Spark Plugs - What type to use?

[diebythereaper]

Hi lads,
My mate has just got a GK76 and we are having difficulty with the type of plugs to use...

Here's the story:
I have a GK73 and I use CR9EK plugs in it - my engine number is K707 - 124779
I also have an NGK plug guide book so I took it out and looked at suzuki 400's, Bandits are using either CR8EK or CR9EK and the only listing for a Gsxr 400 I could find is for a 400H and plug number C8HSA

Considering my mates bike is a GK76 we went out and got the CR9EK's that I use. We took out the plugs in the GK76 to find that they were C7HSA (hotter type for 400H). So assuming the incorrect plugs were fitted we then proceeded to fit the CR9EK's but discovered the they were 10mm longer than the C7HSA's we took out ??????

Which do I fit?? Engine number in GK76 is K7909 - 104269, what is the correct type plug?? I dont know and if we fit the longer type plug we could hole a piston. I think the CR9's are correct and that some mechanic who had the bike before fitted the wrong plug. What do ye think???

[Variablevalves suck]

All the info you need-
http://www.400greybike.info/newforum/vi ... 53&t=11538" onclick="window.open(this.href);return false;

[diebythereaper]

I found where it says CR8EK so thanks for that, Im going to run the cooler CR9EK's that I run in my own GK73. Unless someone advises me otherwise??

Does anyone have a GK76 and can compare their engine numbers to the my mates GK76 (engine number K7909 - 104269) so that I defo know its a 76 engine and hasnt been changed at some point?? The bike is not mint so it could have been changed and we dont know.....

Thanks,
Karol

[Variablevalves suck]

I think the book says CR9EK but they run better on the 8.
What engine do you think it might have in? Apart from the early slabby that has a two peice cover on the right side (like a 750) the rest of the models hang from the cylinder head.

[diebythereaper]

I havent a clue what engine is in it,only for the spark plugs I would say it is the original engine but bike is fair from immaculate so it wouldnt surprise me if it wasnt the original.... engine numbers begin with K7909 and the right hand side casing is the same single piece one as my GK73 engine (engine number is K707)

If it had the same numbers as my engine id just put in the longer plugs but you can imagine how worrying it actually is to find shorter spark plugs in the engine when you believe that longer ones should be in it. VVS what engine numbers are on your bike? What model is it??

Thanks

[Variablevalves suck]

Not got a 76A, just a 73 a few b4's and half a slabby that i got as scrap, going to be a cafe racer when i get to it.
The longer plugs are correct for the 76A, why dont you look down the plug hole and it should be clear if the old plugs are short as the threads will be black halfway down.

[diebythereaper]

Very good idea, its just hard to see down with everything in the way, ill have a look tmrw, thanks mate!

Anybody shed some light on the subject with their own engine numbers??

[mattley87]

Yep. sounds right k7909. Have ran both 8 and 9's on my 76 with no problems. hth.

[diebythereaper]

Great stuff,
I'll take it so that all GK76's are K7909, Anybody else confirm that for me once more please??

Then away we go....

[mattley87]

That's a 76 engine


that's another


Sorry the pics are crumby.