Minton Mod observations

[jd750ace]

I used to have a link for a chart that calculated the minimum airs space (andconsequently the max oil height) relative to the inner tube diameter and total travel, but I can't find it now. Good looking out on the over fill caution. Escaped me as I responded. 20mm was safe in my EX500 forks, with an inch less travel, just as a point of reference. Increased fluid volume, just likeIincreasing preload excessively, is a compromise, and while a compromise might better one situation, it generally trades off to a deficiency somewhere else. I bought my last set of Race Tech springs for 89 bucks off Amazon, and the emulators for 129. A decent discount on both. Gary has tried out the Mike's knock off emulators. Might quiz him on them. They are significantly less.

 

[racerdave]

I understand what you guys are saying and I don't disagree. I may have used fork oil, I just don' know. I can't find any fork oil in my cabinets, which I know I had some. It was Spectro. It's gone, so I used it somewhere. The bike if it is ever finished will get more time being looked at in the garage/driveway, while I and buds drink a few beers and bench race. Rides will be through the neighborhood at 30 mph, and maybe a short ride in the country on the local paved farm roads. Omar probably wanted to get rid of these Progressive springs that's why he talked me into them. It is not that I can't afford $100 or whatever for heavier springs, but the money could be better spent elsewhere on the project. Griz those Mikes springs, have no specs listed on his site other than dia and length, and they also say they are Progressive like you say.

Do you guys thinks 7oz of 15 weight and a 1/2 inch spacer will help without causing leaking or binding?

 

[TwoManyXS1Bs]

You can kinda reverse engineer your springs. Get all the spring measurements, then google "spring calculator" or "spring rate calculator", and feed in your values...

 

[grizld1]

Dave, re. springs, Mike's used to sell dual rate springs with a soft section rate of 35 lbs/in and a stiff section rate of 50 lbs. They were listed as heavy duty springs, and the rate specs were given in the catalog. I don't know if they're still available--I've avoided Mike's when I can for quite a few years, as I don't care for their business practices.

Calculating max preload before coil bind is easy to do. Measure the free length of the spring. Then count the coils, measure the wire diameter, and multiply coil count by wire diameter. Subtract that number from the free length. The result is spring travel; that is, travel allowed by the spring before coil bind. Next, with the fork springs removed and the slider at full extension, set up a zip tie on a dust cover, compress the slider, and measure its movement; that's your fork travel. Subtract fork travel from spring travel. The result is the total of preload and sag that can be applied before fork travel is restricted by coil bind.

 

[racerdave]

Thanks again Griz. I copied all that for future use. This is what I did this afternoon. Got some 15 weight Spectro. Drained forks well . Removed the Progressives and reinstalled spring's that came in forks. All measure the same length. I added 7 oz of 15w. The oil I drained was red, so is the Spectro. Now I really don't know what I had in there. I added 12 mm of spacer and washer total. I have the 3 position caps. With that spacer length added, position 1 and 2 are still less than 3 no spacer. Put together and went for my 30mph semi hard stop. Zip ty is now 1.125 from upper triple tree, vs on it when stopping before. I have to guess it is the oil that gained my reduction in compression? Maybe the springs are a little stiffer also. The spacer has not come into play yet. Tomorrow I will go to 3 and see what I get on that 30mph stop. I did accomplish what I wanted at least so far.

The shop I bought the fork oil at is a Honda/Yam/Zuk/Kaw dealer. I ordered some Suzuki copper head bolt washers while I was there. The 08 Bonnie had several lookie loo's around it while I was inside.

 

[Lasper01]

I have a xs650D with a spacer over the springs. And when you guys say you put 1" pvc spacer in, does that mean I can make a spacer thats 1" longer than the stock?
Like this:

 

[racerdave]

My forks only have the spacer I made.

 

[Lasper01]

Like the one to the left?

 

[racerdave]

Neither. 12mm is just under a 1/2 inch long. My pvc spacer and the oem flat washer equals 12mm total on mine. On your ruler pic , 12mm is 2 lines above the 1cm mark on the right side., or 12 lines up from the bottom.

 

[Lasper01]

Im not sure what you mean? The stock spacer to the right is 40 mm and the one to the left have I made 1 inch longer (64mm). My question is about the 1 inch preload.. is that also in the early type 35mm fork or just in the late style with the adjustable nut?
Hope this makes sense

 

[5twins]

If you're trying to stiffen your forks up then it applies to any fork. Whether the additional inch will do the trick can only be determined by you testing it.

 

[racerdave]

I don't know how else I can state it. I can only state what I have in my forks. One spacer only with a washer for spring support, the 2 together measure 12mm long. That is less than half the length of the spacer that is on the right side of your ruler in your picture. Nothing else. Maybe my pic will help. The only thing I have above my forks spring is my pvc spacer and a metal washer, the length of my red arrow is 12mm between the black lines I made on the short spacer to the right of your ruler. You need a flat washer for the spring to have a surface to push against

 

[Lasper01]

Now I get it Dave
Okay thanks 5twins, I'll try it out and maybe change to find the right preload..
I have also opened up the holes; the Four holes to 6mm and the small 2mm.

 

[XSLeo]

Over the years they used several different lengths of springs. Some used longer spacers than others.
So to this poster and others who read this thread, when people suggest adding a spacer you can either just add the spacer, or make a spacer that is the length of the stock spacer plus the suggested added length.
Leo