Kawasaki ER-5 Cafe Racer

Exuptoy

Active Member
I really decided to do this as the bike was so cheap to buy and with a 40k 500cc commuter level bike being worth less than a grand it seemed the only way to add value was do do something unique.......then I started and as it has taken shape I’m sorta proud of my work thus far and I don’t think it’ll be sold once complete as it’s my creation. (Unless someone offers me silly money for it! :D )
I also want to try and do this on a budget and maybe even using cheap Chinese parts where I can trust the quality (ie. no structural parts like wheels)

As it was found just before new year 2020.

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Shortly after getting it I sourced a Lithium Ion battery for it as I knew these things were light but were far from cheap! The Shido battery weighs 0.8kg as opposed to just under 4kg for the old lead acid one. I found one in Halfords for £67 with my trade card (May have been £57???) It also has built in short circuit protection, maintains its charge value until almost flat (lead acid just gradually gets less and less until its flat at around 11.2v), barely needs charging, but needs a little thought if you are going to use one (you cannot charge it with a maintenance charger which puts a battery through a desulphation phase) but any loss in charge can be topped off to full within about 15mins of riding as opposed to hours on a regular LA battery.
Anyway, back to it....I stuck the battery on with my Sealey remote tank full of old fuel (the diaphragm in the petcock is goosed so using the tank was no go). I turned it over a few times and eventually it fired into life and slowly cleared its throat until it was idling nicely!

 

Exuptoy

Active Member
Now it was running it really was time to make a start and rip it apart. Out came the wiring, headlught, clocks, footrests, radiator, handlebars and mirrors, exhaust, top yoke and undertray.
I sourced a set of Chinese shocks and straight away found out they are dire (but apparently can be rebuilt to make a reasonable shock)....I decided to find something from a modern bike with retro looks and scored a set of Triumph Street Twin shocks from a 2017 bike on the bay of E for £21, although they are 50mm longer and will need mods to account for the extra length.
I also cut off the 60mm outer sleeve from the exhaust and modified the inner tube to fit a modern slip on exhaust can as the Kwaker Zorst is a one piece affair.

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Exuptoy

Active Member
Trawling though AliExpress I found a set of clip ons for £18 which seem very good although I will subject these to some abuse prior to riding the bike as a failure in this area could be fatal, I also sourced a cafe racer seat complete with vinyl seat pad for less than £50 delivered and any cafe racer shop in the UK wants in excess of £150 so I thought it was worth taking a chance.
Less than 12 days later it arrived in Blighty with slight damage to the front corner in transit which I was able to trim off and got a $10 refund! My tame machinist took my upper yoke (triple tree) and shaved to risers off which immediately improved the visuals.

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This spurred me on to taking lots of measurements before hacking off the upper subframe tube after mounting the tank support on an offcut of tube blobbed on to the lower rail and placing a wooden support to carry the seat unit to trial fit it.
It was at this point I started to get abuse over on CR.net so I left! My attitude was that the shock mounts haven’t changed (or moved), we’re still attached to the main frame tube, we’re still braced across the frame hence were still an original datum point for any modifications.

My main reasoning for hacking off the subframe is that the design when covered by acres of plastic is not an issue. Now remove that plastic and the look is all wrong, hence everyone who modified one sticks the old side plastics back on, but for me this was not an option.

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It’s sitting too high due to the shock length!

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With the original shocks back on, the back end and the rake and trail have not changed.
 
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Exuptoy

Active Member
Next I sourced some 22mm (7/8”) ERW 2mm wall steel tube and using the seat plastics as a guide I managed to bend a new upper subframe tube in one piece with my electrical conduit tube benders to follow the lines.

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You can see the lines I was trying to achieve and the original tubes below which just don’t work!

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Exuptoy

Active Member
This next bit really blew the minds on CR.net as they couldn’t understand why I would drill my main frame. The reason was to place spigots inside the frame rails at an appropriate angle, plug welded from the back which allowed the new subframe loop to be welded to the original frame whilst adding support and strength. The tube was welded with multiple passes before being smoothed out as I don’t like the look of a wide welded joint (only because I had to slide the tube back to get the rear in the right place, which created a gap on my frame spigot (the spigot is still inside the tube though)

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The only fly in the ointment at this point is the fuel supply pipe runs very close to the frame. The solution was to core the tube, place an insert through the tube and seam weld it then dress the weld with a file to tidy it up. I’m not concerned about strength as this will be cross braced before this project is finished.

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Following reading Tony Foale’s frame design book I found you can notch tube to be welded without a tube notcher (which are not really that good) by cutting the ends and profiling with a flap wheel. This allowed me to prepare and weld in this brace.
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Exuptoy

Active Member
Next, once my 25mm (1”) tube arrived I made a start bending the new suspension support lower tubes, before slicing them to fit around the 22mm upper loop.

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Then after tacking my tank to the frame, I removed the tank / seat mount, then using a spot weld drill I removed the support itself from the carrier plate and welded it to a piece of angle iron dressed to fit between the frame rails.

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Here you can see the desired height on the original shocks. At this point I am about 7 days in since starting the project. It’s getting there I think?


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Exuptoy

Active Member
My tame machinist made me another couple of spigots for the larger 25mm frame tubes to plug weld inside the mainframe then a plug weld in the lower tubes after driving them home and clamping them at the upper loop for welding. I also made a support gusset to carry the upper suspension mount from a piece of 2x1 box section.

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The flat was machined to clear the ERW internal weld. You can just see the spigot between both tubes below.

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It really isn’t going anywhere!

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Exuptoy

Active Member
I didn’t like the pointed rear section of the gusset and thought a radius would improve the visuals so I cut along the green lines before closing up with a hammer, cutting to length and welding up.

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I really don’t like the look of welded joints they were all dressed back but before powder coating I may seam weld a few for extra strength and so you can see they are solid.


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Exuptoy

Active Member
My machinist knocked me up a couple of shock spigots which will be seam welded both sides of the gusset and will allow me to mount the shocks close enough to maintain a vertical even though the shocks are substantially larger. Also I have made new lower shock mounts but I am waiting for lower bolts to be made.
At this point the geometry hasn’t changed (which is proven by the fact that the opposite side shock is still attached to the original mountings) thereby the rake and trail are unaffected as the angle hasn’t changed. Also the spring rising rate shouldnt have changed as the reduction of length on the lower shock mount and increase in shock angle has maintained the effective spring rate (worked out using the pivot to wheel centre/pivot to shock mount and the Sin of the shock angle. Also placing the shock more upright increases the effective spring rate. The only unknown is really the spring rate of the Triumph shock but with the reduced mass of the bike with all the rubbish that has been removed and the shocks only being 2 years old and barely used I hoping they will prove to be ok, also an ER5 is listed at 180kg against the Triumphs 198 so I will assume that the springs are progressive as they actually feel softer! If not I’ll re-spring them.
Once the shock mounts are seam welded I can completely remove the original down tube and braces and finish my cross braces before stripping down for seam welding and powder coating.

One last addition is the ZX10R rearsets, ironically the rear brake pedal support shaft is identical to the original 20 year older ER5 one and the only mod to fit them is a steel mounting point for the lower bolt hole and shortening the brake actuator arm by approximately 2.5 inches! The gear lever will be removed from the rearset as it will foul the frame and the original one will be extended (maybe....watch this space!)

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This is pretty much where I am just now after 8 or 9 days work (full days!) and I’m back offshore for the next 2 weeks, so I can start browsing AliExpress and eBay again now! :D

If anyone wants to comment OR criticise any of my work / decisions / techniques please feel free as I welcome any input both good and bad.
 
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Jimbonaut

Over 1,000 Posts
DTT SUPPORTER
Hurco took the words right out of my mouth - the lines on that subframe (and bike in general) look absolutely killer. I'd be sorta proud too!
 

teazer

Over 1,000 Posts
DTT BOTM WINNER
This next bit really blew the minds on CR.net as they couldn’t understand why I would drill my main frame. The reason was to place spigots inside the frame rails at an appropriate angle, plug welded from the back which allowed the new subframe loop to be welded to the original frame whilst adding support and strength. The tube was welded with multiple passes before being smoothed out as I don’t like the look of a wide welded joint (only because I had to slide the tube back to get the rear in the right place, which created a gap on my frame spigot (the spigot is still inside the tube though).....
I have no idea what the OP said over on CRnet, but I would suggest that they were appalled at the use of a solid slug through a frame tube taking suspension loads. It is not a good idea to drill through frame tubes and insert large solid slugs

I have used drilled and tapped slugs through frame tubes to locate footpegs but the slugs are much smaller diameter than the frame tube and are hollow, so there is less of a stress riser. With a solid slug inside a tube, the tube is most likely to fail at the end of the steel slug because of the significant change in section. Solid slugs are also very heavy. And the last thing and probably most important is that gaps between parts should be almost non existent. It is very poor practice to fill gaps like those with weld. My fitting up is rarely perfect either, but it's really important to get that right - especially when they are taking suspension loads.

Your welding and pipe fitting generally looks to be very good, so I'm not being critical. Just pointing out some of the possible reasons that CRnet was upset. Many of the guys over there build and race bikes and generally know what they are talking about.
 

Exuptoy

Active Member
Cheers for the comments guys. Yeah,@teazer I get where you are coming from but there will also be 2mm or 3mm steel gussets fitted to triangulate the under seat area to carry any stresses along with more triangulation with cross braces.
I admit I did f***up with the gaps on the upper loop but I wasn’t remaking that as it was a ball ache, I did a far better job on the lower ones.
As I said I am open to comments and advice (Good or bad) but the guys on there just seem to want to tear people down, and I understand the logic when every second post on there is someone who likes the idea but has no clue how to achieve the task in hand but just starts cutting up a useable bike then sticking it together with pigeon sh!t, but they don’t give people a chance either as they see it all too regularly and think everyone is the same.
I don’t need smoke blowing up my ass and for people to massage my ego, but at least see where things go before shooting someone down. There are some real harsh threads over there!
 
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Exuptoy

Active Member
This bike is only being made for my enjoyment, I don’t do track days and if I want to wring my bikes neck I’ll take out the MT-10. This one is just gonna be for the pose and for pottering about, almost as much as for people to notice something different. I honestly don’t intend using this to carve up the tracks or to sell on to someone. I am sorta getting attached to it.
 

Exuptoy

Active Member
Yeah, thanks @The Jimbonaut . They are a real tool! Mines running a K-Tech DDS lite rear shock and dialled in front end, J-Tech tail tidy, SP front fender, comfort seat, bar ends, R&G crash bungs and engine sliders, Leo Vince baffled decat and Scorpion RP1-GP. It’ll live with a Superbike on the roads I ride and handles very well now it’s sorted.

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doc_rot

Oh the usual... I bowl, I drive around...
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Ive wanted to ride an MT-10 to experience the cross plane engine.
 

Exuptoy

Active Member
I’ve ridden nothing like it! Overtaking a vehicle, it spins up so quick then 92mph in 3rd has it trying to stand up on the back wheel! You ride it like a tool everywhere! :D
 

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