OzVMX Forum
Marque Remarks => CZ => Topic started by: Ji Gantor on February 17, 2009, 09:00:24 am
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Completely strip the chassis of everything including, bearings,rubber grommets, bolts, compliance plate and most of all oil and grease. Cap all bearing areas to save time having to remove the powder coat later.
The powder coater will sand blast the frame but sand blasting does not remove oil.
For this spend some time degreasing the chassis. If the engine had an oil leak most likely the frame tubes around the foot pegs will be coated in oil.
If you do not remove all the oil from the frame when the chassis is placed in the oven the oil will heat up and flow all over the new paint job.
Degrease it and Gerni it over and over, some restorers soak their frames in degreaser for a time.
Be patient and good luck.
Ji
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Use plenty of spray can degreaser to get into those hard to reach areas. I also use a wire brush, a piece of wire and S/S wool to remove all the oil, grease and dirt deposits.
Don't forget to clean the steering head area.
The hot oil will flow all over the powder coat before the paint has hardened. The oven is set at, I think, about 200 deg C. Once the oil has mixed with the paint the only fix is to sand it back and use touch up paint or start again. Your powder coater will not do it for free the second time.
Ji
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Another tip to stop people from falling into the same pit I did.
Get all your new plastic covers, seat and any other attachments that will be going onto the frame and pre fit them before you send the frame off to be powder coated. If there is a missing bracket now is the time to weld it on. If the brackets are bent now is the time to adjust their position because if done after the paint has been applied the paint may crack when the plate is bent.
Ji
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To plug bearing areas I used a hole saw on a sheet of alloy and a length of Booker rod. Easy and cheap.
Ji
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Another thing not to forget before the frame goes off to the powder coater. Now is the time to make an engine mount spreader. I use a piece of Booker rod 2 nuts and 2 washers. Place them as shown and rotate one of the nuts. When you are hanging onto a 35 kilo engine and it just slides in you will thank me.
Don't spread the flanges too far apart just a few millimetres wider than the engine block.
Ji
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The powder coat colour chart can be found on this web site.
Colour Selector
With 132 colours on display, the Dulux Powder Coatings’ Colour Selector includes:
http://www.duluxpowders.com.au/powd/cda/powd_cda_card/1,1198,,00.html
Ji
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CZ and Maico red in powder coat colours is one of two tones.
Signal red or Flame red.
It is hard to see the difference between the two colours in the Dulux catalouge. But when you see them face to face standing side by side the Flame red seems to be a little more orange than the Signal red (this may be my old eyes).
Maico's have been powder coated in both colours by restorers and it is your decission.
Colour selection is personal but I selected Signal red for my Maico and I will use it for my CZ project as well.
Good luck.
Ji
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I wouldn't spread the mounts. I would install a bolt/nut with oversize washers instead. If you powder coat the mounts, you won't get a ground for the ignition.
After the powder coating be careful the grease and loctite, both will stain the frame and you can't remove it. I have found that model airplane paint works well to fill in chips and scratches in the powder coating.
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Hi OSSA PHANTOM,
I spread the engine mounting brackets because the bracket plates are the same distance apart as the engine block which has to fit inbetween or usually less. When holding a 30Kg engine in a chassis is not the time to start fighting with the brackets. It is better to widen the bracket plates a small amount so the engine slides in easily. When the engine mounting bolts are done up the bracket plates will close up.
I usually let the powder coater paint the chassis except those places blocked off and come back at the end with a Dremel and remove the paint so an earth can be made. After all I still have to ream some bolt holes and tap all threads to remove the powder coat.
Thanks for your input.
Ji
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Ji,
No problem, I rode and worked for a CZ many years ago, If you really need to find a bizarre CZ part let kme know. Once a year I fly back to the US and drink beer with the old boy who owned the shop. I know his shed has many secrets like a 400 Falta, "0" miles 1972 250 enduro and my old 250 cz.
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Hi OSSA PHANTOM,
Thanks for the offer I may have to take you up on it.
I am always surprised at what comes out of old sheds.
Great tip about the aircraft paint.
Ji
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Hi guys, the company that powdercoats my frames puts the frame in the baking oven before powdercoating to make sure oil doesn't leak. I had an Yamaha XT500 done not long ago and because of the oil tank in the frame he was concerned oil would leak, which it did.
John
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Hi HL500,
Where is your powder coater?
I have been suggesting this for years.
Thanks Ji
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Hi Ji Gantor, Perth base mate. The frame, swingarm and other bits cost $80. Good price I thought.
John
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Hi HL500,
Damn.
We pay $180.00 for the frame and swingarm and $15.00 for each and any other small bits.
Ji
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Hi Ji Gantor, Perth base mate. The frame, swingarm and other bits cost $80. Good price I thought.
John
Who is that with? (I'm in Perth) and I have used All metal finishes in Balcatta as they get everything sandblasted first and have always charged about $250 for a frame/swingarm tripples and sundries.
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Hi cyclegod,
It would cost us more than $80.00 to get the frame sand blasted over here.
Ji
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I snadblast most of the parts myself, bar the frame. That is expensive but I am working towards doing that as well. The $80 is just for the powdercoating.
Are you North or South of the river Ji Gantor
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North.
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The compliance plate has to be removed.
It is fixed into place via two nails.
These things are really interesting to look at, a steel nail.
They have a cork screw thread, I guess you could call it.
Anyway they have to come out so the plate can be removed.
I have a steel shaft that has a rounded end on it. Place the rounded section onto the internal end of the nail and pull back. The nail will pop without to much effort.
Ji
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Another tip re fitting the engine back into the frame.
Plastic milk carton plastic is pretty resilient and slippery so you can use it to protect both castings and paint and it can be withdrawn easily after the engine is slid in.
I have used it many times and never a dud.
Keep up the good work Ji - Good to see some sensible posts !
Dave Mac ;D
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Hi maicomc490t,
Great add, I will have to give that tip ago when my chassis gets back from the powder coaters.
Keep well
Ji
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My foot pegs are not being powder coated because I believe it makes them very slippery until the paint rubs off and technically they are not the chassis but one of mine was brocket and needed to be repaired.
The main backing plate had parted company with the serrated bear trap foot gripper thingy and needed to be welded back together.
Ji
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One of the side flange plates was bent. The peg is held together by a riveted end shaft which makes straightening the plate hard.
Ji
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Place the bent flange into a vice and tighten, work the flange around in the vice until you get the desired outcome.
Ji
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First thing is to clean the surfaces with a wire brush.
Then seperate the return spring so it does not get too hot from the welding or it will lose tension.
Ji
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Grind back the original weld and point your electrode at the groove and give it some amps.
Ji
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Turn the peg over and support your local energy supplier one more time.
Ji
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The brake pedal stop bracket was missing in action.
I have been told that this bracket was the first thing to break off when the bike was laid down.
If you have the bracket to fix back on the frame that is great but my bike came bracketless.
Ji
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I placed the foot peg back on the frame and set up the brake pedal so it will be in the right position when riding. This allows you to see all the parts and how they interact with each other.
Ji
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Others like me have come up with a clever solution that solves this problem.
Take a trip to your local bolt supplier and pick up an M8 coupler nut.
Clamp the coupler nut in place so you can measure where it has to be cut.
This also allows you to see how much pedal adjustment the new bracket will produce.
Ji
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After you have measured where the nut needs to be reduced take a hack saw and burn some calories or if you have a lathe part the nut don't bust a gut.
Ji
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Grind down the old weld and remove some paint to provide a good earth.
Ji
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Clamp the nut onto the frame and melt some filler rod.
Set up the adjustment bolt and lock nut and test.
Another job done.
To prevent splatter you can purchase an anti-splatter spray from your welding supply guy or use CRC or the spray that stops food sticking to your fry pan. Don't let this stuff get in the welding zone or it will contaminate the weld.
Ji
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The steering head stiffener plates on my bike are a bit sad. Some brain surgon took to them with a hammer or something.
Ji
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First I used a large shifting spanner to align them as best I could.
Then I employed a large diameter rounded end drift to push out the dent further down the plates.
Last of all I used a dolly to straighten out the mild ripples. I had to weld a small amount to fill in a piece that was missing.
Ji
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For some reason only konwn to the person that did it the frame had some drill holes with alloy rivets installed. I drilled out the rivets and cleaned up the area.
Ji
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With the welder humming fill that hole.
Remember to spray some anti-splatter or you will be cleaning up all those little balls of filler rod that stick to the job.
Ji
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Wire brush the welded surface and grind flat to suit.
Ji
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I will be using a 1974 CZ swingarm on my 1973 frame. The 74 swingarm was stiffer and is a legal modification for pre 75 class.
That said now is a good time to check its fit and the wheel travel.
Pre 75 wheel travel is only 102mm or 4 inches measured at the axle.
Install the shock minus the spring and measure the distance from the axle to a vertical spot on the frame. Compress the shock and measure the distance from the axle to the same spot on the frame. Subtract the two figures and it should be 102mm or less.
Ji
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The 1974 swingarm I imported from the States had some tell tail modifications, plates that had been welded on and semi removed. These have to be removed before paint.
Ji
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The weld to be removed is in a tricky place, not much room and we do not want to damage the original weld. The air die grinder was my first tool to hand. Use the small collet stones so only the foreign material is removed.
I ground the valley where the two pipes joined so it looks correct. I had to take my time so I did not remove any of the original weld.
Ji
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To straighten out and level all the surfaces use sand paper and or an abrasive flat disc.
Don't use an angle grinder as they cut to deep and leave marks in the metal that have to be removed.
Hand sand the area so all the metal grains line up so you can see if the surfaces are true.
Ji
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After some hand sanding it is looking good.
Ji
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The 74 swingarm was set up in America for me by a well known restorer. Unfortunately he welded imperial nuts on the shock mounts. This bike is all metric and that is the way it is going to stay.
Ji
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I cut through the welds securing the nuts with a cut off wheel on my trusty Dremel.
Great little tool is the Dremel.
Ji
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With a sanding flapper I smoothed the surface.
Ji
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The swingarm has a lot of grooves and dents that will look terrible when powder coated.
Ji
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The heat involved with powder coat does not allow body filler but these marks have to be filled by welding or brazing.
Because this metal could be chrome molly I selected Brazing.
Ji
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The swingarm over its life had the original shock brackets cut off and new ones welded on in a forward position. These misguided brackets were cut off. New shock brackets were welded on in their original location by a supplier in the States. I was informed that the welding technique used was TIG.
When I received the arm the welds looked more like manual arch welding to me. I decided that to do this arm justice these welds had to be removed.
Ji
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After 2 hours of grinding all the post manufactured welds off it was time to warm up the TIG.
We used Cr Mo filler rod just in case these tubes are Cr Mo.
We also pre and post heated the tubes just in case.
Now it is starting to look good.
All it needs now is a sand and the powder coat will make it look magic.
Ji
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To hone the rear engine mount that the pivot pin goes through. Place a shaft into a lathe and just wrap some 180 wet and dry sand paper around it. Feed the engine mount onto the shaft and start spinning.
Ji
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We need to plug the bearing areas so paint does not get in. We also need to plug these areas so the sand blasting does not effect the surfaces.
Buy some large diametre washers and some booker rod. If the internal hole does not match the booker rod place washer in the lathe and bore out the hole to match.
Ji
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Cap all bearing areas with the washers and the booker rod.
Ji
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Don't forget the steering head.
Ji
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Or the swingarm pivot bearing housing.
Ji
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The imperial nut that was welded on was removed and a new metric nut was TIG welded back on.
Nice job.
Ji
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When the frame gets back from the powder coaters, blow all the sand out of all the joints from the sand blasting. Remove all the bearing area caps and patch any oil leaks with touch up paint.
Ji
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With a tap remove all the paint from the threads.
Ji
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With a tap remove all the paint from the threads.Ji
Very nice work. A trick I found with my last frame I had powder coated was to get a heap of old bolts and screw them into the threads to stop sand and powder coating going in. Some of the bigger bolts I would carefully cut around the fresh powder coat with a razor to stop it cracking off.
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Good one Zorroz
Ji