Using a SkyHawk 66cc Angle Fire at over 8000 Feet

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GearNut

GearNut

Active Member
Aug 19, 2009
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Well, rule that out then. A black plug means a rich fuel mixture, IMO too rich.
The only way to find out the cause of the noise is to do an autopsy.
Expose the internals and see what you find.
Are you positive that the noise is not coming from the clutch area?
The clutch shells on all my engines have alot of radial play on the hub, which does not seem good to me, but they make strange noises and operate just fine.
 
GearNut

GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
TEAR IT DOWN!
I highly suspect that the wrist pin bearing has gone south on you.
It could be any of the bearings, but preventative maintenance is cheaper that blowing it up. (well almost, with the cost of these toy engines)
 
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oldtimer54

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May 15, 2010
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Its brand new I think ill exchange it and start over. I bought it from bikeberry and it came with a six month warranty. Anyone have to warranty anything with bikeberry? Wonder how good there warrantys are? I guess Ill be finding out.
 
GearNut

GearNut

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Aug 19, 2009
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Warranty is always a good option too.
It really pays off to do business with a good vendor.
I am sorry I cannot give you any personal experience with bikeberry, I hope that they are good on warranty issues.
 
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oldtimer54

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May 15, 2010
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From what Ive just been reading here Ill be lucky to get a good motor from bikeberry. Looks like Ill have to learn to rebuild one to get it fixed. Hope Iam wrong seeing how I havent had it for 2 weeks yet.
 
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oldtimer54

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May 15, 2010
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Ya I just got off the phone and they only warranty the parts not a motor. Sooo I need help rebuilding this brand new motor. My motor feels like it will explode if I try to run it now. I have re bolted the head bolts to 15lb and lapped the head flat. I was told the head might be to tight and that would do it? Would my head torqued to 15lb make it want to explode? So I will retorque to 10lb. I will go to 4oz of oil to one gal of gas but now my throttle cable just broke. The little lead end came off in my carb!? Can it be fixed? Do I have to buy a new throttle cable and does anyone know where I can get a better one? I was thinking of getting a "REAL" carb that comes with its own cable. These are the two Iam thinking about:

Dellorto Type Carburettor
This one would cost me about $80 (ouch!) but I bet I would get great support.

I can get this from bgf on ebay for $55 but when I need support bgf wont be able to tell me what a carb is much lell help me set one up:

bicycle Motorized BIKE ENGINE - Performance Carburetor - eBay (item 170488032581 end time Jun-17-10 11:48:22 PDT)

Now with my motor seeming like it is going to explode you migh ask why spend more money? Well I wont give up and I want to do it right. I ordered a new expansion chamber Ill buy one of these two carbs and If I need to ill buy another motor from someone who stands behing there motors with a real warranty. Iam thinking Dax. So is there any to fix this cable and what carb do you guys think would do the job at over 8000 feet? Who should I buy a motor from and WHY is a brand new motor feeling like its going to explode? Could it be my oil mix Iam doing what bikeberry said 16 to 1. Iam feeling like dumping the last of my tank of gas and going over to 32 to one oil mix as its tank two and almost done anyways? I have no bike now so any advice to help me would be great! If your in colorado and want to help ill pm you my ph number any thing to get thing to go! lol!! Thanks
 
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GearNut

GearNut

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Aug 19, 2009
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1. No need to change out the carburetor, unless ya really have your heart set on it.
2. Good-n-tight cylinder head nut torque will not cause an engine to act like it will explode.
Too loose and you risk blowing the head gasket, too tight and you will tear up the threads down in the crankcase holes.
3. DAX is a good vendor, he has a good reputation for standing behind his products.
4. Norm has an excellent tutorial in his help section on how to repair or customize the length of a throttle cable.
Here: http://motorbicycling.com/f39/norm-shortening-throttle-cable-9010.html

5. 16:1 is acceptable for a break in ratio. I prefer 25:1, but everyone has differing opinions on that subject. The idea is to have it heavy on the oil until break in is done, then switch to a thinner ratio for normal operation.
6. Sorry, I am in Kaliforgnia. If we lived closer, I would be happy to help you out.
7. Did I overlook anything?
 
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oldtimer54

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May 15, 2010
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Great Thanks. I think Ill retorqe the head bolts to 10lb. Thanks to your link I fixed my throttle cable! Iam having a very hard time getting my carbs to work at 8000 feet.(hmmm head leak? lol) The motor came with a SPEED brand carb but it would not idle so I bought a stock carb and I can get a nice idel but I get way to much 4stroking and was hopping a better carb would help at 8000 feet. Ive tryed the rejetting of these carbs and it just showed I have a warped head and jug. I lapped the head not sure how to do the jug? Will a good carb help up here? (if I can fix the leak that is) Can I get any more power with one of the two carbs I have listed? And is there a thread giving a how to for rebuilding a skyhawk slant head 66cc? Looks like Ill be needing it today. Thanks for all the help guys I would haven't gotten this far with out it!
 
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GearNut

GearNut

Active Member
Aug 19, 2009
5,104
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San Diego, Kaliforgnia
Head bolts @ 10 ftlb is good for the 8mm cylinder studs which you should have.
Congratulations on the cable repair!
Before you end up pulling your hair out over the carburetor problems, baby it if you can and let the engine break in more. They are notorious for running poorly untill break in is done, about 2 to 3 gallons of fuel or 500 to 700 miles. They seem to grow up and behave themselves after that. I know that you want it to behave right now, but if you have all ready tried to lean out the air/ fuel ratio by adjusting the slide/ jet needle clip position and resizing the main jet, then you have all ready done what I would have done myself. The only other beast in the works is a poor operating ignition system. It could be a bad spark plug, spark plug wire. If you are using the stock plug in connectors on the ignition wiring, they are notorious for causing problems. Cut off the krappy connectors, solder the connections together and tape them (or best: use heat shrink tubing) to seal and insulate the connections. The worst it could do is eliminate a very common problem with the ignition system. The best it could do is provide a much more reliable interface between the engine and CDI box, and perhaps cure the 4 stroking.
 
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oldtimer54

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May 15, 2010
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Thanks I had allready soldered every thing I could trying to get rid of RFI. Iam going to start using 32 to 1 oil mix today hope that helps. I should hear from bikeberry today (I hope) and they might send me a new head and jug.
 
GearNut

GearNut

Active Member
Aug 19, 2009
5,104
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38
San Diego, Kaliforgnia
Changing out the spark plug wire to a resistor type will help curb the RFI.
Inside the CDI box, there is a steel screw that threads down the center of the wire to both make contact with the inner conductor and hold the wire tightly.
Changing out the wire is as easy as using a known good automotive resistor core wire.
Just cut off the end that will not fit the spark plug, unscrew the stock wire and screw on the automotive wire. I am pretty sure that the wire size needed is 7mm.
It may even help with the poor engine operation.
 
CoastalCruiser

CoastalCruiser

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It strikes me that the piston clatter you are experiencing is pre-ignition or "pinging". Perhaps you have an over lean mixture which is causing the fuel charge to ignite from compression. Try diddling with the needle position and going to a cooler spark plug.
 
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oldtimer54

Member
May 15, 2010
540
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On a bike
Ok this seems strange? I was copper coating my head gasket when I saw my piston could twist just a little in the piston sleeve? Is this where my piston clatter is coming from? Are these pistons meant to beable rotate a little?
 
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oldtimer54

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May 15, 2010
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On a bike
From what thatsdax tells me my motor cant be fixed unless I pay more then the motor is worth. I guess a rotating pistion is not a good thing?! Bikeberry is doing nothing not even answering the phone. Never once have they even returned my calls. I only bought it from bikeberry because they are a sponsor of this site but they are not to be trusted just a heads up! I dont think having bikeberry as a sponsor here looks good for this site.
 
GearNut

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
The ability to twist the piston in the cylinder means something horrible has happened. Either the small end bearing has gone south, or the big end bearing has, or both.
I am sorry to hear of your loss, this is devastating to the engine. :(
 
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oldtimer54

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May 15, 2010
540
6
18
On a bike
GearNut said:
The ability to twist the piston in the cylinder means something horrible has happened. Either the small end bearing has gone south, or the big end bearing has, or both.
I am sorry to hear of your loss, this is devastating to the engine. :(
Click to expand...
Kind of devastating to me to?!:-||
 
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Drewd

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Jul 25, 2008
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oldtimer54 said:
From what thatsdax tells me my motor cant be fixed unless I pay more then the motor is worth. I guess a rotating pistion is not a good thing?! Bikeberry is doing nothing not even answering the phone. Never once have they even returned my calls. I only bought it from bikeberry because they are a sponsor of this site but they are not to be trusted just a heads up! I dont think having bikeberry as a sponsor here looks good for this site.
Click to expand...
A while ago, I bashed bikeberry because I heard similar complaints about their warranty. Bikeberry didn't appreciate my comments and I thank you for validating them.

I'm sorry about your engine. Write it off and buy a Dax motor. Dax offers the best service after the sale PERIOD, plus you are buying from a Colorado vendor. Its a win-win situation.
 
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