Spark plug heat ranges

[gsxrboy]

I recently had an experience which I would like to share with you all as it might save another one of us undergoing the same wallet raiding grief I had to undergo.

Firstly When buying a second hand bike do not take it as gospel thats it is as good as the seller tells you, he is trying to sell it and will mostly tell you anything.

You have to go with your gut feeling and buy or reject the bike at this point unfortunately so good luck!!

Secondly When you get your new bike home get the tank, seat and all plastics off and have a really good poke about to see what you have just bought, maybe you would have spotted what I missed.... Dont be afraid to ring a main dealer and ask for information if you are uncertain and believe something looks wrong.

Thirdly If you are going to do something do it to the best of your ability or dont bother, a bodge will bite back!! beware

I missed a small but crucial bodge that cost me £130 (Yamaha wanted £200) basically the bike was over fueling and to compensate the previous owner put hotter grade spark plugs in to burn the excess fuel, bad move.
The manufacturer spends hundreds of thousands of pounds in developing an engine and have worked out exactly what values and tolerances have to be used to make the engine perform as they have designed it, altering certain values can result in pretty horrific things happening.....

After riding it to work on the 5th day of ownership and giving it a right royal arse whooping it went pop, resulting in a just backed off the throttle seize, a big skid/snake up the road and a pretty knobbed off rider.

Putting a 5 grade plug in a 9 grade engine wont work all that well if you are thrashing it to within inches of it's life..... I rang yamaha and was told "running that engine on a bp5es will probably burn the top off the piston mate!!" See pic bellow.

I hope you learn something from my misfortune.

On a much lighter note may I wish you all a very merry christmas from the Brown family (may your misfortunes be tiny and your good fortunes huge!)

EDIT - This is the same picture I posted in an earlier post whilst still in the dark as to what had happened...

[divuk83]

Gutted, I once got my bike back from the garage and it had a B6ES plug instead of a BR10ES. That was odd enough, but when I rang the garage they couldn't work out how it had got in there as they didn't even sell the B6ES plug!

Dave

[tatters]

when my got my KR1-S one cyclinder was running on a BR10ES and the other one on a BR9ES, first thing l do when l get a new bike is to strip the fairing and tank off and check for things like that, did,nt stop the bike blowing up though.
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[Kickstart]

Hi

Using a 5? Ouch. Don't think I have seen a bike using anything less than an 8.

While going up or down one grade is probably worthwhile depending on the use, but going from a 9 to a 5 is likely to be lethal to the engine. The spark plug takes a lot of heat from the combustion chamber, and the 5 will take a lot less heat than a 9. Normally this would result in burning a hole in the top of the piston.

I would suspect that the previous owner just needed a new spark plug and didn't realise that there was such a thing as a heat rating. They just found one that was the right size and stuck that in.

Mind you a friend (mechanic for a living) had an old Volvo which became a pain to start. He bought some new plugs for it and went to fit them, then found that the car had the wrong plugs in it. The existing plugs were short reach ones while it should have had long reach ones. Ran far better after that.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[dandit]

sorry to poke my nose in but I am having trouble with my bandit in the cold should I change my irridium plugs back to standard for winter or could I try cr 8 or 7 ek standard is cr9ek
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WHAT DO YOU MEAN 100 MPH THATS IMPOSSIBLE I STILL HAD 3 GEARS TO GO OFFICER. Currently riding a naked cbr 600 and driving a 52 plate 2litre tdci mondeo

[Kickstart]

Hi

Going down to an 8 might help, but I suspect more likely your bike is set up on the lean side.

My 1200 Bandit is a pig in the cold now that it has been played with.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[dandit]

[pipnet11]

Thats a bugger. Agree with your advise though, I was conned when I bought my bike. Needed a rebuilt gearbox and the head taken off as the head gasket was dead. The bloke who sold me it had just cleaed the oil leaks away and had learnt how to change gears without making it crunch, which it did almost all the time. The work wasnt the problem, the fact that I had just payed £1200 for something that needed all this doing was very annoying. Didnt cause the sort of major problems you had, but could have done (gearboxes dont like having collapsed bearings )
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I love the girls that do, I hate the girls that dont, I hate the girls who say they will and then they say they wont, but the girl I like most of all and I think youll say Im right, is the girl who says she never has but looks as though she might. - Max Bygraves