engine trouble please help
- Thread starter raudogsmotors
- Start date
Well I loosened them up there tightening n loosening just fine n the heads not cracked so I dodged that bullet all I need to do now is check the head gasket n order a new one would an auto parts store carry the head gasket I need the engine is a 66/80cc angle fire black horse
I have about n hour a day if lucky to try n fix it its my work transportation n since its down I have to walk
2door is right about the acorn nuts, they can bottom out before they clamp the head down to the jug so even properly torqued, the gasket can still leak, you can get some regular nuts from the hardware store and problem solved...
I do agree that you need to make time to read these things others are telling you about... lapping means sanding to match... in simple terms. This can be done by using a piece of sandpaper on a sheet of glass, or if the engine is disassembled and can be cleaned thuroughly, you can use lapping compound between 2 parts and rub them together to make then match up perfectly... the sandpaper on glass method is more practical, stuff like lapping valves is where you'd use compound and direct contact of the parts to be lapped.
The head gasket is made of dead soft aluminum and can be reused several times as long as it's not damaged. Thr head surface shuold be lapped to ensure a good seal, and same for the top of the jug... read up on this and also search this cylinder head lapping on youtube as well...
Here's some easy reading as well as some decent videos to watch for instructions... http://juicemotoparts.com/high-performance.html This guy also sells some goodies others dont like copper head and base gaskets, these are excellent for boosting compression or accurately placing the jug on the block to advance or retard port timing or set piston squish clearance, but read and watch the videos and get the basics down really good before trying anything advanced... you can go from never took an engine apart to very proficient at these things pretty fast by reading and watching the youtubes from this guy and several others.
I do agree that you need to make time to read these things others are telling you about... lapping means sanding to match... in simple terms. This can be done by using a piece of sandpaper on a sheet of glass, or if the engine is disassembled and can be cleaned thuroughly, you can use lapping compound between 2 parts and rub them together to make then match up perfectly... the sandpaper on glass method is more practical, stuff like lapping valves is where you'd use compound and direct contact of the parts to be lapped.
The head gasket is made of dead soft aluminum and can be reused several times as long as it's not damaged. Thr head surface shuold be lapped to ensure a good seal, and same for the top of the jug... read up on this and also search this cylinder head lapping on youtube as well...
Here's some easy reading as well as some decent videos to watch for instructions... http://juicemotoparts.com/high-performance.html This guy also sells some goodies others dont like copper head and base gaskets, these are excellent for boosting compression or accurately placing the jug on the block to advance or retard port timing or set piston squish clearance, but read and watch the videos and get the basics down really good before trying anything advanced... you can go from never took an engine apart to very proficient at these things pretty fast by reading and watching the youtubes from this guy and several others.
Im purchasing a new head gasket off of gasoline.net and it has two options to choose from for hole size idk if this means the large hole or the bolt holes but the options are 6mms or 8mms the engine is a 66/80cc angle fire black horse does anyone know
They blow mainly by undertorquing... basically when these are assembled at the factory they're torqued, but after a few heat cycles they work their way loose and need to be re torqued once or twice before thtey sellte in and stay put.
These gaskets are solid soft aluminum so they can be reused.
When you look at the gasket you can usually see where the exhaust blackened the aluminum, sometimes it's on the head side and sometimes it's on the jug side... that's where lapping the head really helps, these heads aren't always perfectly flat but lapping them by placing a sheet of sandpaper on something perfectly flat like a sheet of glass then moving the head over the sandpaper in a circular or figure 8 pattern until the whole sealing surface is clean fresh aluminum will help considerably... Here's a video on head lapping, the same thing can be done to the cylinder deck (top) https://www.youtube.com/watch?v=_k1..._embedded&x-yt-cl=85027636&x-yt-ts=1422503916
This vid is more toward increasing compression (which you can also do) but this is the same technique for getting the head and cylinder deck surface nice and flat so they seal better, just stop when it's flat for sealing, sand away more to boost compression.
These gaskets are solid soft aluminum so they can be reused.
When you look at the gasket you can usually see where the exhaust blackened the aluminum, sometimes it's on the head side and sometimes it's on the jug side... that's where lapping the head really helps, these heads aren't always perfectly flat but lapping them by placing a sheet of sandpaper on something perfectly flat like a sheet of glass then moving the head over the sandpaper in a circular or figure 8 pattern until the whole sealing surface is clean fresh aluminum will help considerably... Here's a video on head lapping, the same thing can be done to the cylinder deck (top) https://www.youtube.com/watch?v=_k1..._embedded&x-yt-cl=85027636&x-yt-ts=1422503916
This vid is more toward increasing compression (which you can also do) but this is the same technique for getting the head and cylinder deck surface nice and flat so they seal better, just stop when it's flat for sealing, sand away more to boost compression.
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So, Did ya just try snugging up the head and starting it? This isn't rocket science. This is the simplest engine I've ever seen. It really dont take much to get one running. Ya gotta remember, The chinese have been using these for years. Those guys aint trying to build racing engines, They just want it to run the cheapest way possible. So,at most, Check the head on glass and FINE grit sandpaper, Buy a head gasket and snug it down to about 10ftlbs. But first I would just snug the head and try to start it. And the 66/80 cc is prolly the 8mm studs
fatdaddy.
fatdaddy.
Yea I tried snugging it down there's no way it'll run with the blown gasket when the new one arrives ill assemble it n snug it down to 10ftlbs I have a feeling it'll run like a dream after that n im gunna check the head bolts every couple of heat/cooling cycles till it settles
Ok im flabbergasted here i replaced the head gasket rewired everything so the have there copper male and female ends replaced the spark plug cap with an ngk one replaced the spark plug with an ngk bph6s plug checked the engines electrical and coil only thing i havnt opened and checked is the electrical box that holds the male ends of the engine and kill switch i cannot get a spark or keep power blue is to blue black is to black and the kill switch has been wired every way possible including taped off please help im about to give up n scrap it
What about the magneto coil? These are notorious for failing and ive even bought an engine from a very reputable source with a bad one before. These are under the left engine cover and can go pretty easily if they get wet or moisture under that cover. With an ohmmeter check the resistance between the black and the blue wire with it disconnected and make sure your getting a reading of 350 to 500 ohms give or take about 50... if its reading really low or not reading at all replace it, and buy another spare just to have on hand.
If this reads good it could be a broken or missing key on the mag rotor causing it to fire off timing, or if the rotor was removed it can only go back on one way and wont fire at the right time if on backward.
The cdi its self is pretty reliable but can also go out, these are cheap to replace and another piece to keep a spare if budget allows.
If this reads good it could be a broken or missing key on the mag rotor causing it to fire off timing, or if the rotor was removed it can only go back on one way and wont fire at the right time if on backward.
The cdi its self is pretty reliable but can also go out, these are cheap to replace and another piece to keep a spare if budget allows.
If what yer calling the electrical box is where the black and blue wire come out of the engine, then yer talking about the coil cover.. once you've tried everything else, I'm gonna vote for the coil. They go out ALL the time. The only consolation here is that they are cheap enough. If yer getting no spark, Then spend the $10 for a coil and yer problems SHOULD be over. 4 screws hold in the coil and only two wires to hook up. ignore the white wire, just cap it off and never use it.
fatdaddy.
Hey Dave, we just went through this for almost 2 weeks with another guy. he claimed to get good readings on his meter, still no spark. replaced the coil and fired right up. so I dont know if his meter was bad or he didnt know how to use it, but I dont really trust others to use a meter properly. AND you and I both know 99 out of 100 times ITS THE COIL.
fatdaddy.
I'll send you a ebay link to a coil at a fair price. I just ran into bunch of real cheap coils, I've never seen them this cheap so I dont know whats up. If you go to BOYGOFAST he may charge more than $3.83 but you'll have it in 3 or 4 days instead of a month comming from asia.
from BGF
http://www.ebay.com/itm/66cc-80cc-5...parts-magneto-coil-/400654747727#ht_108wt_914
From the other side of the world.
http://www.ebay.com/itm/New-Ignitio...es&hash=item3f40f5a455&vxp=mtr#ht_1912wt_1151