| Author | Message | ||
     Zecca |
Saturday I changed the the original spark plugs by iridium.. The bike had less vibration in the engine! That makes no sense !?!!? I felt loss of torque at low and medium rpm the gap is 0.8 http://img8.rivercrane.jp/photo/article/35/1242457 550035L.jpg the compression ratio could have been lessened? by the difference in electrode size and quantity or is that irrelevant? | ||
| Boogiman1981 |
wrong spark plugs... the motor was designed for the open top ones. you are not getting the same combustion properties. | ||
| Zecca |
can damage the engine? | ||
| Boogiman1981 |
don't know enough about the difference in the combustion profile to answer that question definitely but i would get the correct plugs in there soon. | ||
| Sparky |
0.8 what units gap? Maybe you meant 0.080 inch (eighty thousandths) and if you did, why set it there? | ||
| Syonyk |
My guess is 0.8mm. According to The Google: 0.8 millimeters = 0.031496063 inches A bit small for a modern ignition system... what's the stock gap? | ||
| Boogiman1981 |
i wanna say 60thou per side? may not be remembering correctly though | ||
| Zecca |
original is 0,8 or 0,032 inches | ||
| 1_mike |
The Iridium ground strap is far enough over that the spark is unshielded almost as far as the stock plug. Why the loss in power....recalibrate your butt dyno...? The only difference is the electrons are "suppose" to travel easier in the fine wire electrode. This is the reason they were trimmed way down from their original design years ago. Both the diameter of the center and the tip of the ground strap has also been trimmed way down. Though....many high perf. auto ignitions recommend "not" using them in high performance applications. Not positive why except for the difficulty of the power traveling in that particular metal (note the "supposedly"). Mike | ||
| Dennis_c |
I could go for less vibration but not less power. the answer to your question is ?,?? | ||
| Rsh |
I was trying to find some iridium plug info, I have not even found a listing for the 1125. NGK has iridium plugs for the XB and Blast and older model Buell's but not the 1125, Nippon Denso same thing, no 1125 listing What cross reference did you use? | ||
| Boogiman1981 |
those are not the right plugs for this engine and it's combustion chamber and ignition system | ||
| 1125rcya |
Could someone put this spark plug issue to light..What kind of spark plugs can we use and gaps? | ||
| Daggar |
The OEM plus work great for me. | ||
| Dcmortalcoil |
"those are not the right plugs for this engine ..." Boggi, where did you hear this info? If iridium plugs indeed are not proper for 1125 engine, I would take them out. Would like to know the source of this info though. I've been using Denso racing iridium plug IU01-27 rear and IU01-24 front on since 2004 on my XB9, XB12ss, and 1125R with no issue. BTW, IU01-27 crosses with NGK CR9EKB. The main reason I use it is because it suppose to last longer. Iridium tip won't wear down as fast as a conventional plug tip. | ||
| Boogiman1981 |
the shape/type of electrode that the stock plugs have are what the engine was designed to use. i don't have the research at hand at the moment. however the shape of combustion chamber the compression ratio the ignition advance curves fuel timing and power output all go into making a choice on the style of plug. there also could be in our case given it's a 4 valve head and indexing issue they ran into with a standard style spark plug that didn't allow for full power and/or detonation issues. if i can find an iridium/platinum/yttrium plug with the same shape as ours i am all over it due to the longevity that those precious metals would bring until then i will keep what Rotax/Erik found was best for the helicon engines. as for where i 'heard' it i didn't i know enough about IC engines from building and modding them for the last 15yrs to know that when a designed/engineer chooses a spark plug he does it for a reason. the brand is easily explained via marketing etc but the heat range and tip style in my experience are not due to compromises of the marketing type. | ||
| Kicka666 |
CR9EIX no probs here, it sparks & ignites the fuel on the compression stroke thats all I ask of it...... | ||
| Zecca |
we put the bike on the dyno today! 117.8 ~ 118.5hp. max torque 62 ~ 62.5 with iridium 119.9 ~120.8hp. max torque 65 ~ 66.3 using the used original spark plugs let's do more tests using a bigger gap on the iridium! I'll post the results tomorrow.. **I remind you that all fuel in Brazil have 20 ~ 25% alcohol mixed! may have different effects for the U.S. fuel? | ||
| Boogiman1981 |
never said bike wouldn't run however it will have an effect on it. will it ruin your engine? hopefully not. personally changing plugs really isn't that big of a deal. about every second oil change adds maybe 30 mins to the deal. | ||
| Zac4mac |
I'm at 27+k miles on Loretta. Little riding lately but the CREs last about 10-15 k miles. They actually wear out from the spark.. Personally, I think if you shim to "loose" with the cam shims. do a 25k service interval, not 12k, but the plugs only last 12k. Z | ||
| Skntpig |
The iridium plugs have a smaller electrode which increases the combustion chamber area. You are lowering your compression ratio a small but measurable amount by using the iridium. I'm sure it runs a bit worse because you used the wrong plug. (Message edited by skntpig on September 28, 2011) (Message edited by skntpig on September 28, 2011) |
