the point in time when the front bearing is most likely to lose seal is coming off a wide open pass and letting off the trigger.... that is the moment that the crankcase/atmosphere pressure differential will be at its highest....... flaming out the instant you let off the trigger is a sign of this happening....

Agree 100 % castor oil is critical...

Agree 100% bearings should be replaced...tho we have many with no issue on stock bearings, we also have seen too many with issues with the stock bearings...not worth messing around....

agreed , that would be the point when the most pressure change occurs

Thanks, more helpful input, and of course a new question!!!

How often should you put in a new plug, or perhaps better to ask how do you know when to put in a new plug. Obviously I don't want the wire going through my engine to be the first sign I notice of plug needing replacement! Are there some general guidelines to follow re plug replacement?

I am using the C6TGC in a Plus-4T with 30% nitro.

this is a pic of my roma 25 with about 6 litres on it. thankfully i have recently bought a huddy bearing puller and decided to replace the front bearing with a 17011. now all that im reading on this thread about the vacum port is that you dont have to worry with the stocko motors, just the modded ones need the port blocked. now i have to admit that i was thinking that nova knows best and that it is there for a good reason. since removing the front bearing, im beginning to think that nova might have made bit of a f*ck up here with this issue. so i have two questions for the tech elite guys who know what they are taking about.

Will this corrotion affect the proformance for the motor?

and what type of silicon can i use to block the vacum port. is standard plumbers silican ok, (im doubting that it is) of do i need rc type nitro resistant silicon.

another pic to show corrotion

Why is Novarossi moving away from the 17011 front bearing? I have a $200 Nitrotec with a 17011 and a $300 bttA with 17011 and they both have about 5 gallons on them with no leaks also run great! Anyway I just don't understand not using the bearings that make these motors worth the money and time it takes to break them in properly. Has anyone bought a bttA lately have they gone back to the 17011? I am going to give the new Orion Team motors a try if not because I am not trying to replace bearings after a gallon or two thats when the motor really loosens up and runs best IMO! Love my Novas but not if they are going to change out quality for price! Thanks!

Get yourself some Three Bond 1211 to seal the port. That's what I use. You might be able to use a high temp RTV gasket silicone that can be bought at any autoparts store as well.

A few things I have found

- 17011 will impact with dirt just the same as any other double shielded bearing will ..it may be sealed better, but its anything but bullet proof......

- the engine ingesting dirt thru the bearing has very little to do with the bearing itself.....

- Several brands of engines will do this if you run in excessively dusty conditions...Nova is not the only one we are seeing this with......If you run is very dusty conditions it is possible your engines are ingesting dirt, not matter the brand, no matter what front bearing your running....start looking for it a little more and many of todays tuning and engine issues can be solved.....US as racers need to be more aware of dusty conditions and put more pressure on tracks to keep the conditions clean.... There is a direct relationship between dusty conditions and tuning/engine troubles...the cleaner the conditions, the better these engines run and the longer they last....

here is a Bonito that was run in very dusty conditions, it had a 17011 in it already ...this engine was having tuning issues, multiple experienced racers tried tuning it and it was untuneable....It got sent back here and it was very easy to see why it would not tune or run correctly

this could be happening to your engine right now and you don't even know it.... Till you pull the front bearing and inspect everything you will not know...this is a perfect example of why everyone should own a Hudy bearing tool......

some good info here lucky we have mostly blue groove/hard pack track thanks for the info

Give you guys a tip , keep your engine clean!

Do not use any chemicals to clean around the front of your engine , denatured alcohol,simple green and air only

Being an actual racer myself i see many different track conditions and as i said earlier if you just maintain your equipment properly you wont have much issue with premature front bearing deteriation .

Front bearings suck in dirt , it sucks and thats why we change them , some brands/models need to be done sooner than later depending on the type of tracks you run on but its inevitable , things that wear need to be replaced .

The decision to put a subpar front bearing (compared to 17011} in the engines came when they were switching bearing suppliers and needed a bearing to fill the gap , its kinda funny how all this talk of "vacuum port" came about right at that time


Novarossi knows it was a mistake and they are not impervious to making mistakes , it is an entity ran by humans , as humans its inevitable that we make a bad decision here and there , imo they should offer anyone who has purchased an engine that the exploded view says 17011 for front bearing but the engine comes with 17004 a free front brng

Thats just the way i see it

Would running a Bonito in a rc8t require the set back motor mt?

RC8-015NJ - EZ CHANGE MOTOR MOUNT 1.5 MM SET BACK

It wouldnt "require" the mount just using the engine with stock clutch , it would be adviseable to use it with another brand of clutch or aftermarket such as the BUKU power komp clutch

I agree Monty. Keeping the engine, and the buggy for that matter clean really helps prevent so many issues with racing. I like to take my engines apart and thorougly clean everything after say 3 race days for my engines. I have gone back and double checked the double sealed Nova bearing and it was clean as can be everytime, but I have cleaned friends engines that looked horrible after 4 + gallons without any cleaning. Dirty glowplug holes, poorly sealed air filters, neglect, etc. all contribute to bearing issues. I do think Novarossi should just use the good bearing and stop using the other ones. Back in the day the front bearing lasted longer, and I think most of the issues are from low oil content fuel, and higher nitro and just plain we are running these engines way harder than in years past, and bearing tolerances are not quite what they were for the standard front bearing.

What about running the bearing protector novarossi sells?

+1 lack of frequent maitenance=more breakdowns