Trying to read plugs on pump gas is near inpossible get it on a dyno & get a/f checked , Al is right bigger cams might go back wards i put bigger cams in a efe i had a while back & before & after dyno showed they cost hp over stock efe cams & they wern't real big cams either .

Mark

Be afraid YOU could be next

Go your hardest sunshine

They must be 2 exhaust cams then Al. I have the actual figures here but some don't mean much to me. written on some scrap paper.

Inlet - 327 lift, 245@.040, 15/50, 107.5 degrees

Exhaust - 330 lift, 245@.040, 14.5/ 50.5, 108 degrees

That mean anything to you?

The inlet you have has the duration but not enough lift, in my opion. The factory race kit inlet has the same duration but .350" lift and 12.5:1 comp. The exh cam is the same as the kit cam but set at a lower lobe centre of 102.5.
The inlet you've got may work better with more comp and lower lobe centre. Again kit inlet cam is set to 100deg lobe centre, with 12.5:1 comp.
Both of those lobe centre settings are for a qualifying/sprint set up.
The "F,G,H" GSXR750's had 10:1 comp on a good day.

Going by the lobe centre numbers with the std cams, this would be an import engine, is that correct? My 'Limited Edition' (an import) had the same high numbers, I replaced those cams with "'88 J750" cams set to sprint specs, bored std carbs to 33mm etc. The bike performed far better than std. Just need to bump the comp and build a replica factory F1 exhaust.

The other way to fix your topend issue is an 1100 engine, 1216cc minimum and 1 of 3 different spec cyl heads I have. Carbs and pipe and no more top end issues.

Al.

Hehehe Al, fix your top end issue, put a big block in it. Yep that's the way I am going. It's more just the not knowing why that causes be problems.

I've organised a 1370 JE piston kit from USA and a value kit for the bandit engine. 26/30 values.

I've got a 31/27 'R750' head underway that would be just the ticket on that. I was going to use it on a 1500 EFE street bike, but for the right money I can change my plans.

Bump up the comp in that 750 and should go better with that inlet cam.

Al.

That'd be nice, but I can't justify spending another $800-$1000 on new pistons and a rebore to make a 771cc when the money would be better spent in your pocket for that cylinder mentioned.

Too many things can effect color.

Chopping and killing the motor on my bike would cut the oil supply to the turbo which (assuming is now under full boost) is a real bad idea to begin with.

Think of a spark plug as a data logger. It has memory that can stored for a very long time, even when riding.

Assuming you start with a brand new set of plugs, make your pass under full power. Do not be concerned about turning off the motor or riding the bike back to the trailer. None of this effects the plug. What we want to look at is how the heat transferred into the plugs base. The deeper it penetrates, the more heat or leaner.

Normally you would look at the side of the plug, along the threads. Count how many threads the heat has discolored.

I do not know what would be your target for your setup but guessing there are some people who would be able to help you.

Do not assume that all 4 plugs will look the same. Plugs are cheaper than motors. Make adjustments, change all four, then retest.

Nitrous seemed to play into this and is why I am looking at using a wideband sensor.

If this is not clear to you, I can post a few pictures. Just keep in mind that my setup will be different than yours.....


Good luck with it.

put the bloody thing on methanol with some normal heat range plugs and maybe some of us old gits will be able to read the plugs . or the easy way if you dont want to do the dyno thing is one of them inovate loggers with o2 sensors no more guessing!.slim