Backfired on start up

[Whitty30]

Hi just gone to start me bike after about 3 weeks and it backfired on start up .I’ve not used it for 5 month because of covid but I do start it up for ten minutes every 3 weeks .I also put a drop of iPhone fuel stabiliser in as I have a full tank of fuel in.any ideas why it’s done this n will it damage my bike 😢

[Corringdon]

It is essential when you start any internal combustion engine that you run it until it gets hot otherwise condensation will form on metal parts. One of the main problems associated with this is emulsification of the engine oil. In your case it could be that condensation has formed somewhere in the fuel/inlet system and this has been sucked into the cylinder. Water does not compress and in cases can cause piston and con rod damage. The only easy way to check (without removing the spark plugs) is to see if the engine turns over normally on the starter.
Modern fuels in metal tanks do not need a fuel stabiliser.

[voodoo]

Define backfire.
It takes a hell off a lot of condensation before there us enough liquid to cause damage to the engine.
More likely your battery us not charged enough to rotate through tdc, hence causing a backfire. My bike is at 67.000km on it's first battery, and now starts to have difficulty starting the engine.

[Whitty30]

Yes it starts normally the battery has been on a trickle charger most of the time .after it backfired I turned the bike of then restarted it and everything seems fine it ticks over as normal .thank you all for your replies.

[Corringdon]

Originally Posted by voodoo

It takes a hell off a lot of condensation before there us enough liquid to cause damage to the engine.

Quite correct, Mr Voodoo, but as Mr Whitty said he has only run the engine for short periods over a total of 5 months. Condensation will not evaporate in an enclosed space and could possibly accumulate over a period of time. It was only a suggestion on my part as even a small amount of liquid mixing with the fuel could cause a backfire. I was unaware when posting my original reply that Mr Whitty had turned the engine over after the backfire.

[Gramps99]

Its a very very good engine that Mr honda built for the CR , it wil run and run.
Anything unusual like a single backfire can be put out of your mind as long as it does not repeat. If the bike runs well afterwards, just enjoy it.
Have a look at fortnine on youtube. He explains the issues with modern fuel, and with fuel additives.
I do prevent vermin having access to the exhaust and I also run my bike every now and again in the Winter, and have done for decades.
As for hydraulic lock,  you havn't ridden through any 3 feet deep streams have you ?

[Whitty30]

Lol no I don’t do streams. I’ve just been out on it n it runs like a dream mind it should do really it’s only done 6k 2019 model .thanks again 👍 oh just a quicky what oil do yous use coz It’s due an oil change and was wondering if I’d be ok putting 10w40 instead of 10w30 in.

[Corringdon]

Why not stick to the manufacturer's 10W30 recommendation. I use Silkolene Comp 4 10W30 and find it to be an excellent oil. The oil manufacturer, Fuchs, claim it is specially made for the latest Hondas. Castrol Power 1 10W30 is also an excellent oil. Perhaps you should initially let the dealer do the oil change especially as your bike is still under warranty.

[Whitty30]

Warranty runs out next month 👍

[Crosspurpose]

Similar age to mine then, though nearly double the mileage! I changed the oil in mine last year anyway because the dealer was shut during the first lockdown. I also use Silkolene Comp4 10/30 - it’s actually what the supplying dealer put in from new. I get mine from Opie oils.
I don’t start mine up at all when it’s laid up. I can’t see what good it does; it’s not a human needing exercise. In normal times I would ride it in a dry salt-free day but COVID has knackered that. The thing with these oil threads, should I run it occasionally when laid up or not or should I let it warm up before riding off or ride off immediately from cold is that there are no definitive answers as to what is best. Until such time as two identical bikes are run on the same journeys over many miles and years we’ll never really get beyond opinion. Even if bike x don’t d 200,000 miles without issue, who is to say it wouldn’t have done 300,000 miles if the opposite opinion had been adopted? It’s your bike, do what you think is best.