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Kenny O.
Kenny O., Motorcycle, ATV, Mules, Side by Side's Product Specialist. All Brands
Category: Motorcycle
Satisfied Customers: 1019
Experience:  Worked for Kawasaki Motors as a Product Support Specialist (Factory Support) for 24 years
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So, my 1974 Suzuki TS 125(two stroke) will run perfectly fine

Customer Question

So, my 1974 Suzuki TS 125(two stroke) will run perfectly fine while the choke is on, however it doesn't run all that well when the choke is off. I have made the bike be able to idle on its own at about 1750 rpm's, but when I rev up the engine to about 3500 revs, it gets stuck, or continues to go higher forcing me to hit the kill switch. I have completely cleaned the carburetor and checked to see if the throttle cable was getting stuck , but it was completely free. Please help: it will be much appreciated.
Submitted: 2 years ago.
Category: Motorcycle
Expert:  Kenny O. replied 2 years ago.
Hi Thomas my name is Kenny
OK it appears that you have an air leak somewhere on the engine. This being a two stroke you have to be careful and make sure that you have no leaks.
So on two strokes its always a good idea to pressure check the engine, you need really a kit for this, not sure if you have Harbor Freight stores around you but I believe they sell a kit, the problem is that you will usually having to end up making your own block off plate.
So what happening is the engine is getting air from another source (unmetered) and it creating a lean condition and yes they will rev to the moon, if you try running the engine like this under a load it will usually end up seizing the piston or doing damage to the crankshaft
You can try getting a can of contact cleaner or something like WD-40, anything that will burn, then with the engine running spray around the intake insolater block and the base gasket, it can also be the crankshaft seals, likely the l/h side which is behind the points plate/flywheel.
You mike have an air leaking at the manifold if you just had the carb off.
Let me know of this helps or you have further questions, I will be glad to answer.
Thanks Thomas