Topic: Drilling damper rod for emulator

[cwchan]

Hi All,

78 550k.  i was wondering if there we any suggestions on the drilling pattern.  The existing holes are 10mm apart and about 5mm in diameter

[Steve_K]

I think that you want to drill through the existing holes(both walls of tube) and turn it 90 degrees and centered between the other holes.  That is how I drilled both of the Suzuki forks I have done.  I could suggest calling Race Tech if what I suggested doesnot sound right to you.  I love my emulators and I am quite pleased with them and the fork springs I used.  Outstanding difference in fork performance.  Note: Now you will want to have better rear shocks.
Steve

[stueveone]

I did the same as above for mine. I think the directions had a minimum center of hole to center of hole length. You wouldn't want to drill the holes too close or else you are weakening the tube.

As far as the dampener holes, weld one or both closed. I have one welded closed and and still have a bit of pogo action with 15w. Going to try some 20w next and see if i can slow down the rebound.

stueve

[cwchan]

The holes are too close together to drill bigger.... my thoughts are that the # of holes aren't as important as the overall area of the holes...

6 holes X 8mm diameter is approximately 300mm^2 of area for the oil to pass thru.

the existing 4X5mm holes PLUS 4 new holes with diameter 21/64" (at 90 degrees) will give me approx the same area for the oil to pass through...
any comments?

i'll try to contact racetech but from what i have heard so far is that they don't have great customer support

[Syscrush]

The holes are too close together to drill bigger.... my thoughts are that the # of holes aren't as important as the overall area of the holes...

Agreed.

the existing 4X5mm holes PLUS 4 new holes with diameter 21/64" (at 90 degrees) will give me approx the same area for the oil to pass through...
any comments?

That really sounds right to me.

i'll try to contact racetech but from what i have heard so far is that they don't have great customer support

My experience with their customer support was very good - call them up and let us know how you make out.

[Steve_K]

I was wrong on my earlier post.  I misread dimensions and the other posters are correct.  Likely weld or braze the holes closed.  My Suzuki damper rods were different.
Steve

[cwchan]

The holes are too close together to drill bigger.... my thoughts are that the # of holes aren't as important as the overall area of the holes...

6 holes X 8mm diameter is approximately 300mm^2 of area for the oil to pass thru.

the existing 4X5mm holes PLUS 4 new holes with diameter 21/64" (at 90 degrees) will give me approx the same area for the oil to pass through...

Contacted racetech and confirmed my thoughts above.  Dampers drilled.  i still have to pick up a pipecleaner brush to get all the shards out from inside the rod

[stueveone]

You planning on welding those rebound holes? I'm using 20w fork oil with 1 hole closed and the forks still rebound past the settle height before coming back down. I'm thinking about welding the other closed as well to get that pogo situation calmed down a bit.

[cwchan]

Would JB Weld be good enough?

[stueveone]

I've been wondering the same. Anybody?

[fastbroshi]

Probably so, maybe use a teeny bit of screen and then Weld it on there.

[MRieck]

I wouldn't use JB Weld. You can solder or braze it too.

[Syscrush]

Would JB Weld be good enough?

No.  JB Weld sucks.  It's impossible to be confident that it's not going to work its way loose, and a little piece of hard plastic floating around in the fork could easily jam in somewhere and interfere with the proper operation of the emulator.

You can get a small tank of MAPP gas and brazing rod that works with it for not a whole lot of money and close those holes up right without going nuts and investing in a big welding rig.  Then you've also got a nice little torch for heating up stubborn nuts & bolts or steel stock you wanna bend.  Or you could swing by a welding shop or an exhaust place and I'm sure they'd close those up for you for $10 or less.  It's a 1-minute job.

[cwchan]

Soldered.  how does this look? its not smooth with the surface of the rod.  Should i sand it down a little?

[stueveone]

Sand it. Pretty sure it will rub on the inside of the fork tube. What set up did you use to solder? I swung by the Home Depot after work and picked up some "metal works" solder and a disc of flux. I've got a mapp gas that I'm planning on using with it. Gonna try tomorrow. I'll post pictures and results when I'm done.

[cwchan]

just some tin-lead solder at 700 deg F.

To be honest i got my house mate to solder it.  He's an electrical engineer.  He said the hardened steel damper is not a good medium to solder because it acts as a giant heatsink.  Its difficult to get a good solder because it instantly hardens after touching the steel... and the steel by its own nature is difficult to solder....etc...

[voxonda]

I have brazed them for years, no problem! Can TIG weld them but you use a lot of heat then.

[stueveone]

Used metal works solder and flux from Home Depot with my Mapp gas to solder both rebound holes closed. I am rocking 15w oil. Unfortunately, it's lightning or else I would be out test riding with a report for ya'll.

stueve

[Syscrush]

Used metal works solder and flux from Home Depot with my Mapp gas to solder both rebound holes closed. I am rocking 15w oil. Unfortunately, it's lightning or else I would be out test riding with a report for ya'll.

stueve

Cool.

That MAPP stuff is handy.  Unlike propane, you can actually get nuts/bolts heated to almost cherry red with it if you're dealing with really stubborn stuff.