Weak Midrange RPMs. Loss of "Pull".....goes flat...

It appears the valves could use a bit more lapping. Those black specs are pits. You want them eliminated. On the head I'm doing now, it took 2 or 3 applications of the coarse compound to clean up the exhausts (they were bad). The intakes cleaned up nice with only one application. I'll do the final fine lapping and assembly today.
 
Here's what I started out with. As you can see, the exhaust was pretty rough, intake not nearly as bad but some pitting in evidence .....

SeatsBefore.jpg


Here's the seats after one lapping with coarse. The exhaust still has black pits showing and needs more lapping. The intake was good .....

LapsCompared.jpg


And here's a valve that's good, all solid matte grey with no black specs or discoloration .....

IntValveLapped.jpg


I can still see some black specs on your head seats and some discoloration on the valve. Like I said, you're not done yet. Unless you enjoy tearing this thing apart every couple months, lol.
 
Evenmore look at the exhaust pockets on head 5twins is doing.
Do yours look like it? If not, now would be the time.
 
Yes, or you could stick with the factory's idea of an acceptable port finish (what were they thinking? lol) .....

IntPortBefore4.jpg
 
Well, that's up to you but it certainly won't hurt. Just smooth things out with sanding rolls and a ball cutter for the tight spots and all those gouges around the seat. I use mostly the 191 or 192. If you bought your Dremel as a kit, it may have even come with this cutter .....



On most of the exhaust ports, you'll find a rather nasty bump or lump sticking out one side. Smooth that right out .....

ExPortBefore.jpg


The intakes consist mostly of rough sand casting flaws, lots of little bumps .....

IntPortBefore.jpg


After smoothing them all out, rough them back up slightly with a coarse sanding roll. This helps agitates the gas/air mix as it passes through and keeps the fuel droplets from dropping out .....

IntakePort2.jpg
 
Thanks 5twins. I think I have 1 or 2 of those cutters. I have a nice dremel kit. I'll check on the coarse sanding roll, that one Im not sure about.
 
Well, I got away with one maybe. My dremel cord, little hand held extension guy, went kaput on me near the end of finishing the the ports under the valves. When the chuck broke it bucked just a bit and the hosel bumped the valve opening just below the seat. It didnt do any damage, just made a mark on the surface but you cant feel it at all and it is below the seat. Whew, think im ok. I didnt finish the port after that, didnt think the dremel will fit well without the handy dandy extension guy, which ive had for YEARS. I may finish the port later tonigh, I may leave it. Im deciding. I did get all the BAD stuff done though. Luckily the rest is dark but not terribly bumpy or bad.

After chilling out and gathering my nerves I finished the valves and did another lap job and got the rest of those pesky spots out. Was concerned of over lapping, but it came out good.

Pic of ports before final lapping. Sorry for the bad lighting. Could get it right. You get the idea. Not as neat as 5twins, but an improvement.
 

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Next, Removing the front sprocket with the engine off the bike. This was my first Idea with what I had on hand. Bad idea? Other options. ??? I've searched but havent found what Im looking for yet.

I want to change the seal behind the sprocket before reassembly.

I did the starter seal last night too.
 

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Almost done putting it back together. I may get her running late tonight. Just finished installing my new FR valve cover stud. New Helicoil tapped, new stud ground down to be the correct length. Looks good. I did use red locktite installing the coil and followed with the stud. No extra locktite on the stud, should adhere nicely to the coil, and the coil to the block.

Next, valve covers, sump filter/plate, and I think I can install the engine in the frame. Carbs, fuel tank and exhaust and I cant starter up, chain and I can go for a ride.

Oh yea.....Oil :thumbsup:
 
Well, I got to ride her last night. :thumbsup:

After install and filling with fluids, checked everything out, gave 2 half harted kicks to get a feel for the changes. Kicker is harder but still smooth. More compression :thumbsup:. Turned on the fuel, power, kick....starts on the first kick. Rumble seems deeper and more powerful. I let her idle for a couple minutes to circulate some oil. Sounds good. Switch her off. Now for the compression test.

138 on both sides. Thats not perfect but its much better than what I had. A few more kicks and I may have hit 140.

I put the drive chain on and went for a slow ride thorugh my neighborhood,...at 12:30 am. WAKE UP EVERYBODY !

I didnt push at all, no high revs, just strolling around and going through the gears. Nice and smooth. Idles like a champ. Once warm, wanted to hang a bit but not too bad. Idle control screw actually controls the idle. :thumbsup:

Seems to have more torque at the low end and pulls nice and even. Still gotta push her a bit once shes broken in and see where my carbs are.

Right now Im 1up on the pilot, 2 up on the mains, and 3 turns out on the mix screws, 22.10mm floats. Plugs looked good after my ride, nice and even. Didnt look lean or rich, but not perfect either. Somewhere in the right area though.

Happy guy here :bike:

Shitty weather pisses me off.

I still have the seal behind the drive sprocket to change, front fork seals/fluid, and rear brake shoes. Speedo cable broke too.

"It aint never nothing" :shrug:
 
So I just checked my advance and it doesn't snap back like yours does. I am assuming that my springs are bad. What are the effects if this doesn't snap back into place? My bike seems to be running fine
 
Fantastic thread EvenmoreXS, a great read -- minus your hardship of course.

Would love to see an update on how the bike is running.

I hope all is well in the new year for you!:cheers:


Ps. No pic on your last post; deleted?
 
Not sure about the pic????

She is running great and is my daily rider...I have NOT had to do any work on her since this thread until last week....replace the clutch lever....but otherwise, no news is good news!

Thank you for asking and I appologize for the long delay in response....
 
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