Thanks for all the info/help! Please take a look at the replacement bearing LOSR2814 for R21 on A-Main it's the same price and looks the same as 17001 this the bearing I have. I did post several question about the R21 before I got it and there was no replies about bad bearings. Thats the reason I got a Nova for the quality of bearings and longevity. Oh well I guess I should have got a B5/B6 like everybody else in my state! I am going to just keep running my R21 until it lets go I am still on 2 gallon but I hope I can get at least 5 gallons before it becomes impossible to tune but right now it performs good. One last question would removing the small shim now be a good idea or will that add pressure to case? I know to many rookie questions sorry!

All in all the nitrotec is an awesome engine , I don't think you would have had any better lucj with any other engine brands as far as bearings go , novarossi uses very high quality bearings

The one on A Main for your engine is the best front bearing ever made. I would not get discouraged about Nova engines. they are awesome engines....

started break in on my bonito today. got two tanks thru it via heat cycle method. this engine has been a lot easier to break in then my btt was. going to keep putting as much fuel as i can thru out the week and ill be out saturday to race it.

I have almost 5 gallons on my plus 21 4C team edition and race at sea level and very high humidity should I remove one of the shims on my motor now and if so which one? Thanks for any help.

Thanks for all your input! It does still run good and I guess I need to relax unless it starts flaming out!

I decided to open up motor and examine and remove shim but I can't tell if this is another .30 shim on head button or part of the head button. I didn't want to pry on it because it's soft alum. also the pic of shims is the other ones installed when i opened .10 copper/.20 copper/.30 alum plus the .30 alum. on button if it's a shim thats stuck or part of the head button? Whats the proper amount after break-in .80 right? So I need to remove small .10 copper or just put it back together? I took pic of sleeve /piston how does it look to you and which way does the arrow on head button towards carb or manifold? I am trying to learn more about Novarossi engines and engines in general thats why I ask and don't want to cause more problems. Thanks Guys! Edit/ I figured it out the two alum. .30 where stuck together and I now know thats part of head button because I found other .30 so I am going to remove small .10 copper and leave two .30 alum. and one .20 copper.

I don't know what that particular engine comes with, it should tell you in the exploded view sheet...
But if there is a .30 all shim, a .20 copper, and a .10 then it sounds like you should leave it alone.... .60 is usually pretty good....but most nova engines have two all shims and a .20 copper shim....It sounds like this Losi engine is shimmed perfect....

and you are asking good questions this is what forums are for right...and ur engine looks nice and clean, that's impressive....

Now shimming also is done based on altitude, but I have not seen to much info posted on this subject.....so hopefully someone will add to this...

Just realized the two alum. 30 where stuck together(rookie) so after I removed the .10 there is 2 .30 and 1 .20 which I believe is correct .80 total. My piston and sleeve looked good after 2 gallons(pics above) but I can't test until I put buggy back together and I ordered a ton of new parts and upgrades so I am waiting till I get shipment(Thursday) to assemble. Still looking at after run oil coming from bearing but it is a very small amount but I just got it broke-in(230f heat cycle) and running great and placing in races so I hope it's OK! Getting almost 12 mins in races so I didn't have to rich don't think. Thanks again!

6 tanks thru it total now. Break in is going really well. Bottom end is tuned pretty good not 100% , top end is about 2 hours rich now, it feels really good, still not hammering on it but im excited to see it at the track. wanted to get another tank in but started raining had to pull it in :-/

I have a few questions.

I have a 21-4BTT and it is taking for ever to break in I have like 22 tanks through it and it is still insanely tight. Is this normal? What shims should I use for 30%? Also where can I get the 21000/2 gaskets? Or can I use the old fashioned ones?

Thanks

You can still use the 21000 gaskets , I am having a hard time getting the
21000/2 ones myself

The "team" pistons take a good bit to fully break in, approx a gallong and a half to two gallobs , also if you broke in the engine with a high synthetic oil fuel the oils actually adhere to cylinder walls and make the fit feel tighter

Thank you. Should I just be using the stock shims? I am running 30% nitrotane.

Yes

Nitrotane is not the best break in fuel but great race fuel for power