General Dirt Bike Questions

[glockman]

I have always just replaced seals, wiper and fluid. My bike only had 150 hours on it last time I replaced them though.


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[GAR]

Last time a replaced my seals I put it all back together and noticed some play in the lower fork tubes so I pulled it apart and replaced the bushings which tightened it up. Not sure this is an every time kinda thing though.

 

[jeeper]

Here's another general question:

When replacing front fork seals, do most people replace the bushings as well, or just the seal, wiper, and oil?

I don't do the wiper. The Tusk fork seal kits come with just the seals.. I have not had problems yet.

 

[sixstringsteve]

What's the verdict? Are my fork seals bad? They look fine to me, we just rode a dirty trail. I haven't noticed any oil leaking out of them at all.

 

[anderson750]

What's the verdict? Are my fork seals bad? They look fine to me, we just rode a dirty trail. I haven't noticed any oil leaking out of them at all.

I don't think you have a bad seal, just a dirty one. Pull the dust cover down and take a seal cleaning tool or piece of 35mm film and slip it between the leg and seal to clean out the dirt. A bad seal would be "puking oil".......unless at this point you have lost most your oil and washed it off and gone for another ride.

 

[sixstringsteve]

cool, that's what I thought. Thanks.

 

[jentzschman]

I don't think you have a bad seal, just a dirty one. Pull the dust cover down and take a seal cleaning tool or piece of 35mm film and slip it between the leg and seal to clean out the dirt. A bad seal would be "puking oil".......unless at this point you have lost most your oil and washed it off and gone for another ride.

What is this piece of 35mm film you speck of....

 

[sixstringsteve]

it's what we used to have before we went to digital cameras.


EDIT: nevermind, I just saw the wink.

 

[Cascadia]

So I haven't drained the gas yet in my bike mainly cause I haven't had time. I rode it around a little today and again it ran great with the choke on. When I took it off and hit the gas it bogged down. Does that sound like its got too much air and not enough gas? How do I adjust the fuel? Where is that screw at on the carb?

 

[jentzschman]

So I haven't drained the gas yet in my bike mainly cause I haven't had time. I rode it around a little today and again it ran great with the choke on. When I took it off and hit the gas it bogged down. Does that sound like its got too much air and not enough gas? How do I adjust the fuel? Where is that screw at on the carb?

The jets are in/under the bowl. You either remove the bowl or the bolt on the bottom and that should give you access to the jets.

As I understand it, if it bogs its too rich (to much fuel), you need to lean it out. Only way is trial and error. Go leaner on the pilot and adjust the air screw until you find the sweet spot. This is what I have been doing. Just takes time to get to know the bike. Make small adjustments with the air screw, 1/2 to 1/4 turns are first. Then go even smaller to 1/8th turns to fine tune it.

Here are a few articles I have been using:
http://www.thumpertalk.com/topic/34...ich-read-here/page__hl__ stock jet settings
http://www.thumpertalk.com/topic/229837-2-stroke-jetting/
http://www.yellowdogracing.com/techstuff.htm
http://forum.dirtrider.com/discussion/7169620/spooge-101-/p1

 

[Cascadia]

You can adjust air on a 4t also?

 

[sixstringsteve]

It could also be too lean. If it runs with the choke on, i would assume you are running too lean. The choke adds gas to the circuit.

 

[jentzschman]

You can adjust air on a 4t also?

Ya. They will have pilot and an air screw as well.

 

[sixstringsteve]

The engine needs 3 things to run:

- spark
- gas
- air

Whether its a 4 stroke or 2 stroke, the carburetor determines the air/fuel mixture. If there's too much air or too much gas, it won't run right. The jets are like little nozzles that control the amount of fuel that enters the carb. By adjusting the jets, you adjust the amount of fuel that mixes with the air. Sounds like you have a jetting issue. The good thing about a 4stroke is that its not nearly as dangerous if your air/fuel mixture is too lean.

 

[Cascadia]

I think I'm just nervous to tear into a carb. It seems like there are so many little parts and I don't want to screw something else up.

 

[sixstringsteve]

You'll laugh when you see how easy it is. You don't even have to remove it from the bike. Its 4 screws, then you have access to your jets. Its cake. Its something you're going to have to learn to do sooner or later, its just part of owning s dirt bike.

You might also have a plugged pilot jet. I'm betting that's your real issue.

Bring it over tomorrow night and I'll teach you how to do it. You'll laugh at how easy it is.

Also, assuming you want to keep this bike for a while, it'd be worth getting an online copy of the service manual.

 

[jentzschman]

What steve said. If you loosen the clamps that secure the carb to the air intake and rotate the carb, you can access the jets right from the bottom. If you undo the bolt then you don't even have to fuss with the 4 screws. The jets are right there. The main jet is pretty much smack in the middle of the carb and the pilot will be just to the side. You will need a hex (not sure what size) for the main and then a very small flat head screw driver to remove the pilot.

They are very much different sizes so it is easy to tell them apart. Here is a picture I found. The hex head is the main and the pilot is just to the right in that small hole. Never mind the arrows. I just searched the inter-webs for a good pic of the jets.

 

[jentzschman]

Here is a better one. You can just see the pilot jet screw:

 

[Caleb]

You can adjust air on a 4t also?

2 strokes have air screws, 4 strokes have fuel screws. Same idea but they do just the opposite.

 

[jentzschman]

2 strokes have air screws, 4 strokes have fuel screws. Same idea but they do just the opposite.

Well I was kind of close