Ahh problem solved, thanks

So I haven't raced nitro in a couple of years and am looking for a new engine. My old engine, which I still have, is a 21-4c. Absolutely love the engine. I think the logical choice would be a 21-4 Keep Off, but I also see a-main has a 21-7 Vir-Tus on sale. Has anyone had any experience with the vir-tus?

You can get the Vir-tus much cheaper on NovarossiDirect.com.
The Virtus is more of a truggy engine, I think the 21-4 keep off or MITO 4 would be a smoother buggy engine. But to each his own, come people like blistering power in buggy.

having a little fun trying to dial in the baseline tune, this old buggy doesnt react to throttle or brake inputs in the air anywhere close to my ae buggy but im not going to bash my race car.
nv21b square stroke/werks 086
https://youtu.be/gkvpHMOVxO0

9853/41001 vs the rest
 

Does anyone have any experience with the 9853/41001 setup? Just wondering how the performance compares to 9853/41021 or even 9901/41021. Also, what is the 9901/41001 setup like in compared the 9853/41001

For truck and in my mito 7, 9853/41001 is my favorite setup. Great power down low and generally good power all around with good mileage. I can pit at 10 minutes while still having plenty of rip.

9853/41001 = balls to the wall, plenty of all around power doesn't really sacrifice top end either

9853/41021 = smoother low end, probably a little better on a dusty low bite surface.

Ran both of these combos in truggy last year with the elite 5 and p5xlt, for buggy 9901 might work a little bit better but it probably depends which engine you plan on using also.

My btta engine has a problem with low end, previously it run good but suddenly it dont have low end power n will surge. Some guruS told me the main bearing is tossed. Any idea?

[QUOTE=cczjordan;14479233]My btta engine has a problem with low end, previously it run good but suddenly it dont have low end power n will surge. Some guruS told me the main bearing is tossed. Any idea?[/QUOTE

To check to see if main bearing is toast, run the engine on the starter box. If you hear a ringing noise, like metal on metal contact that goes away when you place your hand on top on the cooling head, then the main bearing will need replacement.

Also, check to see if all your fuel lines and fuel clunk are good and clear, check and replace gaskets and springs, then retune and see if problem persists

[QUOTE=TLR 8 4.0;14479503]Gaskets replaced, retuned done but no clinging sound. Just sudden lost of bottom power n will surge after then same problem happened again.

What's you guys take on factory break in motors done by Factory ? What's the best procedure to use to get motor race ready once installed in the car ?

Try over here:

http://www.rctech.net/forum/offroad-...eak-bible.html

Most of the "broken-in" or "pre-run" engines that manufacturers offer are still not completely broken in engines out of the box. Usually these engines will come with a piece of paper inside the box that says you need to run X amount of cc's of fuel through the engine being easy on the throttle then you can put a race tune on it. If it were me, I would just buy a normal engine, send it to a reputable engine service, and have them break it in. Then all you have to do is throw it on the track and adjust the tune for your area. No additional break in needed. But I also prefer to break in my engines myself. I use the "Bess Method" and have never had any problems with my engines using this method. :D

Only in an heated oil bath for me.

http://www.rctech.net/forum/onroad-n...h-machine.html

The engine MASTER seems to have lots of spare time. Your knowledge with engines is just Crazy!