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Discussion Starter · #1 ·
Hi All

I've finally managed to put off procrastinating, and got around to starting a build thread on my CX500 Eurosport conversion to a cafe racer. I actually started this project some time ago, but have not made much progress on it whilst I have had a lot of other projects on the go. Have now managed to clear the decks a bit and got back into it, so will post some of the early pictures that I have.

Being fairly new to the forum, and not very experienced in using it, please excuse me if there are technical difficulties with my posts (pictures wrong size etc) but I'm sure I will pick it up and work it out eventually.

I have had an interest in CX's for about 25years, as I used most of an imported (I'm in the UK) 'basket case' 650 custom as the basis of a reverse trike project. A few years ago I was looking for another project, and picked up a 500 Eurosport on eBay for about £250. about 3 weeks later, a very similar 650 came up for sale too, which was actually what I wanted, and another £250 later I had two, red, basket case, Eurosports in my garage.

My plan is for the 500 to be a sort of practice piece, and use the 650 as a much more involved project if possible. The 650 will also be used as a bit of a donor bike for the 500 at this stage. Neither of them has cost me much, so if it doesn't work out, I'm sure someone will take them off my hands one day.

My budget is fairly limited for the 500, so I will be trying to keep of lot of the original parts as much as possible, and probably improvise a lot of the rest.

The couple of pictures below show the bike partially stripped and washed down - it had just been raining, which is fairly common for this part of the world. The picture files are quite large, so let's hope this works!

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Discussion Starter · #3 ·
Hi JC, Don't know about the motors - both of them were a long way off of being able to run when I bought them, so it was just a case of taking a risk. Only way to find out is to put the bike back together and see what happens when I start it. If it doesn't work, I'll just have to fix it.
 

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Cool. Looking forward to see your progress. I'm in.
 

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Discussion Starter · #5 ·

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Discussion Starter · #6 ·
Quick update on the project with some historical photos:

This one is with the engine out, and a few more bits taken off. CX650 'donor' bike in the background.

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Engine on the bench for clean up - at this stage, I wasn't sure whether to strip the whole thing and do a rebuild, do a triple bypass, or just clean it up and put it back in. I don't know what the condition is like, and not very practical to do a compression test like this!
I decided to take the water pump off and the right cylinder to check the condition. There was a lot of dried antifreeze and other crud in the cooling system, but the bores all looked good. flushed out the engine as much as I could, new gasket on the cylinder, and put it all back together. Will just have to check the condition more when I eventually get it started up.

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Discussion Starter · #7 ·
Rebuilt the front forks - organisation is a bit of an issue for me, as I do get easily distracted. I start the day with a tidy workshop, and at the end of the day, it looks chaos! Someone please tell me this is normal?
This is about as good as I get sometimes - all the parts from the forks, laid out in the order of disassembly. The only part missing here I think was the fork spring washer, which was wrecked in the removal process (it proved very unco-operative, and needed some persuasion with a heavy object)
There was quite a bit of pitting on the top part of the stantion, but seemed okay in the area where the oil seal goes, so just put new seals in and hope they're okay. It seems to cost about the same to get them re-chromed as it does to buy new stantions, and as budget is limited, I'm taking the risk.

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Discussion Starter · #8 ·
Just thought I would add this in. Appreciate a dirty pro-link assembly is not the most photogenic, but it did have me wondering why Honda did this? The Pro-Link assembly is a heavy old lump of metal adding a lot to the weight. They could have just fitted a mono shock straight between the swing arm and the frame, which is what a lot of people are doing with mono shock conversions these days. My only guess is that it was done for compactness, the keep the shock set low enough in the frame to clear the airbox, and the cantilever action reduces the required travel length of the shock/spring and keeps is short. I'm sure this has been discussed previously by more knowledgable minds than mine on this forum (and also at Honda of course!) Any offers?

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Discussion Starter · #9 ·
This is the rear master cylinder from the original bike - I think this is what's called 'beyond economic repair'!

I'm trying to keep a lot of the original parts, but picked up a decent condition rear cylinder from a CBR600 on eBay - mounting holes are different, but that's only a case of welding on a new bracket. Original bracket is not pretty anyway.

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The linkage is not for compactness but instead for mechanical advantage; have a read up on single shock design and look at modern monoshock sportsbikes and you’ll see linkages absolutely everywhere. I can’t think of a single rear monoshock bike that I have pulled down that didn’t have one.

For the cost of a rear cover gasket/pulser cover gasket I would pull the rear cover and get a good look at the cam chain, blade and guide and stator.

Processes here:

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

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Discussion Starter · #11 ·
Previous photos were quite old - these two are more recent, but still not up to date yet. As I said at the start, this build was started a while ago, and I'm just filling in a bit of the history. By this time, the forks and callipers had been re-built, mono shock and pro-link cleaned up, wheels cleaned, and new Pirelli Sport Demons fitted.

Also fitted some Tarozzi rear sets, which look lovely! But having second thoughts on them. Think they're Italian, and just like their cars, they're intended for those with short legs and long arms:( I know cafe racers are not built for comfort, but don't want to ride this bike with my chest resting on my knees!

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Clip ons and rear sets - a true sports riding position. Once the tank's on you'll be able to grip it with your legs....may grow on you. I love riding in that position. Max 2 hours though.
 

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Couple the spring unit directly to the swing arm wouldn't have allowed the rising rate that the pro link gives, in fact I think it would have given a falling rate, with the springing getting softer as the angle changed. It would also have needed a much softer spring to start with and a very limited amount of travel.
 

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Discussion Starter · #14 ·
The linkage is not for compactness but instead for mechanical advantage; have a read up on single shock design and look at modern monoshock sportsbikes and you’ll see linkages absolutely everywhere. I can’t think of a single rear monoshock bike that I have pulled down that didn’t have one.

For the cost of a rear cover gasket/pulser cover gasket I would pull the rear cover and get a good look at the cam chain, blade and guide and stator.

Processes here:

https://motofaction.org/motorcycles/honda-cx-gl/triple-or-quadruple-bypass-cx500-cx650-gl500-gl650/
Thanks JC - will have a read up on the motofaction link when I get the chance, but good advice. I will be taking the engine back out again shortly, as nothing has been properly installed back in the frame yet - its all put together at the moment so I don't lose bits!
 

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Discussion Starter · #15 ·
Clip ons and rear sets - a true sports riding position. Once the tank's on you'll be able to grip it with your legs....may grow on you. I love riding in that position. Max 2 hours though.
Thanks for the advice - I work on my own most of the time, so it's good to get other points of view on this. Much appreciated.

I will probably be taking the route of the indecisive, and keep both options. I am adapting the original footpeg brackets to take the Tarozzi pegs and linkages, which will enable me to swap the footpeg positions in the future at will. It's tricky to decide what is going to work best at this stage until I get the seat position sorted out.
 
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Discussion Starter · #16 ·
Trying out the rear hump from Cafe Racer Seats - have cut the back end out to leave two tube ends. My plan for this was to put a hoop in, but now considering whether to extend the tube ends slightly, add some more between them, and put some small 'bullet' lights into the ends. They would stick out from under the hump, with the outer two being indicators, the next two being side lights, and the inner two being the stop lights. Will have to do a mock-up of this, as Im not sure if I'm going to like it.

Not a big fan of the Eurosport tank - it has a lot of angles, and is a bit 'clunky' visually. These seem to need a carefully chosen colour scheme to work, with wide stripes or panels to break up the lines of it a bit - most of the ones I have seen that are a single colour look too large, and don't follow many of the geometric lines of the rest of the bike. My favourite option here would be one of the Benji's style tanks or even one from a GL.

I eventually plan to replace the rear mono shock with a Hagon unit, but need some more money in the budget first. I think I'd like to run it with the original mono shock for now, just so I have something to compare it too when it does get replaced.

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Running an experiment on the seat - If I do keep the original tank, I'd like to use part of the original seat into it to retain the knee-pads on the tank. The original seat was a mess anyway, so no harm in cutting it up to try it.

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Discussion Starter · #17 ·
Engine being prepped for blasting - I did have a lot of blanking panels laser cut to cover all the openings into the engine, but these did not arrive on time, so I have filled the holes with washers and rags stuffed in to stop any blasting media getting into the engine.

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Discussion Starter · #18 ·
Engine painted and back in - polished up a few bits on it too, but have some spare rocker covers, so may experiment with black/polished/something else.

Frame is still a bit of a mess, but there is still a need to do some hacking up and welding on it. The interface of the fibreglass hump and the tank is still a bit tricky. Was planning to get this into photoshop and play around with the layout, but my photoshop skills are a bit basic, so may just be quicker to change it for real than all the time altering it virtually.

I've left the centre stand in for now, but this will come out at a later date to save weight - its so heavy!!

Next items on the list are to clean up the wiring, buy some mufflers, start looking at the tank, and sort out the airbox. I'm keeping the original carbs, as I understand there is a lot of retuning with jets to get pod filters to work, so will do what I can to tart up the airbox and keep things simple if possible. The new mufflers may require the jets to be altered still, but we shall have to see.

Ive decided that rear bevel drive needs to be painted the same colour as the engine, so that will come off again soon.



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Discussion Starter · #19 ·
This is the rear master cylinder from a CBR600, but hole fixings don't line up with the bracket. I'm planning on using an upswept muffler on the exhaust, but this puts the cylinder very close to the exhaust, which doesn't seem a great idea for a lot of heat to be so close to rubber and plastic. Still working out the best spot for this, as the rearsets are likely to move, so need to get those fixed first.

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Discussion Starter · #20 ·
This is where the build starts to get a bit more interesting, as I can start to do a bit more in terms of the look of the bike, rather than just fixing up the knackered bits.

As per a previous post, I wasn't a big fan of the original tank. I wanted a tank which is more curved - love this Benjie's cafe racer tank, but don't know if its going to fit a CX500 frame.

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Cut the top off one of the original Eurosport tanks, which I then found had been in an accident once before, and had about an inch thick of filler on it!

Bottom half was still okay, so I can use that as a base. Started looking around at what I could use for the rest of it.

Fabrication skills are limited, and I don't have an English Wheel to smooth out any sheet metal that's been roughly bashed to shape, so need something that is already formed to about the right shape, and weld parts together.

Found some curved metal which was given to me by the Motor Body Cosmetics shop a few doors away - Many thanks to Ian Ellis for that. (They do paint spraying too, so I'm sure they will be getting another mention in this build as it progresses)

A round of applause to however guesses what it is :D

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