mikstr

Check out the link:
http://mototuneusa.com/two_free_horsepower.htm

comments?

cheers
Mikstr

E.Marquez

Been using um for a few years now in my DRZ450. The CR bump is SLIGHT... but its a combo of little things in a single cyl they get you to the end. CAUTION.. in many heads, you have a thread or two on the body of this plug that will extend into the combustion chamber. If you do not remove this plug once and awhile, you will end up with a build of hard carbon on those threads, and do damage to the head as you remove it. I do not know if this is the case on the VTR, but it has been on a few other bikes.

mikstr

thanks for the input

mikstr

shayne

Interesting.

If the plug was too long, and extra washer would sort that out.

E.Marquez

1: You would be asking for a leak
2: Then you would not get much if any CR increase. It's not a problem unless you run your bikes way rich, and or, do not remove your plugs but once a year. This is a simple mod, for those that work on bikes for fun, and or are trying to get every possible HP from a motor.

Scooberhawk

Anyone find the "Break In Secrets" link at the bottom under Motorcycle and Roadracing Tech Features? Interesting article. Makes me wonder...

E.Marquez

Same answer as mine above. It's not a "new" thing,, He was just the first to write it up and set it to a web page. It works very well. Proven by hundreds of motors, both high end race motors and OEM street motors. I've used it on dozens of motors myself, from start to finish, including tear down months or years later. It works. But as this is the internet.. there will now come on 10 people who are going to quote the owners manual, tell us about the OEM engineers are all knowing as opposed to some guy on the internet, ect ect ect. That’s ok.... It's there motor. I've been inside a lot of those "OEM manual" broken in motors........ I'll stick with what works.

shayne

Back to the plugs, agree with the possible sealing problem with two washers.

My other thought is that this mod will work better in 4 cyl engines than twins, and also smaller capacity engines. The smaller the combustion chamber the larger the effect the plug will have, as it will be a greater percentage decrease in chamber size. So maybe on our bikes with their two large cylinders it may amount to "not much"!

mikstr

I came across this topic on a snowmobile forum where someone stated that a well-known Yamaha racer was claiming 2-3 additional hp (in addition to greatly improved throttle response) on a Yamaha Apex snowmobile (essentially a 2002-2003 converted R1 engine).

Scooberhawk

So I guess that means, considering our larger cylinders and lower redline, that we'd make maybe and extra 1/2 to 1 HP...??

Heh, I'm just making a reasonably educated guess, based on the Yamaha racer's claim.

Hey.. seat-of-the-pants dyno is where it's at. Someone should throw them in the SHawk and tell us what they think! heheheh