Just wondering why you say to use a hot plug. I run a cold and have never had any problems. I run byrons 30% in my MTE

Uh I just posted 3 posts above your that I am using O'donnell PLugs.. 77t is recommended..

Ease of tunablilty.. Hotter plugs tune easier for the less experienced.. I noticed a midrange hesitation with medium plug (97T), even when tuned on the ragged edge..

Makes sense. Thanks!

Thanks alot for the info, how about any of the Werks plugs?? Just got a Tebo Edtion off of a buddy and wanna run this motor this week at a invitational race here in Nc. No one running any of the Orion's here in NC so I have to order some plugs next week.

Werks or Sirio Plugs will be fine, virtually the same as Orion..

Thanks Scotty & PitPop, I'll let ya know how it goes this weekend. Do you a 7mm insert or something smaller??

so I'm getting a little better feel for this engine. I was really bothered by how far my top end needle was in but after trying 2 different carbs it appears that's where it needs to be. I'm about 2 1/2 turns out on top and close to flush on bottom. This is a street tune so its not 100% accurate.

7mm is fine.. we don't run anything smaller because otherwise Cody is too deep in the trigger all the time. It might not be a bad idea to run 6.5 if you feel you have enough power.

Re:.. the plug issue.. think of a hotter plug as advancing your timing. If it's not detonating, the hotter plug should be better. If it's super hot outside or it's detonating, you might need a colder plug. Mileage might be a tad better with colder plug but less power as well. Hotter plug will clean out better on the mid range. For our engines I definitely recommend the hotter plug because there is a gulp of fuel in the middle...

Thanks for sharing that

I've been checking this out on a few of my engines. I found out the position where the coil is attached to the housing relative to the headbutton differs with every glowplug. This means that the markings will be right in a new engine but can be wrong when you use a new plug. Not that i think it matters that much but i you want every % of power out of your engine you should check.
Out of 3 engines, all 3 engines had the markings to the exhaust (always install them like that) but 2 engines had the point where the glowplug coil attaches to the body at an 90 degree angle to the exhaust, instead of pointing towards the exhaust. All 3 had their plugs replaced in the past.

Hey there never posted in the orion thread before. I have a few questions for you guys. Whats your opinion on the Orion .21 abi 3 port(with the ceramics etc.) engine? I have a buddy who has one and im just curious here. What temps should these mills run around, also life longevity(speaking as putting at BDC and ARO after every race day and BDC after every heat/main). Last what plugs, i see the #5 is the plug that orion says to use but going from winter to summer in California is around 60's in winter to low 100's/90's in summer... Thanks for the help!

Well NitroXray. The Orion in general is a great engine all around. Like pitpop said earlier the hotter plug #5, Ull be able to clean engine out better, last longer, easy to tune. Temp wise I like to keep it in 220 range. Longevity of the motor is awesome, I got around 5-6 gallons on my .24, may have been a Lil more no less. Lol. I highly recommend the Orion engine and the one u mentioned Is a great motor. And WELCOME TO THE ORION CLUB. LOLOLOL

Has anyone tried using a OS or Novarossi carb? I have one I can pull off my old N21R.

I have a Nova carb on my 5-port. It fitted fine, and I was only using it to test an air-leak but found out that was not the issue.

Other then that it seems fine, but i would use a O.S. carb over the nova just because i have only heard good things from that.

Just wondering if anyone has any orion engines they are willing to let go? shoot me a pm if you do, I just sold my crf 3 port and I'm kicking myself in the ass