Huge Front Fork Problem!

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Apr 12, 2007
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#1
So I put the RT180 back together today, I recently popped the drain plug on the forks just to see if it would stop my fork seals from leaking (NO FLUID CAME OUT, I did this on a work-bench with the forks off of the trees... just air poofed out a bit), I also spun the nut at the bottom of the fork to see if it did anything, but all I heard were the springs spinning inside of the fork-tubes.... well... I think I really ruined something.

My front forks are SUPER SUPER soupy. So soupy that when I turn it feels like I'm going to nose-dive the bike into a corner.

I don't want to ride the bike they're so bad.

What did I do? What can I do? (Kinda spell it out, I don't want to have to bring the forks to a dealer.)

Dan
 
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#4
I dont know much about the forks as those are one of the few things that I havn't had screw up (knock on wood), but I will say that you should not go along "learning" about your dirtbike without knowing what your doing. Defenitely buy all the manuals for your bike and consider some videos like the ones at http://www.motopowervideo.com/ they have a video for about every make and model and year.
 
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#5
If your forks are soupy, it's likely you don't have enough oil in them. Did you refill them with new oil or just reassemble?
 
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#6
First off, thanks.

Second, I'm not trying to learn through trial and error. This was an accident.

How do I go about putting oil in the forks? Do I have to remove that large alen bolt in the top of the fork in the trees, or do I have to completely disassemble the forks.

I NEVER TOOK THE FORKS APART. The only thing I did was pop the drain plug and give the rod-nut a spin to see if it was hanging up... that was it.

Dan
 

dirt bike dave

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#7
DannyMoto07 said:
I also spun the nut at the bottom of the fork to see if it did anything, but all I heard were the springs spinning inside of the fork-tubes.... well... I think I really ruined something.
The head on the bottom of the fork is for the damper rod assembly. It will just spin if you turn it, doing no harm inside the fork.

To remove, the manual will tell you to hold the inside of the damper rod with a special tool. Some folks get them to break loose with air tools.

I would recommend removing the fork cap at the top of the fork, pulling the spring out and pouring the oil (if any) out the top. Leaving the spring out, compress the fork all the way. Fill withe the recommended oil to about 4" from the top. Put the spring in and fork cap on, and go ride.

Oil level has a big impact on bottoming resistance. Higher oil level = more resistant to bottoming. 4" from the top is a good starting point for many old fashioned forks. If you don't bottom them at all, take some oil out from the top using a straw or a syringe.
 
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#8
When loosening the top allen bolt, remember to loosen the top triple clamp pinch bolts. this will allow you to loosen the bolt. Leaving the pinch bolts tight actually tightens the top bolt.
 
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#9
bruno670 said:
When loosening the top allen bolt, remember to loosen the top triple clamp pinch bolts. this will allow you to loosen the bolt. Leaving the pinch bolts tight actually tightens the top bolt.
That was actually going to be my next question.

I do have an alan drive that will fit this nut, so I suppose I'll get started on that in the AM...

Is there a recommended weight for stiffer front suspension? I plan on picking up a gallon of BelRay for oil, but I don't know what weight will be best for my setup. (220lb rider, semi-agressive woods riding). Any suggestions?

Dan
 

dirt bike dave

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#10
If you have an owner's manual, it should show the oil weight. Many bikes use 5w. You might try 10w.

However, oil weight only makes a minor difference on compression. Heavier oil will slow your rebound.

Sounds like you probably need stiffer springs.
 
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#11
I'm almost positive they don't make stiffer springs for this bike, front, or rear. My only option is to change the oil weight.

Dan
 
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#12
You can make some spacers to add more preload to the fork springs. My father added maybe ~1" long PVC spacers to my RT180 back in the day. I don't know how long you can go before getting into coil-bind issues.

Another trick I've seen used by old-school guys is to cut some coils off the spring (effectivly making it a higher rate) and then making up the difference with a spacer. Again, I don't know how much room there is to get away with this in those forks.
 
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#13
That's actually not a bad idea, but I'll have to take the forks apart and see exactly what I can do about the oil first.

Dan
 
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#14
Adding an extra 1/2 ounce to each fork will stiffen it up just a tad--or at least it seems that way.
 
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#15
2strokerfun said:
Adding an extra 1/2 ounce to each fork will stiffen it up just a tad--or at least it seems that way.
Will that put excess stress on the seals or anything? Possibly cause blow-buy on a hard bump?

Dan