Which OS engine ?
 

I am planning to buy a new OS engine, for my buggy.
I am between xz-b blue head and the hara edition speed.
Which one you recommend? Which one is more durable?
what is the differences between the 2.
I am reading that the hara speed is similar to the speed, is it true?

Being the hara is 2x I don't understand the comparison.

The hara is softer on the bottom and screams higher on the top. You will also see more mileage with the hara. Personally I like the hara engine but it's a little soft on the bottom for some.

Btw where are you getting the hara from?

I will get it from a hb distributor.
Which one is more durable ?
the blue head or the speed hara?

I have heard the xz-b blue heads still have some crank wear issues.

Rex

Frank, thank you for your response.

I have heard the the hara speed edition in a very good engine but it is not as durable as the xz-b blue head or the xz-b speed is that true?
out of the three, which one you recommend ?

I have no issues with the Haras that I run. I have one in my buggy now that has 3 gallons in it or so and it runs great and still has nice compression.

The Blue head XZB still have crankshaft pins wearing out prematurely. If you get an OS get one with a DLC coated crank.

I would get the hara its a awesome mill it has great top end and a smooth bottom. It has power make are you run the right pipe

Not everyone has had the crankpin problem.

I've only got 2 gallons on mine, I won't know about mine until the end of next season. I'll bet fuel and tune are part of the issue. Cold starting maybe as well. I heat up for a half hour with a comp heater before my heats. I've had great life from other engines by heating them up and running in the pits for a little while, then shutting down and carrying them to the stand warm just a few minutes before my run, and restarting.

OP, If you don't KNOW that you need a OS Speed, then you're throwing money away. Get the regular XZ-B, or if you want the DLC crank, get the OS/Ninja JX21 BO2. Just by asking "Do I need a Speed?", kinda means you likely don't need a Speed.

The Fusion engines are also something you might want to look at.

just get the ninja B02.. best of both worlds.. good price and DLC crank.. and it out right screams

Why not buy the best engine? Novarossi.

Why not keep your posts in the appropriate thread??

I might want to run a NR in the future. For now I'll stick with OS until I feel that I want to challenge myself again with an engine that's a pain to tune, uses crappy glow plugs, and takes forever to break in wasteing too much fuel.

Fusion Engines are NR based but come with better details. (3 port with a turbo head, ceramic bearings, etc.etc.) They also have a 7 port Bonito like engine that deosn't quite have the Bonito price tag.

Buy one that has a DLC crank.
Personally I've not tried the Ninja B02, but I still run my B01A occasionally, and it's been a great engine for me.

Put a OS plug into a Nova........ works like a charm and makes engine tune much like a OS !!

Less money then a Bonito, but less performance then a Bonito too...so its all in perspective....

Novarossi have ceramic bearings and turbo heads too.......lol...except a 4 port not a 3 port....4 port is better than 3 port..which is why Nova dropped 3 port in favor of 4 port in their regular lineup........