ATTENTION New Cruzzer Motor Owners - Exhaust Mushroom Lifter get's hung up on Cam Bearing - The Repair FIX

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Nov 14, 2018
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#1
Howzit Everyone'

I discovered this problem and I'm sure others have too. But I've never seen it discussed on this FORUM before.
In some or all of the new Cruzzer Motors the Exhaust Valve Lifter Mushroom get's hung up on the Cam Bearing. Not every time just now and then. Even more with thermal expansion. Causing the Exhaust Valve to stick open. Making the motor Miss, Backfire and loose power. Its easy to tell, just pop off the R.H. side cover,remove Cam, look at the Cam Bearing if it is poking out about .025th.(the Cam Bearing Boar was not machined deep enough) I think your gonna have this problem . Move the Exhaust Lifter up and down with your finger you'll be able to feel it get hung up on the cam Bearing. The FIX is easy. Just remove the Exhaust Mushroom Lifter and reduce the Mushroom Dia. by .020th. This can be done with basic tools. Put the Lifter in a drill motor. Put the drill motor in a vise, spin the lifter. Now ya can get a real good straight flat angle at holding a file and filing off .020th from the Mushroom Dia. Then ever so slightly bevel the sharp edge on the mushroom Dia. with the file. "CAUTION" Do not OVERHEAT the Mushroom or you will ruin the temper of the metal. Then the Mushroom will really mushroom.
Sorry I don't have any pictures for ya all. I hope someone else will post pictures when they do this repair Fix. So everyone will be able to understand better. Or next time I do one I'll post repair fix pictures
*NOTE - I'm not saying that all Cruzzer Motors will have this problem. But the 4 I've seen have.
ALOHA Wrench
 
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Joined
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#2
Howzit,
I suggest That if you have a New Cruzzer Motor. Before you even run the motor to inspect the Cruzzer Motor and look for this problem. The repair fix will save you a lot of headaches and trouble shooting. Also will prevent DAMAGE to your New Cruzzer Motor
I hope this info can help someone.
ALOHA Wrench
 
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#3
Howzit,
I suggested to reduce the Exhaust Lifter Mushroom Diameter By .020th to gain clearance between the Mushroom Edge and Cam Bearing Face.
*Measuring the Diameter- To reduce the Lifter Mushroom Dia. by .020th that = .010th on the sides of the Mushroom Dia. Understand?
I have found this to be the Min. amount needed for clearance. (Mushroom Edge to Cam Bearing Face)
I have reduced the Mushroom Dia. by .040th that = .020th. I feel this is the Max amount.
I have compared the Early NE-5 Whizzer crankcase to the New Cruzzer crankcase and found a difference.
In the Early NE-5 Whizzer crankcase the Cam Bearing Face set's FLUSH with the case.
In the New Cruzzer crankcase the Cam Bearing Face is POKING OUT about .025th
in the New Cruzzer crankcase the Boar for the Cam Bearing was not machined deep enough.
Please read this post from #1 for the repair fix and a "CAUTION"
If you just can't tune your Cruzzer. It will miss, backfire, loose power or just bog down. This just might be your problem
I hope this info can help someone.
ALOHA Wrench
*NOTE - If not fixed the Aluminum Exhaust Lifter Boar MAY be DAMAGED becoming out of round. Resulting in FOREVER sloppy Exhaust Valve Lash
I suggest all who have a Cruzzer Motor to inspect the motor and look for this issue.
 
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#4
Howzit,
My friend brought over his brand new Cruzzer Bottom end Motor For us to check out. Never used.
On inspection we found the Exhaust Mushroom Lifter was getting hung up on the Top of the Cam Bearing.
The repair I've suggested was preformed. See Pictures and refer to #1 on this tread for the Repair-FIX instructions.
In these pictures you will see
1 ) The Exhaust Mushroom Lifter hung up on the top of the Cam Bearing and the amount the Cam Bearing is POKING OUT from the case. About .025th
*NOTE - We pulled the Cam Bearing to check the Boar Depth. The Cam Bearing is all the way in.
2 ) The drill motor mounted in a vise. So I could get a nice straight flat angle. To file down the Mushroom Diameter .020th
*NOTE - When I reduced the Mushroom Dia .020th I noticed the Lifter Mushroom was not perfectly round from when it was made.
This might help explain why the Lifter Mushroom only get's hung up every once in a while.
3 ) The Lifter Mushroom reduced .020th after being filed down.
4 ) Exhaust Mushroom Lifter installed.
*NOTE - I'm not saying that all Cruzzer Motors have this problem. But the 5 Cruzzer Motors I've seen have.
ALOHA Wrench
 

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#5
Howzit'
While we were inspecting my friends Brand New Cruzzer Motor bottom end. We discovered another issue.
The Intake Mushroom Lifter was Bottoming Out and touching the case. When the cam lobe lifted the Intake Mushroom Lifter to it's highest position. We could feel the resistance. So we measured and checked. We Found and we could see a uneven surface around the Bottom of the Intake Lifter Boar. Preventing the Intake Mushroom Lifter when at it's highest position from having a nice level surface to meet and not touch the case. This is easy to check. When the lifter is at its highest position. Just grab the top of the lifter and try to move it up and down. There should be a little free play.
In these pictures you will see
1 ) Using a Dremel tool to level the surface around the bottom of the Intake Lifter Boar.
2 ) The Bottom of the Intake Lifter Boar leveled ( Well almost level. The idea is to remove the high spots )
3 ) The Intake Mushroom Lifter Installed
I suggest to inspect this area too and level around Intake Lifter Boar if needed.
I Hope this info can help someone
Taiwan Specs - Close Enough is Good Enough
ALOHA Wrench
 

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