150 xr6 Mods.

[CNT]

What is the best bang for the buck to get some extra Hp out of a 2000 150 xr6?

[kingsbiship]

Cut the heads!

[Ted Stryker]

They can use a little compression, the factory sleeve's have relief cuts in them to bleede a little compression for smooth operation I guess...

[CNT]

Can I remove the airbox and if so will I have to Jet up?

[Trikki1010]

Can I remove the airbox and if so will I have to Jet up?

We cut exhaust reliefs in the lMid(below water at idle), removed airbox and cut head. Put a little kick back in...

You should have to rejet, just run idle, and WOT/cut and see how the plugs for both read. I don't remember the jet #'s.

[RBT]

careful on the cut heads with the idle relief holes, you will get false readings. You have higher compression than you think, as the holes don't bleed off compression as RPM increases.

RT

[diskvalve]

The XR6 heads are actually quite a bit tighter already than the 200 heads. My 1992 XR6 heads were around 37 ccs. stock and my brothers 1995 200 XRI were around 41 cc stock. Although it has been a few years since I cc,d them and can,t remember exact ; these numbers are close. I bought a spare 1993 XR6 engine and the heads were the same cc as the first one . The compression guage reading on an XR6 will read lower than it really is because of those relief slots in the ex port so be careful. I would not cut the XR6heads at all but rather put the thinner head gasket from a 225 promax or 260 2.5 . If your engine has O-Ringed heads which I believe it does then you can not change the squish clearance without lots of machine work --- mike

[Trikki1010]

careful on the cut heads with the idle relief holes, you will get false readings. You have higher compression than you think, as the holes don't bleed off compression as RPM increases. RT

Nothing wrong w/ 32 cc heads ???

[T-REX]

Nutt'in wrong wit 10cc heads either....Makez a 150 feel like a 250!!

[Ron V]

I don't know the cc of the stock heads, but I know that the cold compression on mine is in the low to mid 130s. Mine has the o-ring heads.

Oh, and yes I believe you do need to re-jet if you take the airbox off. The warning label is right on it that says not to run above 3000 rpm with the airbox removed to prevent engine damage.

[Rooster Tail]

I have a 2005 XR6 and I have decided that it's a waste of time and money to hop it up. Just buy a 200hp carb motor like I'm going to do and put it on. Oh don't ever run without the air box on. You will burn a hole in the pistons, Because the mist of fuel needs the box so as on every stroke of the motor it is pure fuel mist or it might suck just air(lean) a couple of strokes then fuel then lean fuel then fuel then lean you get the picture!

[kingsbiship]

And how does the air box make a difference?

[David]

I don't know that it would be worth while upgrading from an XR6 to a 200. Were all the XR2/4/6 series really at the high end of the +10%. That would mean 165 HP.

Take the XR6, remove the spark module, on a light boat I bet it would run close to a 200 with a rev limiter.

200XS or 200 Pro Max is another story.

[Ron V]

I agree that hopping it up is a waste of money and the real cost will be the reliability. A 200 isn't much more, though you can't get a new one with carbs or EFI anymore. The only thing is that the 200s blow up a lot more than the 150s. I would agree the XR6 is a strong 150. I don't know that removing the rev limiter would do a lot except on a really light boat, they are more of a workhorse and make their best power under 6 grand. Over 6200 is pretty hard on the internals anyway from what I'm told, and you don't want to run it 6500+ with the oil injection hooked up in any case.

[The Big Al]

I agree that hopping it up is a waste of money and the real cost will be the reliability. A 200 isn't much more, though you can't get a new one with carbs or EFI anymore. The only thing is that the 200s blow up a lot more than the 150s. I would agree the XR6 is a strong 150. I don't know that removing the rev limiter would do a lot except on a really light boat, they are more of a workhorse and make their best power under 6 grand. Over 6200 is pretty hard on the internals anyway from what I'm told, and you don't want to run it 6500+ with the oil injection hooked up in any case.

Well who ever told you was wrong!

Been thier done it plenty of times.

One thing needs to go is the chocked down Tuner! It's very long and small!

This is one engine that a tooner change helps! And helps a lot!
Carbs were our biggest gain!!
With reeds and cut heads!
And it lasted only 8 years!
And believe me! It had a hard life! Run the liven **** out of it!