hello,

I'll soon change my engine, and I think take a mr21 r01a. I would like to know the level power of this engine against a xenon (not the R)? for the people who use this engine, what is the main part that you change frequently? the rear bearing? the rod?
if you have some critical (bad or good) about this engine, I take :blush: :blush:

thank for your answer ;)

The "A" version and the "02" version are the same thing. Example: MR21 R01A = 02 version.

I have Ninja engines for almost a year and I can assure you (as many in this thread could) that power output of the MR21-01 is really great, maybe they don't have the rip of other engines, but it makes it easy to drive it hard (laptimes are there... and easy to do).

The carburation is very stable and sensitive to changes so you will not battle with it. You could do easily 5 minutes with the fuel tank so runtime isn't a big problem except in some tracks.

Comes with the 8.5mm carb venturi and gives good power and runtime. You have the 9mm too if you want 'a little more' but runtime suffers a little.

Is a great engine. Get the engine, pipe and a pair of headers (long and short) and see what suits for your local track.

I don't know in the new units, but.. you need to raise the combustion chamber. Before starting, do a look on the previous messages on this thread just to get what worked for the people and values and compare them with the ones you get from your engine.

The 'gripe' could be the price of the plugs, but... I've been using Sirio ones and work great with them (and of course, are way cheaper). Taper isn't the same, but... after a full year of using Sirio plugs I didn't had sealing problems on the plug.

Changes from the Original MR to the Series 2...
 

Well... got one unit of those marked with a '02' on the crankcase (Series 2) and found now some subtle differences, need to do a complete teardown to see what changed between the originals to that one unit.

Seems that Ninja is making some running changes between engines without changing the model number.

What I've found so far is on the carburetor.
- Carburetor retention mechanism (the original didn't came with o-rings and the 02 comes with o-rings to improve the seal).
- Low-end needle. The original came with a blunt shape on the needle and the 02 comes with a conical shape, this changes the fuel curve vs. barrel movement. Cannot confirm, but... the spraybar seems that changed too. This could affect to the power curve of the engine.

This weekend I'll do a complete teardown of the two engines and see what changed. But... seems that are subtle changes rather than revolutionary modifications. Cannot assure it 100%, but... seems that sleeve received too some slight changes on the underside.

hey guys i was running in my mr12 engine in 2day and before i got it started it locked several times, does this cause damage to the engine?

If the engine locks is due to the massive pinch they have, some units need to be pre-heated before staring just to alleviate the massive pinch and make it easier to the conrod and other parts and materials.

You can cause some harm to the engine (conrod basically), use a hairdryer at least to heat it a little at least on the first start-ups. After, when the break-in finished it will not lock itself on the TDC.

which is the best plug for a RO1A on 25%

Hi, I recently purchased an Ninja MR12-T01 and have been trying to get it started and run in. Everytime I placed the car on the starter box the engine was so tight it would just not turn over. Even after heating it I still could not get it to turn over. So in desparation here's what I did. I heated the engine, removed the plug, sat it on the starter box, got the motor turning over with the starter box and while it was turning over I stuck the plug back in, tightened it up, put the glow starter on the plug and the engine fired up. Ok probably not what the experts would recommend, but as I said I was desparate. Anyway have run about 10 tanks through so far and now starts like a dream.

Ninja plug #7, but... I routinely use Sirio #7 too. Have different taper, but I'm using them for more than a year and never failed me.

cheers mate ;)

Just a small but important detail. If you start to use Sirio plugs, stick to them or when you want to change plug brands you will need to change too the head button to a brand new one just to assure yourself a nice sealing of the combustion chamber.

What Efra # pipe is reccomended for the R01. thanks

EFRA 2053

Thank you very much!

would somebody have pictures of the interior of the MR21 r01a?
I don't find big pictures of the crankshaft , the sleeve :nod: :nod:

so no info on a normal in-car break in?

I'm pending of comparing the original R01 with a new unit R01a but the changes up to what I've seen are subtle. No radical changes there.

There are some posts on the previous pages describing the break-in made by several people (including me). Some did the four stroking method some used the break-in bench, what we found is those engines run apparently hotter than Nova and others due their different cooling head and the combustion chamber height needs to be raised before using it.

Check it with the solder wire method (measure the crushed part of the solder wire and tell us what height you have and which fuel you plan to use with it before grenading it).

First let me say i'm not a newb. I've checked the obvious things and it's not them.

The problem I had this weekend with my Ninja 12 is that the carb. popped out. It didn't twist or run away (thank God) it will just pop out and cut off. I checked my servo end-point when I installed the engine, but the first time this happened, I turned it down a couple more clicks just to make sure. But, it happened again. After the 2nd time, I checked the pinch bolt and it wasn't loose. It was still tight but the carb was out. So, I put loc-tite on the pinch bolt, tightened it down hard and went back out. In 2 min it popped out again. The carb is no-where close to touching the break disc so it's not that either. And, it slides smoothly with no binding at all.

I'm pretty much out of ideas on this one. The only thing I can figure (and I know this sounds crazy) is that i'm pushing down too hard on the carb when installing it and the crank is pushing it out. I'm going to check the bottom of the carb to see if there are any marks on it.

Other than that, i'm out of ideas. I'm considering putting "safety wire" on the carb to keep it in. I figure either that will hold it in and that will be the end of it, or something else will happen and i'll see where the problem really is.

Any other suggestions?

Well, the only thing I can come up with is the following... The pinch-bolt is there to hold the carb on. If the carb's coming off it's not doing it's job. Simple math really. Why? Can't say but to quote Conan Doyle, who puts it in the mouth of Sherlock Holmes: “When you eliminate the impossible, whatever is left, however improbable, must be the truth.”

Terrances 8th scale did that last year, ask him about it.

I have seen this happen to a few different motors over the years, usually it is a bad pinch bolt, what happens is, the 2 halves of the pinch bolt bottom out on each other before actually tightening up on the carb. It might even feel fairly tight when sitting there, but when everything heats up, it will expand and come loose. You could try a different pinch bolt, or just dremel a little off the face of the two halves of the pinch bolt, the parts that meet up, so it can "pinch" more before bottoming out. The other thing to check would be that the phenolic ring around the carb, if it has one, is not cracked, or tapered or something like that. If it is a one piece type pinch bolt, the end of it could be bottoming out on the nut before it pinches well. I think the only way you could fix that would be a new pinch bolt, or a washer between the nut and motor case, the washer would need a big enough I.D. to go over the pinch bolt itself. GOOD LUCK!

Thanks for the advice on the pinch bolt. I think I might try to cut a little off the ends to try to get a little more pinch out of it. The insulator looks fine too so it's not that. Since it is a 2 piece pinch bolt, cutting a little off each side will probably help. That would explain why it felt tight but actually wasn't fully pinching the carb. This is good advice. Thank you.

I will check with Terrance too Craig, thanks.

Hi

I have now put about a gallon through my R01A.
Should I change the rod ?
Have any R021A rods failed?

Thanks

MRT
 

HI Guys

check this OUT!!! :D :D :D

this engine is really lightweight !!! :eek:

Great! Cannot wait to see the .21 version of the Tuned mills. Have you got one unit? Please, give feedback of it if you managed to put one of those on your car.

is that a composite carb? sirio like :weird:

how is the tuned one compared to the stock one?
is there really that much different?
do they put out the same numbers?

Looks like a metal carb to me. What are you smokin Gent? :lol: I'd love to have one of these but they're wayyyyyy out of my price range.

Carb is metal only made black with anodisation.

putting on one today :D

running in tmr :sneaky:

saw the .21 version too. :D

will update on the performance :D

finally is on the car :D

can't wait to run in tmr :D

Do you also own the MR12-T01A? Would be good to get a performance comparison.

that is f***en sexy!
take a vid of it running

i think its way over priced to have no wins and track time, i love mugen but beeee real

Wierd
 

Hi all,

Something really wierd happened today. Picked up a new Ninja .21, Murnan modified full ceramic, pre-run in...Ran great, did 1.5 litres through it on the first day out without leaning the top or bottom end too far out. The engine ran fine all day. Took it home to check out the internals for the first time to make sure everything was ok and I found something wierd had happened.

There were two 5mm long triangular shards of metal in the crankcase...but no other evidence internal damage whatsoever. It seems that the pieces had not been bouncing around either as the inside of the case and other internals looked fine. The pieces turned out to be from the bottom of the exhaust port side of the piston. That has not happened before with my other .21 Ninjas. I guess that I will have to replace the damn thing as the balance will be all out etc. etc.

Anyone had a similar problem with a Ninja? Plain wierd considering the engine was not run hard in the slightest and still on the rich side...

hi, the engine is really powerful :eek:

and not fully run in yet :D

and is better than T01A :D

You have suffered a piston breakage (yep... s*it happens sometimes). Your P/S is shot, you need to replace it with a brand new kit. Sorry for giving you bad news about this.

Piston breakage is a very rare ocurrence, seen only two in so many years.

What I'm seeing so much lately are sleeve failures due to over-porting the two small eyelets on the exhaust port, they weaken so much that could break and fall apart and leave a big exhaust port (seen lately on a brand new JP Eagle 9pt).

So people need to start giving a look on their exhaust ports from time to time to see if their 3 exhaust ports have changed to 1 big port.

Have you checked the combustion chamber height? how high came it? still come too low or ir a thing that has been fixed on the new units? My last R01A came slightly higher than the original R01's.

I have still some very nice STi's but.. planning to get a T01 on the next weeks.