Calling Mikuni Tuning Gurus!!!!!!

Make sure the front of chain is pulled tight so all the slack is at the back
After you have tensioner in place, rotate the crank several times, bring it up to LTDC (LT) and check the cam sprocket lines are level with head gasket surface
 
Rotated the crank several times after the tensioner was tight and the slack was up in the chain, the markings were still coming up parallel to the top of the head.

Put the head and cover back on and both cylinders are showing 95psi now...?

What is next to check? Should I start getting quotes from machine shops to lap the valves?
 
Didn't have carbs on?
How fast are you turning motor?
Need about 10 sec with electric start or 5~10 good kicks so motor is spinning
If valve adjustment is correct you'll have a lot more than 95psi, unless valve is actually bent
Did you try putting head on edge (intake ports standing on bench) and fill exhaust ports with kerosene, diesel, etc?
bent or leaking valves are real obvious.
After you check exhaust valves, tip fluid into a bucket or something, flip head onto exhaust ports and fill up intakes
If combustion chambers remain dry, valves are not a problem
 
No didn't try filling with anything, I'm doing one hard kick at a time for about 8 kicks (not continuously spinning motor)
 
Need to get motor spinning or take head back off and check valve sealing.
Don't fill combustion chamber, it's the totally wrong way to check anything (even though it looks like it will save time and be easy)
If your getting 95psi from whats really a single kick, I don't think there's much wrong with top end of motor
You do have both plugs out and only compression tester fitted?
 
Both plugs out, exhaust and carbs are off

Maybe I'll try putting a socket and power drill on the stator nut to spin the motor during compression test instead of kick it. Any issues with doing that?
 
So long as you're spinning in the correct direction, you should be OK. Watch the bolt on the end of the rotor though... it'll need to be torqued down pretty tightly.
 
Gotcha, might pick up a leak down test kit on the way home also

When the exhaust was taken off last night there was a little oil residue in the left part of the exhaust port. Might be a leaky valve seal so I'll keep a lookout for those too.

Really want to get this done soon, I have to take the bike to the highway patrol station to investigate my engine VIN in 10 days :-\
 
Finnigan said:
Both plugs out, exhaust and carbs are off

Maybe I'll try putting a socket and power drill on the stator nut to spin the motor during compression test instead of kick it. Any issues with doing that?
Click to expand...

Not really but if you have a high torque, low rpm (around 400 rpm) it's better to get someone on kick start side and don't pull the trigger until it's actually turning
The initial torque can be enough to unscrew the bolt
 
On the way home I got a leak test kit, air compressor (cheap and loud as shit in my studio apt), and the hoses and fittings.

With the head OFF it held air like a champ, with the head ON and the LT mark lined up 3/4 valves leaked like CRAZY. I'm going to get the supplies for lapping them this weekend and see if that does the trick.
 
If they are leaking real bad you may find they are bent
How can it hold air with the head off?
 
If it didn't leak with rocker cover off, there is nothing wrong with valves. You probably had them on overlap when you used leakdown tester, or, your valve adjustment is way off
 
crazypj said:
If it didn't leak with rocker cover off, there is nothing wrong with valves. You probably had them on overlap when you used leakdown tester, or, your valve adjustment is way off
Click to expand...

+1
 
Thats good news, while its apart I'm debating replacing the valve seals. I know at least one of them leaks.

As for the valve timing I feel like there is something I'm missing by following the manual. Could be that I'm not adjusting them at the proper engine position?
 
I think you mean valve adjustment?
You have to make sure your on compression stroke, watch the intake valve go down then come up again
You also need to bend feelers into a 'J' shape at the tip then use 0.001" either side of settings
For intake, you'll have to use 0.0015" which should slide in easy, 0.002" should slide in but not as easy, 0.003" shouldn't fit at all
exhaust is set at 0.003", 0.002" should slide through real easy, 0.004" shouldn't go through gap
I think you may be tightening things down to far but you are on compression stroke or you wouldn't get leakage (it would rattle like crazy)
If you have a 0-1" micrometer you can 'measure' feeler gauge to get a feel for the correct 'drag'
 
Sorry I meant the actual arms themselves, is there a difference if you interchange any of the 4 to a new location or is the arm itself identical?
 
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