Hong Nor .28 Force Break In

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guinnessdublin

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Finally got a chance to start breaking in my new shiny engine today, engine started pretty much straight away with no real grief.
When running the first tank through I noticed the revs would go up & down with it cutting out only twice whilst going through whole of tank.
It wasn’t until I had used the first tank & giving it the once over that I realised I had the glow plug undone slightly the whole time which to me now makes sense as to why I was getting the high revs.
The engine was still on factory settings & if anything running more richer with plenty of smoke & oil spitting out of exhaust, do you think this has done any long term harm to engine though? ??
 
Okay thanks was thinking that just wanted a second opinion, at least I know what engine sounds like when I get a severe air leak! Lol ??
 
With a lot of engines, you back the glow plug out 1/4 turn to release some compression to make them start easier, then when it's running, you tighten it back down. Although, prolonged running could damage the threads in the head, but if it tightened back down ok, then your more than likely fine.
 
I've forgotten to retighten a glow plug and wondered why it stopped during running a minute later The glow plug was never found as I think it was sent into orbit. Short term leaning rarely has any long term issues.
 
Still having trouble bedding this engine in have done about 5 tanks through it now & too me it just isn’t running right. It starts up fine & runs okay ish but to me the idle is to high as it try’s to move forward & when I go to lower idle to a smoother lower setting it cuts out.
Did notice smoke coming from g/plug area so tightened this up which did not help & this is new g/plug & washer, checked tightness of head bolts which were tight.
Have noticed when you apply brakes sometimes although engine revs lower back down to idle it can then rev up by itself. When I pinch fuel line it just cuts out after about 3 seconds.
Does this sound like an air leak issue as engine was not sealed up, will try new washer on g/plug next time.
Any pointers please.
 
Could be too large idle gap so reduce idle gap and lean lsn to compensate. Have you leaned hsn? Checked clutch shoes and spring tension?

Is carb staying closed after coming off brakes?

Pinch test isnt always reliable imo.
 
Have reduced idle gap but got to admit have not then leaned ISN at same time will have to try that also, have also tried leaning HSN to no real effect.
Tried running on factory settings which were leaner when trying needle settings with screws both set flush.
Brand new Fioroni clutch shoes fitted & idle gap staying the same when brakes applied or not!
 
Have had a further look at engine with air filter off & while operating throttle/brake the gap is being slightly closed off. Did not see this happening before, so have altered carburettor linkage length to stop this.
While altering linkage length found proper place for throttle spring to go also.
Hopefully this will improve things & have taken needles back to flush settings to see how it runs now.
Will look at why smoke was coming from g/plug area also, fingers crossed! ??
 

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Further looking on this great site found article on leak testing with soapy water solution, applied soapy solution on different areas on engine. Took a while but low & behold it showed up slight bubbles coming from pinch bolt, now drummed home to me the importance of sealing a new engine up.
A good lesson learned here & for others that if they are having tuning issues & did not seal engine up to do this very simply check first & can easily be done with engine still fitted in place.
Fingers crossed this with other issue will make a difference in idle/running of engine! ??
 
Some say do it, some say don't... I've done it pretty much always since I learned about "air leaks". I made it a habit of tearing the engine down, rinsing it out with DA as there's always some aluminum bits/filings in them, lube everythign nicely internally with ARO, then seal the carb neck/banjo and backplate with RTV and put associated green slime on the LSN/HSN o-rings. I do that before I install it the first time.

I've never had an "expensive" engine, so not sure how those do. I've had a few there were expensive to me... the only one I never sealed was a picco 28 that I never installed and recently sold. I bought it on a forum, drooled on it, then put it in a drawer until I had an engine die that needed replaced, but none ever died, so it just sat in it's box, for 6+ years.
 
Well as said big lesson learnt today, I just felt something was not quite right with engine & just hope this sorts it as was beginning to think I had a lemon on my hands! ??
The Team green slime you use is out of stock currently in England, what could I use instead & what exactly is it please?
 
I think it's just a silicone based grease, typically used to lube shock o-rings, but I use it on carb o-rings as well. Helps keep them lubed when they sit, so they are less likely to dry out/crack, especially since my nitro's tend to just sit the past few years.

Was searching for an alternative and ran across a few:
https://buzzysusa.com/#
https://www.spoke-store.com/sram-pit-stop-judy-butter/

fasteddybearings.com used to list some, but I'm not seeing it anymore. It was blue.

cowrc had something too:
https://www.cowrc.com/Udder-Butter-2-5oz-Pre-Filled-Syringe-p59318081
 
Okay finally run a tank through savage since sealing engine after finding air leak on carburettor neck & sorting out throttle linkage where now when applying brakes it has no effect on carburettor slide today. Got to say was able to get rpms down a lot lower while still keeping engine to idle so happy with that.
What I was finding was & not every time was when coming off full throttle the engines rpm would race/scream away, luckily I had savage raised up on a block all the time.
All the research I have found says it’s to rich on the LSN & others say the opposite so slightly confusing.
This is set back to factory settings & was going to lean out LSN next & see what that brings, had to call it a day as engine screaming was going to upset neighbors if carried on tuning!
 
Get fuel through it. Rich or not, it's going to take some time to get it to settle down. Many engines don't tune well until you get the first half gallon or so through them anyway, which is getting near "broken-in" and many don't fully stabilize until you get to the 1 gallon point. Usually by 1.5 gallons, it's fully worn in, tune is solidifying and temps stabilize. Even RTR engines take 1/2-3/4 gallon to wear in well.
 
Okay olds97 thanks for info, this will be the 6th tank through it now & perhaps it’s me being inpatient!
Can you explain the fact it revs it’s nuts off still when you take it off from 1/2 throttle, is it where it’s too rich on HSN & burning off the excess fuel still after shut down never had that happen before & cant find any videos on this problem only conflicting posts about it?
 
I'm not sure what you mean. Do you mean after going past 1/2 throttle and dropping the trigger back to idle the engine is still revving high?
 
Yes exactly what I was meaning, have checked factory settings again today & turns out was set richer on LSN when I last run it don’t know how that happened guess that what help matters!
 
I stink at tuning for the most part, pretty sure I get too aggressive with the adjustments. I usually end up with a high idle that drops after a bit which I think is too rich LSN with the idle set too high.
 
Just waiting for this lock down to end so I can drive somewhere & properly run the truck & spend time tuning it in, rather then upsetting some of my neighbours! ??
 
My work has required 1 furlough day a week, so I use Wednesday. I got out and ran for the first time in a long time last week. Saw very few people at the place I run now. I rarely saw people there before and was somewhat surprised to see any now. It's a public grass bmx park off the edge of a town in a newer residential area about 45 minutes away. I've only run nitro there a couple times, would really do well with a single speed truggy or 1/8th buggy if they keep up on the mowing of it. The last time I had the savage there, I was fighting my own stupidity and tune. I ran my 21TM revo there a couple times and it did ok, but the grunt of a big block would do better. The big air jumps lend themselves to a flat chassis of a truggy/buggy though.

My 1/8th electrics do well there. The stampede 4x4 struggles a bit, but when it's mowed short, it's still fun to run it there.
 
Sounds like your spoilt for chose, Happy Days! ??
I had to google that phrase "Spoilt for choice", never heard it before. LOL!

Considering the cut backs... I'll be happy if I have a job in 6 months and my company still exists. Definitely cutting back on the purchases this RC season...
 
Lol very old school English saying I guess!
Yes not looking good this side of pond, we thought Brexit was going to be our biggest concern! ???
 
After another further two tanks through this engine it appears to finally have come alive & wow what an engine. Still finding idle is not quite as smooth as I would like it & seems abit twitchy still.
Since break in I’am now on my second O.S. g/plug & might try another new one when I run savage again to see if that helps with smoother idle!
 

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