Is this plausable?

[bajus22]

So I was at the MX track with my buddy. I was on my 87 KDX200, and him on an 81 KDX175. For fun, I suggested a drag race. We both have Boyesen Reeds, stock exhausts and same rear tires. He beat me. We both drag race street bikes, and we're of equal riding ability in the dirt, and he out-weighs me by 30lbs. His bike just screams in the top end, mine just seemed to level off. On one or two runs, and WOT, in second gear, my bike felt like it was losing revs, and as soon as I switched into third, it picked up again. I did the plug chop, and the jetting was spot on. Mind you, I did it back in September, when the air temp was about 20 degrees celsius. When we raced yesterday, it was only eight degrees. Would that effect my jetting enough to change performance that much. I checked the plug afterwards and it looked alright. The bike felt great all day, until I raced him and realized he was quicker. Should my bike be quicker? Thanks.

 

[IndyMX]

is the gearing different?

 

[bajus22]

We were both running stock gearing.

 

[Rich Rohrich]

Maybe it's a technique problem. Here's a secret video of the BIG race:whoa:

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[ellandoh]

lucky guy, seeing a kdx jetted spot on?? is as rare as seeing a sasquatch :boss:

 

[IndyMX]

Of course if you live in Moscow, ID you can see one every day.. Just sayin.. ;)

 

[_JOE_]

Maybe you need air in your tires?

 

[dirt bike dave]

Gearing, tires, slipping clutch on the 200, o-ring chain vs. non o-ring, etc...

 

[Joburble]

If I remember rightly didn't the old bikes scream more and have a little more top end. I Rode a friends 93 KDX200 and I don't think it went as well up top as his old 81 IT175. Anyway, back on topic, his motor may be fresh and yours not so fresh. His reeds may seal properly, yours may not. His bike may just be faster in a drag race and yours easier to ride in the wet slippery woods. If you definately want to win a drag race with him I'd go with sabotage every time.

 

[ellandoh]

your buddy sent his motor into eric gorr and its now a kdx 232 or something. next time he beats you just start screming to the judges "IM CALLING AN INSPECTION ON THE 175" :cool:

 

[reepicheep]

The last 10% of tuning on my KDX-200 (now a 225, thanks Eric) netted the last 40% of performance. So I wouldn't be surprised in the least that a well tuned 175 outran a 200.

I'm restoring a 1971 Kawasaki F8 Bison (250 rotary valve two stroke). Arguably the KDX's great great great grampa. Or maybe the KLR-250's great great great grampa. Probably both.

Anyway, finally got the thing to run (still not jetted right), and the sucker pulls hard! Those old bikes weren't much weaker, particularly at higher RPM's.

 

[bajus22]

I've done all the work on both bikes. I cleaned and jetted both carbs. I just put new reeds in both machines. And both machines have new chains. The only differance is, that I took of the top end off of the 175 and scraped off all the carbon build-up on the piston and head. I haven't done that to the 200. And the cylinder on the 175 was scored pretty good in one spot. I guess I'll try another jet next time and see what happens.

 

[dirt bike dave]

My guess is you are a little too rich on the main jet.

Perhaps your power valve is gummed up a little.

FWIW, I had an '84 200 (no KIPS) and two of my buddies had an '86 & '88 (with KIPS valves). Their bikes 'felt' stronger on top, but there was little to no difference in a drag race on level, hard ground.

But they would pull me on high speed long hill climbs when they could keep the revs up. Sometimes it seems like a grade is what it takes for the power differential to show up.

Try racing him up a hill, or in some deep sand and see if the result is the same. You should have more power than him, so try another playing field that emphasizes power.

 

[bajus22]

Stupid question, what's the 'power valve'? Is that part of the KIPS system?

 

[Dirtdame]

That little arm that comes up out of the primary/clutch cover and disappears into the side of your cylinder connects to the powervalve system. There are two valves and corresponding little ports on either side of the exhaust port that are closed at low RPM, then cetrifugal force from the crank as the RPMs increase causes the lever to pull those valves open to move the air/fuel through the motor better at high RPMs. If those are not timed right or are sticking, it would cut down on top end power.

 

[whenfoxforks-ruled]

Someone throw the manual at Bajus22, PLEASE? Whats the power valve, and I do all the maintenance a post later? And the carbon, yes, very bad, nice friend though! Rich, I was witness to that same event at the old US 30 dragstrip, this guys bike cleared the guard rail as a jump, and nailed the tree dead vertical and no rider, wussy. The drag racing KDX's? Ellandoh nailed that issue! I know that was bad, there are some clean running frogs out there. WAY too many variables though. I can beat most guys on the start, before the gate drops. Its all attitude. Now for the rest of the track, work in progress. The plug chop is good for the main, thats all. The important to us jetting is the pilot, air/fuel screw, clip, slide and a crappy attitude towards your enemy. And some fuel with an ether oxygenate is a cheater, crisply jetted of course, and TRY hanging on.

 

[Dirtdame]

I'd post up a picture from my 86 manual, but they somehow put the wrong information and photos in there on that year model. :think: And this was the OEM manual that came with the bike.

 

[whenfoxforks-ruled]

That is horrific. Is the oem shop manual the same way?

 

[reepicheep]

The OEM manual for the 95 and up 200's has the wrong picture of the crank, which you will discover at the precise moment you are about to drop your crank (fresh out of your deep freeze) into your cases (hot off the BBQ)... this will give you stress and doubt that even though you checked it 8 times, you are indeed about to drop the crank in upside down (because of course the picture of the crank end showing in the manual is different then the crank end you are looking at).

Be strong, stay the course, and don't flop the crank over and slam it in there. :bang:

(They just reused pictures from older models, I've seen it in a few other places in there as well...)

 

[whenfoxforks-ruled]

Thank you Reep! Thats awesome, Kawasaki had a brainfart? And has NEVER felt responsible to fix this! Just charge more for oem parts, that will fix it.

 

[bajus22]

Ouch, the manual hurt.