Sudden loss of power everywhere

[fatboyslim]

about 2 weeks ago repacked my silencer. Went out riding and the bike ran fine. On the third day I went out riding I was pinning it in third gear and all of a sudden my bike goes louder and there is a big loss of power everywhere. I repacked it and it sounds fine now but it still run crappy. There alright bottom end, but nothing like there used to be and same with the powerband. It also misses and goes bah bah bah when ever I pin it at high rpm. The bike ran awsome before thid too! Before this happened I put a new top end in, new clutch plates and springs, reeds are fine, power valve is fine, cleaned carb and air filter. Maybe floats? Or elctrical?
Any help would be awsome. Thanx.

 

[ctrlaltdl]

It could be as simple as a new plug. Check float level, reeds, and then check the compression with a compression guage.

btw, I thought Fatboy Slim was from UK?

 

[fatboyslim]

I put a new plug in and the bike ran crappy. Then I put the plug in that the manual called for (iridium) and the bike still ran crappy. I checked my reeds and they are fine. When I take it into the shop I will ask him to check the floats and the compression. I'll tell you the news when I get the bike back.

My name is fatboyslim in one word. The guy from Britain is Fatboy slim as you say.

 

[xr250rob]

im having the same problem wit my quad ( yamaha blaster 05) and i put a new top end on it like piston gaskets piston rings new carb airfilter and plug and the reeds i changed like a week b4 it did it so they should b fine and i got it jettd and had a full exhaust system put on and it dont run any diff it bogs out and now my case is cracked so i was jw if the prob u have is the same as mine

 

[fatboyslim]

ppretty close.
Any adivce would be great

 

[John Cena]

Change in weather maybe effecting the jetting?

 

[rmc_olderthandirt]

From your description it sounds like the silencer packing blew out and you experienced a power loss at the same time. If that is what happened, the two happening together, then I am afraid that your top end is toast.

Two strokes really need a proper pipe in order to work properly. When the packing blew out it could have caused the bike to run lean, which could cause the piston to sieze.

 

[fatboyslim]

But when I push on the kickstarter there is good compession and it moves freely. Also, when ever I'm warming it up it sounds boggy when ever I twist the throttle. It's gutless! I don't thinks it's jetting because I never had this problem with it last year.

 

[xr250rob]

thanks *******

 

[adam728]

But when I push on the kickstarter there is good compession and it moves freely. Also, when ever I'm warming it up it sounds boggy when ever I twist the throttle. It's gutless! I don't thinks it's jetting because I never had this problem with it last year.

Check compression with a gauge, not your foot or hand.

Clean your carb, a bit of dirt or grass or anything like that could have made it's way into the tank and then through the fuel system and plugged up the pilot jet.

Pull and inspect your reeds. Frayed edges, chipping, or a small gap between them and the reed cage means they are shot.

 

[fatboyslim]

Carb is clean, reeds are fine, the problem is that my compression is at 105 and it's suppoesed to be around 130. What could be the couse of this?

 

[adam728]

You'll have to pull the topend and find out. It could be the rings getting past their wear limit, a ring "stuck" in the piston, a partial siezure or melt down causing damage to the rings/piston/cylinder. Since you called it a "sudden lose of power" I am guessing it is something damaged and not just worn out. Time to pull off the cylinder and see what's going on.

 

[2-strokes-4-life]

, my compression is at 105 and it's suppoesed to be around 130. What could be the couse of this?

theres your prob.without proper compression the bike cannot run correctly or make decent power.if the compression is low you need a new top end.most likely just a piston/ring change as long as the cylinder is in good condition.i would advise not to ride it anymore until the top end is rebuilt.otherwise you are flirting with disaster if you continue to push it.also with a stock 125 you should have a minimum of 150 psi of compression

 

[fatboyslim]

So basicaly I just need to get a new piston ring if my piston is fine. What about the o-ring on the head or the head gasket? Could any of those maybe been brurnt out or just worn?

 

[adam728]

So basicaly I just need to get a new piston ring if my piston is fine. What about the o-ring on the head or the head gasket? Could any of those maybe been brurnt out or just worn?

You'd be pressurizing the cooling system like crazy if the head gasket was letting that much compression leak out.

Pull the engine apart
Look for which parts are damaged
Order new parts accordingly

 

[fatboyslim]

K. I pulled the top end off and here's what it looks like: The o-ring is still there, the piston looks fine and same with the cylinder. Could it just be the piston ring being worn out? Or a slight seizure to make it wear out? Another thing is I have the old piston of mine that I took out of the bike as soon as I got it last year. It's a stock one and the one I have in there now is a vertex. The thing is the vertex is 54.20 and the stock one is 54.25. I still have the ring from the stock one. Do you think it would be a good idea to put the stock ring on the vertex piston?

 

[adam728]

A new ring for the Vertex is only $18.93. Don't use the stock ring on the Vertex piston.

You'll need to pull the cylinder to determine if the piston will need to be replaced as well.

 

[xcracer72]

do not mix and match pistons and rings unless you recieve a financial grant from either manufacturer for research. You will lose big time. did you point the "arrow" toward the front of the bike? dumb question, simple oversight. also just because the head gasket (s) look good sitting on the cylinder doesn't mean crap. take them off clean them with soapy water and slide them through your thumb and index finger to feel for any small tears, gouges, etc. The "pressurizing" mentioned earlier ia asymptomatic with what you are experiencing and event the slightest "pressurizing" will cause it. this starts in very subtle increments. at first you won't know a thing then you will hear a hissing noise coming from your radiator hose but will think its a hole and not worry about it since you have enough coolant to ride out the day. this happened to me not a month ago. of course it may be something else but i come from the school that teaches to look for the least expensive fixes first since there so much maintenece is required big $$$$$

no such thing as a "slight seziure"

 

[fatboyslim]

So I looked at my head gasket and there area few tiny little peices missing from it. But not enough to make such a significant decrease in power as I have. I have my old stock piston from the bike when I first got it. I took it out b/c the dealer told me it was the cause of my starting problem (but it wasn't). Could I just use the stock one instead. I'll put some pictures on here of it.

 

[xcracer72]

you could use the stocker but at least put new rings on

 

[fatboyslim]

Alright, I put the stock piston in with the stock ring on that I had before (because The ring I ordered won't be here for another week or so.) I push started it (because it wouldn't kick start) and let it sit and warm up. I checked for leaks and everything you're supposed to after you put a new top nd in. Tried to push and kick start it again for a test ride and the thing won't even push start! I just goes baahahhhh even when it's in first rolling down a hill. What now?

 

[xcracer72]

pictures?

 

[fatboyslim]

Do you think I should repack the silencer at all? I'm just gunna get a new stock piston kit. Is that a good idea. Do you think that theproblem to all this is that the vertex is 24.20 mm and the stock one that was in the bike when I got it is 24.25mm?

P.S. I'll try and get some pics of my top end on here.

 

[adamant]

Bare in mind altitude may affect the reading of a compression test. Does the bike start easy still ?

 

[fatboyslim]

Nope, it won't at all. Even when I try to push start it, down a slight hill in 1st it just goes baaahhhhh.