Go faster

grumpy225 Posted February 6, 2015

On my SIP speedo/tach I was hitting about 360f on the CHT (at the plug) while running at WOT @ around 6600rpm Not having run a CHT for an everyday bike I was wondering if that sounds inline with what others have found? RT205, 19deg btdc, PHBL24 95main, 22 needle on 3rd clip down, ram air, MDB big bore exhaust. Vader19 Posted February 6, 2015

Yeah. running wide open at relatively lower RPM like 6600 sounds about right.. if you were to increase the revs you'd see it drop. I always cool it down if it hits 400.. some guys go up to 450 but I'm in no hurry to seize a top end... and don't find myself at or over 400 that often. Have you got an EGT on that bike? grumpy225 Posted February 6, 2015

No, wish I did. If I could figure out the values on the for the CHT in the speedo, I think I could add a resistor in the circuit to make it handle the higher numbers for the EGT. Then just know what the multiplier is and it would be good to go. Vader19 Posted February 6, 2015

That would be nice.. but you have to pay attention to the thermocoupler.. there are ones for analog, others for digital, grounded, ungrounded etc.. compatibility is key.. here's a nice info source.. EGT reacts much quicker though.. much quicker.. it's def worth the investment. http://www.alcorinc.com/index.php/learning-center/ Solerunner1 Posted February 6, 2015 Bell's book says you can pull max power up until 205C/401F, but in his wording he appears to call 218C/424F and above entering the meltdown zone. Pretty much in accordance to what Vader says. Anything above 400F I would consider danger. The one thing I like about measuring at the spark plug is that it's a solid and repeatable connection to accurately compare notes between riders and bikes. I'll be adding them to several bikes this season, so hopefully learn a lot more on temps. I've read various opinions, pro and con, on both CHT and EGT gauges. They both seem to have their strong and weak points. Vader19 Posted February 6, 2015

On 2/6/2015 at 5:23 PM, Solerunner1 said: They both seem to have their strong and weak points. I agree... as we know.. best is to just have both. grumpy225 Posted February 6, 2015

On 2/6/2015 at 5:23 PM, Solerunner1 said: Bell's book says you can pull max power up until 205C/401F, but in his wording he appears to call 218C/424F and above entering the meltdown zone. Pretty much in accordance to what Vader says. Anything above 400F I would consider danger. The one thing I like about measuring at the spark plug is that it's a solid and repeatable connection to accurately compare notes between riders and bikes. I'll be adding them to several bikes this season, so hopefully learn a lot more on temps. I've read various opinions, pro and con, on both CHT and EGT gauges. They both seem to have their strong and weak points. Ok good to know because I'm hard on the throttle and 360f is the highest temp so far. Doing 1 mile + straights. Feels crisp in the response also with no loading up or weak spots. I only have 68 miles on the top end so I still have a little way to go before it's broken in. Spiderwebb Posted February 8, 2015

If I downshift at 50mph for a hill my CHT drops 50 plus degrees. At top of hill doing 60mph temp are back up near 400 F. A quick downshift and some clutching / blimping thrortle to cool it down I coast down hill while leaving throttle at half or higher using rear brake to keep speeds down. All of which you do I bet Vader19 Posted February 8, 2015

For my own edification, I'm going to do a test with these two CHT sensors.. one is the 10mm type on a cylinder stud, and the other is screwed directly into the head.. I want to see what difference I get.. then I may get a 14mm plug ring and compare that to each of the others.. I have had the plug sensors come loose and never liked them.. I'll need to mill a little area for the 14mm sensor, as they can be a hassle to screw the plug in.. Also, I don't like using the 14mm type with the plug's crush washer as the sensor raises the plug all that much further out of the dome.. and I don't like cutting the crush washer off the plug to compensate either, as the sensor ring really doesn't act the same as the plug's crush washer.. Anyway, when I get to it, I'll report my findings.. a fried on another forum did extensive testing between sensors on all 4 studs, the spark plug and I think direct into the head.. IIRC the biggest difference between spark plug sensor and stud mounted was 15 or 17 degrees (the stud furthest from the center of the head) and the least difference was 3 or 5 degrees (the stud closest to the center of the head) Don't quote me on those numbers.. I need to find the thread.. but I think I'm correct. ps.. Thanks to Travis for the use of his custom tap.. the sensor screw is a weird size... not a standard size grumpy225 Posted February 9, 2015

Clever to tap the sensor in to the head. Vader19 Posted February 9, 2015

I'm not sure how much material are on other Lamrbetta heads like stock or BGMB RT etc... but the RB has a good healthy, thick section right there next to the plug that was a perfect candidate to be drilled and tapped. I'm looking forward to seeing simultaneous comparative readings. gone Posted February 9, 2015

I run up to 426 degrees grumpy225 Posted February 9, 2015

On 2/9/2015 at 1:31 AM, Vader19 said: I'm not sure how much material are on other Lamrbetta heads like stock or BGMB RT etc... but the RB has a good healthy, thick section right there next to the plug that was a perfect candidate to be drilled and tapped. I'm looking forward to seeing simultaneous comparative readings. The rt head has a lot of material to it On 2/9/2015 at 3:00 AM, upjettr said: I run up to 426 degrees That sounds a little on the high side according to everyone else. Hows the plug look?

• 2 weeks later...

GP Kevo Posted February 22, 2015

I would think that the flash point of whatever 2T you use should be considered when choosing your "max CHT" to run at. Vader19 Posted February 22, 2015

On 2/22/2015 at 5:52 PM, GP Kevo said: I would think that the flash point of whatever 2T you use should be considered when choosing your "max CHT" to run at. The flash point of Motul 710 is only 190.4F ... pretty low in comparison to what the heads get up to at times. TRs Posted February 22, 2015

Vader - Love the sensor install and can't wait to see the data from the study you are conducting! A multi-channel data recorder would be great to get all data points simultaneously... GP Kevo Posted February 25, 2015

On 2/22/2015 at 7:50 PM, Vader19 said: The flash point of Motul 710 is only 190.4F ... pretty low in comparison to what the heads get up to at times. Which is partly why I run Motul 800 Road Racing (Flash Point 525 F) grumpy225 Posted February 25, 2015

With 4.84 final drive I hit a solid 69 mph (ran out of road) and 360f on the CHT. That was sustained WOT for over a mile. I'd say it's jetted correct now. I could probabbly bump that temp up by jetting changes and gain a little top speed but to what end? It's fast enough for the riding I like and starts 1-2 kicks every time. Also on the topic of oil Yamalube R2 at 32:1 every time Vader19 Posted February 25, 2015

On 2/25/2015 at 6:46 AM, GP Kevo said: Which is partly why I run Motul 800 Road Racing (Flash Point 525 F) Copy that.. If I were running HARD all the time, I'd use 800, but for street riding the 710 does just fine.. and the lower flash point means it gets vaporized and I don't get gummed up.. I hear what you're saying.. I'd be interested in trying something with a flashpoint somewhere in the middle of 190 and 525.. that's a big jump. The Yamalube 2R is lower at 149F. Thanks GP Kevo gone Posted February 26, 2015

Amsoil Dominator: Flash Point 216.5 degrees jimmyb Posted February 26, 2015

I have been using the yamalube R2 as well, consistently and at a little under 3%(full mix cup). With a better sense of jetting i have had absolutely no problems.(knock on metal) My machines get ridden pretty hard. My fav is sitting on the freeway for mile after mile at speed. I like where my bikes are set now. Skippy Posted February 26, 2015

Is this the stuff you are referring to ? jimmyb Posted February 27, 2015

On 2/26/2015 at 9:11 PM, Skippy said: Is this the stuff you are referring to ? No sir. I havnt seen that bottle. Mine is red label with a couple dirt bikes racing on it. grumpy225 Posted February 27, 2015

Same here, The thing to realize is Yamaha are/were at the height of two stroke technology. It's the same oil their race team used. I've used it for years and years. No problems and cheaper than most any other. Skippy Posted February 27, 2015

Cheers, the search will continue then, and this stuff certainly isn't cheaper.

CHT question By grumpy225, February 6, 2015 in go faster Skippy Posted March 2, 2015

FYI. Yamaha just got back to me. Apparently you guys are the only ones that get that type, everyone else gets an ester based fully synthetic with a different viscosity and a much higher flash point of 485 F. I am also assuming from it's price that they follow you around and then measure and add it to your fuel when you fill up to save you getting oily hands! grumpy225 Posted March 2, 2015

On 3/2/2015 at 3:34 AM, Skippy said: FYI. Yamaha just got back to me. Apparently you guys are the only ones that get that type, everyone else gets an ester based fully synthetic with a different viscosity and a much higher flash point of 485 F. I am also assuming from it's price that they follow you around and then measure and add it to your fuel when you fill up to save you getting oily hands! It's been a while since I bought some but I don't think it's that expense (certainly no more than motul). I think it was about $1