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Main Area => General GS500 Discussion => Topic started by: sashkar2000 on September 22, 2013, 12:24:34 PM

Title: Engine overheats after rebuild
Post by: sashkar2000 on September 22, 2013, 12:24:34 PM
Hi guys. I took off the head and cylinder block end to replace broken intake valves. Finally put it all back together. It starts easily but the left cylinder heats up within a few seconds and exhaust gasses come out of the exhaust port. Id think its a simple exhaust leak because I didn't replace the exhaust gasket, but the rest of the exhaust pipe is also very hot.

Dieing to know What could be the problem?

Thank you!!
Title: Re: Engine overheats after rebuild
Post by: sashkar2000 on September 22, 2013, 03:36:51 PM
Actually it looks like the colder cylinder wasn't running. I swapped the exhaust gaskets and the leak is gone but  it still heats up extremely quickly. Is it normal for the engine to heat up to where its uncomfortable to touch it within 30 seconds? Meanwhile the exhaust pipe is scorching hot but i imagine that's normal.

Compression on both cylinders is 100 psi which sounds ok considering the rings got disturbed and havent seated yet, though maybe that's wishful thinking.
Title: Re: Engine overheats after rebuild
Post by: adidasguy on September 22, 2013, 04:12:43 PM
Balance the carbs. if you don't have the tool, do a search for "hill billy carb sync". It will get you really close.
Do that then report back.
Title: Re: Engine overheats after rebuild
Post by: sashkar2000 on September 22, 2013, 04:53:14 PM
i definitely need to get the other cylinder running, and it's probably a carb issue. but can you elaborate on how disbalanced carbs or a non-firing cylinder would affect engine temperature?
Title: Re: Engine overheats after rebuild
Post by: Big Rich on September 22, 2013, 06:25:48 PM
Well, a non-firing cylinder won't get hot ......

And if your carbs are out of sync, then one carb can be running the engine at idle - the other carb isn't doing anything.
Title: Re: Engine overheats after rebuild
Post by: adidasguy on September 22, 2013, 08:42:59 PM
If one side is doing all the work and the other side is doing nothing, then one side will get very hot while the other stde stays cold.

If both cylinders working, then, basically average the hot and cold and both sides will be very warm, as opposed to one side hot and one side cold.
Title: Re: Engine overheats after rebuild
Post by: Janx101 on September 22, 2013, 09:43:01 PM
.. and now we wait for a 'thermal' engineer .. (http://freezone.photoimpact-international.com/images/emoticons/smiley-fingertap-gigi.gif)  ;) :flipoff:
Title: Re: Engine overheats after rebuild
Post by: adidasguy on September 22, 2013, 09:51:28 PM
Surprised Sledgey hasn't jumped in to say I'm all wrong......
Title: Re: Engine overheats after rebuild
Post by: radodrill on September 22, 2013, 10:03:35 PM
Only one cylinder firing you'd expect one hot cylinder and one warm cylinder due to the thermal conductivity of all the cylinder block.  Both running they'd both get hot, though there can be some temperature differences based on variations between air/fuel mix, oil flow path and temperature, etc.

The engine/exhaust can certainly get hot quickly when you aren't moving; and the exhaust will invariably be hottest.
Title: Re: Engine overheats after rebuild
Post by: Janx101 on September 22, 2013, 11:54:04 PM
20 mins.... a bit tardy!! ..  ;) :D
Title: Re: Engine overheats after rebuild
Post by: yamahonkawazuki on September 23, 2013, 12:36:21 AM
Quote from: adidasguy on September 22, 2013, 04:12:43 PM
Balance the carbs. if you don't have the tool, do a search for "hill billy carb sync". It will get you really close.
Do that then report back.
^^^ agreed ^^^^