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Discussion Starter #1 (Edited)
Hola!

Started a new build on a 1982 CX500 Shadow (Australian model). Bought it 1 year ago and bike had been garaged for last 10 years or so, but to PO's credit, he had maintained it and started regularly. It was in pretty good condition but was difficult to ride as clutch cable was stuffed.
This model came with a transistorized ignition system, and apart from some aftermarket Staintune pipes, was as far as I could tell quite original and intact.

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My current midlife crisis demanded that I build a cafe racer. So I looked up what a cafe racer was, and decided I wanted something that looked like this...
SCB750 creenshot.png

This is a CB750 by Cognitomoto in the US.

A few problems were encountered along the way:

1. CB 750's in ANY condition are now listed in the NY stock exchange with prices just below Apple shares.
2. The only things I have ever fabricated were laminated storage shelves in my garage.....10 years ago.
3. My previous attempts at things mechanical.....when I was a teenager some 30 years ago...... ended in horrible disasters, so although I have had motorcycles since then, they have always known how to make their own way to the mechanic's.
4. My proposed knowledge accumulation was coming from you tube and although inspiring, was less than adequate.

So, setting myself a modestly generous budget so I would not end up with a danger to society and CX enthusiasts everywhere, I decided it was best to start with a "kit" and found the CX500 kit from Cafe Racer Kits in the UK a good place to start. I thought that I would start with their concept of a "roadster"....

CRK cx500.jpg

....and I really liked it, but couldn't get the look of the CB out of my head, and started to change how I was going to do things. It was all starting to take shape...in my head.

Fortunately, in my youth I learned how to read, so I bought a Haynes manual, read it, didn't understand it, and then started to dismantle bike. I would figure out the rest as I went. It seemed like a good plan.

The Staintune pipes were so stuck on to H-box and header pipes that I couldn't separate them. Trying to work them out from under bike with my feet whilst holding on to bike and ended up with bike on top of me. But it didn't stop me.
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The tear-down continued.
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When my brother saw what I had to the bike he was horrified. Why change what was, as he put it, a perfectly good machine? I'm certain many in this forum will likely feel the same way.
The answer?......my mid-life crisis demanded it.
 

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Discussion Starter #2
It became evident from you tube wisdom that when dealing with a bike's engine, if it ain't broke, don't fix it. And this was my original intention.

However, my thirst for knowledge got the better of me, and I decided to pull the engine apart completely, change anything that needed to be changed, either through wear or need as a result of my actions, and in the process, learn how it works. I don't think there was anything wrong with it.
It is clear to me now that I'm further along that my admiration for motorcycles, of any kind, has shifted from their appearance, to their working heart.

I still have the picture of the CB750 in my head, but I am coming to terms that the CX will never look like that. But my admiration for this engine and its design is growing on me by the day. This of course is from the perspective of a complete amateur. I don't know anything about any other type of engine.

Here's my progress with the engine dismantling.

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Oil pump and transmission visible. Getting quite out of my depth now. What am I talking about? I couldn't even swim!
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The water pump impellers I've seen on you tube all looked pretty corroded. This one doesn't.
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ROTOR OUT AND LOOKING STRAIGHT DOWN THE CAM MECHANISM BARREL. VERY NERVOUS AT THIS POINT
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THAT'S THE TRANSMISSION IN MY HANDS.....BUT I'M HOLDING IT LIKE A BABY!
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I FINALLY ARRIVED AT THE PISTONS AND CRANK. THAT SPACE WHERE THE BIG END BOLTS ARE IS PRETTY TIGHT!
1011.jpg

VALVES DISASSEMBLED. ENGINE PULLED APART COMPLETELY. WHAT NOW?
1012.jpg
 

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Your enthusiasm is contagious ! I would have kept it 'original' likewise your brother's thinking. Follow the FSM and all the info tagged to this forum to the letter. Never be shy to ask amateurish questions. There are lots of patient experts here to take you by the ear lobes to lead you in the right direction. Most of all: enjoy the tinkering and the toying and riding YOUR bike , safely . :)
 

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Discussion Starter #4
I should say that I started out with no tools, and that my first task was to kit myself a workshop. This was an expense which I don't regret. It's a work in progress because as I delve deeper into the project, I find I can't proceed without this or that tool.

Once the whole engine is pulled apart, I felt no choice but to clean everything and ready to inspect.

I also got my hands on the Ricky Burns book on restoring the CX500 and got a few tips.

Keeping things separately and not losing parts is a real challenge.
100Cleaing heads.jpg

Scotch-brite scourers and hours of scrubbing.
101Clean head.jpg

But the results are worth it.
102Very Clean head.jpg

I got myself a sandblasting cabinet and used walnut shell to clean things up nicely, washed with a household Gurney (pressure washer), dried, and started taping up in preparation for painting. The engine on the CB is black. So will mine be.
103Prep for painting.jpg

Some parts I didn't want to paint. I used a bench lathe I have for my work, and using different cutting compounds, tried to get some shine going.
104Clutch cover 1.jpg

It's not mirror finish, but I was happy with result.
104Clutch cover 2.jpg

Polished the fins of the oil filter housing, and some on the engine block.
105Oil filter 1.jpg

Taped to block out for painting.
106Oil filter 2.jpg

VHT Engine enamel primer x 3 coats and VHT Black Pearl x 3 coats, followed by 1 hour in oven at around 90 degrees celcius. After removing tape I had to detail using some wet'n'dry to get rid of the burred finish at the edges (not done yet in photo).
107Oil filter 3.jpg

Other parts getting same treatment.
108Engine cover.jpg

Rocker cover on right polished on bench lathe also.....but....
109Rocker cover 1.jpg

......couldn't polish in between the fins. Any suggestions??
110Rocker cover 2.jpg

Started to check all the parts that have specs against the figures in the manual to see if any parts needed replacing.
100Measure tolerances.jpg

It turned out that after 85,000Km over 35 years, there was no significant wear on any parts measured.
101Measure cylinders.jpg
 

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Discussion Starter #6
Your enthusiasm is contagious ! I would have kept it 'original' likewise your brother's thinking. Follow the FSM and all the info tagged to this forum to the letter. Never be shy to ask amateurish questions. There are lots of patient experts here to take you by the ear lobes to lead you in the right direction. Most of all: enjoy the tinkering and the toying and riding YOUR bike , safely . :)
Thanks for slap on back izak. It's good to know. There's bound to be different likes and opinions, but one has to follow one's life crisis demands.

I still changed bearings where I could find them. Big end shells are not easy to find by all accounts. I managed to find some that did not correspond to my bike's specific codes found on the crank shaft and conrods. I read the codes on the crank and con rod of one cylinder and got that I needed a "green" bearing shell replacement. I assumed that it was the same on the other. It was not, and it called for a "yellow" shell. Well, I don't know if there are any. I found the green but coudn't source the yellow.....
103New big end bearing shells.jpg

...so I used the "green" that I was able to get. The specs show that the yellow is too small, but after trying them on and using Plastigauge to check oil clearance at crank pin and bearing interface, I found that the clearance was at low end of acceptable clearance (somewhere around 0.025-0.030mm). The quoted tolerances are 0.028-0.052 with a limit of 0.08mm.....it's tight but it should work.....shouldn't it?
102Plastigauge for crankpin oil clearance.jpg

Can't turn back now. New piston rings went on.
104New rings.jpg

Honing cylinder with an inexpensive honing tool and my cordless drill.
105Honing cylinders.jpg

Honing criss-cross pattern visible.
106Honed marks.jpg

Pistons and con-rods going in.
107Ring compressor - pistons going in.jpg

This is the rear crank-case cover, which is a pressure fit, and required great care to remove and not damage the oil bearing. This one is damaged. It looks like pitting....but more likely that I damaged it on removal. I did not tape up the teeth on the crank shaft and the thing popped out violently.
108Damaged Rear cranck case bearing.jpg

Again I had to source bearings, which again were not the exact match to my engine. This oil clearance can't be measured as far as I know, so I took a chance on a slightly tighter fit, counting on some minor wear to work in my favour. The specified bearing on this engine is "black" but I could get "blue,", which are big and increase the clearance, or "brown", which again are tight. I chose "brown". It will either run, or burn up if insufficient clearance is available. Note the tape on the crank shaft gear to protect the bearing during refit of back cover. Once bitten...twice shy!
109Rear crank case - tape to protect.jpg

New mainshaft and countershaft bearing in transmission holder....
100New mainshaft and countershaft bearings on transmission holder.jpg

....and in the transmission case.
101New bearings in case.jpg

Assembling the transmission.
102Assemble transmission.jpg

New clutch friction plates and springs.
103New clutch friction plates and springs.jpg

Made a tool to lock the crank-shaft so I could tighten clutch lock nut to the high torque specified.
104Crank locking tool to tighten clutch lock nut.jpg

Oil pump in place. Preparing to close the front cover. New gasket will be placed, and note all the little pieces of the puzzle that can soooo easily get lost in the many months that the engine is in pieces.
105Oil pump and ready for front cover.jpg

I used new stainless steel allen bolts. They look quite good against the black background. But are looks important? Sure...why not!
106New SS bolts.jpg
 
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Discussion Starter #7
Welcome. That bike looks great - and don't throw away those Staintunes, I had been looking for a set of those for a while and had no luck at all.

If you haven't seen it already some of the articles on here may interest you;

https://motofaction.org/motorcycles/honda-cx-gl/

...and perhaps:

https://motofaction.org/motorcycles/honda-cx-gl/triple-or-quadruple-bypass-cx500-cx650-gl500-gl650/

I'm not far from you so if you need some advice or parts drop me a line.
Thanks JC. Good resources in Motofaction. I've just been using the Haynes manual but it's good to have colour photos to go with explanations. Do you know who wrote that article?

I heard the Staintunes before dismantling and they sounded pretty sweet. They may end up being too long for the end bike result. I have some Gasser Customs slip ons on a Triumph and they sound orrrsome and are shorter reverse cones. I may end up putting on some of those if there are funds left over. I'll let you know towards end of build.
 

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Cam followers in place and well lubricated.
100Cam followers.jpg

Well greased cam-shaft going in. Where the bloody hell is the drive pin??? Took me 3 days to find it. It was hiding under the flap of a cardboard box where I had placed all the related components.
101Cam shaft.jpg

Cam mechanism in place. New cam chain. This is an automatic tensioner. I'm showing all the parameters that need to be in place to have timing correct. All from the manual.
102Cam chain mechanism.jpg

Tacho gear. I read on this forum that this is a good time to replace the tacho gear adjustment screw (phillips head from factory) with an allen head, as there is very little access when bike is assembled.
103Tacho gear.jpg

New oil seal. The mechanical cam-driven fan goes on the protruding portion of the cam-shaft. I am looking at replacing for an electric fan which means cutting this protruding section to allow fit of fan assembly. Also read up from this forum. There's a lot of good shit on this forum!
104Tacho gear oil seal.jpg

Clutch cover in place. Still touching up oil filter housing.
105Shiny clutch cover.jpg

Flywheel and gear shift linkages.
Flywheel and gear shift linkages.jpg

New final shaft and gear shift spindle seals. Note some chipping paintwork form over-handling. Will need to touch up once engine assembled.
New final shaft and gear shift spindle seals.jpg

Excellent opportunity to change the mechanical and oil seals on the water pump.
Water pump seals.jpg
Mechasnical seal.jpg

Cleaning the valves. I saw this technique on a youtube video by The Workshop, where he dismantles a CX500 engine, but never gets around to putting it back together. He says that his sole purpose was to explain the workings of a four stroke engine. As a novice myself, I learned much more when I put it together than when I pulled it apart.
100Cleaning valves.jpg

But they did come up pretty good.
101Cleaning valves 1.jpg

The valve seat cuts looked in a good state, but dirty and carbonised, especially on the exhaust ports.
102Lapping valves.jpg

After lapping, they came up clean and shiny. Valves seated well.
103Lapping valves 1.jpg

New valve stem seals.
104New valve seals.jpg
 

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Preparing the block to receive the heads. Once again, hold on to all the little parts so they can go back on. New O rings where old ones were removed, like the oil orifice.
105Preparing head.jpg

New head gaskets and sealant.
106New head gaskets.jpg

Push rods and rockers.
107Push rods and rockers.jpg

Tappets set. After I had reassembled the engine I was told that I should swap the rocker shafts and redress the tappets to minimize noise. The kind gentleman referred me to an article on this forum
http://cx500forum.com/forum/technical-help-forum/19487-am-i-crazy-can-you-guys-hear-tapping-video-too.html.....
....but it was too late. I will listen for noises if I ever get it started and if necessary will do it then. They are fairly accessible.
108Tappet adjustment.jpg

Rocker cover back on. Almost done but I did lose a locating dowel as shown. I'm waiting for it to arrive and then back cover can go back on.
110Almost finished.jpg

I need to finish the cooling system and a few other things, but I needed to take a break from the engine. This has taken me quite a while. I needed to start looking at the rest of the bike. I'm pretty pleased but the proof will be in the Brroooom.
1015.jpg
 

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You are no amateur, that looks pretty professional to me.

I think however it finishes will be an excellent restoration that you will be proud of.

Nice photos as well.
 

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Thanks JC. Good resources in Motofaction. I've just been using the Haynes manual but it's good to have colour photos to go with explanations. Do you know who wrote that article?

I heard the Staintunes before dismantling and they sounded pretty sweet. They may end up being too long for the end bike result. I have some Gasser Customs slip ons on a Triumph and they sound orrrsome and are shorter reverse cones. I may end up putting on some of those if there are funds left over. I'll let you know towards end of build.
MotoFaction is all published by me :)

I have a box of those dowels kicking around if you wanted one sooner.

Motor is looking really nice... did you check the oil pump tolerances while you had it out?

Which head gaskets did you use?

What was your bearing to journal cap clearance for the mains?

I have a selection of NOS rod bearings here, but that's a bit late since you have already reassembled!
 

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You are no amateur, that looks pretty professional to me.

I think however it finishes will be an excellent restoration that you will be proud of.

Nice photos as well.
I think so too 81custom - thank you!....but truth is...I am an amateur. There's no point doing thing badly though.

Time to start working on frame. Here's where the AMATEUR starts to show his limitations. I am no fabricator. I hope to become one one day, but for my first build, I had no choice but to go with a kit. This is the hoop supplied by Cafe Racer Kits in the UK. All I have to do is cut at rear of tape marks.......
precut frame.jpg

.......and cut straight and perpendicular. Not so easy.
Precut frame 1.jpg

This is the other component supplied that has to be welded. This supports the seat cowl and seat which bolt on to it.The advice given is to give it to a local welder.......
Precut frame 2.jpg

.......but oh no....I had to try it myself. So I borrowed a mate's MIG welder and off I went.
Precut frame 3.jpg

I won't show you the other side because it got embarrassing. My mate, when he saw the weld with a slightly disgusted look, asked me if I had done some trial welds on some scrap metal beforehand. Answer = No. It's ugly, but will be unseen, and I have no doubt it will hold.

To keep with my vision of the CB750 as the model I had in mind, I bought an 18x2.75 Sun rim with spokes and GXSR conversion hub from Cognitomoto for the front, and laced and trued it after watching a you tube by D ray smith......
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.....a 2007 GSXR-600 pair of forks, axle and calipers from ebay....
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....and upper and lower fork clamps and stem, also from Cognitomoto. This was an indulgence, but that was the vision.
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Fitted an Avon AM26 110x80x18 with a tube....
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So I could see what the bike will start to look like.
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My impressions when I looked at it for the first time as follows:
I'm stoked with the front end. Should be for what it cost.
The seat supplied is incredibly comfortable, but apart from being too high, I don't like it. Please note that the stuff supplied from Cafe Racer Kits is really high quality stuff and fits together perfectly.
There are no rear springs and bike is on center stand which pushes rear up a little, but even if it was lower, I still don't like how it looks. Bloody vanity....it's a curse.
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I realize that I still have to adjust the cowl to fit frame more closely, but with this kit the curved spine line is kept...this is not the traditional Cafe look, but I actually don't mid that. I took the seat off and it looked a whole lot better.
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I put shock on shocks....Progressive (The ones that were on the bike were stuffed) and it's starting to grow on me. The seat is a molded plastic pan that fits perfectly onto cowl, so I'm thinking I will modify it and fit a slimmer cushion pad to keep with this line.
1025.jpg
 

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Discussion Starter #13
MotoFaction is all published by me :)

I have a box of those dowels kicking around if you wanted one sooner.

Motor is looking really nice... did you check the oil pump tolerances while you had it out?

Which head gaskets did you use?

What was your bearing to journal cap clearance for the mains?

I have a selection of NOS rod bearings here, but that's a bit late since you have already reassembled!
Great work JC. Like I said...it's an excellent resource, well photographed and clear and to the point descriptions.

The oil pump clearances were all within service limits. I have to say that my impression was that this was an engine that did not need surgery. It was me that needed to do it so I could learn. I actually felt like I was violating a perfectly good machine....but how else does one learn?

After fitting the "brown" oil bearings, clearances were 0.02. Tight. I don't necessarily trust my readings, especially measuring with a bore gauge and then transferring to a micrometer for a reading. The crank rotates freely without any binding, but it's bound to be tight and may require a prolonged and gentle breaking in.

Thanks for the offer. I did get the dowel and it's all assembled.
The head gaskets were from an Athena full set. I think they were composite but don't know much about the different types.
 

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Next step is the rear tyre. I have to match with a spoked wheel, and like so many before me, I want to put on a wider tyre.

I have read many threads on the rear tyre....on this forum and on other forums.....and found many many opinions.

It appears to be a subject that brings out a lot of passion, and some strong reactions. Comparisons have been made with respect to the turning ability of a tyre - perhaps these comparisons are valid....perhaps not. I hope to ride within my ability and the properties of the tyre compounds, which in a modern tyre, is likely to be excellent in most cases.
So right or wrong, this is what I'm doing.

I set up the existing rear wheel and tyre...a 110x90x18 which has probably replaced the stock 3.75x18 in the old nomenclature.
Rear tyre calcs 1.jpg

I worked out the limitations are not at the axle point, since the cush drive could be removed if necessary to fit and remove the wheel. I made some marks to see where an 18" and a 17" tyre would end up.
Rear tyre calcs 2.jpg

It seems that the limitation is in the swing arm clearance. So I measured the clearance at the 18" and 17" marks, and found those to be 125 and 131 cm's respectively. This is pretty crude seeing that it does not take into account the sidewall dimensions which will to an extent determine the final tyre end points....but it beats getting an opinion. There's just too much division.
Rear tyre calcs 3.jpg

So I'm getting some Comstar conversion bolt on flanges from Cafe Racer Kits, keeping the drum brakes, and I will fit an Avon AM26 120/80 x 18" to a 3.5 rim to match the front. This tyre is quoted in the Avon website as being 120mm wide so should have clearance on both sides, even though there is asymetry in the swing arm. I could have gone for a fatter 17" tyre but I decided that I wanted to keep the orientation as it is. This is my solution and seeing I have no experience in the matter, I can't enter into an argument.

Of course this is not original. I sifted this forum dry for opinions and threads so I would NOT have to make a decision myself, but ultimately one has to. It's my bike, my vision, and my responsibility.

And that is where I'm up to. Thanks for listening.
 
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As one who is not a particular fan of the "cafe" style (not comfortable for me at all), I do appreciate the artistry that goes into building one.
It appears that you have a clear vision of what you want to accomplish and are taking the necessary steps to get there along with having a safe ride when done. (more than many who start such projects)

Did you find a way to clean up the ridges on the valve covers?
If not then look up, "Mothers polishing kits", it will include some polisher tips that will fit into the small spaces (tapered ends) so that you get it all nice and shiny.
 

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So, if the engine was running fine, why did you rebuild it? I missed something there. Sure, take it out for a triple bypass, but generally you can just leave the motor alone beyond gaskets and the triple bypass.

Charles.
 

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It's interesting watching someone who has, at least, the curiosity to expand his horizons, even if there may be a sacrificial lamb along the way (which doesn't really seem to be the case here). A padded wallet helps a bit.

One thing that caught my eye earlier in the thread was calling out the mythical Philips Head screws on the CX. There really aren't any, stock anyway.
Here is a nice read on the overall subject, and a pictorial for a quick glance. Subtle differences, to be sure, but designed, purposefully.
http://cx500forum.com/forum/general-discussion/26109-japanese-industrial-standard-say-what.html

 

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As one who is not a particular fan of the "cafe" style (not comfortable for me at all), I do appreciate the artistry that goes into building one.
It appears that you have a clear vision of what you want to accomplish and are taking the necessary steps to get there along with having a safe ride when done. (more than many who start such projects)

Did you find a way to clean up the ridges on the valve covers?
If not then look up, "Mothers polishing kits", it will include some polisher tips that will fit into the small spaces (tapered ends) so that you get it all nice and shiny.
Thanks OCR. I have n't yet, but will give this and suggestion by Steve1 ^ a try.
 

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It's interesting watching someone who has, at least, the curiosity to expand his horizons, even if there may be a sacrificial lamb along the way (which doesn't really seem to be the case here). A padded wallet helps a bit.

One thing that caught my eye earlier in the thread was calling out the mythical Philips Head screws on the CX. There really aren't any, stock anyway.
Here is a nice read on the overall subject, and a pictorial for a quick glance. Subtle differences, to be sure, but designed, purposefully.
http://cx500forum.com/forum/general-discussion/26109-japanese-industrial-standard-say-what.html

WOW....just read the article and blew my mind.Thanks Ramprat06. Sorry members, but I did not know the difference....then again why should I, having never fiddled with anything mechanical. This explains a lot. I was going to pull carburetors apart to clean and re-jet and found I could not undo screws. I didn't try too hard to avoid damaging heads. Another tool acquisition is in the pipeline. I'll have to see if the long screws on the starter motor are also JIS 'cause these were also not turning, so left alone.
Like I said before....there's a lot of EXCELLENT stuff in this forum.
 
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