running hot... overheating 2 stroke

[Spare_Parts]

I only tried the one. It may have been defective.

 

[BIG BOBBY]

coarse threaded rod always worked for me,...or a coarse thread bolt with the cap sawed off (sawed off and hand file chamfered after I got it in there with red Loctite) ---stayed in there for the remainder of that top end's lifespan.

seems to me a reed/longintake/big carb/big air cleaner is like a long lever,...with all the weight wayyy out there at the end,...making the strain on those studs a LOT greater than just a 4 inch stock tube and an NT. --and then add mucho vibration= those poor little studs are being tortured. i'm just stating the physics of the situation. maybe some sort of support to reduce that leverage......reduce that vibration,.....

 

[CrazyDan]

coarse threaded rod always worked for me,...or a coarse thread bolt with the cap sawed off (sawed off and hand file chamfered after I got it in there with red Loctite) ---stayed in there for the remainder of that top end's lifespan.

seems to me a reed/longintake/big carb/big air cleaner is like a long lever,...with all the weight wayyy out there at the end,...making the strain on those studs a LOT greater than just a 4 inch stock tube and an NT. --and then add mucho vibration= those poor little studs are being tortured. i'm just stating the physics of the situation. maybe some sort of support to reduce that leverage......reduce that vibration,.....

My thoughts exactly. I've seen many builds, irl and online, that has no support bracket for the intake or exhaust. Most kits come with an exhaust bracket that almost nobody uses, and folks wonder why their muffler broke off or bolt holes stripped out. They wonder why they are constantly dealing with vacuum leaks. The longer something is, the more support it will need. Doubling the length of something unsupported is doubling the torque it receives when shook up.

 

[Anthony711]

Any air leak coming from the engine can cause engine to run lean.

 

[Anthony711]

Install a temp gauge I wouldn’t exceed pass 380 f. Do a leak test any leak can cause motor to run lean. Never eye ball your oil gas ratio. More oil will flow through your jetting slower cause it to run lean visa versa. Hope this helps

 

[inspectorcritic]

Get laser temperature gun you get more uses out of it.
My temperature if I remember right was 280 not 380.
Then they have frankenstein cooling heads got one on mine just makes it run a little smoother and while your pondering about the mix check the to cap of your carb did yesterday the cap unscrewed that gave me a richer mix cuz it pulled the needle up.

 

[Deleted member 12676]

safest maximum cylinder head temperature

 

[inspectorcritic]

safest maximum cylinder head temperature

I'm not sure what a Grubee is I picture it as a scooter the compressions you mention are way up there on a stock 49cc ideal compression is 118psi mines lower.
I just tried a B6HS it ran rough as s**t crap out on any hill I got a fat fin cooling head the B6hs ran better on another bike with standard flat head than a C4Z.
But when I took out my plug I notice oil drip off the plug and it was wet do I went to the carb place it on the leanest grove stuck a NGK TR55 or it a 66 V power plug in and the bike ran smooth maintaining speed speeds of + - 30 MPH which makes me happy about same speeds I had before I blew a piston. And I think when I had my laser temperature gun the top heat was a mer 180° unless it was on a centigrate scale

 

[Street Ryderz]

I'm not sure what a Grubee is I picture it as a scooter the compressions you mention are way up there on a stock 49cc ideal compression is 118psi mines lower.
I just tried a B6HS it ran rough as sh*t crap out on any hill I got a fat fin cooling head the B6hs ran better on another bike with standard flat head than a C4Z.
But when I took out my plug I notice oil drip off the plug and it was wet do I went to the carb place it on the leanest grove stuck a NGK TR55 or it a 66 V power plug in and the bike ran smooth maintaining speed speeds of + - 30 MPH which makes me happy about same speeds I had before I blew a piston. And I think when I had my laser temperature gun or top heat was a mer 180° unless it was on a centigrate scale

Grubee is the original manufacture of these bicycle engine kits we use.A 48cc engine should have the same compression or close to the 66-69 versions and 118 psi is almost dead.If you run these engines above 300f you're killing it quickly,220f to 240f is ideal externally checked temp with ir gun because the internal temp running will be higher!Heat soak is apparent after 280f where a severe power loss occurs and continued use is just asking for trouble.