RMZ450FIRST4T

Member
Sep 11, 2012
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Hi I'm new to this forum(as a registered member, been reading some of the threads). I'm sorry to go right to my problems but I'm desperate! I bought a RMZ450 2007 that has been standing for 2 years(last time started December last year), I'm waiting for new backweel and other ods and ends. I got the motor started and it was backfiring alot, header glowing bright red, almost white hot after only a couple of minutes. All simtoms point to it running lean exept for the fact that there is black smoke coming out of the exaust intermittently when revving it up. I know some theory about thumper engines but am no mechanic and don't want to open the motor if I don't have to. I think I also have to mention that I have a custom made exaust(seems like good quality but don't know about design). Can someone please help and give me some pointers as to what might be wrong(already cleaned carb).
 

BSWIFT

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N. Texas SP
LIFETIME SPONSOR
Nov 25, 1999
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The exhaust will glow when it does not have air flow across it, very common. You really need to check the valve clearances and inspect the valves. There are quite a few threads covering this, even if it is not your specific model it will still apply.
 

Ol'89r

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Jan 27, 2000
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BSWIFT said:
You really need to check the valve clearances and inspect the valves. There are quite a few threads covering this, even if it is not your specific model it will still apply.

After checking your valves like BSWIFT suggested, take your carb apart and clean out the pilot jet. If the bike has been sitting for two years, the pilot jet and possibly other jets are clogged. If the bike won't idle and pops and farts down low, it's usually the pilot jet.
 

RMZ450FIRST4T

Member
Sep 11, 2012
11
0
I already took out the carb and cleaned everything, everything is set to manual specs on carb. Is it possible that the factory settings with my aftermarket(made by a private guy, my fmf system is on its way, going to take at least two weeks I live in south africa) I just want to make sure it has got nothing to do with my engine as I don't want to open my head or motor(never opened a 4t before). Can it be the exaust.
 

BSWIFT

Sponsoring Member
N. Texas SP
LIFETIME SPONSOR
Nov 25, 1999
7,926
43
Checking the valve clearances is not that difficult even for a 1st timer. Lots of info on how-to. If the bike has NOT had the valves checked, they REALLY need it, not doing this could be costly.
 

RMZ450FIRST4T

Member
Sep 11, 2012
11
0
It's been a long time since I've been on this forum. Reason being I had trouble free riding since now. Few questions If someone can give me some advise please. My bike (RMZ 450 2007) is spluttering at high revs? Only high revs, otherwise running perfectly. Doesn't start as easy as it used to. What should I do? Shim valves, check sparkplug, check carb (jetting). And also I got the fmf factory 4.1 and fmf powerbomb exaust system. Can someone give me some advise on getting the most out of it by tuning the carb, at certain altitudes and temp? Jetting and so on? Any help wil greatly be apreciated.
 
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