Old review and general chat

[Ninjinsky]

Just came across this old Brit pregen review. Concurs almost exactly with my own opinions, which was refreshing, particularly about the 2 strokiness of the engine

http://www.motorcyclespecs.co.za/mod...x250r%2086.htm

I was looking at tests because I always thought mine was around 40 bhp and it ran similar times, in fact slightly better, than my RD400. I had read people talking abysmal outputs for pregens and they didn't seem right. also it will run well into 3 figures not the 97 often given. I know there was a carb size change at some point and a 33hp restricted version for the UK so maybe I'm just lucky.

Anyway here's a nice little ride video by a Kiwi if you haven't seen it yet. Hope it doesn't give the yanks a co-ordination crisis

Link to original page on YouTube.

[Alex]

[momoru]

It looks so fast when the speed is in kilometers!

[subxero]

Originally Posted by Ninjinsky

Just came across this old Brit pregen review. Concurs almost exactly with my own opinions, which was refreshing, particularly about the 2 strokiness of the engine

http://www.motorcyclespecs.co.za/mod...x250r%2086.htm

I was looking at tests because I always thought mine was around 40 bhp and it ran similar times, in fact slightly better, than my RD400. I had read people talking abysmal outputs for pregens and they didn't seem right. also it will run well into 3 figures not the 97 often given. I know there was a carb size change at some point and a 33hp restricted version for the UK so maybe I'm just lucky.

Anyway here's a nice little ride video by a Kiwi if you haven't seen it yet. Hope it doesn't give the yanks a co-ordination crisis

I'm no genius but how does roughly the same engine go from >40hp to ~26hp? The spec sheet on the write up says 45hp ill give them benefit of doubt they are claiming at the crank and the later reported 37hp is at the wheel. Even still 37hp from a cheap 4stroke 250, I just find it hard to swallow with out any data to back it up. People today have a hard time getting over 35hp even with boring out cylinders and upping compression along with a nice port & polish. Where did they find >10hp where tuners today can't from standard bore and stroke?

If these engines and bikes had so much power why aren't 250 class racers snatching them up like hotcakes?

[Ninjinsky]

Okay,
This is down to differences between early and late pregens.
The first UK and oz bikes were 40 hp (39.4)
The US bikes were 37
There have, over time been a whole raft of carb and timing changes to these engines as detailed in the wikipedia page
http://en.wikipedia.org/wiki/Kawasaki_Ninja_250R

The 40 hp engines had large carbs and were peaky developing less mid range and torque than the 37 hp.
The UK bikes are sluggish unless you keep them above 8000 when the "scalded cat" thing happens Hence our opinion that they feel "2strokey" to ride.
The US and later UK revisions developed less peak but more tractability.

Hope that Clarifies the issue for you, ( and 45 must be a misprint in the test article)

ps The early CB 750 went the same route with an initial 67hp dropping to 63hp once the model was established.
As a racer the GPX didn't stand a snowballs chance against the Suziki's exquisite 60-70 hp RGVs and Yamahas of the day but its durability as a workaday bike is excellent by comparison

PPS What do you guys successfully Race Ninjettes against, It can't be 2 strokes.

[subxero]

Originally Posted by Ninjinsky

Okay,
This is down to differences between early and late pregens.
The first UK and oz bikes were 40 hp (39.4)
The US bikes were 37
There have, over time been a whole raft of carb and timing changes to these engines as detailed in the wikipedia pagehttp://en.wikipedia.org/wiki/Kawasaki_Ninja_250R

The 40 hp engines had large carbs and were peaky developing less mid range and torque than the 37 hp.
The UK bikes are sluggish unless you keep them above 8000 when the "scalded cat" thing happens Hence our opinion that they feel "2strokey" to ride.
The US and later UK revisions developed less peak but more tractability.

Hope that Clarifies the issue for you, ( and 45 must be a misprint in the test article)

ps The early CB 750 went the same route with an initial 67hp dropping to 63hp once the model was established.As a racer the GPX didn't stand a snowballs chance against the Suziki's exquisite 60-70 hp RGVs and Yamahas of the day but its durability as a workaday bike is excellent by comparison

PPS What do you guys successfully Race Ninjettes against, It can't be 2 strokes.

just FYI wiki does not serve as an acceptable reference. Find me a handful of legit dyno's then we can talk.

Again, why can't tuners today hit these numbers with stock bore and stroke if it is simply carb/intake/exhaust mods + some timing? Why can't a 40hp engine go over 97mph? but it does a 1/4mile in 13 odd seconds and hits over 80mph in that quarter? There is a lot of conflicting info that just doesn't add up but I wouldn't expect anything less with info that is pulled off of wiki

as far as cb750 dropping 4hp ~ 6% I hardly consider that comparable to a 250 dropping >10hp ~ 25%

not sure about your "what do guys successfully race ninjettes against?" question Ninjettes race against other ninjettes in stock classes. People mainly seem to race the stock new gens. But I can't imagine rules could prohibit you from racing a stock old gen from 1987 which somehow has a >25% increase in hp but for some reason people don't race them in stock 250 classes? Clearly in stock 250 classes 2 stroke 250's are no allowed for obvious reasons. Similar to Motocross. The 125's 2strokes get paired with the 250 4's and the 250 2's get paired with the 450 4's But unfortunately it seems in sportbike racing a lot of places don't let 125 2strokes even race against the 250 4strokes, they are forced into other classes

[Ninjinsky]

I just posted an old road test I found, that's all.
I'm not here for an argument
Sorry to spoil your day

[subxero]

You did post an article... and I read it and I voiced my opinion and I asked some questions of concern regarding the article and what it had to say. I am not a fan of misinformation it happens all to often in the news or any media for that matter and this article reads to me as such. I could be wrong but unfortunately I like hard facts based off of good data and I just don't see it.

you need to relax

[Ninjinsky]

The Official Kawasaki Ninja 250 R service Manual :-

Maximum horsepower 40 ps (39.5 bhp) @ 12,500 rpm

[subxero]

Originally Posted by Ninjinsky

The Official Kawasaki Ninja 250 R service Manual :-

Maximum horsepower 40 ps (39.5 bhp) @ 12,500 rpm

conflict of interest and that would still be at the crank even if it was legit

[Ninjinsky]

Definitely crank, that we can agree on

I have contemplated Slick 50 http://www.slick50.com/ as a way to get more of the crank numbers to the back wheel but chickened out because I am not sure how it fares with wet clutches.