Im trying to decide between the nova Plus 21-4cteam and the Axe Rossi mamba/cobra.

Both Good motors Not gone to say any thing Bad about the Nova Plus 21-4. I would run the Cobra motor i have had Nova motors good Motors but the Price to fix the Motor is Higher that way i went with Axe Rossi motors for so many years. Rods are only 45.00 bucks and a new Piston and sleeve for the Cobra is only 110.00 Bucks Price a Rod and a Piston and Sleeve for a Nova Plus 21-4 a Lot higher and if you are on a Budget like i am you will wont to fix the motor some time and not just buy a new motor. Amain dose not even have Parts for the Nova21-4 in Stock.

Not knowing a whole bunch about engines, I'm just trying to get the best run times, punch and top end I can. I only want to have to buy one engine this year.


Oh yeah. I wanna smoke the guys I run with.

Wrayth it was Nice talking with you on the Phone and if you need any more Info i will be Glad t help.

O and By the way get an Axe and Smoke your Buddy's .

Axe 21 mamba is a great motor I have one with jp 2 or axe rossis pipe have been gettin 10 mins runtime and tons of pwr with coldfusion30 blackmagic fuel

hi, quick update on my engine.

Oh and thanks for the info about the locktight on the carby screw. this is only teh first new engine i've had and my first one had a screw/nut combination.

anyway...

Axe Cobra X1 evo .21 engine.

it's had 3 tanks through the engine while it's sat on blocks.
the 4th tank i ran it around the backyard. i had to wind the HSN in about 3/4 turn to get it running on the ground without stalling out. the temp didn't get overly hot, so i kept the aluminium foil over the heat sink.

today i put the car on the road out the front and ran 2 tanks through it.
when i started it for the first time today i had to turn the HSN in 1/8 so it wouldn't stall.

the sound of this engine on the road is preety sweet, when i back off the throttle the engine makes a gurgling sound... i guess kinda 4 stroke like. after turning occassionally the car will surge a little, then take off again.

i very rarely went over 1/4 throttle.... it's quick enough at this speed already. but i did give it a little squirt every now and then when it seamed to bog down a little at a certain speed...... is this just too much fuel going into the engine. obviously to get this engine started and remain running i've tuned it from being extremely rich.

sorry for the long post, but i just want to update what i've done and get your thoughts on my run in progress so far.

engine has now done 6 tanks.

oh yeah. temps... spit test indicated spit evaporates off in about 4 - 6 seconds.

Sounds good you are doning it just as you should keep up the Good Work.

changed down to the 7mm restrictor from the 10mm restrictor. runs a lot more rich and very close to the same temps. sounds like a 4stroke even on throttle now.

been watching a few youtube video's re. breakin procedures and figure i'll put 6 full tanks through the engine at this setting, or while it remains hot, then start slowly leaning it out.

from what i understand it's going to take the whole gallon of fuel before it's even close to run in, so there is no huge hurry to start leaning it out.

Start to Lean it out as you go just a little at a time and you should have it tuned and ready to run by the 1 gallon mark. Most Axe Rossi will be ready to run Hard after the first Gallon and ready to race.

Hi,
I have an older 'gold head' Axe Cobra 198R21. I ended up buying a turbo plug head button for it. It has the number 3 stamped on it. I use AT 25% Fuel, just wondering how much shimming is required? THX

Two .20 Shims should work for 25% i run Two .20 shims for 30% so it should work for 25% to.

well. i've now got a good 2L of fuel through the x1 cobra evolution and she is now starting to find it's power.

still has a way to go before fully broken in, but if the results of the last few tanks are anything to go by, it's going to be one powerful engine

Yep the X1 is a Strong Motor and get good run time you will be happy with it i am sure. Keep in touch and let use all know how its been doing for you THANKS.

starting to give this engine a decent tune.

run times are starting to steady out now. last run was 9 1/2 minutes.

not having any issues i was before with engine bogging. LSN fixed that.

HSN is just about spot on. could maybe go 1 more hour in for a little more power. but not while it's still running in.

engine has now seen about 2.5L.

spit test is now down to a fast evaporation of 3 sec.

Sounds like you are jusy about Spot on with your Tune if the Spit test is at 3sec and your run time is at 9 1/2 that is about what my buggy gets.