Bogging

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#1
My kdx bogs of the bottom due to improper jetting and i was wondering if changing the pre-mix ratio and adjusting the air screw will help at all before we jet it? I run 40:1 right now to cut down on the smoke and the bike has no idle and runs rich currentley. I have a DG Pipe on the bike and the Answer SA pipe. I dont know the current jetting off hand, but I have it written in the manual. I wet foul plugs every once in a while, but i remeber before i got the dg pipe i had the stocker and it ran lean. Currentley i have to rev scary high just to be able to drop the clutch from first or it bogs and dies. I know that u are supposed to do that for 2 strokes but this is higher than i rev my friends 125 so. I just dont want to run it like this for too long and damage the motor. Thank You and feel free to move this to the proper forum if I placed it in the wrong one.
 
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#2
Well no one has answered yet so here goes.
Leaning the oil ratio out means more petrol in the gas that gets sucked through the jets so you have richened the petrol air mixture worsening the problem

Use the recommendations from the just kdx website & various threads as a starting point.

Make sure you have a clean airfilter & the muffler isn’t blocked (repack it). Plus once a plug is fouled it may never recover properly.
 

BRush

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#3
Originally posted by NorCal_Red
Currentley i have to rev scary high just to be able to drop the clutch from first or it bogs and dies. I know that u are supposed to do that for 2 strokes ...
Not on a KDX :eek:

Ok. maybe it is jetting, but your description makes it sound severe - so don't get tunnel vision and focus on jetting the exclusion of all else. There are some other things to consider. My bike once exhibited this same symptom when I screwed-up in repacking the silencer and left the packing material (way) too loose. I had to rev it to the moon and drop the clutch just to get it moving. Great top end, zero bottom, so check your silencer. You can jet till the cows come home and not compensate for a blown out silencer. In fact, before beginning any jetting exercise you should repack your silencer on general principles (clean the air filter too). Another thing to consider is that malfunctioning power valves could contribute here. Generally, this is only likely to be a factor if it has been a really long time since your last top end.

Good luck.

ps. You should include what model year you have when posting this kind of question.
 

canyncarvr

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#4
quote:
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Originally posted by NorCal_Red
Currentley i have to rev scary high just to be able to drop the clutch from first or it bogs and dies. I know that u are supposed to do that for 2 strokes ...
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Ha! Yeah...if you don't mind standing on your head watching your bike tumble into the distance without you!

Your situation certainly sounds severe. As david says, take a look at:

http://www.justkdx.dirtrider.net/

for some excellent info on carb tuning, jetting and such.

I'd suggest taking your carb apart and LOOKING at what you've got before relying on what's written somewhere. ..well, unless YOU wrote it and know for a FACT that nothing has changed since. And if you KNOW that..then take the carb apart and check it anyway!;)
 
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#5
ok so

ok so, thanx for all your help. We think we might have found a base problem to start at. I have a few cracks in the old intake manifold the silencer has no packing and the exhaust sleeve has completely shredded from a crash a while back. The only thing that seems to be new to me is the intake. The silencer I knew about and the exhaust sleeve 2. However, the intake is new 2 me so i am wondering if after I repack the silencer and put on an exhaust sleeve if that along with a new manifold will help greatly? I didnt think that the silencer would have really mattered but i guess that motorcylces need a certain amount of blowback to perform correctly. I am very new to 2 strokes so any help with anything i should also check would be great.
 

Canadian Dave

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#6
You'll need to clarify a couple things to get a meaningful answer.

Intake manifold - I'm guessing you are talking about the rubber boot between the carb and cylinder, is that right.

Exhaust Sleeve - ?

Manifold - is that the same as the intake manifold?

David
 
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#7
yeah sorry

intake manifold and manifold- rubber boot between carb or as kawi calls it the carb holder.
the exhaust sleeve is the little rubber clamp on the outside of the pipe and silencer joint. sorry about not clarifying that
 
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#8
One other thing, if you're talking about a 95-01 KDX with stock silencer, there is no packing to blow out, just baffles. Sounds to me like you may have a deeper problem (like dirty carb, bad ignition). Is it hard to start as well?
 
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#9
1984

no its is and 84 and has no packing. Dg Pipe and Answer SA. THe air filter is cleaned and so is the carb. I dont know the jetting off hand. I went to my local motorcyle shop and they said kawasaki doesnt have or make the intake any more. The previous previous owner also put in a roost bottle by just cutting a circle in the intake and epxoying it in. But now the whole manifold is cracking and i dont want to run it messed up 2 long and have it seize. Any way i can fix the manifold if i cant find a new one?
 
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#10
The only fix is get on the phone or web & find one at a wrecker. You might have to fax a drawing including mounting holes.
 
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#11
yeah i thought so but just had 2 check.....unless any of u happen to know of a place 2 look or might know somebody who has the bike and would sell me some parts. Or if u have any knowledge of if the peice off of another bike that would work please respond. ITS FOR THE CHILDREN! j/k
 

dirt bike dave

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#12
There was a completely thrashed red '84 KDX on e-bay for $200 - maybe it is still there. It is ratty but might make an OK parts bike or maybe the guy will sell you some parts if he can't sell the whole bike. The '83 and '85 KDX200 should have the same manifold as your bike.

You might be able to seal the cracks in your existing intake manifold with extensive use of a silicon sealer like Shoo-Goo. Any auto parts store or hardware store should have several products to choose from. It won't be pretty, but it probably won't leak air, either.

If my memory serves, your bike should have a 260 main jet stock. I have an owner/service manual for an '84; your welcome to it if you will pay for postage.
 
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#13
Nice idea but I’m afraid silicon will not stick to the rubber after you pass some gas through it, seen it tried, never works. Fax a few wreckers they will know what other models to try.
 
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#14
does anybody know which years might work for a carb boot (manifold)? i know that kawi has my vin# as an 83-85 (mines an 84). Do you think an 87 would fit?

Canadian Dave- you said u used to have an 84.. do u have any usefull info for me?