Total Motorcycle Community Forums

OK, this "reduced effect" thing is bugging me. There are sites all over the internet saying things about reduced effect motorcycles, so they must exist, but nobody knows about them.
According to bikez.com reduced effect is:
"In some countries certain motorcycle models are sold with less horse power to comply with legal or insurance regulations in that country. For instance, a country might allow 16-year-olds to drive 125 ccm bikes with no more than 15 hp. The bike would then have to be modified to output no more than 15 hp. In another example insurance companies may not want to insure bikes with more than 100 hp, or may increase insurance rates for these bikes to the extent that most people would want to buy a reduced-effect version of their bike instead."
I have a 1984 Yamaha XS 400 Maxim. I wanted to know how powerful the engine is so I looked it up on the internet. This is my bike to the button:
http://www.bikez.com/motorcycles/yamaha ... t_1982.php

That page says that the 399cc DOHC engine is 27hp.
My friend has an '82 XS 400 Herritage Special. It's a completely different bike, different engine, SOHC, it is also rated at 27hp. My engine should be more powerful because of the DOHC so I looked at another bike that has the same engine. The XS 400 Seca:
http://www.bikez.com/motorcycles/yamaha ... c_1984.php

That website has the seca's engine at 45hp, same engine (DOHC 399cc)

I asked my mechanic, a yamaha specialist, very expierienced motorcycle mechanic, if he knew about this and he said that it was very unbelievable to be able to have a 400 @ 27hp and 45hp. And that he has driven lots of maxims and secas and they are both just as fast, and that the website probably just put the numbers there.

The reduced effect is what bothers me. I'm not sure if I have the reduced, 27hp version, or the 45hp version. I believe that there is a reduced effect engine, I'm not sure if it was even in Canada, or if its for just certain countries. I also dont know if it's just on the Maxims or if its for both, maxim and seca.

This is already too long, read, ask questions.
This is a russian motorcycle specs website, they also have differeces between regular and reduced effect.
http://yamaha-automoto.podkapotom.ru/ca ... 7m488.html
compare 2 of the bikes, ie: XT 600 and XT 600 (reduced effect).

If you bought the bike here in N.A., I doubt it is a reduced effect (restricted) bike. Unless it was imported from the Europe or Japan market, where many bikes are offered in both 'regular' and 'light' versions.

But I'm just guessing at this one, so......

...I think I should race my friend who has the Herritage Special. I should win since mine is DOHC. but his is a 6speed and mines 5speed

...tomorrow

unfinite wrote:...I think I should race my friend who has the Herritage Special. I should win since mine is DOHC. but his is a 6speed and mines 5speed

...tomorrow

There's all kinds of "I should slap you" wrong here starting with "think I should race..."

Why are you assuming that DOHC means its going to be faster or accelerate better? Theres more to an engine than how many valve cams it has. The idea of racing someone to test weitehr or not you have a "reduced effect" bike is riddiclous.

Does the bike go where you want it to go?
Is the bike fun to ride?

If you answered yes to these, then quit worrying about it.

So, for engines that have the same power output, the one with dual overhead cams has more power output?

And, of course, the weight of the bike+rider and the gearing and power delivery have nothing to do with who will win the race

Buzz is correct. You are unlikely to find a reduced effect motorcycle in N.A. unless it was imported from Europe or Asia. Even when they have been, the importers usually remove the simple restrictors on the intakes to make them full power again.

As for SOHC versus DOHC. Yamaha upgraded the XS400 twin's engine in '82. The most noticable feature is the extra cam. As far as hp claims are concerned, don't believe everything you see on a website. I've seen some silly hp numbers proffered on the Bikez website. The 399 cc DOHC twin did make a few more HP than the 392 cc SOHC, but 45 hp is an extremely optimistic number. Factory hp claims from the 80s are at all over the chart. Some had a basis in reality, others didn't.

Forget the numbers and just ride. If you and your buddy want to have a horsepower pissing contest, just find a dyno. After 22 yrs. claimed hp numbers are pretty meaningless. The condition of the bike will have a lot to do with how much actual hp the engine will deliver.

flynrider wrote:Buzz is correct. You are unlikely to find a reduced effect motorcycle in N.A. unless it was imported from Europe or Asia. Even when they have been, the importers usually remove the simple restrictors on the intakes to make them full power again.

As for SOHC versus DOHC. Yamaha upgraded the XS400 twin's engine in '82. The most noticable feature is the extra cam. As far as hp claims are concerned, don't believe everything you see on a website. I've seen some silly hp numbers proffered on the Bikez website. The 399 cc DOHC twin did make a few more HP than the 392 cc SOHC, but 45 hp is an extremely optimistic number. Factory hp claims from the 80s are at all over the chart. Some had a basis in reality, others didn't.

Forget the numbers and just ride. If you and your buddy want to have a horsepower pissing contest, just find a dyno. After 22 yrs. claimed hp numbers are pretty meaningless. The condition of the bike will have a lot to do with how much actual hp the engine will deliver.

Hey, cool. A real reply.
I didn't end up racing. lol. Don't worry, it would have just been a friendly race to see if mine is actually so powerful. I'm just curious, I like to know stuff...and knowing what kind of bike I have is knowlege.
I didn't know what reduced effect was, and now that I know that mine probably isn't reduced, I'll assume its better than my friends lol.
From what I've seen, if an engine doesn't have DOHC or at least SOHC & 4valves/cyl, they're usually not as great for performance.

I just didn't like that my bike was rated at either 27hp or 45hp. that was a big power drop, I didn't want to be getting less than what I'm supposed to get.