Alpha Sport LG90 lack of power Hey guys/gals. I just bought a used 2003 Alpha Sport LG90 and it just doesn't have the power to go up a small incline. It has a new air box, new carburetor (air screw turn out 1 turn from gentle seat and idling smoothly), new spark plug (gap set at .024), removed old oil and put in new 2 cycle oil, and fresh non-ethanol gas. When I hit the throttle it is slow to take off and takes a bit to really get her up to speed. If I slow down it takes for ever to get her up and running top speed again. She can't climb up small inclines without a running start. The belt looks fine and both front and back clutch look ok and clean. My guess is that the clutch is worn but I can't get the nut off it to check it out. Does anyone have any idea what it could be? Any help would be great. Thanks!

 

My guess would be a blocked exhaust. Two strokes need the exhaust cleaning out now and again. Most of them have removable baffles in the silencer so you can do this. I have known exhaust ports to "coke up" as well, on Suzuki 50s.

 

^^^^^^Could be this but, I would remove the variator ( front clutch ) and take it apart, inspect/clean, then reassemble.

 

Unfortunately my exhaust is all one piece. I took a look into the exhaust end with a flashlight and I can see a plate with small holes (screen) and the holes are blocked with what looks like a fine screen. I cannot tell if this is build up or normal. I debating on removing it from the engine to see if it's plugged at that end. Alpha -Sports.com want $225.95 for a new exhaust system. I know it an AEON motor and it's the same thing in a Polaris Scrambler 90cc. Don't know if this will fit the ATV or not. Any after market fits out there or quick fix for the one I've got?

 

I have looked at both front an rear clutch. I was surprised how clean these were. I'll try removing the front clutch (variator) and look it over well. Do you think the rollers are bad in it? Or do you think it might be the secondary sheave assembly clutch carrier that's worn? I can't seem to figure out how to keep it from spinning so I can get the nut off it. Might need to apply the rear brake??? Looking at the scrambler repair manual doesn't give me instruction on how to disassemble this... just says to remove the nut and rubber washer. But says nothing about keeping it from spinning while removing the nut.

 

When I remove them, I use an impact...anyway, yes, the rollers may be worn out or full of debrie from the belt. I think you can take the cover off, place the rear on a jack, then rev it up to see if the variator and rear clutch are moving in and out freely. The rollers do go bad.

 

I would have thought that the symptoms of a variator fault and exhaust would be very different, in that the engine revs would increase but the bike wouldn't go much faster if the fault was in the variator, but the revs just don't increase much with throttle opening if the exhaust is blocked. Extremely anti-social, but I have removed the exhaust complete, and started an engine, the resultant power increase on a small two stoke is unbelievable, as is the noise.

 

I just re-read the thread....before you do anything, do a compression test. Hopefully you will see 110-130 pounds of pressure.

 

I think that be the best option. I'll find someone who can do a compression check for me. I have thought about removing the exhaust and starting it to see if the power is there. I did this once when I was much younger to a twin 500cc snowmobile and nearly blew out my eardrums. I'll try to get it down to a shop for a compression check soon.I will keep you both posted. Thanks so much.

 

Merryman and FASTERATV,

Sorry for the delay on this post. I have been pulled in so many directions lately. I did a compression check and it's just a tad over 90PSI. A bit low but I'm not really worried about that. However the exhaust system is plugged and I had to cut that open to get to the inner. It was so bad we just did a bypass and sealed it back up. Pretty sure it's gonna be a tad louder. I haven't had the time to install it and test it. I have checked the belt and it was worn down (so I thought). What I discovered is that the previous Owner didn't put the correct belt on it so I replaced it with the correct one. Again I haven't tested it yet. I have not checked the variator rollers and not sure if I will at this time. I'll let you know how the ATV runs as soon as I put it back together.

Can anyone point me to a place to get a new exhaust for this bike that's reasonable. I do not want a racing exhaust, just a stock one. If I can get a slip on exhaust that would be great. Thanks!