Went out for a test ride on the 800EX last week. It started hesitating under throttle. A burst of speed then bogs down. After the shop looked it over they said the spark plugs were dirty. As in cover in red clay dust(they showed me the plugs). It somehow passed the seal and the threads! Picking it up today but they replaced the plugs and it runs fine now. They scoped the cylinders and saw no damage luckily. Reaction from the collective?

Thanks.

[2015 Z Force 800 53/Trail EPS]

Not possible for anything to get by the plug's threads and seal..even left loose it would blast out more then it could ever pull in. You do have the Unifilter on it...right? If not, better get one and check that the stock filter hasn't lost it's top like others have.

Good morning!
Yes, sir, I do have the upgraded air filter. The mechanic said the airbox was clean. It's an anomaly, to say the least. Time will tell I guess.

[2015 Z Force 800 53/Trail EPS]

Good morning!
Yes, sir, I do have the upgraded air filter. The mechanic said the airbox was clean. It's an anomaly, to say the least. Time will tell I guess.

That's good..well,.. another CFM mystery

 

HOPEFULLY one of those single incident mysteries!

I'd have liked to see a picture of the old plugs

When you say, "I have the upgraded filter' do you mean a Uni or the CF Moto version of foam filter?

I agree that nothing gets past the spark plug seal and threads. The mechanic will have said that the plugs were that colour because that's all he saw. If he took the heads off I'll bet that the whole underside of head and top of piston was the same red shade. Wouldn't be JUST spark plugs alone with red clay dust.
The intake tract needs secure airtight fittings, proper foam filtration and that filter properly oiled with the right foam filter oil.
I keep being amazed at the number of people even in the business, who still don't understand how foam filters work and who still think it's fine to use K&N oil on them and tell their customers that 'advice', as one instance.

[2015 Z Force 800 53/Trail EPS]

Yeah I think I would pull the filter and with a flashlight and someone with their foot on the throttle, take a long, deep look into the intake track..even take some swabs and take a real look. Bet there's a leak somewhere..and bet no one at the shop even bothered to take a look.

I use the stock foam/paper air filter that my 2018 came with I like them all I did was add some oil works great and the paper is a good indicator to see if any thing is getting passed it. Mop