Yes there is...670HO has the X stamped between the spark plugs on the head, also the oil injection system is different then a regular 670.
A 670HO will have DESS thether cord.

 

Sometimes its just a D or a blob. Can be on other side also. Usually by the T but can be on the other side of writing

 

also on the head there is 2 sensors on either side of the thermostat housing. on a regular one there is only the temp sensor.

 

easy -- no 670 HO in MXZ until 1999. That's a std 670

 

Yup ^^^^ only the Summit had the HO in 98.

 

Thanks Guys for all the Helpful Answers. With all the Engine Transplants in some of these older Sled's, it's nice to be able to recognize maybe a Gem. I once bought a 93 670 Engine that was advertised as a 617. Had No Data Plate, but I recognized the bigger PTO Taper.

Not really what I was looking for, but for the price I'm going to go look at it.

Thanks Again!

 

alot of people assume that it's a 670 it's a HO, i've boughten one like that, advertised as an HO. but to use HO motor you need all of the electrics that go with it too, different ignition. the key way is in a different spot on an HO crank then a non HO engine. your almost better off with a non HO motor and build from there, cause to find CDI for an HO or summit x, well they only made the X for 2 years and the HO for one. regular 670 you can use 583 cdi. more common parts and you can make a 670 run harder then a stock HO without too much fuss.

 

What does the HO even stand for?

 

What does the HO even stand for?

I believe HO stands for High Output! The Standard 1993 670 Dynoed (112hp at 7750rpms) used a Domed Piston and 11.5cr, and the 670HO used an almost Flattop Piston and 12.5cr and made around 122hp at 7750rpms, never found any real good Dyno data for the Stock 670HO. But the two Heads Combustion Chambers are different, and Cylinder Porting/Timing is a little different. Of course, Single Tuned Pipe vs Dual Tuned Pipes can also affect HP made, usually 10-14hp. To my knowledge, there has only been a 380HO, and a 670HO, from the 90's, and the 380HO was never offered in the Continental USA or Canada, only Norway and Alaska that I ever found. In the 2000+ engines, there is only I think a 600HO(125hp) and a 800HO(160hp) is all I think. I don't really keep up on the new stuff that much so there maybe others.

Almost all Standard Liquid Cooled Rotax's use 11.5cr. I have seen a 532UL based off a 521 Skidoo, manual that showed a 12.6cr. But no one has ever confirmed here there was ever a Sled Engine called a 521HO. All 532UL's are based off the Skidoo 521 Engine I have ever seen showed 11.5cr and made 60hp at 6500rpms. The 521 Skidoo was rated around 85hp at 7750rpms I think. The 583 was rated 97hp at 7750rpms.

Found this neat Calc: Approx Numbers depending on Head Gasket used. I used .050mm instead of .050".

http://www.csp-shop....rennraum_en.php

670 Race Head.

Result combustion chamber volume calculator

Diameter: 78 mm
Stroke: 70 mm
Compression ratio: 14.5 : 1
Deck height: .050 mm

Combustion chamber volume: 25 ccm

670HO

Result combustion chamber volume calculator

Diameter: 78 mm
Stroke: 70 mm
Compression ratio: 12.5 : 1
Deck height: .050 mm

Combustion chamber volume: 29 ccm

670 Standard

Result combustion chamber volume calculator

Diameter: 78 mm
Stroke: 70 mm
Compression ratio: 11.5 : 1
Deck height: .050 mm

Combustion chamber volume: 32 ccm

 

What does the HO even stand for?

High Output

 

The nice thing about a 1998 670 is that they changed the front suspension geometry for that year -- I owned one and it rails turns. A real nice setup

 

Well another bust, the guy sold it already and hasn't taken down his ad! Another guy still has his ad up, and I know that Sled was sold 3 weeks ago. Wasn't what I was really looking for anyway, but was a good price. Stumbled upon three vintage JD sleds, and a basketcase Skidoo from the late 80's.

 

He had it sold and other guy backed out, so he texted me to see if I was still interested, had it delivered today.

 

i love my ho just saying. lol

 

i have a 99 mxz ho 670 and a 98 mxz. love them both but the ho has a little more pop under the hood

 

Look on the head the HO will have a port on both sides of the top coolant hose. They all have them on the right with 2 prongs to plug wires in and the HO will have another port on the opposite side of the coolant port on top