BMW K bikes (Bricks)

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zaubertuba

zaubertuba
Silver member
Silver member
Time always seems to conspire against you---the best laid plans and whatnot.  I'd hoped to get my RS painted and outfitted for work and my regular monthly drives around my district for work last Spring, but time and conditions didn't really materialize until late Summer...and our Summer seemed to short us a bit. :p

Anyway, after reading extensively, and developing a good relationship with our local paint supply shop, I took a stab at doing my own shoot.  There's still some runs and drips (it's a *very* fine line between putting not enough paint on to make a smooth finish and putting too much on), but in the end I was really happy with how it turned out.  Some lessons learned:

-Buy good paint.  It's expensive but worth it.
-The Harbor-Freight paint gun I used was plenty up to the task, but make sure you clean the reservoir strainer *thoroughly*--I ended up ditching it completely when the water-based primer I used didn't clean out totally and conspired to foul my next coat.
-Clean the gun religiously.
-A 21-Gallon Air Compressor is just *barely* large enough for this job. If you're patient.  And it's not too hot.  30 would be better.
-Prep and Sand, Sand, Sand, and when you think you're done sand some more--you can't possibly prep enough!
-I created a "booth" by hanging plastic in my garage.  I vacuumed the space meticulously, left the shop vac running for awhile to try and clean up any "floaters" and dust, and then used the Shop Vac to blow clean fresh air into the booth and create some positive pressure to try and keep dust out.  I *still* ended up with a few drifters here and there but it was wayyyy better than in an "unconditioned" space.  Oh...another good tip, hose down the floor and keep it damp to capture dust and overspray and keep it from kicking back up.  Also, when shooting, between coats, I used the "paintless" first stage of the gun trigger to gently blow off any dust that did happen to show up.
-Degrease and use a tack cloth right before shooting.
-Read the instructions for your paint and clear coats carefully.
-Wear a real respirator--these pro-level solvents are positively *evil!"
-I had one piece in particular that viciously Orange-peeled *twice.*  After the second try, I went, wondering what went wrong, to the paint supplier and he told me "probably not your fault--you don't know what's deep down under those coats" --he said the solvents in the reducer will sometimes draw crap up out of older paint.  He suggested a water-based primer, which I used, and seemed to do the trick.


My "Materials" Table:
Spring Paint Job becomes Winter Overhaul Painta10


Prepared Workspace and parts resanded after a first botched shoot (I didn't prep enough and had some bad sanding swirls still showing):
Spring Paint Job becomes Winter Overhaul Paint110

After the final Clearcoat shoot:
Spring Paint Job becomes Winter Overhaul Paint310

Orange-peel on a re-painted part.   Crying or Very sad
Spring Paint Job becomes Winter Overhaul Paintb10

And here's why--how many coats can you count?  A water-based primer sealed these out and I didn't have a problem on the third shoot for this part.
Spring Paint Job becomes Winter Overhaul Painth10


Mostly together.  The mirrors dripped *badly* so I may reshoot those at a later date, but I'm still pretty happy with how it turned out.  Very Happy
Spring Paint Job becomes Winter Overhaul Paint410

Spring Paint Job becomes Winter Overhaul Paint610


Next up:

-Finding a seat for my '85-->Post '85 cowl change
-installing the Parabellum screen
-Touring bars (the "not actually BMW" C-style bars I'm using will hit the Parabellum shield before full lock), Heated Grips, and Touring Dash cover.
-Rebuild of the Gen II Gas Cap I bought from Cambridge....England (because I bought the gasket kit not remembering my cap was a Gen I)  Embarassed
-Longer control cables (have my throttle and choke cables, just need the center throttle bracket bits and a clutch cable.
-I think a tranny-seal refresh may be in the works, judging by the drips on my garage floor.  Rolling Eyes


So much for riding this (Short) Summer, but hopefully she'll be fully ready in the Spring!  Very Happy


__________________________________________________
1985 K100RS
    

Rick G

Rick G
admin
admin
Lookin good  that red will make an extra 10mph. Oh and those runs on the mirrors I just use hedge trimmer when it is good and dry. Very Happy


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1986 K75 GS.
    

duck

duck
Life time member
Life time member
What trans seal are you referring to?


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
That is a really nice job!  Is that Mystic Red?  That is not a real easy color to shoot due to the flakes in it that are sensitive to gun pressure and coat thickness.

I suspect your bike was repainted some time before you got it.  In my experience, the factory paint is pretty immune to the solvents in aftermarket paint systems.

Orange peel is pretty much guaranteed if you don't use a $300+ pro gun. I always do a 2000 to 2500 grit wet sand and buff with Perfect-it #2 and #3 to get a nice smooth finish.


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

duck

duck
Life time member
Life time member
Rick G wrote:Lookin good  that red will make an extra 10mph. Oh and those runs on the mirrors I just use hedge trimmer when it is good and dry. Very Happy

It depends upon which red. Mystic Red adds 10 MPH. Marrakesh Red adds 8 MPH. Very Happy


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

Dai

Dai
Life time member
Life time member
It's not so much the size of the compressor in gallons, but how much CFM (cubic feet per minute) it moves. I used to have an HVLP setup (DeVilbiss JGA gun - was their top of the line back then) when I was doing mostly custom stuff and I know from experience that a continuous 11.0 CFM at 40 psi is the minimum you need for a successful lay-on with the JGA. I stilll see 8 CFM at 40 psi recommended but that's pushing the lower end and pushing it hard. I also used to reckon on using a full reservoir of thinners to clean the gun between colour chnages. As you found out, you also need some form of barrier coat if overpainting old stuff. I prefer to rip all the existing paint off, if only to see if there's any damage underneath that needs patching first but admittedly, that is a habit gained from having other people pay me to paint their bikes. Finally, as you also found out, a good VOC (volatile organic compound) mask is a life-saving necessity. Double-filter is best.

Having said all that, that's a really good job you've done there! Spring Paint Job becomes Winter Overhaul 212902


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Some comments on the Harbor Freight "purple" "HVLP" gun.

The purple Harbor Freight gun is okay, the atomizing and pattern aren't too bad (there's a bit of dry spray at the edges of the fan), but you have to control the leaks.  I consider it a "one job" gun that I toss when I'm done.

The early ones had a nasty habit of leaking where the reservoir joined the gun's body and a bunch of air leaks.  They seem to have sort of solved that problem, but the one I bought sprung a leak in the packing around the needle between the trigger and the nozzle. 

Last spring I painted the hull of my 32 foot sailboat with a new HF purple gun.  I carefully prepped the gun by cleaning out all the silicone caulk they use at the factory and putting teflon tape on all the air leaks.  I even went in and tightened up the packing to where it barely dragged on the needle.

After shooting about 4 quarts of base and 1 quart of clear the packing started to leak.  Since it wasn't dripping onto the hull I decided to keep going because I really couldn't stop to clean, disassemble, tighten, and reassemble the gun because I had to keep building the clear.  At the end, I would estimate that about 10% of the clear coat was leaking out onto my hand.  What a mess!


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

zaubertuba

zaubertuba
Silver member
Silver member
duck wrote:What trans seal are you referring to?

Well I'm getting a tranny fluid drip from the bottom of the housing.  I was actually figuring, if I'm pulling the tranny anyway I might as well do a complete seal kit on the darned thing.


__________________________________________________
1985 K100RS
    

zaubertuba

zaubertuba
Silver member
Silver member
Point-Seven-five wrote:That is a really nice job!  Is that Mystic Red?  That is not a real easy color to shoot due to the flakes in it that are sensitive to gun pressure and coat thickness.

I suspect your bike was repainted some time before you got it.  In my experience, the factory paint is pretty immune to the solvents in aftermarket paint systems.

I have to confess, that's actually a VW OEM color.  I was really particular about the tone I wanted and probably looked at about 30 chips out in the sun in front of the paint shop before I settled on one--I'm glad I took that time!

This paint had "pearls" instead of metalflake.  From what I've heard it's a little more forgiving.

You're probably right about the repainting--but those parts came from four separate bikes, so that's probably why I had the problem with *just* that side cover, lol!



Last edited by zaubertuba on Sat Nov 12, 2022 3:59 am; edited 1 time in total


__________________________________________________
1985 K100RS
    

zaubertuba

zaubertuba
Silver member
Silver member
Dai wrote:It's not so much the size of the compressor in gallons, but how much CFM (cubic feet per minute) it moves. I used to have an HVLP setup (DeVilbiss JGA gun - was their top of the line back then) when I was doing mostly custom stuff and I know from experience that a continuous 11.0 CFM at 40 psi is the minimum you need for a successful lay-on with the JGA. I stilll see 8 CFM at 40 psi recommended but that's pushing the lower end and pushing it hard. I also used to reckon on using a full reservoir of thinners to clean the gun between colour chnages. As you found out, you also need some form of barrier coat if overpainting old stuff. I prefer to rip all the existing paint off, if only to see if there's any damage underneath that needs patching first but admittedly, that is a habit gained from having other people pay me to paint their bikes. Finally, as you also found out, a good VOC (volatile organic compound) mask is a life-saving necessity. Double-filter is best.

Having said all that, that's a really good job you'vedone there! Spring Paint Job becomes Winter Overhaul 212902

Good point on the CFM--and I actually did check that on both the gun and compressor before I bought them.

On the longer shoots, I actually flushed the gun every time I had to mix a new batch of paint for the reservoir.  Maybe that's overkill but I'm not an expert and I was taking a bit long on mixing each batch, lol.

I debated stripping that one part all the way down, but I also had the bags to do which I know *had* been repainted at least once, and was running short of time.  One of these days, I'll have a shop that I don't have to revert to housing the Wife's car during the week!  Laughing


__________________________________________________
1985 K100RS
    

zaubertuba

zaubertuba
Silver member
Silver member
Point-Seven-five wrote:Some comments on the Harbor Freight "purple" "HVLP" gun...

That's indeed the gun I used, and I kind of gathered it may not have a long production life, lol.  But I seemed to be lucky and didn't get any leaks/issues on this (relatively short) shoot.

They had a better gun at the pro shop I was at.  If I end up doing more painting I might look at that, but as a "throw-away" gun the HF gun did pretty well.


__________________________________________________
1985 K100RS
    

charlie99

charlie99
VIP
VIP
Dai wrote:Having said all that, that's a really good job you've done there! Spring Paint Job becomes Winter Overhaul 212902
Spring Paint Job becomes Winter Overhaul 112350


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OSpring Paint Job becomes Winter Overhaul Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

duck

duck
Life time member
Life time member
zaubertuba wrote:
duck wrote:What trans seal are you referring to?

Well I'm getting a tranny fluid drip from the bottom of the housing.  I was actually figuring, if I'm pulling the tranny anyway I might as well do a complete seal kit on the darned thing.

The reason I ask is that there's a small seal at the back end of the clutch pushrod that can leak. Gear oil then travels up the pushrod "pipe" in the center of the input shaft and comes out at the bellhousing weep hole. I had this happen on one of my Ks.

When you pull the tranny check to see if the clutch pushrod has any gear oil on it or in the "pipe."

#12 in this diagram:

https://www.realoem.com/bmw/enUS/showparts?id=0511-USA---K589-BMW-K%20100%2083%20(0501,0511)&diagId=23_1155

It's a PITA to remove. I screwed up the first one replacing it. On the second one I used a small socket (same diameter as the seal) to drift the seal in and that worked really well.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

zaubertuba

zaubertuba
Silver member
Silver member
duck wrote:When you pull the tranny check to see if the clutch pushrod has any gear oil on it or in the "pipe."...

Ooh that's great advice!  Thank you I'll make a point of checking that when I go in.   Very Happy

    

duck

duck
Life time member
Life time member
zaubertuba wrote:
duck wrote:When you pull the tranny check to see if the clutch pushrod has any gear oil on it or in the "pipe."...

Ooh that's great advice!  Thank you I'll make a point of checking that when I go in.   Very Happy

The reason that shaft seal is so hard to get out is that it has a metal collar that you need to pry out. I can't remember exactly how I got it out, just that is was extremely frustrating.

I did this a LONG time ago. If I were doing it today I'd probably be smarter and put the new seal in the freezer overnight to shrink it a bit in the hope that it goes in a little easier.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

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