1972 Suzuki MT-50

oldmt50

oldmt50

Member
#1
#1
Hello everyone!

Hope you could help. I have a '72 MT50 that I just can't get runnin. This was my childhood bike that holds a high sentimental value to me. Trying to get it runnin again so my kids can ride it. Haven't had luck finding a service manual either. FYI, I live in the Metro-Detroit area. Any help would be appreciated.

Thanks in advance!
 
trailhopper

trailhopper

New Member
#2
#2
If I lived closer to ya I could help you out. I replied to your other thread about parts. I redid a 72 MT50 back a few years ago. You can see pics of it on Minidoodle. Its the blue/white 1972 Model. Cool bikes and that one was a blast to ride.
 
oldmt50

oldmt50

Member
#3
#3
Last time it was ridden was in the early 90's. Didn't run right though. I think it ran up to only 20mph when the throttle was just right. My father purchased it used in the early 80's and made the carb cover frim aluminum and used a bike shift lever for what seems to be a choke. Finally, over the 4th if July week, I took out the carb and overhauled it. Re-assembled and it almost started with the first kick but seemed to have flooded...not sure. Removed the plug and gave it a few kicks. Spat quite a bit of oil/gas mix out the head. Not sire if that's normal. Did this motor come with an filter at the carb hiusing? My carb is open (no screen on it). Haven't really dove in on the troubleshooting just yet as I'm not that familiar with the repair of the bike. Wish I had a service manual.
 
trailhopper

trailhopper

New Member
#4
#4
There are several Service Manuals on EBay right now. That's where I would start. That's a 2 stroke engine so I hope you made sure the auto oiler has oil and most importantly....is working. I disconnected mine cuz I didn't trust it and mixed my oil and gas separately then filled the gas tank with the mixed gas.

Oil and gas spitting out of the head is not good. If all of your head bolts are tight and its still doing that then you either have a blown head gasket or a cracked head.
 
oldmt50

oldmt50

Member
#5
#5
Thanks for the reply. I'll check the compression this weekend. So should I see a minimum of a 100psi? No visible cracks. There is a plug underneath the engine from which fuel tends to leak when attempting to start. Any ideas to why that's happening. I'll take some pics and post them to this thread.

Thanks again!
 
jesse8931

jesse8931

New Member
#7
#7
trailhopper said:
There are several Service Manuals on EBay right now. That's where I would start. That's a 2 stroke engine so I hope you made sure the auto oiler has oil and most importantly....is working. I disconnected mine cuz I didn't trust it and mixed my oil and gas separately then filled the gas tank with the mixed gas.

Oil and gas spitting out of the head is not good. If all of your head bolts are tight and its still doing that then you either have a blown head gasket or a cracked head.
Click to expand...
better buy a new motor.

your crank bearings are gonna fry.



Thats the same system on the mt50
 
oldmt50

oldmt50

Member
#8
#8
Took some pics!

So I took some pics over the weekend and tried to get her started again with no luck. Removed the plug and gave it a few kicks to clear any gas/oil from the head but it seemed quite dry. So, I suppose my earlier comment of it initially spitting some gas/oil was just at the beginning of trying to start after all those years.

Ok, so, I checked compression. 100 PSI at one kick. 150+ at a few kicks. Looks good, right?
I didn't, however, change the oil. Looks pretty clean but should know better that even oil shouldn't stand for more than a year without s change. So, not even sure if it's 2-cycle oil. Gonna have to change that out next time.

The bike wanted to start, but no-go. Any suggestions? Take s look at the following pics.
 
oldmt50

oldmt50

Member
#11
#11
Pic of the carb (after I took it apart and cleaned it correctly). I don't have the original carb case cover (mine's a makeshift from aluminum, no gasket). Also, missing the rubber hole plug for the adjustment screw. Hopefully that doesn't affect anything.

 
oldmt50

oldmt50

Member
#14
#14
Not sure what this cable is and what it's purpose is as it's never been connected to anything. Please help on this one. The part diagrams I found online don't seem to show it. Is this crucial to operation?? Definitely don't
look right.



 
trailhopper

trailhopper

New Member
#16
#16
Try these things.

1) Drain all old gas out of tank. Mix a gallon of gas with a 4oz. of a good 2 stroke oil and put in tank
2) Make sure the auto oiler tube is either pinched off or disconnected.
3) Get a new spark plug. Then try to restart.

If still nothing:

1) Make sure you have a good spark.
2) Check to see that the choke is working properly. (open/closed)

Your question on that cable that goes to the top of the engine. To me it looks like someone had tried to wire in a kill switch and ran it to the spark plug. As far as the wiring splice job....well your on your own there.
 
oldmt50

oldmt50

Member
#17
#17
The cable connects into the top if the engine. You can see it in link #14 (2nd pic). Doesn't look like a kill switch. It's a braided pull cable similar to the throttle cable, etc. Does yours have one?

I made sure to use fresh fuel and the bike has excellent spark. Just the oil hasn't been changed. I'll need to try your suggestion. So 4oz to one gallon? Is that correct or a safe guess?
 
jesse8931

jesse8931

New Member
#18
#18
trailhopper said:
Try these things.

1) Drain all old gas out of tank. Mix a gallon of gas with a 4oz. of a good 2 stroke oil and put in tank
2) Make sure the auto oiler tube is either pinched off or disconnected.
3) Get a new spark plug. Then try to restart.

If still nothing:

1) Make sure you have a good spark.
2) Check to see that the choke is working properly. (open/closed)

Your question on that cable that goes to the top of the engine. To me it looks like someone had tried to wire in a kill switch and ran it to the spark plug. As far as the wiring splice job....well your on your own there.
Click to expand...
Again these motor's can not be premixed.

Premixing will kill the crank bearings.
 
The Restore Kid

The Restore Kid

New Member
#19
#19
The cable is most likely your choke cable... Goes into the carb kinda off to the side of the throttle cable.. It pulls up a plug that opens an extra hole, allows the carb to suck extra fuel..

The bike looks fairly clean for the most part... 150 PSI is real good.... Lots of times these engines are just plain worn out, and rebuild stuff is hard to find for them...

But seals and stuff out of a similar sized engine should work... Might be a Oliver tractor magneto seal or something, but as long as it's the right size, it'll work....

I don't think it needs all that... Most likely just a good solid day or two of someone pissing with it.....

I'm like two hours from ya.. But I'd work on it for ya if ya wanted..... Cheezy Bill might haul it for you if he ever makes it back up this way... :shrug:
 
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