Fork Question

[pa23driver]

well i just took apart my forks. the PO somehow jacked the front end up on this thing to help with 2 tracking (dirt bike conversion). I'm trying to bring the front end down to stock height but i have no idea how he went about getting the front end up so high. All the stock parts seem to be there. the only thing i can figure is he used a different sized spacer. Let me know if this is the correct spacer or if you have any other ideas. should probably add that it's a 1977

 

[nj1639]

That's home made. Figure how much lower you want it to be and trim that down to fit....just guessing here.

 

[5twins]

Stock spacer length in the '77 forks was 39mm long (about 1 1/2") so that one is quite a bit longer.

 

[pa23driver]

awesome, thanks guys.

i thought it was weird that the spacer was made out of plastic pipe...

 

[MrBillohnooo]

While on the subject of fork springs, when using Progressive springs, do ya use the stock spacers? I bought some from Mikes, and there were no instructions as to use the spacers or not. I tried, and couldn't compress em enough using them...thought I would give em awhile to settle. Then try again.

 

[TwoJugs]

I am not sure but I don't think the spacer will change height much. It will just preload the springs more and stiffen the ride? Overall lenght of the fork tubes needs to change to get the front end higher.

 

[lafayette]

While on the subject of fork springs, when using Progressive springs, do ya use the stock spacers? I bought some from Mikes, and there were no instructions as to use the spacers or not. I tried, and couldn't compress em enough using them...thought I would give em awhile to settle. Then try again.

Did you end up using the spacers? I just picked up progressives myself. Can't seem to jam the things down. Instructions that came with them said no spacers. But without them there's absolutely no preload.

 

[XSLeo]

Try them with out the spacers. Measure the sag. If between 25 to 35 mm then they should be ok.
If the sag is over 35 mm then cut some spacers from PVC pipe in 1/2 inch increments. Add the 1/2, remeasure. Adjust the spacer length to get about 25 mm for a firm ride, 35 mm for a plusher ride.
Measure the sag on the rear shocks. Best if the front and rear sag matches.
Leo

 

[5twins]

The easiest way to install top fork caps is with a T handled wrench. You can push down and turn at the same time. Anyone even half serious about working on bikes should have one (or more) of these .....

 

[XSLeo]

Progressive springs are spings that compress at an increasing strength. If you look at the ratings it might be something like 40/90. This means the spring takes 40 lbs of pressure to compress the first inch. Then as you continue to compress the spring it take progressively more pressure to compress, up to the 90 lbs which is what it takes to compress the last inch.
Now as you ride down the road hitting small bumps then the spring compresses easily. Makes for a smooth ride.
Now you hit a largre bump, the spring compresses more. Remember that this spring gets stronger as it compresses, the bigger bump means a stiffer spring harsher ride. Kinda backwards don't you think.
A straight rate spring compresses the same at the last inch as the first inch.
With this spring, big bumps compress the spring the same as little bumps. A good ride on both big and little. Much better, don't you think.
If they could wind a spring that gets weaker as it compresses would be even better.
I replaced my spring for a straight rate set for older Harley 35 mm Showa forks.
A bit stronger and a bit longer than stock springs. Did the Minton mods hole drilling in the damper rods. With the adjustable fork caps the sag is about 25 on the lowest setting, about 12 on the middle setting, and I could not get them to the tightest setting.
I run AFT for oil.
They work very well. Firm but not harsh.
Leo

 

[gggGary]

nothing wrong with plastic pipe as the spacer, just get out the hacksaw "adjuster"

 

[5twins]

Just be sure to use a washer between the spring and PVC.

 

[Downeaster]

I want to soften the ride on my '79. There won't be any high-speed twisties at my age so I'm willing to sacrifice a little cornering stability to avoid getting my fillings jarred out on every seam in the road.

Looking at the above pictures, it doesn't appear that there's a removable spacer on mine. What are my options here?

 

[XSLeo]

Downeaster, does your fork have the adjustable fork caps like in 5twins pic marked 78 up?
If so just use the lightest setting. That's with the adjuster in the most upward position. As you look down in the fork cap the adjuster will be in the top position for the softest ride.
I use a big screwdriver with a push down and twist motion to change settings. push in, turn right makes them tighter.
If your shock has the flat cap like the one marked 77, then once you pull the cap the spacer just may be stuck. With the cap about 1/2 way out, bounce the fork a bit, compress, release. This should get the spacer loose, now when you take the cap out the spacer should come out.
One thing about the adjustable caps. If you springs are sacked then no matter how tight you adjust it it still may be not firm enough.
A cushy ride can be nice, but a bike that wallows in turns or bottoms out can be scary. I might suggest trying several weights of oil in the forks. A lighter oil will give you a softer ride than a heavier oil.
The lighter oil flows through the damper easier, so it's the fork reacts quicker to bumps and won't feel as harsh as the heavier.
Fork oil isn't that expensive to experement with. Try one weight, like 15w. ride it see how it feels. Then try 10w oil. Ride it, see the difference.
Leo

 

[gggGary]

Downeaster have you had em apart yet? Are the springs sacked? the fork shouldn't that harsh.
+1 you should have the adjusters in the caps.

 

[5twins]

If you do the Minton Mods to the damper rods, that will give a plusher ride. These mods improve the overall fork performance but in particular help the forks react better (quicker) to the little stuff. This gives you a noticeably smoother ride in just normal driving around.

 

[Downeaster]

Thanks for all the input!

When I drained and replaced the fork oil (with ATF) I didn't pull the springs out, and I don't remember what the caps looked like.

I'll investigate further and report back.

 

[5twins]

ATF is equivalent to 10wt. however it doesn't have any of the special additives that real fork oil contains. Just switching to real fork oil may improve the ride quality as well. I don't understand why people cheap out on this. It's not like you're changing it every thousand miles, more like every 5 years. Wanna save money? Paint your bike with a brush, lol.

 

[Downeaster]

That was mostly because ATF is what I had on hand.

I pulled the caps off this morning, and they are indeed the 3 position adjustable types. Unfortunately, they were already in the softest position.

NICE day today, so I went for a little ride and noticed something. My front wheel is out of balance. I balanced it with the static method and got it REAL close, but all I had was the "peel and stick" weights. I used 1 oz in quarter-oz pieces, and one or more have come off. Particularly noticeable at low speeds (25 and under). I'll find some crimp ons and change to 10wt fork oil and I think it'll be fine.

Also noticed that the seat has all the give of a 2x4 so I think I'll have the cover removed and some new foam put in it.

 

[5twins]

If you ever do venture inside your forks, another little improvement can be had by polishing your damper rods. Yamaha did so in '77 but stopped from '78-on, probably as a cost cutting measure. A polished damper rod will slide through the fork tube bushing easier and may reduce stiction a bit. It only takes a couple minutes with some 600 paper .....