Barrels from M,A and B motors

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Nicholasj
On the street
Posts: 11
Joined: Thu Jan 06, 2022 12:13 am
Country: Australia
Suzuki 2-Strokes: 1975 GT750M

Barrels from M,A and B motors

Post by Nicholasj »

Hi - I have a question that I think is w a a a y out there.

Just when I thought my resto. was done, karma came back and kicked me in the goolies.

I’ve been having reasonable surging issues and I’ve done all the normal things: kept the chain tension tighter rather than looser; made sure the foam around the airbox mating area is sealed and the foam strips around the chrome edge covers are good; lowered the idle speed to 1000rpm; taken the mixture screw from 1/2 turn to 3/4 of a turn and in-between in experimentation; I’ve installed 0.8mm jets in the Pilot Air passage and bought new carb mounting rubbers-just in case.

So I decided to remove the carbs and go through them and fit the new boots. Clear all passages; check float heights etc etc etc.
To my utter astonishment once I pulled the carbs off, I found one reasonable slit in #2 inlet manifold pipe and 2 slits in #3 in the same location!
It appears the previous moronic brain dead cretin of an owner attempted to Port them and only managed to hole them! These are all AFTER the clamps that seal the rubbers to the respective inlet manifolds. And they ALL are on the edges of the lips that the Carby boots abut. So the boots cover the holes- but provide no airtight seal.
So she was sucking air BIG TIME. Running lean on 2 of 3 pots.
I’d attach photos: but I tried and they were too large.

My options now are :1 to either strip the motor down, take the barrels to a Pro and get the holes welded up.Which I DO NOT want to do. Absolutely not. Unless that is the ONLY recourse available.

: 2 Fill up the holes from the bottom of the inlets with JB Weld ( or some such) so if it fails it cannot get into the bores.
:3 Try and use Aluminium brazing rods to fill the holes in - again from underneath. As mentioned, the carb boots cover the holes so if whatever I do fails, then the material won’t go into the motor.

Does anyone know the metallurgy of these Suzuki Barrels? Straight Aluminium? Aluminium alloy? Nickel alloy? Whatever.
Just a reasonable guess should do. A Pro.Welder could probably tell by just putting a torch to it- but I don’t want to pull the motor down. If it’s mostly Aluminium then the brazing really ought to work.
I hope!
Abject apologies for such a lengthy ( and possibly stupid) missive, but any insight will be welcome and certainly more than I know.
Thank you.
Cheers. Nick.
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jabcb
Moto GP
Posts: 4241
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: Barrels from M,A and B motors

Post by jabcb »

We can’t post images to this website.

Post your images to a photo sharing website & then include links to those pics here. I use Flickr. It’s free & easy to use.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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