engine troubles

[lukerogers94]

On my mini chopper i have a 120cc two stroke victa lawn mower engine but its quite about 1965. but it doesnt seem to be powerful enough. i have pulled off the clutch and carb and everything and inspected them they all seem fine. when the back wheel is on the ground the engine wont start, but if i pull it off the ground the engine starts up but it dieswhen i put it back on the ground. does anyone have any ideas on how i could try to make it more powerful or is it time to get a new engine. i also thought it was a clutch problem as the clutch is heavy duty and the engine wouldnt produce enough power to loosen the clutch, i took it apart and banged up the springs a bit to loosen them up,the wheel now spins so i think its working but i still need it spinning faster.
i can upload some pics if needed
any help is appreciated

 

[brendonv]

Tune the carb, if its revving real high and still doing nothing maybe the rings are gone. These victas are pretty strong so i doubt it, would only be the carby. If it is the engine it doesnt really matter if ur in aus as theres about 20 victas at the tip everytime i go. Im putting a victa on my kart and the shaft adapter wouldnt fit as it is meant for the older victas so i just went down to the tip and took a pick out of all of them. If it breaks ill just get another one for 10 bucks or wait till bulk collection and find one sitting on the curb. Get a 160cc victa, the 120cc might not be powerful enough. Have u got the full or half crank version? If its half crank maybe its loosing pressure through the pull starter. If u undo the three bolts u can take the pull start off. Theres a rubber o ring in there to seal the crankcase, it might not be sealing and loosing power through there.

 

[lukerogers94]

yeah i dont think its that carb cause it looks pretty clean in there the engine revs real high with no chain attached to it but when i attach it back up it seems to just be going so slow maybe the gearing ratio is messed up or somthing i can figure it out because i though the victa would go great. and to about the pull start i have already taken it off cause im using a drill to start her up. i really should work i mean its an old engine but i have replaced the piston, rings and gaskets. i have another engine thats a 6hp four stroke, but i dont know if it will fit in the frame, and plus this was a vertical shaft victa so i had to do a mounting plate and everything it would be shame if she didnt work so any other ideas? btw what do you mean tune the carb?

 

[brendonv]

There will be a mixture screw on the carb or a hi and low screw to adjust how much fuel goes into the engine. U might have enough fuel going in with no load but not enough with load. Why did u get a new piston, rings ect for a victa? U could get a "new" one at the tip for 10 bucks. btw wat carby are u running on it? If its the stock g3 or g4 carb then that would be ur problem, there really crap. I got a Walbro LMS carby on mine.

 

[Kaptain Krunch]

whats your gearing? tire size?

 

[porsche930dude]

definatly sounds to me like your clutch isnt fully disengaging

 

[lukerogers94]

umm the front sprocket is 12tooth and the rear is 42 i think the wheels is about 10 inches, i dont know if that helps
umm if you think its the clutch not disengaging what could i do to fix it?

 

[toofarnorth]

It seams like that would be way too high geared especially for a 2 stroke, I don't know anything about a victa but most 2 strokes like to rev high and don't build much power at low rpms.

 

[lukerogers94]

so cut my losses and put the 4 stroke on?

 

[brendonv]

wow no wonder. Nah leave the victa on, even with the 4 stroke it will be battling to go. U need a 60 or 72t sprocket on the back. 72t for more acceleration and 60t for more top speed. I would go with a 72t if u were u.

 

[Ferrari motors15]

definatly sounds to me like your clutch isnt fully disengaging

I think you have the good answer beacause on my kart I got the same problem I removed my chain and my my engine runing perfecly now I wait for a tav2

 

[Kaptain Krunch]

12/42 with 10 inch tires isnt too high, sounds like your clutch just isnt disengaging. 12/42 (3.5:1) with 10 inch tires and 3600 rpms (not sure what a victa revs too) is about 30mph which isnt too high to aim for especially on a minibike.

 

[porsche930dude]

take apart the clutch and get the rust and corrosion out and make sure everything is freed up and no parts are bad. Also could be your springs are sprung you might need to take a few coils off

 

[lukerogers94]

thanks for all your help guys
i tried taking the clutch apart but there was no corrosion or anything i put a screwdriver in between the the coils and hammered it in they loosened up lots so i put it back on but there was no improvement, i thought maybe i could put the sprocket straight onto the shaft and then see if it works that would be able to determine if its a clutch problem right?
i will upload some pictures tommorow

 

[brendonv]

stay tuned, ill have my 160cc victa go kart done soon and ill post up some pics.

 

[lukerogers94]

how fast it gunna go? how olds the victa? why dont you try to make a bike?

 

[brendonv]

It will go about 55kph but i doubt i will ever go that fast. Its from about 1970 im guessing but im not really sure. Ive already got 2 motorized bikes, i dont want another one and i want to be one of the very few who posts up videos and pictures of a victa kart. I cant find any info on victa karts or anything on the net so i want to be the first and include many pics so others can learn. I might take the engine apart and lightly port the intake and exhaust port and give the motor a set of new gaskets.

 

[Russ2251]

120cc Victa kart:

 

[brendonv]

im aware of this one, however, is this urs? If so, did u make your own adapter on the lathe because i need the take that boss off on shaft or my adapter wont fit. Looking at it again, you would of had to make your own adapter as its a power torque model therefore the adapter wont fit. btw that is a 160cc not a 125cc.

 

[lukerogers94]

heres some pics the engine is 1969