mercfocus

iTrader: (3)

I finally got my Hyper 21 running right after all this time.

BUT, there's still this issue:

It will never warm up unless I turn the HS needle clockwise a 1/4 turn. I have to watch that though. After about 2 minutes, I have to turn it back where it was or it will just keep getting hotter.

Is this the plug?

I've been using a Duratrax carbon medium plug.

Do I need a hotter plug?

If so, what's a good hot plug to use?

fastchvy

iTrader: (15)

check your front bearing...

jrx2

Try an os #8 plug, they work great for me.

mercfocus

iTrader: (3)

I just put in new ceramic front bearing.

mercfocus

iTrader: (3)

Looking it up, I see those are also medium plugs.

Maybe they're a hotter medium plug than the Duratrax Carbons?

ozziii

Go a little hotter on the plug, O.S #7 med/hot, hotter plug can help when running in engines, tuning window can be slightly larger & hotter plug can help keep a rich engine run better.
Your engine may not be getting hot because its a bit to rich, just turning one needle won't fix it, you will have to tune using the LSN as well, but before anything, adjust idle gap on carb to between .5 - .7mm, then set LSN so engine idles but is still rich for running in, set HSN to flush so top end is still rich & go from there.

Roelof

Go a bit leaner on the LSN. Sometimes a to rich LSN is giving a lot of cooling and so preventing the motor to get warm. Pre-heating could be a solution.

MitchelG

definitely need a hotter plug. O.S. 8 or 7 probably. i run a #7 in my argus .23

merdith6

iTrader: (3)

I remember tunning one of those and that is one of the reasons I hated it. I don't mean to discourage you from trying other plugs or anything else but If I remember right it's just a pain in the butt engine that goes from barely start rich to lean in like 3 minutes.

mercfocus

iTrader: (3)

I agree.

This does seem to be a really crappy engine.

I'm mostly just using it for experiments and learning from it.

I put a new Nova Rossi carb and shimmed the head for 30%. That seemed to correct a lot of issues. It was have other problems.

The new carb is very tunable but the rotating assembly seems to need something more to get the temps right. That's why I came on here about the plug.

I havn't done much with plugs so this is kinda new experience too.

Anf

Quite clearly you do not know how to distinguish a worn engine or how to tune an engine...you choose!

merdith6

iTrader: (3)

I just remember coming across several of those engines back in the day they came in hyper OFNA cars I think. Not one ran good. Could have been worn out but every one of them, Possibly. As far as tuning I have been helping racers tune .21 buggy engines for about 15 years. I started out with inexpensive force 4 and 6 port Taiwan engines about 20 years ago and they ran without issues for a long time. The hyper engines just had terrible carbs and lost compression quickly in my opinion. I always recommended they get another engine. It ran crappy. end of story.

houston

iTrader: (96)

I may not agree with Mr. Roach on too much but i do know he can tune a nitro engine , he knows a few things

D8

iTrader: (2)

The OS 20E carb works great in the Hyper 21 Pro engine.. the OS plugs are a little too short for that engine.. many years ago I used to run RB plugs in the Hyper Pro engine and it was crazy fast., the low end power wasn't the best but, it got the job done..

mercfocus

iTrader: (3)

Which RB plug?
I found these:
http://www.amain.com/rb-products-hot...plug-5-1/p4744

http://www.amain.com/rb-products-ver...plug-4-1/p4743

And there’s this LRP that looks like it might be good:

http://www.amain.com/lrp-platinum-ir...um-hot/p272990

The Duratrax Carbons I’ve been using are short too. I’m wondering if that’s been part of the problem.