670 rotax head

[bigjohn1]

i was wondering if anyone might have an extra head for a 670 that they would be willing to part with i know this is the wrong spot but i need it asap and this is the spot it would get noticed first my buddy cooked a piston last night and we are planing a trip west for friday if anyone has one pm me
thanks

 

[synergycycle]

To get one you are going to have to share what year it is.

 

[bigjohn1]

its a 97 mxz

 

[magnet]

pm beachsled on here he might still have one kickin around.

 

[maxwell]

guaranteed he does lol

 

[BeachSled]

I do have one for sure!! Shoot me a pm with your number, I have so many 670 and s chassis parts I would be more then willing to help a guy out. Not looking to make a mint at all.

 

[TROLLCAT]

I got 2 670 HO/X heads cheap pm me

 

[magnet]

I got 2 670 HO/X heads cheap pm me

wont work on a non x engine.

 

[TROLLCAT]

wont work on a non x engine.

that,s why I put ho/x so there are know screw ups lol

 

[Bogger]

I may want those trollcat..I can only clean mine up so many times

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[TROLLCAT]

I may want those trollcat..I can only clean mine up so many times

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one has been chewed up a little on one side , the other chewed up both sides

 

[TROLLCAT]

here they are

 

[SierraNV Summit]

I was just looking at these heads. I guess luckily for me I have experienced for the first time a piston failure on 670ho. My head looks similar to these and just on one side. It does look like these where polished as smooth as possible though as mine is still quite jagged.

If I was to polish, sand, etc. mine and it was similar to these does anyone think I would have a problem re-using my head?? I'm not looking for optimum performance as this is my second sled that usually my wife or beginners ride. I just want reliablity.

Any info would be appreciated.

Thanks

 

[Armilite]

I do have one for sure!! Shoot me a pm with your number, I have so many 670 and s chassis parts I would be more then willing to help a guy out. Not looking to make a mint at all.

=======================================================
Hello:

Looking for a Skidoo/Rotax 670 head made by Unionbay. Also need there rubber intake for their roatary side cover. Thanks.
Rich

 

[Armilite]

I was just looking at these heads. I guess luckily for me I have experienced for the first time a piston failure on 670ho. My head looks similar to these and just on one side. It does look like these where polished as smooth as possible though as mine is still quite jagged.

If I was to polish, sand, etc. mine and it was similar to these does anyone think I would have a problem re-using my head?? I'm not looking for optimum performance as this is my second sled that usually my wife or beginners ride. I just want reliablity.

Any info would be appreciated.

Thanks

==============================================================================
I heard the Crankshop can machine them for inserts. Not cheap. But then all you have to do is replace an insert.
Rich

 

[Armilite]

here they are

============================================
WOW, what are you burning for gas, octane? What rpms do you run? I know they say 50:1 oil, but a guy who builds these Rotax 670s for airplanes, who use a constant rpm for hours, MAX 6800rpm for take off, then use 4000rpm to 6250rpm constant, depending on how fast you want to go, says 670s like more oil, he recommends 40:1 oil, 92 octane gas. He puts 670HO rods(Big Bearings top & bottom) & HO flat top pistons on a std 670 crank/case, with the std. head chamber. 89HP@6800rpm for plane use. The 582UL/618UL dual angle plug head has the same chamber as the std. 670 head.

Has anyone here put 670 cylinders on a 470, a 583, or a 617, case? What piston rod combo work? I know the 583 case needs very minor machining for the 670 cylinders to fit. Like 1/16". They fit ok on the others.

Seadoo(Rotax), made a 650 with a 617(68mm stroke) and a 670(78mm bore) for 650cc.

Is there any other engine combo's anyone knows of. I personally wish to keep my rpms to 6400rpm MAX. The std 670 with 618UL dual angle plug head, and 618UL dual ignition, 618UL pipe makes 90hp@6400rpm.

Rich

 

[neilsleder]

============================================
WOW, what are you burning for gas, octane? What rpms do you run? I know they say 50:1 oil, but a guy who builds these Rotax 670s for airplanes, who use a constant rpm for hours, MAX 6800rpm for take off, then use 4000rpm to 6250rpm constant, depending on how fast you want to go, says 670s like more oil, he recommends 40:1 oil, 92 octane gas. He puts 670HO rods(Big Bearings top & bottom) & HO flat top pistons on a std 670 crank/case, with the std. head chamber. 89HP@6800rpm for plane use. The 582UL/618UL dual angle plug head has the same chamber as the std. 670 head.

Has anyone here put 670 cylinders on a 470, a 583, or a 617, case? What piston rod combo work? I know the 583 case needs very minor machining for the 670 cylinders to fit. Like 1/16". They fit ok on the others.

Seadoo(Rotax), made a 650 with a 617(68mm stroke) and a 670(78mm bore) for 650cc.

Is there any other engine combo's anyone knows of. I personally wish to keep my rpms to 6400rpm MAX. The std 670 with 618UL dual angle plug head, and 618UL dual ignition, 618UL pipe makes 90hp@6400rpm.

Rich

Deano670 on here might know some info on 670. He has a turbo 670 that he is building now. Or you probably give him a shout at his shop. Just search Mad Motorsports on here it should pop up he a supporting vendor