Topic: Viscosity of Silicone Oil in Instrument Dampers/Dashpot

[grumpy]

The damper pot is just above the spring .

OK - now how do you get the fluid in there??? ?

[wrenchmuch]

I've got pics that show disassembly to the point where the cap comes off the damping pot . I put some 10000 cst fluid in my tach and tried it on the weekend . It worked well with just a little oscillation at idle . I'm going to try the 30000 next and see if this slows up needle responce . I'll probably go with the thickest stuff that offers quick needle motion . When I get to the point where I am re assembling I'll post pics of the whole thing with a description of what I did . I'm doing this on a K4 tach and I'm doing my K1 tach after . Anyone know where to get oem style gauge faces ?
Mike

Edit : The first pic on page 1 shows the damper pot with the cap off .

[scottly]

Anyone know how to get the stain off ?

I have a paint-prep cleaner that I bought years ago at NAPA that removed waxes and maybe even silicone?

[wrenchmuch]

I tried Windex . Took of the stain and some of the paint too .

[grumpy]

I've got pics that show disassembly to the point where the cap comes off the damping pot .

Oh yeah (short attention span)

Did you figure out how to reseal the cover to the pot?

[wrenchmuch]

I've got pics that show disassembly to the point where the cap comes off the damping pot .

Oh yeah (short attention span)

Did you figure out how to reseal the cover to the pot?

I'll probably steal some of my wife's nail polish and just paint it around the cap . It looks like that's all they did .
I still want to try some thicker stuff first .

[fire113]

Hi Mike,

...did You finished Your test with 30000 cst ? Just changed the face plate of my K1 speedo and on the backside of the old face were full of silicon oil  
Think I have to fill it up, I just bought the speedo and have to test it but the oil is a bad indicator 
 
I used the faceplates from Lecram, very good stuff !!! http://cgi.ebay.com/ebaymotors/Honda-CB750-K1-gauge-face-plates-MPH-KM-H-/140512953950?pt=Motorcycles_Parts_Accessories&hash=item20b739865e#ht_2370wt_1137

have a good one...Georg

[ekpent]

Rick Brett over at RB Kawasaki Triples,a renowned Kaw dealer,collector does tach and speddo repair. Have read that he has found the recipe after a very long and extensive research and of course says that it is, and will be,a top secret 

[fire113]

...for sure it is silicon oil need only to know the right viscosity!

EDIT--> contacted a gauge repair shop and they will send me some ml of silicon oil  
EDIT2--> YES  the stuff came today, now I can finish the speedo's and tacho's.

Have a good one...Georg

[CB750faces.com (Lecram)]

I've got pics that show disassembly to the point where the cap comes off the damping pot . I put some 10000 cst fluid in my tach and tried it on the weekend . It worked well with just a little oscillation at idle . I'm going to try the 30000 next and see if this slows up needle responce . I'll probably go with the thickest stuff that offers quick needle motion . When I get to the point where I am re assembling I'll post pics of the whole thing with a description of what I did . I'm doing this on a K4 tach and I'm doing my K1 tach after . Anyone know where to get oem style gauge faces ?
Mike

Edit : The first pic on page 1 shows the damper pot with the cap off .

I thought: why not drill a small 1mm hole in the pot, fill it with oil by a injection needle and seal the hole with a small dot of silicone sealant? (I have tested to drill on a broken gauge mechanism)

(BTW: I am the guy of the gauge face plates, see the link below)

[wrenchmuch]

That's a different type of damping pot from what I have .

Mine has a cap . By the time I got it this far apart taking the cap off was easy . With the type of pot you show I don't think there is any alternative but to drill like you did . I ended up putting 10,000 CST R/C rear diff fluid in the pot and the needle responded quickly and without erratic movement . I got side tracked by other projects after that . I still want to try the 30,000 CST that I have to see what happens . The gauge in the photo is from a 750  73~75 tach . What year /gauge is yours from?

[CB750faces.com (Lecram)]

It came off a 72 cb750 k2.  the older models do also have a cap, but the cap has been glued on the pot.

[brandEn]

Any of you guys have an update on the best oil to use? Did drilling the side of the pot work? My tach needs to be reworked due to bounce (new cable) and a search landed me in this thread.

[brandEn]

Drilling didn't work. You'd do better to dissamble the damper. I am using 20,000 viscosity and that works well.

Thanks. I did my tach just now and used 30,000 cst diff oil. I think I would rather have used the 10,000. My damper had a clear rubber cap on it that was just pressed on and not glued at all. Once I got everything put back together my tach would not work with the cable hooked up because of the extra tension I put on the spring. I tried to loosen up some of the tension and broke the spring at the clamped end. I managed to get the spring to work but I don't think my tach is accurate now. It does work and my test ride showed the needle was very stable.

[grcamna2]

wrenchmuch,
     How did your Tachometer repair work ? I have one from a 75' CB400F that needs to have the same treatment.Did you finally end up using the 30,000cst or 20,000cst Silicone damper fluid ? How has the work held up for you over time ?

I'd sure like to know because I need to dive into my Tach soon..,"Knowledge is Power"
     

[CB750faces.com (Lecram)]

I have refilled dozens of dampers and I use a viscosity of 50,000. That works great.

[bollingball]

wrenchmuch,
     How did your Tachometer repair work ? I have one from a 75' CB400F that needs to have the same treatment.Did you finally end up using the 30,000cst or 20,000cst Silicone damper fluid ? How has the work held up for you over time ?

I'd sure like to know because I need to dive into my Tach soon..,"Knowledge is Power"
     

grcamna  As soon as I saw this I thought about you glad you saw it. Did you see Lecrams post? He would know for sure.
Ken

[Old Scrambler]

The silicone fluid treatment is fine for those of you that have dis-assembled your clocks.......I have used DuPont Teflon with Graphite shot through a spray tube to direct it upwards to the clocks mounted on the bike.........a quick shot seems to do the trick. My clocks were sticking and hanging after sitting for several years. Now work fine since this application about 5 years ago.  I now treat all other clocks in my garage (Honda, Yamaha, Triumph) with the same Dupont spray before trying to run a motor or ride the bike.

This method does not seem to upset the magnet-spring and I have not stained the faces.......Yes, never store a clock face down.

[grcamna2]

The silicone fluid treatment is fine for those of you that have dis-assembled your clocks.......I have used DuPont Teflon with Graphite shot through a spray tube to direct it upwards to the clocks mounted on the bike.........a quick shot seems to do the trick. My clocks were sticking and hanging after sitting for several years. Now work fine since this application about 5 years ago.  I now treat all other clocks in my garage (Honda, Yamaha, Triumph) with the same Dupont spray before trying to run a motor or ride the bike.

This method does not seem to upset the magnet-spring and I have not stained the faces.......Yes, never store a clock face down.

Old Scrambler,
      Did you direct that fluid toward a certain area inside the clock in particular? & have you ever tried any other procedures for fixing your clocks ?

[grcamna2]

The damper pot is just above the spring .

You still out there wrenchmuch ? how did your tach.repair work out for you last year ?

[grcamna2]

wrenchmuch,
     How did your Tachometer repair work ? I have one from a 75' CB400F that needs to have the same treatment.Did you finally end up using the 30,000cst or 20,000cst Silicone damper fluid ? How has the work held up for you over time ?

I'd sure like to know because I need to dive into my Tach soon..,"Knowledge is Power"
     

grcamna  As soon as I saw this I thought about you glad you saw it. Did you see Lecrams post? He would know for sure.
Ken

Yes I did see this and I've taken note of that viscosity silicone liquid. 
                                       Thanks Ken.

[grcamna2]

I'd sure like to learn how to do this.   

[grcamna2]

AshimotoK0,
       Are you out there ? 

[wrenchmuch]

I ended up using 30000 cst. I found thicker fluids were causing the needle to respond slowly in cold weather. I ride till the snow flies here. If you live in warmer climates thicker fluid (50000) like lecram uses will be fine. The needle remains
stable when it gets hot in the summer here.

[grcamna2]

I ended up using 30000 cst. I found thicker fluids were causing the needle to respond slowly in cold weather. I ride till the snow flies here. If you live in warmer climates thicker fluid (50000) like lecram uses will be fine. The needle remains
stable when it gets hot in the summer here.

wrenchmuch, How is your Tach. after you've done the damper fix to it? has it been responding well in all types of conditions w/ 30,000 cst. ? I PM'd you..just wanted to know more about how much to fill the damper pot,etc.
I hope to hear from you..,I want to ask a few questions before I attempt to do my own.I'd like to attempt working on an old Tach. in bad shape cosmetically & the needle was reading too high..possibly dried out & thickened damping fluid?
I'd like to give it a go on this old one before doing another one that matters more to me later on.
                                                                                           Thanks,   Bill