Overheating cure?

I have a 76 KZ750 twin. I haven't done much engine modifying. Just simple things that change how it runs and sounds. I cut off the mufflers for the bobbed pipe look but add inserts for back pressure (home made ) and added a K&n air filter and re-jetted and a Dyna S ignition. My Bike runs good for a while but when it heats up it tends to bob up and down pretty bad from the engine and when I'm on the hiway it'll kinda cut a cylinder out every once in a while. I just gotta get on it to fix it then its good for a couple minutes. If I do shut it off or it dies then its near impossible to start till it cools down. I dont know if its just getting my coil too hot so it doesn't want to work right or what. It's only kick-start so it'll give me a lot of kick back when it doesn't want to start. Does anyone know if there's a way to hook up an oil cooler to my motor. i know its not very common cause its not a high performance motor like the 1100 or 900.

Personally, I don't think your problem is related to overheating. I would guess that it is a tuning issue. Either your bike is flooding, thus causing the hard starts with lots of kick back from the kick-start or you have a failing coil that only makes it's self appearant when the bike is fully warm. Sounds to me like you need to get out the service manual and check your ignition system and probably the float heights in your carbs to eliminate any tuning issues.

Just exactly how short are those exhaust pipes now? Is that the source of all your heat?

Just my two cents, testarossa is probably right, but overheating may be a possibility. I used to have a TW200, by no means a performance motor. I put a very short high-flow pipe on it as well as a K&N pod filter on the carb. Re-jetted and adjusted needle height in my carb. Ran really damn well, about 25% more power than stock, but after riding for more than 20 or 30 minutes, it would start to get really really hot. I actually burned my hand once just by touching the side of the case. After it got too hot, it would stall out and was a pain to start again. I ended up buying a second bike, and kept the TW200 just for getting groceries or short rides.

To sum it up, improving performance on your bike's motor can cause overheating. You must equally match your performance upgrades with upgrades to your cooling system. My clymer manual actually says that too!

KZCool wrote: If I do shut it off or it dies then its near impossible to start till it cools down. I dont know if its just getting my coil too hot so it doesn't want to work right or what. It's only kick-start so it'll give me a lot of kick back when it doesn't want to start. Does anyone know if there's a way to hook up an oil cooler to my motor. i know its not very common cause its not a high performance motor like the 1100 or 900.

I never found a aftermarket oil cooler for my 750 twin.

I would check the timing advancer assembly.

have you checked the plugs to see if it's rich or lean?

Are you running the right plug? It's B6ES for the twin. You could try the B7ES (colder plug) if the plugs are getting too hot.

i agree with a tuning issue. the carbs could need a good cleaning too. maybe try running some Sea Foam through it .

:laugh: Proper tuning...

Do all the crap said above.

:evil:

I seafoamed it at the beggining of the season, and for some reason my floats have never worked fully. It'll leak gas when I let it sit for a day because the petcock is crap too. my run-off works just fine though so I'm not too worried about that. I do need to play with the tuning though. I have a gun but dont know how to hook it up with out taking a spark plug out. Anyone know where I can connect the trigger wire to use it while my bike's running? I feel like this will help with the heat and rough running. I do also think that the coil is going though Anyone know where o connect my ohmeter to test it?

Your overflow may be working fine when the bike is parked, but where do you think all that fuel is going when it's running? Seems to me like my original theory is holding up. Leaky petcock + leaky floats = running rich, fouling plugs, and flooding. Oh yeah, parking the bike with fuel leaking around a hot motor is a good way to burn your problem to the ground eventually.

You have a gun? You mean a timing gun? Doesn't it have a trigger wire that clamps over a plug wire? That's how mine hooks up.

Perhaps a good shop manual ---

kz.bike-night.com/

Scroll down to and click on "The Bible (aka the shop manual) and wiring diagrams"

It's free.

Good Fortune!

Yes, Testarossa makes a good point.

Yes, deffinately get a good service manual.

Get the carbs off and go through them thoroughly.

Good luck.

Its not running rich. A little to the lean side but nothing serious. And I'll try the wire. thanks