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2008 fz1 sputtering on take off when not up to temp

JayredZ1

JayredZ1

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Joined
May 30, 2025
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25
Age
40
Location
Eugene oregon
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When I start the bike up and if I don't warm up long enough it sputter and stutters on take off mainly when I give it a little too much gas, it only happen when I first start it up and it doesn't warm up enough after that it never happens again at least not until it cools down and the same scenario happens again. I read somewhere possibly thermo wax unit? Anyone have any similar issues?
 
The thermo wax unit just increases idle speed when cold so shouldn't have much effect when opening the throttle. Is the cold idle speed faster than warmed up idle speed? If so, the thermo wax unit seems ok.
 
Yes cold idle and warm idle seem fine, if I let it get to 160 before taking off it does t happen, I also read injectors or potentially TPS? But it only happens on this very specific occasion... I can live with it but it would be cool if I could nail it down to a specific issue I have no check engine lights and no other issues at all.
 
JayredZ1 said:
When I start the bike up and if I don't warm up long enough it sputter and stutters on take off mainly when I give it a little too much gas, it only happen when I first start it up and it doesn't warm up enough after that it never happens again at least not until it cools down and the same scenario happens again. I read somewhere possibly thermo wax unit? Anyone have any similar issues?
Click to expand...
A couple thoughts. When was the last plug change? Also, try pull the coils to inspect and use a mirror to look inside plug hols for any moisture.

I know the gen 2 (at least mine) was sensitive to the standard ngk plugs going longer than recommended. RMATVMC used to sell the iridium’s cheaper than standard, fyi
 
cannedSardina said:
A couple thoughts. When was the last plug change? Also, try pull the coils to inspect and use a mirror to look inside plug hols for any moisture.

I know the gen 2 (at least mine) was sensitive to the standard ngk plugs going longer than recommended. RMATVMC used to sell the iridium’s cheaper than standard, fyi
Click to expand...
I'm not sure I picked it up at 19k I'm at 23k now and not sure if they have ever been changed lol
 
I use the standard NGK CR9EK (4548). The Yamaha schedule is 8K but that seems way over conservative. I changed mine at 44K and they were actually still in spec. I usually change my FJR around 32K and it's at the high end of the gap spec but it's also a single electrode plug.

The FZ1 is kind of a pain to change plugs on.
 
I didn't think changing plugs was all that bad in my experience, but I do recall ignition coils failing, insulators leaking, on some of the early years of gen 2 COP setups. My coils never gave any trouble, but I've replace a ton of them on other vehicles.
 
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