I haven't seen anyone talk about the new R2105 yet minus the one guy who loves his Muran R2105. Just curious if anyone has squeezed the trigger on one or better yet measured the timing numbers. I ran the Gold 2102 a ton which I realllly like and oddly the 2103 which was not an engine I liked anything about. I'm thinking a got a dud on that particular model. I think the 2105 is gorgeous with the polished head so I hope it runs as good as it looks. OS claims to have picked up midrange with the new crank without any loss on top end but I have no idea how the 2104's top end was. If anyone can chime in and get me up to speed on either the 2015 or the high rpm power/revs of the 2104 I'd be grateful. If you can compare either of the two to any Novarossi engines that will paint a vivid picture for me as I have ran them all..literally all lol. Thanks Fellas

Nope, did not get one yet for break-in or modify. But seen many OS through the years I doubt the timings are different than what I have seen before.

From the stories it seems the ports are different shaped and I have heard it is easier to break in. (one of the reasons why many people are using the 7 port engines)

Thanks for the response Roelof. I was hoping for some significant changes out of the 2105 but like the old saying goes "if it aint broke dont fix it ".

This is hard to say anything about it. If available, consider test-driving the R2105 or finding a demo at a local hobby shop or an event. This hands-on experience could provide valuable insights into how the engine runs and performs. If you've run all Novarossi engines, create a list of what you specifically liked or disliked about them. Then, ask for comparisons to those specific traits in forums or with dealers familiar with both brands.

You are real?
"consider test-driving the R2105 or finding a demo at a local hobby shop"
Give me one hobbyshop who would do this.

I wonder if you know a thing about this hobby/sport
"If you've run all Novarossi engines, create a list of what you specifically liked or disliked about them. Then, ask for comparisons to those specific traits in forums or with dealers familiar with both brands."
This to me sounds like some standard marketing talk....

Hi, accept my apology if I post the wrong information as I heard about this somewhere in my group discussing it. I will come with the facts/accurate data.

I wish there was a LHS who sold nitro let alone had a 2105 bolted in a rig full of fuel waiting for me to rip it in a random parking lot lol. I have one waiting for me to break in sitting on my bench. I'm going to have to get another head for it, she's too pretty to run lol

So how good is the 2105?

At least just as good as the 2104, 2103, 2102 and 2101

Kings Racing
There's a video of R2015, timings

Have put about 8 litres through my 2105...it was a Yurugix prerun and I have taken it very easy on the engine and always been on the rich side of race tune. However, the piston still got a pickup where it passes the right hand edge of the exhaust port...similar to some of my 2104s.

Though it looks bad, i can bearly feel it with my nail and don't think it effects the performance much at all (engine is a monster)...just disappointing that OS released a new engine with old problems.

What we have found that the factory needle settings on this engine is a little on the lean side for the high needle, and rich for the bottom.

What happens during break in, is that when the engine is rich, you naturally start leaning out the high needle. This is what causes the the burn mark on the piston you describe, because we're all making that high needle TOO lean.

Start by leaning the bottom needle first, and you won't get the burn mark. Be very careful with that top needle.

Good general advice but this did not happen with my engine...it was never too lean on top. Unfortunately there is more for OS to address than factory carb settings and I think that this is fairly widely understood withing the racing community.

I know that we have had that issue on the exhaust side for a while now. We have been cleaning that port. Well, my boy Ricky has been doing it for us....LOL

Just passing by and want to give you some extra info on the R2105

OS is using a different crankcase on this engine which has a lower volume in porting and explains the improvement in rpm climbing.
With this they also use a new main-needle with 2 orings and this makes the engine less sensitive on the main-needle.
Also a different spraybar is used(thinner shape) not sure what this should bring but a change is there too.