Yamaha Starbike Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hey all I replaced my plugs with the iridium BPR7EIX and it ran like crap, bogging down on acceleration etc, going to put the old plugs back in tonight. Anyone else have this issue?

Bike is a '05 vstar 1100 xvs1100a classic.
 

·
Premium Member
Joined
·
345 Posts
My first guess is the gap was incorrect. You'll want to read up on what the gap is supposed to be and verify your iridium plugs were set correctly. If adjustment is needed, do not try to wedge off the center electrode. Use a proper tool and then verify. Just a guess, though.

VStar 1100: .028" - .031"
BPR7EIX: Looks like they come stock around .032"

Just a hunch that's your issue.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #3 ·
My first guess is the gap was incorrect. You'll want to read up on what the gap is supposed to be and verify your iridium plugs were set correctly. If adjustment is needed, do not try to wedge off the center electrode. Use a proper tool and then verify. Just a guess, though.
Gap should be the same as stock and I was told they came pre gapped... I had checked with one of the wedge style tools and it was at 0.76 / 0.030 which is withing tolerance as per the manual.

Should I go smaller?
 

·
Administrator - "Loose Nut" - Bandera, Texas
2001 VS1100 Classic (sold), 2006 HD EG(totaled) 2006 Vulcan 900 and 2019 HD Freewheeler (current)
Joined
·
14,868 Posts
Always check gap on all new plugs, pre gapped or not. Plugs get knocked around a lot between shipping, stocked on shelf, etc. Did you remove the end ball screw. If not the plug boot won’t totally set.

Light Product Automotive tire Font Line


It’s also an issue at times the plug wire will pull from boot, check that also.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #6 ·
Always check gap on all new plugs, pre gapped or not. Plugs get knocked around a lot between shipping, stocked on shelf, etc. Did you remove the end ball screw. If not the plug boot won’t totally set.

View attachment 120653

It’s also an issue at times the plug wire will pull from boot, check that also.
I did check the gaps and they were at 0.76 / 0.030. I also removed the cap. The plugs wires are secured to the plugs.
 

·
Administrator - "Loose Nut" - Bandera, Texas
2001 VS1100 Classic (sold), 2006 HD EG(totaled) 2006 Vulcan 900 and 2019 HD Freewheeler (current)
Joined
·
14,868 Posts
Let us know after you put the old ones back in if it runs better. I have run iridium plugs for years and never had an issue.
 

·
Registered
2009 650 classic white
Joined
·
485 Posts
May I suggest that you might have gotten a bad plug. I have bought new plugs and had one of them cause a miss in the engine. Yes a new plug was bad!
 

·
Registered
'18 SVTC
Joined
·
1,048 Posts
May I suggest that you might have gotten a bad plug. I have bought new plugs and had one of them cause a miss in the engine. Yes a new plug was bad!
Same here, one of 4 new plugs was bad right out the package. Engine wouldn't idle and throwing codes with them in, put the old ones with 100k+ miles on them and returned new plugs to parts store. (Car engine, but same principal).
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #12 ·
I swapped the one plug on my way home as it was running rough and rear cylinder wasn't firing properly, and it would even start. I will be putting the old plugs back in this afternoon, I wonder if the stator is going bad and not putting out enough power?

I have the bike a friends so headed there after work to try and use the old plugs, Ill check the boots while I'm there.
 

·
Registered
Joined
·
306 Posts
As an auto tech, I was always taught to never gap an iridium plug (Only to CLOSE the gap, since you're not touching the inside of the electrode in that case), as it damages the coating that makes them last 100k miles.

The incorrect heat range (Too cold, usually) can make a bike misfire badly.

I remember many moons ago I had an '87 Honda CR125 that misfired like crazy at full bore with a NGK V-Racing plug. It was a BR9EV. If I ran a BR8ES (Standard), it revved to the moon, pulling deep into 5-digit RPM's. Same gap on each. Never ran into another instance since, where just one heat range level change caused a high-load miss like this. Could've just been a bad plug. It happens from time to time ... and MUCH more often today with chinese counterfeit plugs all over the internet, namely Amazon and eBay.
 

·
Registered
05 Road Star Midnight Silverado
Joined
·
9 Posts
Spot on with this one. You always want to use the same type and if possible brand it came with. As much as we all don’t like to hear it the engineers that design the engine use the plug type specified because it has the correct characteristics for how that engine runs, mostly resistance.
As an auto tech, I was always taught to never gap an iridium plug (Only to CLOSE the gap, since you're not touching the inside of the electrode in that case), as it damages the coating that makes them last 100k miles.

The incorrect heat range (Too cold, usually) can make a bike misfire badly.

I remember many moons ago I had an '87 Honda CR125 that misfired like crazy at full bore with a NGK V-Racing plug. It was a BR9EV. If I ran a BR8ES (Standard), it revved to the moon, pulling deep into 5-digit RPM's. Same gap on each. Never ran into another instance since, where just one heat range level change caused a high-load miss like this. Could've just been a bad plug. It happens from time to time ... and MUCH more often today with chinese counterfeit plugs all over the internet, namely Amazon and eBay.
 
1 - 16 of 16 Posts
Top