1973 gt750

[aslsmm]

So i got the 73 running on all three.

got familiar with the carbs and how they work.

got everything ready to start riding my 29k miles gt750 every day for the rest of riding season.

then KABLAM. fire out all 3 exhaust pipes.

i was going 65 down the highway and i realized that i had to keep giving her juice to maintain speed. i decided to pull over when i realized she was all open and slowing down.

as soon as i stopped i saw a huge puff of smoke and flames out the pipes. kinda kool accept i was only going 65 not 165.

any way she didnt have any power till 3500 rpms and i had an incling that she was on her way out. so lucky for me i have a 74 motor that i practically got for free. ill drop that in her and get her going again then i will start rebuilding the 73.

bernie will love hearing this. maybe we can do more work together lol.

i will post pics of the inside of her when i get them. stay tuned.

[aslsmm]

got the head off. looks like a bad gasket. it runs like hell right now. i will be throwing the pod filters in the trash. they are crap. any one have a original air box for a 73?

[aslsmm]

got the head back on. i used the ld gasket because i am just trying to trouble shoot. i have a new gasket but i didnt want to use it yet. i want to make sure thats the problem. so any way i put it all back together and let it idle fr 10 min. i got my gear on and went to take it up the road.

when i got out side she was dumping white smoke out of the L cyl and dripping black oil from there also. the other two cyls seemed fine. im thinking the seals are bad and its leaking tranny oil into the cyl. could this be correct? i can throw up a vid if you think it will help.

[aslsmm]

http://www.youtube.com/watch?v=OjgDDB4I ... e=youtu.be" onclick="window.open(this.href);return false;

here is a vid. as i removed the exhaust the l cyl pipe had coolant in it. possibly a cracked block?? working on getting the other motor running.

[T350guy]

Since mine is doing the same here's what I have learned.
Left crank seal if leaking will suck air and unlikely to suck oil from what I've been told.
If you have a bad oil line check valve it could be leaking a good amount of oil into that cylinder.
If it was the center seal Then it should fog pretty good out of all 3 cylinders.

[aslsmm]

im thinking the cyl block is dab. when it warms up it seems to dump coolant into the cyl. it comes out the pipe.

[Barry S.]

Sounds like the head gasket or base gasket may be leaking. There are O rings under the cylinder that could leak coolant into the cylinder. The smoke coming out around the left pipe in the video didn't look too bad, just tighten it up or put in a new crush washer with red RTV. Take it out and flog it if you get the coolant stopped leaking and see if the smoke clears up.

[aslsmm]

thanks. i will try that.

does any one know how to bypass the gear position switch? i dont have a 74 guage cluster and i cant wire up the 74 motor without bypassing the gear position switch. thanx.

[aslsmm]

on to the restoration/ build. here is a few pics and a video.


this is an oil leak from the exhaust. both engines are doing this. what does this mean?



the 73




the 74

and here is a video of the motor running.
http://www.youtube.com/watch?v=weMjcnHQ ... e=youtu.be" onclick="window.open(this.href);return false;

[Barry S.]

Flooding carbs will dump a lot of gas into the pipes and wash out a lot of grease, these old petcock are known for not shutting off and flooding the cases.

[GT750Battleship]

Good luck with the resto....shame about the "oil spill" on the pavement!
My wife would have killed me for that...
Cheers,
GT750Battleship.