With the help of KnowsAlot, I tracked down the MotorCycle our powerplant was birthed from. It is the Yamaha Tenere 660XTZ. you can see her @ www.tenere.ch then hit "Tech Tips" then "Story Der Tenere" scroll down. Notice also the "Super" Tenere 750cc. Hmmmm..... a 750 Raptor in the Future? From what I am understanding, this is one bada$$ little b!tch.

 

Zombie......do some searches around late 2000 under my nickname. I dug up a ton of info concerning the origins of the Raptor engine. You will find several street bikes used the engine in several configurations. One interesting note is the street bike version and the '01 Raptor have the exact same internal gear ratios.

 

Here are the specs translated.

Model XTZ660
production years 1990 - 1999
capacity 659cm3
performance 48PS
torque 57Nm
starter electrical
level of fuel in the tank 20lt
Wheels v/h 21 "/17 "spring travel v/h 220/200mm
weight 195kg.

I assume performance would be horsepower?

 

So our Raptors are in fact powered by a 12 year old design. Kind of humbling if you ask me. The fact that the transmission gear ratios are the same as a European street bike makes me suspicious as to just how much time Yamaha spent on development time. If the gears are the same, that definitely explains why the transmissions were giving out (higher torque loadings due to increased contact patch and weight of quad). I just lost some respect for Yamaha on that one...

 

Yep, add reverse, lower the compression, de-fang the cam, and add another induction......we have Raptor! The ratio thing is why reverse is so fast.....only changed the ratios when absolutely necessary. A 12 year old engine had it's advantages though......proven.....but in a street bike version.....haha.

 

The conversation went hypothetically like this from deep within Yamaha of America.....
Excellent idear Knobby (nickname for the guy that designed the Raptor)....we can transplant the engine from an existing motorcycle and everything will be fine in an atv application.
Knobby: Me think me can de-tune it enough so we will not have to worry about breaking parts. Me think me is a genious. Reply: Me think so as well (slaps Knobby on back with big grin).

 

The heading "Performance" does refer to the horsepower. The German word for horsepower is pferdestaerke which is abbreviated PS. So the motor in the bike had 48 freakin' horses stock! I think I'll order that cam and piston now. . .

 

http://www.tenere.ch/english/eindex.html is the english version...

That 750 engine is not based on the 660, the article says it is a twin... now wouldn't that be sweet!!! [img]i/expressions/face-icon-small-happy.gif[/img]

 

A 750 twin, shoe horn that bad boy in the Rap,can you say OOooffaahh!

 

I believe that the 750 you mention is a two cylinder model.

You can look farther back than the SZR and TZR660 for the source of your engine. Try the air cooled xt500.