cb 350 engine temp?

[legendary_rider]

Just wondering how hot it actually gets inside the cb 350 engine. Not at the exhaust but inside where the cooling fins are. Anyone ever measure it?

 

[crazypj]

Good question, no idea ;D
I checked my XS650 several years ago but I've forgotten what the temps at head were (I think it was up around 400f)
Intake side is around 200f

 

[teazer]

Inside 2,000F or more, outside probably closer to 200-240f depending on where you test it and how hard it was running.

 

[legendary_rider]

Good point. I guess it depends on where and when. Makes it a difficult question. Thanks guys.

 

[crazypj]

At instant of flame propagation in combustion chamber, the spark causes an instant temp rise to around 5,000deg F between electrodes but temp 'drops' to around 1,800F during combustion (depending on mixture, ignition timing and load)
Plug tip temps rarely get above 8~1,200, usually less (it's why they make different 'grade' plugs)
Normal combustion temps average around 12~1,400 deg F (I've forgotten too much to give any more details)
The major area's of concern are exhaust valves and piston crown, heat transfer into cylinder head keeps combustion chamber relatively 'cool'
The piston problem is the reason Suzuki were the first manufacturer to use oil jets squirting at inside of piston (SACS motor)
Today, every manufacturer uses oil jets to cool bottom of piston crown
Multiple smaller valves have shorter heat transfer paths so can operate at higher rpm before overheating becomes a problem.
There's a lot of stuff going on, the more you know, the more you'll be amazed the damn things run at all ;D

 

[Kanticoy]

Re: Re: cb 350 engine temp?

There's a lot of stuff going on, the more you know, the more you'll be amazed the damn things run at all ;D

Well said, i think this is why I have stayed interested in them for so long.