Modest beginnings of my M750 project

[ducpainter]

There is a closer assist spring on the valves to aid starting. They remove them on race bikes.

It's normal to feel the cam get hard to turn when you try to open the valve and overcome that spring.

The binding the video is referring to is when you turn the cam a few degrees. You're trying to feel the rocker rubbing on the cam with the valve closed. That would mean your closer was too tight.

[memper]

I felt none on the horizontal cam then.
But if you chk out the feeler measurements i just posted for the horiz intake, they are pretty tight. Had a tough time pushing down the rocker to even check. Yes, motor was at proper TDC for that cylinder.
Highly confused. But im determined.

[ducpainter]

I felt none on the horizontal cam then.
But if you chk out the feeler measurements i just posted for the horiz intake, they are pretty tight. Had a tough time pushing down the rocker to even check. Yes, motor was at proper TDC for that cylinder.
Highly confused. But im determined.

Openers are tight. Closers are loose. Pretty normal for most motors under 18K.

You can sand the openers, but you'll need to replace the closers.

Not sure what you're confused about.

[memper]

Mostly about how now after reassembly the cam stops after going over the lobe.

*Edit: i just realized that when i worked on the valves i put a bolt on oil galley hole. Its probably still in there causing the binding! Duh. Will confirm tomorrow.

[MendoDave]

Well i dont know the tolerances by heart and im not looking at the specs but .004 is too tight for sure.

[memper]

Mostly about how now after reassembly the cam stops after going over the lobe.

*Edit: i just realized that when i worked on the valves i put a bolt on oil galley hole. Its probably still in there causing the binding! Duh. Will confirm tomorrow.

Nope. No bolt in there. But I realized the problem. It's dumb so I won't go on about it. Monday I will be sanding and doing math for shims. Sure glad I pre-measured them all to make it a bit easier. FCR kit will be ordered on Mon as well.
I'm considering polishing the intake ports while I have the carbs off.

[MendoDave]

Nope. No bolt in there. But I realized the problem. It's dumb so I won't go on about it. Monday I will be sanding and doing math for shims. Sure glad I pre-measured them all to make it a bit easier. FCR kit will be ordered on Mon as well.
I'm considering polishing the intake ports while I have the carbs off.

BTW you new avatar is much easier on the eyes.

[memper]

I'll say! That man put the 'fab' in Fabio.

[brad black]

don't polish inlet ports.

[ducpainter]

Well i dont know the tolerances by heart and im not looking at the specs but .004 is too tight for sure.

Intakes----.004 Exhausts---.005

All closers as close to .000 as possible with no rubbing on the cam.

If you install the half rings back the way they came out the adjustment will last longer.

[memper]

don't polish inlet ports.

Thanks for the heads up Brad. Just found this:
"Laminar flow is unattainable using only a highly polished surface as you actually induce drag by increasing the surface area between the air and metal surface. (NASA and its predecessor did a lot of research on this beginning in the 1950's) For this reason, in areas with subsonic aiflows, a lightly textured surface which induces micro vortexes will actually increase the airflow, as it creates a buffer zone that works like a lubricant. It doesn't matter if you are talking before or after the injection of fuel, as we are talking about airflow itself. Polishing the combustion chamber is, however, a good idea as it will eliminate carbon buildup, reduce the transfer of heat and reduce hot spots that can create pre-ignition.."

[memper]

So according to the feeler measurements I took from the horizontal head (of course the vertical will be measured up before ordering shims) I need bigger closers (as stated).

Intake closer is: 8.25mm with a gap of .0635mm (unloaded).... [8.25+.0635=8.31mm to get ~.000mm gap]

Exhaust closer is: 8.05mm with a gap of .0254mm (unloaded).... [8.05+.0254=8.075mm to get ~.000mm gap]

With the goal of ~.000mm for the closers I need a shim of:

8.3mm for the intake 
8.1mm (sanded down to 8.075) for the exhaust


Sound right?

[ducpainter]

That sounds right, but I'd measure the opening clearances and order some shims to reduce some of the sanding. You'll be quite a while removing .003-.004 from those shims.

It's also possible you might be able to move some shims around to get the tolerances you need.

[Speeddog]

~~~SNIP~~~

Intake closer is: 8.25mm with a gap of .0025mm (unloaded).... [8.25+.0025=8.2525mm to get .000mm gap]

~~~SNIP~~~

That looks like you're adding mm and inches.....

[ducpainter]

That looks like you're adding mm and inches.....

Happens all the time...