Originally Posted by porkchop

last year i ran a 08 plus 4 with 9901 40210 what ever header the team told me to run. the to me did not seem to have alot bottom just a lil mid and never lit on fire and took of.

what dose the plus4c do better and if i dont run that 9901 pipe what can i run i need some motor if i dont have more then i need i stand on the trigger and my millage gose out the door any help would be great.

also i found that the standered plug made more power any reason why?

is the p5 better then the plus 4c?

Originally Posted by houston

i dont find the 9901 pipe impressive in performance by any means charles .

call me and we can BS not right now though

Originally Posted by houston

ENGINE RUN IN

use a heat gun to heat to 200 before you start at each step

You will have to play with the needles a little bit and cover the head of your engine with a pit rag (or similar)

do 3 heat cycles within the first tank at 190-210 degrees (3-5 min. intervals),
at idle on stand? yes.

then run it around on the ground gently only slightly rich keeping the temp between 210-230 (monitoring temps frequently ) careful not to let the engine get into its powerband , do this for about 1 full tank at a time but do not let it run out of fuel .do this for 3 tanks (cooling in between tanks), quarter throttle or so with short blips of more (full) throttle ..

not fast? slow pulls on the throttle in 30-40ft bursts .

then richen the needles a bit and run it about 190-210 on the track for 3 straight tanks monitoring temps frequently(every 2 laps) for the first couple of minutes until the engine runs at a consistent temp and feel.(start to lean out slowly)when you get it tuned in to where its not totally screaming but you have enough power to make the jumps with a slight bog at full throttle and runs at about 210-230, let it cool

(check the plug at this point),

what am I looking for exactly on the plug ? make sure the plug still glows and looks new, if it looks all distorted pull it out as you dont want a plug filament to go through the engine

go out and run the rest of the gallon til the engine richens up dramatically on its own and the temp drops instantly (i call it "dropping its nuts"). this process sometimes takes more than a full gallon .hope this helps ya , pretty detailed

I have had great success with this method and longevity , monty
www.houstonsengineservice.com

Originally Posted by zixxer

Just speaking from what I've seen houston post. He means 3 times during the first tank get the mtr running at the temps he said idle for a bit. Then cut he mtr off cool down to ambient temp. 5-7 minutes of idle time. That's what I do anyways. Hope that helps.

Originally Posted by Stirex

So picked up a 21-4C, so far real nice sounding motor. Quick question, after break in I flushed the motor, but the carb doesn't seem to want to re-seat. It sits on the O-ring around the carb throat. I seem to remember when I moved it earlier it wasn't sitting on the O-Ring. So question is... O-Ring out or should it be down the throat a bit?

Originally Posted by jubibamse

Hi
First of all sorry for my poor english.
I need a new engine for my truggy.
I am considering 21-4 or P5XLT, but I can not really find out what would be the best. I prefer stable idle, good run times and reliability. Last season I ran with Sirio CL7B it lives up to the first two things but not the last.
I hope you can help me.