1972 T350: Smoke from only one exhaust + hotter

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GT500-2stroke
Around the block
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Joined: Wed Aug 22, 2018 10:55 pm
Country: USA
Suzuki 2-Strokes: GT100, GT500

1972 T350: Smoke from only one exhaust + hotter

Post by GT500-2stroke »

Just replaced piston rings on both cylinders. Replaced old gaskets.
Cleaned both carbs.

Why does it smoke from only one cylinder? ( Right cylinder ).
Left cylinder does not smoke. ( Checked that left cylinder is firing by putting hand near the end of exhaust ).
Also, right cylinder and exhaust is hotter to touch than the left cylinder. Why? and how what is the solution?

Still need to reduce the idle speed on both cylinders.
Where is the idle screw located on this bike ? ( 1972 T350 )

I looked on carbs that only one screw exits ( I believe it is air screw ), so still need to know how to
adjust the idle speed. Where should I adjust the idle speed from?

I still have to bleed the oil pump. I have added little oil to fuel just for time being.
As I am not sure oil pump is working yet.

so:

1. Why just one cylinder is smoking and is getting hotter than left cylinder?
2. How do I adjust the idle speed ? ( 72 T350 )

Thanks.
karl pa
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Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: 1972 T350: Smoke from only one exhaust + hotter

Post by karl pa »

GT500-2stroke wrote:Where is the idle screw located on this bike ? ( 1972 T350 )
If you slide up the rubber cap on top of carb., the idle screw is on carb top next to cable.
GT500-2stroke wrote: Why just one cylinder is smoking and is getting hotter than left cylinder?
Could be one of many things, points, timing, blocked carb. passage, unbalanced carbs., blocked exhaust.
Word of caution, I believe the left and right main bearings are oiled by the oil pump, premix gas does not allow oil into the bearing with the oil guide plates on the crankshaft, so you should get oil pump working, these oil pumps are pretty reliable.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
GT500-2stroke
Around the block
Posts: 80
Joined: Wed Aug 22, 2018 10:55 pm
Country: USA
Suzuki 2-Strokes: GT100, GT500

Re: 1972 T350: Smoke from only one exhaust + hotter

Post by GT500-2stroke »

karl pa wrote:
GT500-2stroke wrote:Where is the idle screw located on this bike ? ( 1972 T350 )
If you slide up the rubber cap on top of carb., the idle screw is on carb top next to cable.
GT500-2stroke wrote: Why just one cylinder is smoking and is getting hotter than left cylinder?
Could be one of many things, points, timing, blocked carb. passage, unbalanced carbs., blocked exhaust.
Word of caution, I believe the left and right main bearings are oiled by the oil pump, premix gas does not allow oil into the bearing with the oil guide plates on the crankshaft, so you should get oil pump working, these oil pumps are pretty reliable.
Thanks.
I will start with oil pump as per your guidance..

One more question:
Is it normal that the air screw on carbs is facing inside the engine?
( On the suzuki bikes, I have always seen air screw facing outside, so I want to make sure )

1. Points: I need to understand how to adjust points.
2. Timing: I need to understand how to do this.
3. Unbalanced carbs: <same as above>

thanks.
GT500-2stroke
Around the block
Posts: 80
Joined: Wed Aug 22, 2018 10:55 pm
Country: USA
Suzuki 2-Strokes: GT100, GT500

Re: 1972 T350: Smoke from only one exhaust + hotter

Post by GT500-2stroke »

karl pa wrote:
GT500-2stroke wrote:Where is the idle screw located on this bike ? ( 1972 T350 )
If you slide up the rubber cap on top of carb., the idle screw is on carb top next to cable.
GT500-2stroke wrote: Why just one cylinder is smoking and is getting hotter than left cylinder?
Could be one of many things, points, timing, blocked carb. passage, unbalanced carbs., blocked exhaust.
Word of caution, I believe the left and right main bearings are oiled by the oil pump, premix gas does not allow oil into the bearing with the oil guide plates on the crankshaft, so you should get oil pump working, these oil pumps are pretty reliable.
Q: How do I adjust points, timing and fix unbalance carbs?

Thanks.
GT500-2stroke
Around the block
Posts: 80
Joined: Wed Aug 22, 2018 10:55 pm
Country: USA
Suzuki 2-Strokes: GT100, GT500

Re: 1972 T350: Smoke from only one exhaust + hotter

Post by GT500-2stroke »

karl pa wrote:
GT500-2stroke wrote:Where is the idle screw located on this bike ? ( 1972 T350 )
If you slide up the rubber cap on top of carb., the idle screw is on carb top next to cable.
GT500-2stroke wrote: Why just one cylinder is smoking and is getting hotter than left cylinder?
Could be one of many things, points, timing, blocked carb. passage, unbalanced carbs., blocked exhaust.
Word of caution, I believe the left and right main bearings are oiled by the oil pump, premix gas does not allow oil into the bearing with the oil guide plates on the crankshaft, so you should get oil pump working, these oil pumps are pretty reliable.
Oil pump:
I believe it just needs to be bleed, which I did not get a chance yet.
But I will know/confirm once I get to it..
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: 1972 T350: Smoke from only one exhaust + hotter

Post by karl pa »

GT500-2stroke wrote:Is it normal that the air screw on carbs is facing inside the engine?
I would think the left and right carbs got swapped. To swap back you would need to swap choke mechanism.
GT500-2stroke wrote:1. Points: I need to understand how to adjust points.
Turn the engine over till the points are open all the way, use feeler gauge to measure gap .014 inch.Also check they are not pitted.
GT500-2stroke wrote:2. Timing: I need to understand how to do this.
Not sure what BTDC should be on this.Remove spark plug, measure piston to ? BTDC ,this is when plug should spark. I set the piston to this point, then check timing marks on rotor,these marks are not always on so I note where the lines are, using timing light I then set timing to this spot.
GT500-2stroke wrote:3. Unbalanced carbs: <same as above>
Remove air cleaner, looking in carbs, the slides should lift at the same time when throttle is turned, to adjust this you loosen or tighten cable adjuster on top of carb, to set idle, I pull one plug wire note rpm, then pull the other plug wire and set the rpm to match, to do this you may need to increase idle speed to run on one cylinder, when matched turn idle screws back equally.
You must check oil pump adjustment after adjusting throttle cable.
Another word of caution, do not over tighten the nuts that hold the carbs to cylinder, over tightening distorts carb bodies and wont allow carb slides to move freely.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: 1972 T350: Smoke from only one exhaust + hotter

Post by karl pa »

According to T350 shop manual at oldjapanesebikes.com, the BTDC should be 0.113 inch, so the plug should spark when the piston is 0.113 inches Before Top Dead Center.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
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