mikuni t34

[zr2highrider]

I recently aquired my 89 banshee. It runs great but is having problems overheating. I just bought a new aluminum radiator, still boiling the coolant. Its not overflowing, its just when i shut it off after it has been run hard, it sounds like air bubbles comming up through the radiator. This lasts a minute or so. I have put it through a few heat cycles to try to get the air out but still no sucess. Top of rad is hot while the bottom is warm so its cycling coolant. I am 99% sure its my jetting.

Took one of the carbs off tonight to see if I could get some help and advice on jets. The mods are listed are what i know are done to the bike.

The cylinders look heavily ported for stockers- the guy who I bought it from said he had it as a drag bike/trail bike (hard for me to believe). They have boost ports added. He said that the engine was built by K&T performance.

Has pro design cool head - unsure dome size. He said run 91 pump gas in it so I dont think they are too radical.

T-5 pipes and silences

+3 timing. Has an adjustable cdi on it. +3 is all I can go before I put it to +5.

Looks like Rad Valves for the reeds. Aluminum cages. Looks like 1/2 inch reed spacers(?) also.

99% sure stock stroke and bore. Im also running 40:1.

No airbox lid but running k&n airfilter.

Carbs are t34 mikuni's.

The mains are 320's and the pilot looks like it says 50. The air screw is 2 turns out.

Elevation here in LV, Kansas is 850 ft.

The thing that gets me is that this thing flat out runs. Doesnt make any funny noises other than when I shut it off and starts gurgling. I am going to do a plug chop tommorrow and post pics. If there is anyone on here that has any advice on ANYTHING please chime in.

Thanks,

Cam

Edited January 19, 2012 by zr2highrider

[#1JUANstunna]

Have you checked the water pump to make sure the impeller hasn't melted if it's a stocker? Just a thought.

[zr2highrider]

yanking the clutch cover off tommorrow to take a look at it... this is a new shee to me so i honestly dont know if its a stocker or not.

Edited January 19, 2012 by zr2highrider

[RadarRacing]

A banshee wont usually overheat like what you are saying from just lean jetting. Im thinking it may be impeller as well. Usually the the radiator will be close to the same temp from top to bottom if water is flowing properly. You can check your jetting by looking at your plugs and doing a plug chop. Is it possible that the head gasket is leaking pressure out into the water jacket?