pumpkinfish

iTrader: (4)

I just dropped in a new piston/sleeve in my 621T and never wrote down the initial carb settings when it was broken in. Does anyone know what I should set them back to for break-in?

Thanks!

Robert.Hull

iTrader: (11)

your gonna wanna riching the bottom end and the top end ofcourse but depending on your temp before you put the new piston in if you were runnig around 210 riching the top end about half a turn mabey a little more to be o the safe side and richin the bottom end 3/4 a turn and see what it runs at as your breaking it in......its actully pretty easy just keep the first few tanks around 130-140 but all you would have to do is just richin it and then slowly lean it out as you break it in like you probally did the first time around

NitroOB4You

iTrader: (36)

The Radical line likes an entirely different tune than other engines. Fully broken in, the bottom should be approximately 2 1/2 turns IN FROM FLUSH!This is very important, as most other carbs like (generally speaking) to be flush with the base of the carb. On top, it should be 2 to 2 1/2 out from closed. Given that, I would try starting it at - bottom 1 turn in from flush - top 3 1/2 turns out from closed. Be sure you're using the O.S P3 plug if using the stock turbo button, 30 % is fine with no extra shims needed.

NitroOB4You

iTrader: (36)

Update...I asked on the Grid, where Radical has a thread in that the owner of the co, Dominick, responded...this is his reply...
"Sounds pretty good, but I would use the heat cycle method, and use the
original settings you posted....3.5 out on the top will be way too rich
and more than likely will not run...just have him set it at race tune
and riched the top a tad more...."
So basically, run it slightly more rich, maybe 1/2 turn on top than what would be your normal race tune.

pumpkinfish

iTrader: (4)

Thanks. Just to confirm, I have two shims in there 0.1 + 0.2 = 0.3mm. Is this enough? I am going to run 20% Byrons in it.

Also, please clarify "flush". I have the older model with the carb that came with the 3 Venturi Inserts. I noticed it has a cone shaped depression. Is it flush with the bottom of the cone or the carb body?

One final question (I know I am a pain), but what Venturi Insert should I use in a truggy on a blown out outdoor track? Small, med or large?

NitroOB4You

iTrader: (36)

If I understand correctly....you say you have a carb that allows the use of inserts? That being so, then you have a newer version. I have an older version that does not allow inserts.That being said, I go flush from the outside of the body. From your description, and looking at mine, I believe they're set up the same way. The only difference between the carbs is the carb neck...wether or not inserts can be used.As for which to use....the best I can say there is to experiment. Which will allow you the best combo of mileage and comfortable/useable power? Id start with the middle one.
Shims- Im not 100% sure. I took mine apart and know that there is two there, but I couldn't get one off to measure both of em. All in all though, if you bought yours new and never touched it, then you should be fine...especially if you're sticking with 20%.

pumpkinfish

iTrader: (4)

Thanks again! I know for a fact mine is the older model because a friend bought a new one and has the round cooling head with a bull on it. I have the cooling head that looks like a cog. His is a fixed carb while mine has the inserts to use.

Mindcrime

iTrader: (4)

You are correct, the carb with the 3 inserts is the older one, we found thier was no advantage to the inserts so we went back to the ixed 8mm carb, less to go wrong

and just for the record I (Dominick) do not own the company I just work there