Adding the extra shim for break in the way to go. I got my latest one to come around much quicker so there is less fuel wasted with a motor that isn't performing as good as it should. I removed it after 1/2 gallon. I probably could have stayed as there is still massive pinch. Please start with it and you'll have a better experience. I highly recommend using heat indefinately.

Yes a heat gun is a must for initial start up, I broke the starter box belt being too impatient. I also noticed the carb slide is very tight tolerance, and at first our was sticking in certain area's. I had to re-adjust to make sure I had a straight pull and its fine.

Well, ran my GTR at the first UK Truggy Nationals round this past weekend... in 140 ,minutes of running including a solid hour of finals not one hicup from the motor. My only issue was a glow plug coming lose costing me a bump-up on the second day, but that's user error:cry: Tune was easy, and didn't need touching all weekend once set.

The motor was running 30% Byrons Gen 2, P3 plug, extra shim and JP4 pipe and header. I ran the 9mm venturi. Truggy was an 8ight T 2.0, stock clutch, non-lightened drive train, but really good bearings fitted.

The motor started the weekend with about 3/4 of a gallon on it but was producing really good power, bottom end was fine for short run up jumps and the truck had really good top end on a big, wide open track. Traction was quite low and the power delivery was very smooth which helped get consistent laps and also run time (no spinning up the wheels). Fuel economy was excellent, I could pity at 10-11:30 easily with some fuel left in the tank as a safety margin. We never tried but I think I might have been able to get close to 15 minutes by rolling the throttle a bit more... to me it's not worth the risk of trying.

In short, I'm loving this motor and it was attracting a lot of attention over the course of the weekend.

you guys adjusting the low-end or top-end more? I kinda like to leave my top-end at the same spot and adjust more of the low-end more frequently. some engines are different though....

I would think it will respond correctly to that methodology.

well the reason i asked was b/c with my RB engine in order to produce high end power you would actually tune the bottom-end more....and NO the bottom-end was not even rich. i just know different engines have different tuning characteristics. if this makes any sense.

thanks Mark

oh and thx James I got my Arrow in yesterday! It looks really good :nod:

quick question? I hear some guys running a 6mm or 7mm carb restrictor. mine only came with a 9mm and 8mm, where would I get the smaller ones???

Either from other engines (OS, Alpha, Go etc will fit fine), or some one like AMain.

Mark, sorry I forgot to mention the Venturi sizes it comes with. LMK if you want some inserts.

As with all engines, your tune will always be the perfect combination of all 3 needles. After break in and when any engine is ready for full out race tune, you should always start with the idle gap. Make the gap about the size of the end of a paper clip. I open a clip and insert it into the carb with no venturi. I then close my idle until it touches the clip. From there you tune the low end to make the idle drop to a purr as soon as you let off the throttle. The high speed needle will control the power and the fuel into the sway bar so you need to find that sweet spot between too rich and too lean. Make sure your engine and chassis are completely heat soaked before race tuning. Once I started tuning from idle my engines have performed much better and run times increased dramatically.

yes I want some! lol

PM to you scoobie doo

Just got back from the Texas State Series in Corpus and ran the Arrow without a single problem. I'm probably just over the 3/4 gallon mark and the motor has very smooth power curve and has a consistant tune. Amazingly the motor was running 9-10.5 minutes and temping at 225, still running the extra shim and original carb insert. Looking forward for the mechanical pinch to break and really see the motors potential, thanks James (Team Terrible) for getting me this motor.

I've been really pleased with all the positive feedback so far. It's great to here all you guys having good outings with this motor. Special thanks to Mike Cleary for all you do for me and for Team Terribles. You made a great call bringing in these engines. I am going to be sending a couple out to Lance at RC Renew. He is going to run half a gallon of fuel through them on a break in bench with computer controlled variables and monitoring. I will then have them available for sale as ready to rip! Just remove break in shim if you want and race tune! Drop on the track ready without the added cost or time of the break in process. Prices will still be less than the original V spec or the new blue XZ ;)

+1 :nod:

The engine looks good and i like the idea.