1973 honda st90

[osmbr1]

if this isnt allowed please remove! thanks

so i have a honda st90 and after i ride it for about 20-30 mins it does this see attached video. carb says pz19 if that means anything or can get me more help, thanks!

https://www.youtube.com/watch?v=tJy2SZf7j-k

 

[ZR9B]

my 69 CT90 does the same thing...Im just too lazy to mess with it....so im watching and good luck for the both of us...also welcome aboard!!

 

[creia]

FWIW: PZ19 = Aftermarket carb
Michael

 

[FirePowerMinis]

Have you verified the fuel tank is venting?

 

[osmbr1]

the gas cap is venting and is on the "on" position there is an option for off, yes it is a aftermarket carb, where should i start off the tuning on this carb, i think i fouled out the spark plug trying to start it after it acted up, so now it wont start. hope we get an answer zr9b!!

 

[1971_MB1A]

I'd probably just try a new re-pop carb. I had pretty much the same problem on one of my st 90's.

 

[osmbr1]

Ysterday i was replcing the battey and noticed the rectifier starting to smoke starting to smoke could this hve anything to do with it?
IMG_1712.jpeg

 

[creia]

The OEM selenium rectifier units do get hot, however, they should not smoke! If yours is original (has the huge cooling fins?) it is LONG overdue for upgrading anyway. For our 1969 Honda CT90 we purchased a new rectifier from Jon Pardue Welcome to the Pardue Brothers - Home of the Pardue Brothers who is also a long time OldMiniBikes member. He REALLY knows the old bikes (especially electrical) and is also a very nice gentleman to deal with.
Michael

 

[osmbr1]

Thanks you, im going to order a new one! Ill check out that site!

 

[minibikegi]

I still ride the 79' ct90. I sold the 75 st 90 cuz of that problem, and I just didn't love it. Both have original carbs, I tore down that carb 4 times, always same thing! Ignition/timing perfect. I gave up that there was an air-leak? I obviously replaced manifold ones. Valve lash was also perfect, still could be the valves though? When it runs great one time, start it up an now it runs like crap? I ran it with no gas cap also. Glad its gone!