Hawk/Enforcer Fork Valve upgrade.

[Megadan]

Originally Posted by ChipToothy

Saw this thread this morning and was inspired to play with mine. Made it this far before a headache took over my life for the past few hours now. What can we buy/do to make this style better? I’m going to add that Valvoline Max Life Synthetic ATF and figured I would snap a pic and ask before I buttoned them back up.

The only way for me to get an idea of what could be done would be to see the internals, which would require further disassembly. They look like a cartridge style fork, which means they would already have a valve system installed. If that is the case, then the only improvements that could be made is different valves, or changing the shim stack to adjust deflection rate.

[ChipToothy]

Originally Posted by Megadan

The only way for me to get an idea of what could be done would be to see the internals, which would require further disassembly. They look like a cartridge style fork, which means they would already have a valve system installed. If that is the case, then the only improvements that could be made is different valves, or changing the shim stack to adjust deflection rate.

Sounds expensive Thanks for the reply, the more YouTube I watched on it the more I figured out it’s cheaper to just buy used Honda forks. I added the 250ml of tranny fluid and went for a ride. The steering seems over sensitive but the smoothness is pretty cool. Wish I hadn’t waited 8 months to do it ha! The original oil looked mostly clear but sure wasn’t providing the best ride. Thanks Mega D!!

[seeinred]

I got the sxs fork valves from mike and they measure 23.70 in diameter and look just like the ones that megadan posted, ill try to post some picture when I figure that out.

[Megadan]

Originally Posted by seeinred

I got the sxs fork valves from mike and they measure 23.70 in diameter and look just like the ones that megadan posted, ill try to post some picture when I figure that out.

Excellent! That means this can be done for a MUCH lower price now. Thank you for taking the chance and confirming my suspicions.

The main curiosity I have about these valves are the slow speed ports. Those are the tiny little holes on the top of the valve close to the spring and adjuster for the valve. The YSS valves have 4 holes, which means they offer much softer slow speed damping by allowing more fluid to bypass. Less holes = more resistance to flow = firmer slow speed.

[Megadan]

I guess now would be a good time to post my initial impressions of the valves that I installed.

5 turns of valve preload was actually a bit too firm for the high speed compression damping. Not harsh by any means, but rougher than I desired, so I turned them back to 3 turns. The 4 ports for the slow speed is just about perfect in my eyes.

After roughly 50 whole miles on the bike thanks to winter showing up again, I can say that it was worth every penny. There is a rather rough stretch of ignored cobblestone road that I like to travel down that is filled with lots of bumps, lumps, and even mild whoops. I took my last Hawk down this road many times, and so I figured it would be a good way for me to judge any difference in how the forks perform. As I already expected, it is a huge improvement. The new bike feels much more planted and under control. Combined with the fork brace this bike responds almost immediately to steering input. The wet noodle feeling of the stock front end is almost completely gone.

One change I do plan on making is running a thinner fork oil. The rebound is actually a little bit too slow for my liking with 15 weight. Now that I can tune it independently from compression, I think I will go down to a 10 weight oil.

The rear shock is kind of a wash at this point. It is definitely better in terms of handling my weight on rough surfaces. I need to play with the damping settings, but as a whole I would say it was worth upgrading. I do wish it had a little bit more rebound damping, but it is also not a pogo stick either.

[seeinred]

Thanks Mega Dan for sharing your shock valve adjustment experience, I will start there. Learning of your mods and those of other members have allowed me to make some truly amazing modification to my bike. I can wait for winter to be over so I can continue to improve the ole Hawk

[seeinred]

Mikes xs valve 27-1086 only has one bleed hole near the spring it measures 1.50 mm.

[Megadan]

Originally Posted by seeinred

Thanks Mega Dan for sharing your shock valve adjustment experience, I will start there. Learning of your mods and those of other members have allowed me to make some truly amazing modification to my bike. I can wait for winter to be over so I can continue to improve the ole Hawk

If the Mikes valves have a firmer spring, then my adjustments might not translate to yours very well. The best thing you can do is start with their recommended base setting and adjusting from there.

Once you get them installed I know I would love to read about your experience with them.

If you haven't done so yet, then I highly recommend the fork brace mod done by Wamey. Link http://www.chinariders.net/showthread.php?t=19349

The fork valves and brace combined is almost indescribable compared to a stock bike, and with the Mikes valves now being a possibility, then a massive upgrade to the front end of the Hawks can be done for less than 100 bucks, including fork oil.

[Megadan]

Originally Posted by seeinred

Mikes xs valve 27-1086 only has one bleed hole near the spring it measures 1.50 mm.

Ok, so that would be one big difference. the nice thing is, that can also be changed/modified if desired. Simply drill more holes as desired to "soften" up the slow speed damping.

[W0X0F]

While doing some research on this mod I found some additional info that piggy backs on the mod Megadan has done. it is on an external website TS500/XS500

Hopefully this assists!

[Megadan]

Originally Posted by W0X0F

While doing some research on this mod I found some additional info that piggy backs on the mod Megadan has done. it is on an external website TS500/XS500

Hopefully this assists!

Good post and thanks for sharing. Great detail for people that might not grasp how it works.

[seeinred]

Megadan do you have a measurement on those rebound holes?

[Megadan]

Originally Posted by seeinred

Megadan do you have a measurement on those rebound holes?

Nothing definitive since I had no reason to measure them the last time they were out, but an educated guess just by looking at them I would say very close to the same 1.5mm that you measured on yours.

[nij_tp]

looking at the instructions on the MikesXS website for the valve the following is included

Enlarge the Holes in the Bottom of the Damper to 8.0mm. (5/16") diameter and drill additional holes as shown so that the damper rod has 6 holes ( 3 sets of 2) as shown. The holes will have to be deburred and chamfered inside and out after the drilling is complete. New holes must be spaced lengthwise at 10mm. (7/16") and must be at 180 degrees to the last set of holes so that the rod is not weakend. No other modifications are required.

Also found this info (http://www.xs500forum.com/index.php?topic=240.0 this has pictures, the text is below)

The Damper valve/Cartridge Emulator
Race Tech lists an emulator part number for the ‘75/76 XS500 at $170. (Dec 2011)
Because they are only $48, I took a chance and ordered the Damper valve set from XS650.com . (MikesXS.com for you Americans)
As the name suggests, this site caters to the XS650 model, but because the later XS500 and ’77- ’84 XS650 all have 35mm forks, I thought they shouldfit. (Note, I have a ’76 XS500C. Some earlier 500’s have 34mm forks . I’m not sure if the emulator that I used will fit 34mm forks.)

These damper valves are essentially knock offs of the Race Tech Cartridge Emulator. Mine came with the flat washer installed incorrectly and no instructions. (See photo)

The washers are easy to relocate. A quick email to XS650.com resulted in the document being emailed to me next day.
Take apart pic here:


You can see in this pic the small plate with has a hole in it. This hole allows compression damping for slow fork movement. The spring holds the plate down with a force that is adjustable with an allen head screw. The flow of oil during fork compression is from right to left.


This pic shows the plate lifted from the emulator body. This is the open position, which would happen when you hit a pothole, ie: the damping would be far less.


With the screw, spring, and plate removed, we can see inside the emulator. Visible is a thin steel washer-shaped one-way valve which is held up by a weak spring. This is the bypass valve for rebound damping. During fork compression the flow of oil is upwards thru the emulator, so this washer valve is closed.

During rebound , the oil flow through the emulator is downwards. The washer valve is pushed down by the flow and opens up a huge hole for oil flow, so virtually no restriction. In other words, the emulator does not affect rebound damping . I’ve pressed down on the steel valve with a plastic rod to show how far it can go down .

Installation
When taking apart the forks, I managed to totally strip the head of one damper retainer bolt. (The bolt at the very bottom of the fork.) I had to drill the head off. And I mangled the bolt head on the other fork. (Lesson learned: don’t substitute a hammer drill when you need an impact driver! )

It initially looked like the damper tube was not compatible with the emulator!

It turns out that the top part of the damper tube is a cap which pulls off easily.

I checked the fit of the emulator to the top of the damper tube-perfect!

Normally the tapered end of the fork spring fits over this removed cap. But to allow enough clearance around the emulator valve , the spring has to be flipped, so that the large end of the spring is at the bottom, against the emulator.

The next step was to drill out the damper tube. The compression holes (the larger holes) in the damper tube are about 1/4”.

These need to be enlarged to 5/16” and a third pair of holes need to be added. Making all these large openings removes any restriction here, so now all compression damping is controlled by the emulator valve.


I installed new fork seals while everything was apart. A 1 1/2” ABS drain pipe, made very slightly smaller with a belt sander , makes a great seal installer.


I installed the damper parts and fork tube, and new damper retaining bolts and copper washers at the fork bottom.
BTW the fork damper bolts available at XS650.com are too big-it cost me $3.92 to find out.
But because Yamaha uses the XS500 damper bolt/washer on many other models, you can still order them through your dealer.


The emulator spring tension determines what size bump will pop off the plate to allow for lower damping. In other words, what size bump do you want the shocks to absorb vs transmit to your arms?
To adjust the tension, back off the screw so that the spring is loose. Slowly tighten the screw until the spring is just held in place. This is the start point for counting turns. I tightened the screw 2 and ¼ turns, then tightened the lock nut. Then dropped the damper into the fork tube , spring upwards.

[nij_tp]

Originally Posted by Megadan

Nothing definitive since I had no reason to measure them the last time they were out, but an educated guess just by looking at them I would say very close to the same 1.5mm that you measured on yours.

Dan, how did you tighten the bolt into the dampening rod? Is it reliant on the pressure of the spring once the whole thing is put together?