plug choices???????

[mick355]

Hi guys, just fitted a set of dyna coils and leads to my '88 GSXR 750 to try and solve a few running dramas.
Question is what is everyone using for plugs with this combo. Do you have to run the std JR9C type plugs that cost heaps, or can you go to something like a D8ea. These plugs have the same iridium cross reference so I thought I'd give them a go at a quarter of the price. I know 8's are probably too hot but its winter here in OZ and im sick of spending a fortune on std plugs that I foul in a couple of kilometers.
Also how many turns out should the mixture screws be? I have read a few different things on the net, and if all set the same can the plug reading be heaps different. Or are my mixture screws just stuffed?

[Tone]

Hey Mick,glad to find out I'm not the only one bitching about the cost of those plugs.If you don't mind me asking what did the coils and leads set you back?And where'd you get them? I'm thinking this'll be an expense for me shortly.

[alfiestorm]

Does this mean JR9B's are expensive here in Auss I have yet to find out that one come to think of it I am still waiting for my bike to be released from customs.

Tone
I am soon to be having a set of acewell high output performance coils up for grabs complete with leads and caps they do the same thing as dyna stuff and they are american same as dyna

[Tone]

Sounds good Alfie,keep me in mind with them.And yeah,I recently replaced all four plugs (JR9C)at $16 a pot.

[cutcat]

Hi Mick, from my experience 9's are fine all year round in Oz. If you are having fouling probs I would first check your emulsion tubes. Where the needle slides up and down it wears the hole into an oval. You have to take the top off the carb, whip the slide out and look down the guts to the needle jet. If it looks oval instead of round, you will be running way rich and as a result will be putting your coils under load as it is harder for them to spark when the plugs are smothered with juice.
Hope this helps.;)

[cutcat]

Also another option as far as plugs go is to try the JR9A. It is a single electrode plug as opposed to the JR9C which is a twin(and considered a high performance plug and the shops will charge you for the privilige). I have run both in my GSXR and couldn't tell the difference. Also another option and possibly cheaper than NGK is the DENSO brand. I have used their equivalent and never had a problem. Its number is X27ETR and has a copper core and groved electrode.

[Tone]

Nice info cutcat,thanks.
I see you live in Camperdown...don't know a guy named Muz Wilson do you? Nothing to do with bikes though.

[Hillsy]

quote:Originally posted by cutcat

Also another option as far as plugs go is to try the JR9A. It is a single electrode plug as opposed to the JR9C which is a twin(and considered a high performance plug and the shops will charge you for the privilige). I have run both in my GSXR and couldn't tell the difference. Also another option and possibly cheaper than NGK is the DENSO brand. I have used their equivalent and never had a problem. Its number is X27ETR and has a copper core and groved electrode.


I had the same thing with my ZX9 - the recommended plug was a twin electrode jobbie which was like $12 ea......or I could go the single which was like $4. Tried both, no difference (on the street anyways), so I'm running the cheapie.

[mick355]

Tone I got the coils from PITSTOP PERFORMANCE on american ebay. $180AUD delivered and they were here in under a week. Got the leads from the same guy and from memory cost $35AUD delivered.
CutCat, I,ve repaced just about everything in the carbs except the needle and seat assembly and the mixture screws. Judging by the plugs the mixtures seem all over the joint when set out the same amount. The plugs also seem to get sooty really quickly if I let it idle for more than a couple of minutes

[Tone]

Cheers Mick,I'll look em up.

[cutcat]

Dunno Mick, I would screw the mixture screws all the way in and see how she goes. Maybe you are drawing in fuel through the choke circuit or something weird.
Also check your compression.