My Valves are at .13mm and .15mm!!!!

[JerryHawk250]

Originally Posted by Boatguy

The test ride is done!

Final report:

It feels like I just dropped a brand new Honda engine into this thing. I cannot believe how smooth it runs now. There is no more cold stalling anymore. I used to have to crack the throttle just a little bit whenever I took off in first gear. Like before I even let the clutch out. Just to get that engine spinning. Now, I barely have to do that at all. I was compensating for the loose valves for all these miles.

And the sound! How can it I possibly sound this smooth? It’s really a beautiful sounding engine now. It sounds more reliable. Just because there are no weird valve sounds I suppose. It had them ever since day one. I figured that was just the Chinese tolerances.

It also seems to grab a little bit faster when you put the throttle on hard. Less hesitation.

I’m a fan of .06mm/.06mm. Seems just right for this bike. And I definitely did a perfect tolerance where the .6 slides in and the .8 will not. Hope they stay like this for a long time. When they do start going, if they do, I’ll be able to notice it a lot faster now.

Weed hopper, you have past your first test. Always listen to your elders. We ain't half as crazy as most people think.

[Boatguy]

Originally Posted by JerryHawk250

Weed hopper, you have past your first test. Always listen to your elders. We ain't half as crazy as most people think.

Oh you better believe I was listening.

Straight away I did what you said and it worked perfectly.

Stay tuned for more drama from BoatGuy’s “Shade Tree Moto Mechanic Hour”. Live from your local Walmart parking lot.

Next Episode: WHY WON’T THIS DAMN TIRE GO ON THE RIM???

[TominMO]

Originally Posted by Boatguy

Oh you better believe I was listening.

Straight away I did what you said and it worked perfectly.

Stay tuned for more drama from BoatGuy’s “Shade Tree Moto Mechanic Hour”. Filmed live at your local Walmart parking lot.

Next in the series: WHY WON’T THIS DAMN TIRE GO ON THE RIM???

Hey, I thought your were some big-brain physics guy. We X-pect better from you.

[Boatguy]

Originally Posted by TominMO

Hey, I thought your were some big-brain physics guy. We X-pect better from you.

Let me tell you a story about physics guys.

Einstein, Oppenheimer, and I think Feynman or Fermi were in a car on the way to work at the Manhattan Project.

They got a flat. Between the three of them, they could not change the tire to continue on to work. I guess somebody saw them and helped them. So don’t get too excited about physicists being really good at fixing machines they didn’t build in the first place. Ha ha ha.

Particle accelerators? No problem. Nuclear rectors? No problem. In my own case, plasma sensors and equipment to send telemetry from the plasma readings on NASA SMEX spacecraft back to Earth? No problem.

I hear doing these tires might really be tough though. For real. I’m doing them with spoons and hoping to get it right. I have never done this before. But I need to practice in case I blow something on the trail.

[JerryHawk250]

Originally Posted by Boatguy

Oh you better believe I was listening.

Straight away I did what you said and it worked perfectly.

Stay tuned for more drama from BoatGuy’s “Shade Tree Moto Mechanic Hour”. Live from your local Walmart parking lot.

Next Episode: WHY WON’T THIS DAMN TIRE GO ON THE RIM???

We like it when the student listens to the teacher. lol There's no dumb questions. Not everyone have the same type of skills. That's what this forum is all about. Helping each other.

But one thing i do refuse to do is respond on Facebook groups. There a whole different level of stupidity there. There are more people bashing than helping. Don't get me started.

[TominMO]

Originally Posted by Boatguy

Let me tell you a story about physics guys.

Einstein, Oppenheimer, and I think Feynman or Fermi were in a car on the way to work at the Manhattan Project.

They got a flat. Between the three of them, they could not change the tire to continue on to work. I guess somebody saw them and helped them. So don’t get too excited about physicists being really good at fixing machines they didn’t build in the first place. Ha ha ha.

Particle accelerators? No problem. Nuclear rectors? No problem. In my own case, plasma sensors and equipment to send telemetry from the plasma readings on NASA SMEX spacecraft back to Earth? No problem.

I hear doing these tires might really be tough though. For real. I’m doing them with spoons and hoping to get it right. I have never done this before. But I need to practice in case I blow something on the trail.

The natural enemy of the designer is the engineer.....

[Megadan]

You just learned the most important lesson in valve adjustment. It's not that it has a gap. It's that the gap is supposed to be a certain amount to allow the engine to not only run more efficiently, but also prevent excessive wear. Too large of a gap means the valve tip and rocker arm adjuster slam into one another with a lot more force, causing wear. Too small of a gap and the rocker arm starts putting pressure on the valves when it gets hot, causing the valves to stop sealing, causing power loss and eventually damage and accelerated wear.

[J4Fun]

Originally Posted by J4Fun

Just a thought here, my Hawk DLX manual says valve lash, 0.05-0.07mm. Tire pressure is front 32 cold, back 40 cold. Both tires say 32 psi maximum. To make my point I think the manual is more generic than it should be including valve lash. Seriously you need too pay attention when it comes to maintenance on these bikes, language is a barrier I believe?

Guys, this comes from my manual, number for number. You may wonder why things aren’t right with your bike if you go by the manual. Thinking out loud doesn’t it seem the mm should be thousands? And how can they tell you to put more air in your tire than it’s rated for? Pay ATTENTION TO THESE THINGS!!!

[TominMO]

Originally Posted by J4Fun

Guys, this comes from my manual, number for number. You may wonder why things aren’t right with your bike if you go by the manual. Thinking out loud doesn’t it seem the mm should be thousands? And how can they tell you to put more air in your tire than it’s rated for? Pay ATTENTION TO THESE THINGS!!!

No, the mm are right. For example, .058mm = .002". You multiply inches by 25.4 to get the mm equivalent. To go the other direction, you divide.

[J4Fun]

Hi Tom, the measurement would be wrong. If .002” then it would be to tight right? Hence burnt valves. Again pay attention .002” is incorrect for these valves! So maybe we go to thousands, like .004 intake and .006 exhaust? Or we can do .005 and .007 in thousands not mm. That would be my choice. Thinking out loud!

[J4Fun]

Another thought Tom, you skipped the part about tire pressure?

[Boatguy]

Originally Posted by J4Fun

Hi Tom, the measurement would be wrong. If .002” then it would be to tight right? Hence burnt valves. Again pay attention .002” is incorrect for these valves! So maybe we go to thousands, like .004 intake and .006 exhaust? Or we can do .005 and .007 in thousands not mm. That would be my choice. Thinking out loud!

It’s a Chinese bike. It’s all metric. No thousandths of an inch. It’s millimeters.

[J4Fun]

Do me a favor and read your manual, plus look at your tires. Pay attention to the printed # on on tires. The tires are especially important when it comes to safety! Would you agree? If you don’t want to understand your valves and how they need to be taken care of……great! Again pay attention!!!

[Megadan]

Originally Posted by J4Fun

Hi Tom, the measurement would be wrong. If .002” then it would be to tight right? Hence burnt valves. Again pay attention .002” is incorrect for these valves! So maybe we go to thousands, like .004 intake and .006 exhaust? Or we can do .005 and .007 in thousands not mm. That would be my choice. Thinking out loud!

You are wrong. Just so you know. The valve lash specs are correct and in millimeters.

CSC TT250 factory recommended lash spec is .07mm.
Lifan Xpect factory recommended lash spec is .06mm.

Most CG200 and CG250 engines run a lash spec of .05-.08mm as a range. Absolute Maximum is .10mm, but I find this to be excessive.

The absolute minimum spec I have seen for the intake valves on a CG250 engine is .03mm

The reason they can get away with such small valve lash specs is down to the way the valvetrain is constructed. The cam rides in the lower case, but the followers, which are rocker arms, do not ride directly on top of the cam lobe but on the sides, so as the aluminum cylinder expands and pulls the followers away from the cam it does not affect the valve gap at all. Then the pushrods themselves are aluminum, so they expand at a similar rate to the cylinder and cylinder head, so it minimally effects the valve gap as the engine gets hot.

Want to see this in action, install some chromoly pushrods in your engine. You can literally set the lash to zero, and when hot your valve lash will be so large the valvetrain will sound REALLY loud. Aluminum expands faster and greater than steel, so the gap increases a ton as the engine gets hot.

If you need further proof, the Honda CG125, the engine all of these clones are based off of, has a valve lash spec of .08mm with a minimum of .06 and max of .10mm. That is why many people run .003" to .004" on these engines, because that is quite literally .08mm to .10mm.

I tell you what though. Go ahead and set your valve lash to .008 to .010 inches for me. Record it so I can listen to the sounds of small hammers smashing the valves at a high volume. I'm entertained by strange things like that.

[J4Fun]

It seems like know one is paying attention too the original post!!!!!! Let’s play with the dot and zero. For instance.13 is different than .013…….get it guys… look at the original post!!!!