cylinder holes and it looks like both inner races are moving when I pull a rod up.

See you guys in another 2 hours.

 

[alfredo]

Got it apart again. The bearing races are in perfect. I guess I was looking at the actual bearing that was moving. Now what? I can just put it back together, but I am worries it will put me right back where I was.

Is 16' too much?

Is there something else I can check?

Btw, the cranks spins freely now with the bottom off.

 

[KentMoney]

i'm not doubting your intelligence, but youre sure that the outer and inner races are situated so that the peg in the cases is in the center hole of the bearing races' oil feed holes?

 

[Punkskalar]

Double/triple check that you don't have any debris in the bearings before reassemble. Make sure each bearing spins freely before you install it in the cases. Then make sure the pins are lined up with the bearings, and you should be ok. I always set the crank in the top case, then install the bottom case...

 

[Tim of DO THE TON]

Definitely put the crank and transmission in the top engine case (upside down) first, to make sure the pins are lined up. Honestly I don't see how you could put the cases together without the pins lined up and not crack the cases. Without the pins lined up the crank doesn't 'sit' properly.

I'm going to go spin mine again to make sure I'm OK Just buttoned my bottom end up and just installed my cam chain tensioner blade. Putting rings on my pistons now.

 

[alfredo]

So. Here is an update.

I got the trans rebuilt with the new mikes fifth gear. Was fairly straight forward. Use Hugh's biker metric tutorials and went pretty quickly. I was able to put most of the motor together with it sort of cocked up on the head studs, but when it came time to put the crank in. I had to improvise. Used the engine lift and some straps to try and level it.

I found and marked the bearing races and checked them about five times to make sure they were set in properly. Took a bit of time to finagle them in there, but I finally got them all in where I wanted them. Spent some time putting Yamabond in all the right places and getting all the nuts and washers lined up with some Loctite.

I went through the gears one last time and spun the crank to make sure everything was happy. It was.

I put the case bottom on and walked the nuts on with loctite. Did them 5, 10 and then 16 lbs all around. Flipped the motor over and checked the trans again through all the gears. Was a little sticky, but I did drench them in lucas so I think that is to be expected. Then I went to spin the crank and bam. Friction.

As some of you might have seen I posted about this earlier, yesterday. The wind was instantly removed from my sails.

So, took the case apart again to find that the far right crank bearing, the big one, had slipped off the oil peg thing by about an eighth of an inch. No clue how that happened, but I must have jiggled the case or something. Maybe the last time I checked the crank to be sure it spun freely. No clue.

Since then I have taken out the trans and crank again and will get to cleaning out the inside of the cases and removing all the yamabond so that I can give it another try tonight or tomorrow night. I guess it's good that I found it now instead of later, but man. I must say redoing something like that is no fun.

Here are some pictures I took a long the way. The finished motor shot is from the first assembly. I will get more after I scratch it all up doing it again

everything in place:

bearings lined up:

assembled:

 

[alfredo]

Press the blue button here if you want to hear the sound when I realized the case had to be split again.

 

[Tim of DO THE TON]

I'm a little concerned and confused about something. How can the big bearing rotate off the locating pin and the cases still be able to be closed up and torqued down?

Wouldn't it be sitting higher and not allow the cases to mate completely?

Oh, and you're not putting an endless cam chain on?

 

[KentMoney]

you're very luck your cases didn't crack from the missed peg. I would make sure to inspect the cases around the area to make sure they're still A-OK.

 

[alfredo]

you're very luck your cases didn't crack from the missed peg. I would make sure to inspect the cases around the area to make sure they're still A-OK.

I'm a little concerned and confused about something. How can the big bearing rotate off the locating pin and the cases still be able to be closed up and torqued down?

Wouldn't it be sitting higher and not allow the cases to mate completely?

Oh, and you're not putting an endless cam chain on?

Not sure really. I went out this morning and checked the cases as best I could. I didn't see any cracks anywhere . I will do another final inspection before cleaning again and making sure.

As far as the endless cam chain, I am going with a riveted DID chain. I will put it on after I am certain the case halves are together good. Let it hang from the bottom and peen the rivet on with the motor on its side and the chain hanging out of the sump hole.

Sound good?

 

[alfredo]

Got a call to come home early from work today. Was my daughter. She was explaining how we needed to get the motor done. Enough to make a guy blush I tell ya'.

Anyhow, zoomed home early and cleaned everything up. Inspected further to find that the oiler guide pin in the rotor side bearing race had been pushed almost all the way in. So, instead of the case cracking it appears the pin pushed in more. Strange, but I'll take it. Checked all over for cracks and saw none. Spent extra time ensuring that after the bearings were lined up, that I didn't move a thing.

Got the case halves yamabond'd, mated, torque'd and loctite blue'd. Turned it over and let my daughter do the test crank, shazzaam! we have lift off

Going to try and get the rest of it together soon. Thanks for all the help everyone.

 

[KentMoney]

most excellent. hopefully you still had some 'locking action' with the pushed in pin? or was it completely pushed in so that the surface was smooth?

 

[Tim of DO THE TON]

Yay!

I just got my camshaft in, so I'm a few steps ahead of you at this point.

Be careful with the piston rings - I tweaked one of the thin oil rings and had to order a new ring kit and lost a night.

To torque down my cylinders to get the cam chain on I just stacked some 12mm nuts as a spacer on the studs. Worked great and once I got the endless cam chain over the sprocket I got my bearings on no problem. I used the rotor to turn the crank with - all the leverage you need.

With the key on the rotor end of the crank straight down, I believe the left side is at TDC (assuming your rephase was done to the right side as most are). Installed the camshaft with the slot pointing straight up as per manuals.

Then rotated it one full rotation which is TDC compression stroke on the left side, adjusted my tappets. Then went around to the right side and set that up. So far so good - nothing banging into anything. Will put a dial into the spark plug holes to confirm TDC and degree the cam, but it looks like it's pretty good as-is.

 

[Tim of DO THE TON]

Oh BTW if you have blue lactate you've got some hormone problems