DannyMoto07

Member
Apr 12, 2007
170
0
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
 

MasonW947

Member
Nov 20, 2006
29
0
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.
 

DannyMoto07

Member
Apr 12, 2007
170
0
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

Sponsoring Member
May 3, 2000
5,349
3
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.
 

bruno670

Member
Sep 13, 2006
394
0
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.
 

DannyMoto07

Member
Apr 12, 2007
170
0
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

Sponsoring Member
May 3, 2000
5,349
3
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.
 

adam728

Member
Aug 16, 2004
1,011
0
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.
 

DannyMoto07

Member
Apr 12, 2007
170
0
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
 

2strokerfun

Member
May 19, 2006
1,500
1
Not 1/2 ounce. The vintage tuners tricks on these forks were: 1) pre-load spacers; 2) weight of oil; and 3) the amount of oil. You can vary all of them to some degree to get what you like.
 

DannyMoto07

Member
Apr 12, 2007
170
0
Well, here's what I did. I went to my local dealer, found out that I need 10w fork oil (the kind they sold me was for Harley-Davidson, but I don't think that matters) and that each fork requires 273cc of oil.

I'm going to take tonight and see about removing the top-cap and springs and draining the old oil out, then add the correct amount and reassemble them to see if it made a difference. If they're still soupy, I'll simply add a little more.

If it doesn't change as I add oil, then I'll take and buy a foot of PVC pipe and make a few spacers at different lengths.

I'll post a few pics when I get going.

Dan
 

DannyMoto07

Member
Apr 12, 2007
170
0
Ok, skip the pics, I got way too frustrated.

I drained the fluid (BLAAACK) and re-filled with about 290cc of oil. Right away they felt stiffer... until I installed them back on the bike.

They feel exactly the same as they did before the change. A TAD better, but not as stiff as I wanted...

The main thing that's wrong is that when the forks compress and come back up if I try to immediately push them down again, there's about a 3" gap where there's almost NO resistance... basically only on the spring.

Does this mean I should add more fluid to compensate for the difference? I may just try it to see what happens. Either this or try the spacer trick to make the spring-itself stiffer.

Any ideas?

Dan
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
http://www.cannonracecraft.com,The pvc thing usually worked,caps off and wheel suspended,is there a gap between where the bottom of the cap ends and the top of the spring,this distance plus a 1/2 inch and add spacers.Beware of spring bind,you still need a full stroke.Air caps were the rage in the late 70's,a schrader valve in the caps allowed you to fine tune the sag,just a few pounds.Then there is cannon,call them and get anything you want for whatever!
 

DannyMoto07

Member
Apr 12, 2007
170
0
Thanks, but I don't quite understand.

When I have the front end up off the ground, caps off the shocks and springs exposed, there is about 2 inches of spring poking out the top of the shocks.

Here's also a new question.... when I put the oil in the forks I try to pull them out (extend them) full of oil, in order to install the spring... well the shock seems to be working in REVERSE... sucking together rather than pushing out.

Now I'm really stumped.

Dan
 

DannyMoto07

Member
Apr 12, 2007
170
0
I found the problem.

The amount of fluid was way off. They need 320cc of fluid, not 276cc.

I also added a 1-1/4" spacer to the springs.

So far the brake side is all set to go, now I just need to do the other side.

Thanks for all the help, I'll let you know how it rides when I'm finished.

Dan
 
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