87 MODEL QUICKER THAN 99 MODEL

[leonard]

My long lasting love affair with my 87 kdx 200 was recentley challenged when I bought a second hand 99 kdx 200. First impressions of the 99 was that it just felt so much better - better brakes, suspension, seat position and low down torque. Problem is when I line up the old and the new in a straight line drag the old takes the honours. Old bike has standard exhaust and new bike has rev pipe and fmf mufler. Both have the airbox opened. Both have a stong mid range but the oldie just seems to have more up top. I checked the compression on both to be 1000 kpA on the 99 and 1100 on the 87, so not much difference. Anyone ridden both bikes and share my views?

[greengoblin]

Leonard.
I recently bought my 87 from a guy that had just bought his 2007 kdx and he had spent over $400 to make it as fast as the 87 in a drag. Now I've since added an FMF Fatty and FMF Turbine Core Spark arrestor. I ride with my brother most of the time, and his 300 KTM MXC doesn't pull away from me any more. We ride mostly woods here in Michigan, but we do open it up on a fire road or a connecting trail on occasion.
There are other Mods I can get done to my carb, but for now I am very happy with the performance that the pipe and muffler has given me. I for one am very Surprised with the power of the old air cooled motor.
Take care down under, mate!

[GS]

New ain't always BETTER!!!.......and one should never underestimate the very slight psychological advantage of riding an 'underdog' bike.

I've heard more than once "where in hell you'd come from?" while riding a TRULY clapped-out Yamaha RT180, way back when. (but, I still have it somewhere)

Makes the beer taste just all that much better....and isn't that good enough reason?

I'm delighted that your 'ol KDX still shines brightly!

Where do you think the KDX 'legend' was born from?

You're ridin it!

[kawagumby]

The air-cooled bikes can't maintain the power under constant load - the power fades where the water-cooled bikes won't - and your jetting effects remain more constant too.

[Green Hornet]

My 85 will smoke the Newer Ones

[2001kdx]

I've heard more than once "where in hell you'd come from?" while riding a TRULY clapped-out Yamaha RT180, way back when. (but, I still have it somewhere)

I still have one of those! T U R D!

[GS]

We call her ( the RT180) 'Artie' ....as in 'R-T'

TURD works too!!

[leonard]

Sounds like I am not the only one amazed by that old air cooled technology. I have tried a variety of the green machines and can summarise by saying that in 1989 when they went watercooled and street friendly they totally lost my respect, when they went to 250 cc in the early 90 they looked the goods but weighed as much as a tractor and went as bad. Finally the 220R model which I have owned (american import) which just had nothing up top but would be suited to climbing Mt Everest was just not for me, you Americans must spend a lot of time in the woods chasing bears. So each time I go for a ride I have to pick between my dinasour 87 model and my shiny 99 model and more times than I would of thought I will take that bouncing ball bearing preastoric monster. BTW If someone has pressure tested their bikes I would be interested to know if they got any reading over 1000 kPA as this is the maximum as specified in the manual.

[TWMOODY]

Leonard.
I recently bought my 87 from a guy that had just bought his 2007 kdx and he had spent over $400 to make it as fast as the 87 in a drag. Now I've since added an FMF Fatty and FMF Turbine Core Spark arrestor. I ride with my brother most of the time, and his 300 KTM MXC doesn't pull away from me any more. We ride mostly woods here in Michigan, but we do open it up on a fire road or a connecting trail on occasion.
There are other Mods I can get done to my carb, but for now I am very happy with the performance that the pipe and muffler has given me. I for one am very Surprised with the power of the old air cooled motor.
Take care down under, mate!

Hey Greengobblin
I spent more than that !!!!!!
Good to hear that bike is rippin good !

[motorhed220]

aight sorry to rain on all ya'llz parade...but i MUST ask this...

1st: Is the gearing the same on both bikes? Do they have the exact same tooth counts on both front and back sprockets?

2nd: When you dragged, did you swtictch bikes and do it a second time? (this would prove its the bike not the rider, or show its the rider not the bike.)

3rd: You say your 99 has fmf exaust head and muffler, is the jetting right?

4th: how bout the tires? are both bikes equipped with the same quaility or tires?

Now if you answer all of these with yes...then and it doesnt suprise me...Your 87 truly IS faster. It doesnt suprise me because back in them days, they built bikes for the drag strip and not for the winding trials.

You said the 99 had beter suspension, seating, brakes etc, so i would still say that if your doing a lot of open riding where top end counts, then the 99 is still a better choice, as it will still FEEL better on the long hauls.

BUT, your experiment proves the age old saying that "They just dont make em like they used to"...Its AWSOME the dinoaur rips faster, and to be honest, i would love to see the looks on some peoples faces when you come tearing past em on a bike thats 20yrs old, and they got brand new KTM's and the like! Rock on dude!

Imagine what would happen if you sold the 99, and bought exaust, reeds, carb and head mods for the 87? Tha damn thing would be a rocket! or do a fork conversion...The list goes on! Keep on Rippin dude!

[Indawoods]

Now if you answer all of these with yes...then and it doesnt suprise me...Your 87 truly IS faster. It doesnt suprise me because back in them days, they built bikes for the drag strip and not for the winding trials.

I disagree... the KDX has always been a purpose built bike....

[2001kdx]

Fork Swap on an '87? Hell no. You mean '87 motor in KX125 Frame! Now there's a party! Bullet proof reliability, Plus you can't beat the simplicity of an air-cooled 2-stroke!

[motorhed220]

i never said he HAD to or SHOULD just that its an idea lol, wouldnt that be something to see thogh? a Tricked out 87? truly a one of a kind bike!

I disagree... the KDX has always been a purpose built bike....

True that, and i take it back and re-phrase..."They built em to rip in a straight line more so, then they do today...or at least to a minor degree...Why else would the 87 be faster? thats a question worht answering!

WHY IS GODS NAME IS A 20 YEAR OLD BIKE SO FAST!

[2001kdx]

I wanna say your '99 is not working properly.

Line it up next to me on my 200 and you will be history

I don't think straight-line performance is important in dirt bikes though.

Except if I had a KX500. Then I'd be pissed if anyone pulled me.

[motorhed220]

Hahahahahahahahahaha, so would I...But your right about the straight line preformance on dirtbikes...its also NOT GODD to rev the bags outta these things in a stright line for a long time...the motors just aint built to do it...thats how ya BLOW HEADS!!! If ya wanna go fast in a straight linethen do this:

Sell your bike/bikes

Buy a Skidoo Rev 600, 700, or 800 and blast away.

Or be the fastest thing alive and buy a Mach Z, and you wont be touched by anything...Put a slick track on em and replace the skies with wheels...take her to the local drag strip and pull ANYTHING!!!

damn frogs shure can build a sled dats fo sho!

[jhard527]

Sounds logical that the 87 would be faster. They both use the same piston. Same displacement. The 87 doesn't have to bleed off power pushing coolant or drag around all that plumbing. Now, line 'em up after a couple of hours of hard riding and it may be another story.

[motorhed220]

i always thought liquid cooled motors were faster and had MORE Horsepower?

[jhard527]

I'm sure that the water-cooled engines do make more horsepower, I just don't think that it's very much more. The water allows tighter manufacturing tolerances and higher compression ratios; but the H models have a 7.9 : 1 and the C has 7.7 : 1. IMHO going fast has less to do with HP and much more to do with the rider, suspension, and condition of the bike. So straight line, the C is probably more than capable of holding its own, it's the trails that may begin separation.

Having said all that, it is interesting to see how the C models were viewed in their day vs. how the H is viewed today. In a 1986 review by Cycle World, they wrote "But the KDX isn't just the king of its displacement range; it's competitive with with enduro bikes of any size..." The whole article showed love to bike.

The H is no doubt a better bike than the C, I just wouldn't underestimate the air-cooled bike. After all, Jeff Fredette used one to make all KDX heads proud.

[kawagumby]

As I said in an earlier post, the water-cooled means more CONSISTENT horsepower LONGER. Period.

I raced the air-cooled models for several years and had three of them. Check my gallery and you can see me on two of them in competition. They were great bikes, true. but if you do more than drag race you'll find that they tend to fade significantly when compared to either of the water-cooled models. Water does a better job of controlling cylinder thermal distortion and combustion chamber hot-spots. The difference is more than just noticeable.

That applies to any like-displacement air-cooled vs water-cooled bike - that's why they're water-cooled today!

http://kdxrider.net/forums/modules/albu ... sized.jpeg

[Indawoods]

My XL350 used to fade out after a while.... sucked.