Engine Trouble Gt80 no power

Discussion in '2-Stroke Engines' started by jhussel13, Nov 3, 2016.

  1. jhussel13

    jhussel13 New Member

    i have the gt80 racing engine and straight out of the box it had no power it's like it's bogging down or getting way too much fuel I've tried a new plug new cdi and bought another carb tuned it and still am getting the same result! I'm get a top speed of about 24 I have a 44 tooth sprocket and I weigh about 175 lbs not sure what the problem is...I tried to rejet it and that didn't do sh*t either I've checked for leaks everywhere no leaks it does have a different cdi not the one they sent it's not a high performance one thinking maybe that could be the problem?

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    Last edited: Nov 5, 2016

  2. crassius

    crassius Well-Known Member

    read on board here about checking gaskets and stuff, but I'm wondering if you have it run in yet
  3. BilalCarroll

    BilalCarroll New Member

    You could have an air leak which would cause a loss in power you should check gaskets like the other guy said. You should also get the high performance cdi makes all the difference. What is your fuel ratio if your running a very rich mix it could hurt your performance. furthermore an overly rich mixture can cause your engine to 4 stroke.
  4. Steve Best

    Steve Best Well-Known Member

    How did you check for leaks?
    The ideal way is to block the intake and exhaust with a plate and pump the engine up to 5psi with a bicycle pump.
    Here is the gear I use. The plates and plug are what I use on Yamaha Blasters and KTM engines:
    A bunch of plumbing fittings, rubber hose, a cut down tire schrader valve to fill it, some plates I made, and a 0-15psi gauge.
    Use a bicycle pump to pump it up to 5psi and listen for leaks or use soapy water.
    Should hold 5psi for 10 minutes. Never more than 7psi or you will blow your seals out.
    I don't have a picture of my motorize bike stuff but it is 2 plates for intake and exhaust drilled and tapped for hose nipples for the gauge and the fill line.

  5. Your bring water to my eyes I got a GT80 andd I only get 3 MPH thats with me pedaling my goes 0 miles PH the motor only lasted a months been trying to fix it for oh maybe 3 been waiting a week for a motor sports place to give me a quote see if they can get it it to run tomorro I'm gonna march in pick up my bike say f**k them take the goddam agony heartach anchore off shove it in the scrap dump order a new motor where they brag have quality WildCat see if that works. The racing motor is a legal catch there is sommething wrong with it when it meets state law thats reason for the yellow sticker 24 MPH fast for me unless your dreaming of being heroe of the Indi 500, still its possib advertisement racers speeds begin around 55 MPH although you can change yyyrocket down to TF 17 ? instead of stock 44 ? also hen breaking in an engine yoou are adding 4 ounces oil to half gallon that will make the engine stumble until break in 3 or - per half gallon some performance will pick up. PS either the forum board is defective or its my tablet having a hard time at text, please check into it moderator.
  6. 21 MPH is designed speed, but if you jiggle an air leak in the carb I had mine going 37 MPH for short 5 miles til died completly so I think with experimenting if you use a thick fabrick gasket right where it bolts to the motor carve out a slot see it gets more air cuz my interior carb bolts came loose I had a speedometer to verify I was not dreaming.
  7. Neptunati

    Neptunati New Member

    Just built one of these myself. Got to it to 35 mph with 41 tooth before I sold it. Get rid of the aluminum block spacer make sure everything's nice and flat you have an air leak at guarantee it. Plus you Really need to make a dime sized hole in the piston (4th transfer port). I have a build thread on the other forum. I went right with opti2 oil about 70:1 from the start. Forget that 16:1 nonsense lolz. That oil is so slick even at the ratio I went with it'd take a long time to break in the motor.
    These kits are not junk at all. The GT80 kit for the price in my opinion is the best 2 stroke kit you can buy. BUT you have to do all the finishing touches. The two regular transfer ports need to be corrected as well. I spent probably 5-8 (I'm slow)hours with my dremell carefully reshaping them to point to the intake. With the finishing touches I mentioned a proper expansion chamber and the right rear sprocket. 45-55 mph can be had with this kit. 55mph being a race motor that probably has to be rebuilt every month lol. 40-45 mph daily driver. But that flex pipe exhaust is only good to say 5500rpm at the most. I'd say that pipe make crazy torque down low.

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  8. jaguar

    jaguar Well-Known Member

    drop the needle and put a good non-restrictive air filter on it
    Neptunati likes this.