CB400 fuel mix

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Kat22
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CB400 fuel mix

#1 Post by Kat22 » Sun Jul 15, 2018 7:00 pm

Spoke to a guy at a classic bike show today who’s suggested i should use super unleaded petrol with an additive to make the peteol more like a 4 star leaded type petrol. He says this is because the engines were made to run on leaded petrol and long term use of unleaded could damage the carbs.
What kind of additive would you guys suggest or any other advice you may have would be welcome.

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Re: CB400 fuel mix

#2 Post by megawatt » Sun Jul 15, 2018 7:28 pm

Never had any problems running my 400/4 on unleaded.
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Re: CB400 fuel mix

#3 Post by Mickly » Sun Jul 15, 2018 7:52 pm

Wouldn’t it be the valves, not the carbs that would be an issue?
Engines built to rely on lead in petrol suffer with eroded valve seats if using unleaded fuel, those with hardened valve seats take leaded or unleaded.
So the question should be whether the CB400 has hardened valve seats or not?
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Re: CB400 fuel mix

#4 Post by Tango » Sun Jul 15, 2018 8:03 pm

Honda were running on unleaded from the early 1970's.......my first bike (Honda CD175) was designed for unleaded......and that was 1975...... :wink:
I think the fella was telling you porkies...... :wink:
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Kat22
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Re: CB400 fuel mix

#5 Post by Kat22 » Sun Jul 15, 2018 8:46 pm

Thanks folks. Sorry , yes youre right it was valves he mentioned. Think I’ll just stick to bog standard unleadeed petrol, won’t be doing huge mileage on it anyway, I’ve got my tiger for that lol. The 400 4 is just for a bit of fun and classic events etc