Hyper.21 Engine tune

[NEEDspeed]

G'day there fellas...as some of you might know I purchased a Hyper7 TQ Sport RTR for the right price (500 with fuel, plugs, batteries).

Now, the carb needles in this were set to a factory rich run-in setting. I've completely run 6 tanks through at low-ish throttle percentages along with one at idle at the beginning. Now I'm looking at whether to start leaning out the high speed needle. Idle is good, but higher throttle positions starts to bog it down a little with a LOT of smoke and unburned fuel spitting out the exhaust. The High-speed has a setting of about 5 o'clock/11 o'clock in relation to the screwdriver groove looking at it straight on.

What to do? You guys reckon I should start turning it in slightly?

[mIKe-]

I was told to break in a nitro like this:

1. idler a tank through.
2. run it round really slow for a second tank
3. run it around more really slow for tank no 3.
4. start tp give it a few bursts, but still pretty slow tank 4
5. same thing as 4 tank 5
6. starting giving it 3-4 second WOT runs tank 6.
7. lean it out 1/4 a turn on the needle for tank 7.
8. keep leaning it out 1/4 a turn a tank till u happy, that can take up to 12 thanks apparently.

I personally have never tuned a nitro, but i have read it a billion times, and thats about what most people say to do it. but everyone has their own method and will tell me im wrong :) but yeah, when i have to tune a nitro one day thats what im doing.

[JD]

idle a tank! no!

u want the break in process to be as quick as possible, when u first start it up let it sit for a few seconds, then start driving it around, varying the throttle up to 60% or so, YOU WANT HEAT into your engine, u need your engine compents to heat cycle, so run around a bit varying the throttle, cut it off, let it sit till its cold again, start it up again and do the same, and cut it off after 5 misn or so, then the next tank start giving mroe throttle, up to 100% blips .

tank 3 - 4 start tuning for performance - so yes you should start leaning it out right now lol.

don;t be afraid of these little engines :P if u do manage to kill it, a new head and piston will not be expensive :D
<span class='smallblacktext'>[ Edited Mon Apr 24 2006, 05:28PM ]</span>

[mIKe-]

Told you someone would say I was wrong..

[JD]

heh :P

[Sempati]

Pretty much what JD said .. plus .. make sure the piston is at the bottom (or close to) of its cycle when letting the engine cool. Otherwise she will distort the sleeve when it contracts. This will not only make it a pr!ck to kick over, but will also cause a loss of compression over time.

[NEEDspeed]

So I should start turning the needle in towards the carby? 1/4 turns hey? What characteristics should I be looking at when its done right? Also it'd be really handy for an indicator when its running too lean.

Thanks for those replies tho, helpful is an understatement.

[JD]

if theres no smoke - its probably too lean, just look at it listen to it, and go with your hunch :D

[BigD]

If it's any good to you, a link I found the other day - nitro advice from Ron Parris http://www.nitrohouse.com/tip,_engine_breakin.htm The break-in stuff is towards the bottom.

[Sempati]

Around an eighth of a turn per tank of fuel inward (clockwise) to lean-out the HSN.

Smoke is always good :-) Basically, you are out of the too-rich zone, when you stamp on the throttle and she goes like **** off a shovel. You are in the too-lean zone when as JD says, not enough smoke ... you want a few metres worth of lovely nitro behind you.

[Sempati]

Ahh yes, I was looking for the Ron Paris link myself but was having no luck (paris racing, gone now that he has too). He is the man with the master plan!

[avablast]

ive found that keeping it rich can break conrods due to the engine struggling to get rid of so much fuel and the best is to lean it out to how ur gonna run it after break in and run it for short periods like 3/4 a ank or so a time for the first 4 tanks and shes worn in without snapping ur conrod but i must admit ive got a hyper 7 tq sport to and broke it in on the factory rich setting for 8 tanks with no drama just extremely sluggish response but leaned it 1/4 of a turn runs wicked cept stalls easily if u leave it idle to long

[NEEDspeed]

Yep I've found that too, it doesnt like being left to idle for a while. Also, it seems to bog down badly until the whole engine is up to full operating temperature, then it absolutely rapes and pilages on acceleration and top end. I'm really having fun with this car.

[desertgator]

by the way the fuel coming out of the exhaust is castor oil it means ur fuel system is lubricated

[avablast]

ive found if u let it sit like come to a complete stop in a turn and let it sit for like 10 to 20 secs then accelerate it bogs but if u have it pumpin only stop for a few secs the acceleration is great

[avablast]

my guess would be the pressure line is to long and forcing to much fuel thru the engine when u dont have the revs to burn it but its no biggy wouldnt matter in a race scenario

[avablast]

to short i should say

[NEEDspeed]

Hey all.

I feel I must revive this thread as I've had a big problem with this motor.
It seems some dingbat at the Taiwan engine plant overtightened the head bolts or I've overheated the engine causing the head bolts to seize (second scenario doubtful, always checked engine temp post-race). I keep rounding the allen wrenches, even the best fitting ones but these bolts stay put. I'm sure the heads arnt stripped, they dont appear to be marked.

Anyway, the engine is back with RMS where the car was bought but I've been told a new engine may be on the cards if they cant free these troublesome bolts. Screw that, cant afford $260 for a new engine I dont need.

Last resort, drill the heads off and rip the block apart or what?

Experience required.

[JD]

make sure ur using high quality allen keys, i have a set of unbrakos they cost like $50 for them, but they are top notch. alot of cheaper ones, the actual allen key starts lossing its sharp edges, and causes round outs.

so if one of ur mates has a good set.. borrow them, or buy ur own set of good ones, it wont be a waste of money, cos u wil need them many times in the future.

[avablast]

sumtimes the two metals ie: the steel screws and alloy block fuse thru heat the screws being steel grow faster thru heat then alloy does and they can fise together alot of engine builders for motorbikes grease the screws rather then locktite them to prevent them fusing together

[avablast]

but thanks for the info was gonna rebuild my engine but if it does the same to mine id rather get a better engine

[NEEDspeed]

Just an update. Radiomodels' Bob had to grind the bolt heads off then get vicegrips on the shafts to get them loose.

Basically I was accused of engine mistreatment and overheating the engine as they claim "There were heat marks all over the piston and liner". That pissed me off a little to be honest. This engine never gave the hint it was running too hot, always was run slightly rich with good smoke trails. Also, I bloody tested the temperature after most runs with a probe and the thing didt exceed safe operating temperature.

Seriously, I'll do me nut if the RMS boys give it shit.