Engine Getting HOT!!! 78 KZ650

Hello All,

I recently put a top end on a KZ650 that I had in the back yard for years. Never really ran but I rebuilt cardbs and put a rebuilt cylinder head, re-used pistons and rings and added a oil cooler with kit from Klasmo (Dyna ign set up with 4 into 1 and pods).

Like I said I never really road the bike until recently its jetted properly and idles and runs very well. However after about 10-15 min of riding the engine cases, head and ignition areas get super hot! I stopped riding because I got scared of damaging the motor.

I have a GS750 and other Honda CB 360 and my KZ engine seems to be really really hot compared to my other machines with same amount of riding.

Any suggestions? Is it a oil flow issue?

Thank you!

Did you have a real temperature value?

You can use a oven thermometer to verify how hot it's getting. Do you hear crackling coming from the engine? Pics of the plugs?
Steve

Thank you guys, no real reading yet

Attached are some pics of the plugs. Pic 1 Left Plugs 1& 2 Pick 2 Right Plugs 3 &4

I'm assuming maybe valve clearance needs to be checked again and also adjust the pilot screws?

Could this be causing the excessive heating issue? I wouldnt think?

Thank you!

It's summer time. What part of the country are you in & what're the outside temps?
Are the carburetors tuned for the aftermarket exhaust & individual pod filters?
1 or 2 of those plugs look white to me, indicating a lean condition. lean is hot & not good.

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Why do you think it's overheating? It's an aircooled engine.

Two look lean. Make sure the pilots are clear and do the float level test.
Steve

Agree two look lean. I am in New Mexico around 95 degrees outside. Needle on 3rd clip I have 115 mains and 17.5 pilots

Ill check the float and air mixture screws.

I think its getting hot because after 10 minutes I can barley touch the motor it is noticeably hotter than any other bike I have.

The engine should be too hot to touch & I wouldn't even think of doing that.
A KZ650 is going to feel hot during the hot hot hot summer months, especially in the desert Southwest.

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odl666 wrote: .................I think its getting hot because after 10 minutes I can barley touch the motor it is noticeably hotter than any other bike I have.

I've owned my 1977 KZ650 for 42 years (62,000 miles). During that entire time I would not even think about touching the engine after it was warmed up. These engines get very hot. Take a look at the link below for more info. Ed

www.kzrider.com/forum/2-engine/453478-oi...possibilities#453667

If your using genuine Mikuni jets the 115 / 17.5 is fine.