Author Topic: Unleaded fuel, fit hardened valves and seats ?  (Read 556 times)

Offline oceanobsession

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Hi folks , first post , just wondered what are choices these days with no led in the  fuel , can you still get additive or is it best to have the head fitted with hardened valves and seats , standard fuel would burn out valves and seats , is that the case , phil.

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A7SS

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Re: Unleaded fuel, fit hardened valves and seats ?
« Reply #1 on: 03.09. 2021 06:30 »
I've been running bikes and other vehicles without modification since unleaded petrol was introduced without any problems. If your bike needs new valves and seats, of course fit new ones. If not, I wouldn't bother.
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Offline BSA_54A10

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Re: Unleaded fuel, fit hardened valves and seats ?
« Reply #2 on: 03.09. 2021 07:04 »
Already in there
Valve recession only happens under lean burn conditions at 30,000 feet .
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Trevor

Offline Butch (cb)

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Re: Unleaded fuel, fit hardened valves and seats ?
« Reply #3 on: 03.09. 2021 08:58 »
I continue to use Castrol Valvemaster octane booster and lead replacement in my iron headed engines. It might well be snake oil but it's cheap enough in the quantities I use.
Warning - observations made by this member have a 93% unreliability rating.

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Online Triton Thrasher

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Re: Unleaded fuel, fit hardened valves and seats ?
« Reply #4 on: 03.09. 2021 10:01 »
My iron head on another popular make of 650 twin got seriously recessed inlet valve seats, back in the good old days when the petrol had lead in it.

Offline muskrat

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Re: Unleaded fuel, fit hardened valves and seats ?
« Reply #5 on: 03.09. 2021 21:21 »
G'day Phil,  *welcome*
Your A7SS will be OK. The valve seats will handle it. The guides won't be affected at all.
My A7SS ran (raced) for years on methanol (no lead in that) without problem.
What year is yours?
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
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