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iridium plugs
- Thread starter rickieh
- Start date
Royboy
many roads, little time
- Messages
- 1,079
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- 63
I run them in both the 650 and the 500. Somewhat less prone to fouling but doubt the horsepower claims. Probably not worth the extra $.
TeeCat
One-Mik Wonder
I have tried them, but like any other tool, they're the "right tool for the right job"; some here feel that any of their benefit is lost on a wasted spark system, such as ours. Do a search on "wasted spark" and "iridium" and you may turn up some hopefully helpful material.
Having said this, no plug will be of optimal value unless your charging and ignition systems (particularly coil(s)) are top flight. Also, be careful of using iridium plugs without using a correspondingly stout coil(s) and wires/caps, as your bike's start-up and cold performance will suffer, since iridiums need more juice to fire and need to be hot to perform optimally. (I learned this through first-hand experience during a SSSA (Spontaneous Self-Stupidity Assessment).
TC
Having said this, no plug will be of optimal value unless your charging and ignition systems (particularly coil(s)) are top flight. Also, be careful of using iridium plugs without using a correspondingly stout coil(s) and wires/caps, as your bike's start-up and cold performance will suffer, since iridiums need more juice to fire and need to be hot to perform optimally. (I learned this through first-hand experience during a SSSA (Spontaneous Self-Stupidity Assessment).
TC
pamcopete
Ride.Enjoy.Life is Simple
Here is a chart of a series of runs I did with my '81/H. The final run was with the iridiums and you can see an increase is gas mileage. If you increase gas mileage without adjusting the mixture leaner, then you will also gain some Horse Power because the engine is working more efficiently. 2 horsepower increase would not be out of the question. In this case I actually increased the main jet size.
Note: I do not sell spark plugs.
Note: I do not sell spark plugs.
hi guys... i,d probably run these plugs purely for no fouling,,, but at the moment its not a problem ... ,,,,,,in australia my local guys want $28 each... so i will be buying some frome mikes when i order some other must have items regards oldbiker
ippytattoo
Just another grumpy old hack.
Ouch! $28 each... I get them locally in the states for about $7 each at my local auto parts store. I wonder how much it would cost and how long it would take if I were to buy some here and send them over.
DirtyErnie
Renaissance Hick
in my '80 I'm running the irridiums with the Part #17-6803 high-output TCI replacement coil. Rigged up wires with MSD SuperConductor bulk wire, right now I'm testing them with a .050" gap, so far so good. Just about to take another mileage run today
E
edit: ~46mpg today
E
edit: ~46mpg today
Last edited:
650performance
XS650 Addict
I have experience using these (IW-27's usually) plugs in XS6650-based race engines, and I can say with complete confidence they are the absolute best plug available ... never foul, don't need adjustment, no misfires even at 11+ compression ratio.
Also use them in RZ350 street bike. Same deal ... never foul, fire today's crappy, water-laden gas just fine and never need adjustment nor cleaning.
I change them out once a year just because.
Also use them in RZ350 street bike. Same deal ... never foul, fire today's crappy, water-laden gas just fine and never need adjustment nor cleaning.
I change them out once a year just because.
whynot2
XS650 Enthusiast
Just put them in a '75 engine, BUB 2into2, jetted BS34's. I like them. It runs stronger, and smoother. It's the smoother part I like the most, especially at low rmp. I would not be surprised if it did pick up a couple of hp.
whynot 2
whynot 2
DirtyErnie
Renaissance Hick
Update: finally got the carbs tuned well. 56.4mpg last night on the city freeways. There's so much power from the ignition I really can't get the bike to idle under about 1,600rpm once it's warm. Final jetting is 47.5 pilot, 147.5 main, Heiden needles in 2nd slot.
ProSimex
XS650 Addict
I dropped em into my more or less (at the time) stock 74, cus they were the only ones I could find at crappy tire that would fit.
They haven't fouled in 4 months unlike the regular ones.
They haven't fouled in 4 months unlike the regular ones.
I have an almost bone stock 81 with the AC AP63 plugs, platinum tips on the center electrode. Last fill up got 59 mpg. About $5 a pair at Wal Mart.
The only thing not stock is the air filters. The ones in it the filter element crumbled apart. Cleaned them off and wrapped with one layer of green foam that went around the airfilter in my old garden tractor. Foam wetted with 50-50 mix motor oil, gas.
Runs well, maybe a bit lean. Ought to do a bit of carb work. The idle mix screw plugs are still intact.
Leo
The only thing not stock is the air filters. The ones in it the filter element crumbled apart. Cleaned them off and wrapped with one layer of green foam that went around the airfilter in my old garden tractor. Foam wetted with 50-50 mix motor oil, gas.
Runs well, maybe a bit lean. Ought to do a bit of carb work. The idle mix screw plugs are still intact.
Leo
CDNTX650
XS650 Guru
high idle has nothing to do with "power from the ignition"....air leak or advance problems or carbs out of sync
pamcopete
Ride.Enjoy.Life is Simple
Generally speaking, you will pick up 2 HP just by changing the plugs. Any plugs will do.
If your bike is fouling plugs, it's not the stock spec plug at fault, there's a problem with your bike. I've never fouled a normal NGK in my 650 or any of my 4 strokes, 2 strokes yes, but never in a 4 stroke.
DirtyErnie
Renaissance Hick
I checked all that, all that is good. The only change I did make that caused the idle speed to increase was gapping the plugs to .050". Kung-Fu coil, copper MSD wires, NGK Iridium plugs. I only changed one thing at a time, and that was plug gap.
It starts like a dream, idles clean, pulls HARD to redline, and gets good mileage on a race cam. I'm not changing anything because my idle is 400rpm fast.
EK
I'm not changing anything because my idle is 400rpm fast.
EK
It's cool it's running so well but the idle speed stops have no effect on anything but the idle speed. I wouldn't worry about breaking anything by fixing the idle rpm.
DirtyErnie
Renaissance Hick
I can stick a feeler gauge between the idle speed stop and the idle screw... I'm straight out of downward adjustment on my idle speed. It's not that I don't WANT to decrease it, it's that I CAN'T get it any lower. If you think of somehow that I might be able to, I've tried it. no exceptions.
Have you had the throttle shafts out of the carbs? If so you might not have gotten them back in right and they can't close completely.
Leo
Leo
