High rpm power problem

ScottSchwarzer

New Member
Apr 16, 2012
92
1
8
North Carolina
Okay first let me describe the problem to the best of my ability then I will tell you guys what I have done to try to fix it. So whenever I ride and I get on the throttle the bottom end punch is there. But, as I continue to push the throttle farther and farther towards 3/4 - full throttle, it seems as if there is something stopping me from reaching higher rpms. It sounds like its stuttering and won't go any faster. Basically I have no top end power. So I first assumed it was just the main jet being clogged so I cleaned the whole carb out thoroughly. That didn't help so I did a leak down test and I had a leak between the intake boot and reed cage but I think that was only because I took it off to fit the correct PVC when making my tester at lowes and I could tell that there fake gasket beads were wearing off. So I fixed that with some rvt and then I was clear with no pressure drop at all. Also while my rvt was drying I cleaned the carb a second time. So now I am here, a bit stumped but I know you guys can help me fix it. Sorry this was very long I just wanted to be in depth to avoid the usual questions like what I had done and what it felt like.
 
Okay first let me describe the problem to the best of my ability then I will tell you guys what I have done to try to fix it. So whenever I ride and I get on the throttle the bottom end punch is there. But, as I continue to push the throttle farther and farther towards 3/4 - full throttle, it seems as if there is something stopping me from reaching higher rpms. It sounds like its stuttering and won't go any faster. Basically I have no top end power. So I first assumed it was just the main jet being clogged so I cleaned the whole carb out thoroughly. That didn't help so I did a leak down test and I had a leak between the intake boot and reed cage but I think that was only because I took it off to fit the correct PVC when making my tester at lowes and I could tell that there fake gasket beads were wearing off. So I fixed that with some rvt and then I was clear with no pressure drop at all. Also while my rvt was drying I cleaned the carb a second time. So now I am here, a bit stumped but I know you guys can help me fix it. Sorry this was very long I just wanted to be in depth to avoid the usual questions like what I had done and what it felt like.

Thanks for the good description. Please list your mods and jetting. This could be because the weather has changed causing a rich condition. Also did you inspect the reeds when you had them off? Without knowing mods or jetting I would suggest the following checklist in this order.

Compression test, check float height, give the carb a GOOD cleaning, inspect reeds, plug chop, new fuel, and new plug.
 
It is completely stock and has stock jetting. I looked at the reeds and they looked fine. I can definitely change the plug. Could it be something with the air fuel mixture adjustment possibly?
 
It is completely stock and has stock jetting. I looked at the reeds and they looked fine. I can definitely change the plug. Could it be something with the air fuel mixture adjustment possibly?

The air/fuel mixure screw should have no effect on top end. Like Larry said, clean your air filter. Does it smoke more now?
 
Okay. My air filter is clean. And I can't notice a difference in smoke it doesn't seem any more than usual. I'm at work now so I won't have the chance to really mess with it. But I will definitely do the plug and check all of my electrical stuff. I should probably have a manual for all these things. But I forgot to add that I did put in new gas and checked the air filter and it was no go for that. So we're narrowing it down to checking voltages/electrical and to the float possibly or the plug. Is there a post where I can learn how to check the coil and what not?
 
Well I changed the spark plug and took it for a ride and it didn't fix it. But I noticed this time that it only happened the first time I really got on the throttle. Then after that it seemed like it cleared away and ran fine. I'm confused.
 
You probably had a fouled plug. When the weather gets this hot and muggy it will run richer. Ride harder and keep it cleared out.
 
Okay sweet. The plug had a bunch of carbon on it and I noticed its all throughout my exhaust pipe and in the exhaust inlet, basically everywhere. And it's pretty chunky. Is this normal or am I much too rich?
 
Okay sweet. The plug had a bunch of carbon on it and I noticed its all throughout my exhaust pipe and in the exhaust inlet, basically everywhere. And it's pretty chunky. Is this normal or am I much too rich?

If you are COMPLETLEY stock then leave the jetting alone until you do some mods. You just have to clear it out some. 2 strokes will load up if you don't get on the gas hard every now and then.
 
Sounds like you are rich.

When did you check the float level last?

Do you have gas leaking from the carby at times?

What is the needle setting and main jet size?
 
It is completely stock lol. Literally no engine mods, air box still on etc. I just ordered some works shocks which will be this blaster's first major upgrade. I haven't checked the float level since I got it which was last summer because it was running fine and there hasnt been any gas coming out of the overflow tube. Needle setting and jets are all stock also. Maybe I do need to run it a bit harder than I do. I do get on it pretty hard but not constantly all the time. Also where I live it is very hot and humid.
 
Very possible that cheap or wrong oil may have been used at some time. By wrong: outboard, chainsaw, weed wacker. Cheap: whatever is sold at B Box stores, gas stations.

Or as mentioned it's been Granny ridden to much of it's life.

Grip it and rip it. Ride it like you stole it.
 
Blasters delivered to countries that had very hot temps had a #220 main fitted as stock.

Take the time and do a plug chop at WOT and on the needle at 1/2 to 3/4 throttle, the problem could be solved by lifting the needle clip one position.