Planet Minis

mx571 · 02-10-2008, 08:16 AM

i have a 03 crf150f with a 175 kit,rev box,modded clutch. i have changed the jets but i dont have any topend.it goes dead after the midrange.the plug is very lean.last night i noticed that it looks like there is a bend or dent in the header right after where the pipes meet(towards the muffler side).anyway dont know if the dent is supposed to be there or it is damaged but what do you guys think could that take away my topend?

dood · 02-10-2008, 11:34 AM

Quote:

Originally Posted by mx571

i have a 03 crf150f with a 175 kit,rev box,modded clutch. i have changed the jets but i dont have any topend.it goes dead after the midrange.the plug is very lean.last night i noticed that it looks like there is a bend or dent in the header right after where the pipes meet(towards the muffler side).anyway dont know if the dent is supposed to be there or it is damaged but what do you guys think could that take away my topend?

The dent is suppose to be back there to make clearance for the frame.
I would try a different rev box or install the stock one back on it's still lying around.
Did you used to have top end? or is this something that just happened recently.

mx571 · 02-10-2008, 08:33 PM

the bbr rev box actually did help,it was worse before that. no its a brand new kit and we just got the bike. the motor was pretty worn out when we bought the bike but it still had topend and now it doesnt. maybe the stock exhaust is too restrictive,maybe the bbr exhaust will clear it up.

dood · 02-10-2008, 11:21 PM

Quote:

Originally Posted by mx571

the bbr rev box actually did help,it was worse before that. no its a brand new kit and we just got the bike. the motor was pretty worn out when we bought the bike but it still had topend and now it doesnt. maybe the stock exhaust is too restrictive,maybe the bbr exhaust will clear it up.

Didn't know that you put the stock muffler back on it. If you are running the quiet core in the stock pipe, that bike won't pull bubblegum off a hot sidewalk.
Put an aftermarket muffler or at lease take out the core and it should wake it right up.

bat999 · 02-11-2008, 07:38 AM

Bent valve? Broken valve spring? How much compression? Did you say that the motor was bad off when you got it???

mx571 · 02-11-2008, 08:46 PM

no bent valves or broken. lots of compresion compared to stock(high compresion piston). and ordered the bbr exhaust today, didnt have it yet but hoping it will clear things up.the stock header is tiny,my x4r pitster header is way bigger and it is stock too.

dood · 02-11-2008, 09:41 PM

It's not the head pipe that will give you the more top end. It's the whole system. Plus the OEM pipe weighs a ton and is pretty restictive. You'll have to go up on the jetting when you install your new exhaust.

02-10-2008, 08:16 AM	#1 (permalink)
mx571 1st Gear Member Join Date: Nov 2006 Location: montgomery,al Posts: 223	dent in pipe? i have a 03 crf150f with a 175 kit,rev box,modded clutch. i have changed the jets but i dont have any topend.it goes dead after the midrange.the plug is very lean.last night i noticed that it looks like there is a bend or dent in the header right after where the pipes meet(towards the muffler side).anyway dont know if the dent is supposed to be there or it is damaged but what do you guys think could that take away my topend?

02-10-2008, 08:33 PM	#3 (permalink)
mx571 1st Gear Member Join Date: Nov 2006 Location: montgomery,al Posts: 223	Re: dent in pipe? the bbr rev box actually did help,it was worse before that. no its a brand new kit and we just got the bike. the motor was pretty worn out when we bought the bike but it still had topend and now it doesnt. maybe the stock exhaust is too restrictive,maybe the bbr exhaust will clear it up.

02-11-2008, 07:38 AM	#5 (permalink)
bat999 2nd Gear Member Join Date: Dec 2006 Location: Greensboro, NC Posts: 370	Re: dent in pipe? Bent valve? Broken valve spring? How much compression? Did you say that the motor was bad off when you got it???

02-11-2008, 08:46 PM	#6 (permalink)
mx571 1st Gear Member Join Date: Nov 2006 Location: montgomery,al Posts: 223	Re: dent in pipe? no bent valves or broken. lots of compresion compared to stock(high compresion piston). and ordered the bbr exhaust today, didnt have it yet but hoping it will clear things up.the stock header is tiny,my x4r pitster header is way bigger and it is stock too.

02-11-2008, 09:41 PM	#7 (permalink)
dood 3rd Gear Member Join Date: Sep 2006 Location: Washington Posts: 2,029	Re: dent in pipe? It's not the head pipe that will give you the more top end. It's the whole system. Plus the OEM pipe weighs a ton and is pretty restictive. You'll have to go up on the jetting when you install your new exhaust.

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