Single shock adj. ???

[84scrambler]

I have a few questions about it , physically wrenching on a mono shock is new to me. I know very little about it so that's why were here.

So this is what I did yesterday,

Set rider sag first and came up with 105 mm being the sum between bike on the stand and with me sitting on it as riding.

Then I checked free sag (bike alone) and came up with 28 mm being the sum between bike on stand and bike sitting on its own.

The article I followed for this info was for newer bikes so my question is, do are single shockers fall under this adj. as well.

They said to check rider sag first and that's how you determine if your spring rate is good for your weight if it falls between these numbers with rider sag adjusted between 100-105 mm.

Free sag 20 mm or less spring rate is too soft for your weight.

35 mm or more spring rates is too stiff for your weight.

If this looks right to you guys I am needing to check the front as well any ideas?

 

[justintendo]

thats pretty much the deal, altho ive seen where you are supposed to pull up on the seat to make sure the suspension is fully extended vs. just sitting on the stand..sometimes this is the same thing however. different tuners will tell you different numbers to shoot for, and it probably can change a bit from bike model to bike model.
i set just a little more sag than 100...like 115..
sounds like the 20 and 35mm numbers are backwards??

 

[84scrambler]

Ok, I had to go back and read it again, but I think it can be confusing because it is referring to the sum of the the two numbers. (I think) lol
My rear spring rate is good for me then and the sag. So I just found a number for the front and it said your looking for 70 mm rider sag give or take.

Is there a way to know when your front spring weight is too soft or stiff ?

 

[justintendo]

lol, well for me...if im pushing as hard as can and i bottom much..my spring is likely too soft..
how much do you weigh, suited up? im at about 230 and the stock rear is way too soft. had to crank the spring the whole way and raise the rear too much..makes a big difference in handling. the front is soft too, but not as bad. i dug around my stash and went "1 step" stiffer.

 

[84scrambler]

I weigh in at 150 lb , never weighed with gear on tho. I think i'm good with factory spring ratings. owners manual says "Too little pre load: if the fork sags more than 30 mm without driver.

It also says "the fork is too soft in the mid-section" when driving downhill the front is too low. wtf...

How should these bikes be balanced ? level while sitting on it ?

 

[justintendo]

oh yeah, you are probably great then..maybe even too stiff..
i guess a better analysis would be to take the bike out now and run it and see how it does, then you can work on damping and such.
as far as balance..with the rear sitting how it should be...i run the forks slid up as far as they go..a few mm from touching the bars. i run in the woods alot and the handling is good. they still are quite stable like this as it is a swede...i know ive shown this pic but this is how my chassis sits now, and it seems to work well.
i can pull measurements if you like. the spring im running is about a half inch shorter in the rear
for your rear shock, try turning your compression (top knob) mostly out, rebound turned up a few clicks..try it from there! do you know what you ar running for fork oil/amount? i run atf and vary the amount..

 

[84scrambler]

I am going to drain and get some atf in there today, check my full range of travel with out springs and caps and record it . Then fill back up and compare measurements and go from there with a certain level to get the measurement close but not too close. AS far as the rear , does the knob work with a line scribed into the housing or does it just click around until it stops either way ? how would you know what number its on?

 

[Kartwheel68]

Setting sag is just a ballpark starting point, every bike and rider combination will be different. What you are doing with the measurements is comparing them to see if your spring is too soft or too stiff. If your spring is too stiff, with the proper rider sag the "free" sag will be too much, you will have too little preload on the spring to get rider sag. If the spring is too soft when the rider sag is set the "free" sag will be too little, you have to use too much preload to get rider sag. The correct spring will allow you to have the right rider sag and also free sag. Once you decide the spring is correct, forget about focusing on a specific rider sag number, ride the bike with more and less preload until the bike handles the way you want it to handle. Once you have done that, check your sag number, whatever that number is write it down so the next time you work on the shock you wont have to repeat everything over again.

 

[justintendo]

I am going to drain and get some atf in there today, check my full range of travel with out springs and caps and record it . Then fill back up and compare measurements and go from there with a certain level to get the measurement close but not too close. AS far as the rear , does the knob work with a line scribed into the housing or does it just click around until it stops either way ? how would you know what number its on?

start at 450 ml each leg, and write down the height that is from the top of the fork tube with the fork leg collapsed so you will have a reference. i prefer to do this work with the legs removed the trees..i run about 500 ml in each leg myself..
with these forks, if you notice gray oil after a ride or two it means the forks need bushings. running synthetic atf it seems to stay nice and clean a good while. im sure theres an actual fork oil that works "perfect" but the atf is readily available and holds up..

 

[justintendo]

I am going to drain and get some atf in there today, check my full range of travel with out springs and caps and record it . Then fill back up and compare measurements and go from there with a certain level to get the measurement close but not too close. AS far as the rear , does the knob work with a line scribed into the housing or does it just click around until it stops either way ? how would you know what number its on?

i think theres around 8-12 clicks for each, you can probably turn them in and out maxed then count in from there. alot of times both can seize up from age.

 

[oldbikedude]

There should be a pointer triangle cast into the alum on the top of shock. Use that for reference with the mark on the knob when adjusting.

 

[84scrambler]

Thanks oldbikedude, you read my mind. Reference mark , i'll have to remember that if I can . lol
So, this is what I found in the forks .

A 4 and 3/4 inch spacer and the springs are 20 and 1/2 inches long they have a factory flattened end on both ends. To my surprise when I drained the oil it was a nice blue stream and I drained it into a measuring cup and it came to 450ml.

On reassemble I added a 1/4 inch to make it a even 5 inch spacer and filled each leg with atf -f trans. fluid. I went with 480ml on the refill to see if I could feel any difference. They were really soft before and seemed like it would dive into obstacles .

I was really having a good time with this little project,cleaning,measuring,recording things,got it all back together and gave her a wash checked over the bike gassed her up and was ready for a test ride, can't wait...

I went to start it up, choked her with two kicks like always and was ready for the next one to fire off and be on my way. But noooo , some one had to steal my thunder..... I then tried her with no choke for a last resort and nothing , I knew I was in for trouble. Flooded like a mother, Ive had this happen once or twice on this bike and I know better than try to keep freaking with it , but I did and that's how I got bit.
Yup gotta nice sore ankle when I switched to my left leg to try and kick cuz I knew my right would be sore tomorrow. Slipped off the kicker and it got me, G.D.M.F. Oh, and it was only a billion to f-ing degrees... (put her away for the night)

 

[Bigbill]

Be careful with the flooding. I seen when a bike is left flooded the cylinder base gasket can rot over time. Then it gets sucked in. Then the real problems start. After taking a gallon of gas out of a used flooded 390 the base gasket was rotted from the gas.

 

[84scrambler]

I'll keep that in mind, I blew air in there for awhile cycling the piston on several occasions . I got her to bark twice, so I knew alot of the fuel down there was mostly gone. I always let it sit with the plug out over night too. I think I am going through the carb next, where is a good place to get a rebuild kit for the 38? I want a new float valve too.

 

[fran...k.]

I have a few questions about it , physically wrenching on a mono shock is new to me. I know very little about it so that's why were here.



The article I followed for this info was for newer bikes so my question is, do are single shockers fall under this adj. as well?

The spring will be correct when the static sag (bike only) and rider on sag can both be obtained with the threaded thing that sets the upper end of the spring. I guess similar with spacers or spring length for the fork spring.

The 85-86 has a much more progressive linkage than what has been settled on for the most part by now. Not sure how or if this applies to the question I quoted above. I would think the wr, te, and ae models with their shorter suspension the rider on sag might ideally be a bit less. The posted values are really for athletes competing in my estimation. I noticed my 88wr has no static sag and rides nice and plush on the forest floor.

 

[fran...k.]

I think I am going through the carb next, where is a good place to get a rebuild kit for the 38? I want a new float valve too.

Look at how tight the slide is in the bore. The floats have a weight cast into them, I think I have had one get heavy. I might get a different float valve needle with rubber on the end if I did it again. I have a briggs and stratton one in my 510, It did not fix the problem I was having but has never caused me any problems. Changing the needle and seat does seem to help on the round slide micuni even if the original one seems to look fine.

 

[everfree]

I'll keep that in mind, I blew air in there for awhile cycling the piston on several occasions . I got her to bark twice, so I knew alot of the fuel down there was mostly gone. I always let it sit with the plug out over night too. I think I am going through the carb next, where is a good place to get a rebuild kit for the 38? I want a new float valve too.

Just a suggestion... try pulling the exhaust off if it won't start.
One of my 430's wouldn't start after sitting awhile. No amount of kicking would start it.
Even after pulling the plug and stroking the kicker over 100 times to evacuate the fuel did not help.
It wasn't until I pulled the exhaust and drained the trans oil. There was about a quart+ of gas in the exhaust pipe. After that it started.
I think the cause was leaving the fuel petcock open and the fuel seeped, and I kicked it over too many times - filling the exhaust. Now I'm more careful and I try and not leave any fuel in my tank between rides.

 

[Bigbill]

On my flooded 390 when I got it home I pulled the plug and flipped it upside down. Turning it over out with the bad gas in with the good air.

 

[84scrambler]

Don't think I'm in for turning it up side down. This is very aggravating because if I was out at a off road park or a place to go and ride, I would be so screwed . I really don't think any thing I could have done at that time would have helped. I want to get to the bottom of this problem tho. Who the hell wants a bike that you can't even ride... I think there is two things that keep these old bikes from being user friendly at any given time the dam ignition and the carburetor every thing else on these bikes seem to last for a long time. I also think that its mainly the oil from the gas that does'nt go away, the gas it self should evap. but it must leave behind the thicker oil residue .

 

[Kartwheel68]

Fuel in the bottom end will NOT cause a gasket failure.

I have turned bikes over that were full of fuel, and I have also done it on deep water crossings when the bottom end was full of water. Turning it over is a pain in the rear, but its the surest way to get it completely empty.