2150cc Evo Custom Updates

Bevelheadmhr

Coast to Coast
DTT BOTM WINNER
Introduction


Back in 2000, I bought a 131 Cubic inch(2150cc) high output 'Harley' Evo motor, fully polished, built by the Merch Performance workshop in Canada and shipped to the UK for me. It was the best Evo of its day, and I could've bought a new Harley big twin for the cost of that one engine.

I still needed a gearbox, primary, frame, forks, wheels, bodywork and so on. It took more than two years to complete, each part being chosen because I thought it was the best option, the cost was not a consideration, it would just take longer as I saved to pay for it all. When the German drop seat frame arrived from HPU, the engine was too tall to fit, so we had to cut and raise the top tube. Paintwork was done by the best in the country, Piers Dowell, who has painted all my Harleys along with a couple of helmets, which are far too nice to actually wear lol..

When it was finally finished, within the first 100 miles, the expensive belt primary had broken, while the handling was pretty damn awful, due to the fashionable 'phat' wheels and tyres I'd fitted, a 160 x 16 front tyre is never a good idea. The primary was soon re engineered, while I spent another £2500 on new Ricks 17 inch billet and titanium wheels which improved the handling no end, it actually wanted to go around corners now, though at the cost of even less ground clearance, and it didn't have much to begin with.

I still have the Merch 131, its evolved over the years, different brakes, different seats, different exhaust, a hydraulic clutch conversion, and after snapping three belts, I switched to chain final drive, well, you get the picture.

Its been on the dyno a few times, the last being when I made a new exhaust for it. It has a Mikuni HSR 42 carb, small for such a big engine, but that was the biggest available when I placed my order back in 2000. A HSR 48mm would no doubt give a bit more top end, but at the expense of low down torque. I prefer the motor as it is, making 145 lb/ft torque and 128 bhp at the rear wheel. To put that into perspective, its making over 100 lb /ft of torque all the way through the rev range. Its too long and low to wheely under full throttle, but it'll easily break traction in first if launched hard. In the wet, the torque can spin the tyre in second and third too, so discretion is needed, then again I try not to take it out in bad weather, it takes way too many hours to clean otherwise.

The trad Harley folk hate it, ''looks too Japanese'', doesn't look right in their eyes... blah blah. I just smile and nod, and reply, I didn't build it for you...

Mid Life Update


Anyone whose built a ground up special will know they are never finished, there's always something that can be improved or updated. Now its time for some more updates of the Merch 131 which I'll detail in this thread..
 

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Mid Life Update


The updates I want to make break down into three areas...

1) The riding position.
Its never been the most comfortable bike in the world, but still things could be improved for me at least, by bringing the bars bag an inch or so and ditto the footpeg position.

2) Improve the Ground Clearance.
This is the trickiest change to make, as like all Softail Harleys the rear shocks live under the gearbox and work differently from most shocks. They don't compress when going over a bump, instead they extend. Coupled to the fact that the shocks on my bike are expensive gas shocks (No springs used) which I want to keep. But I have a plan !

3) Electrics and Instruments
The bike has basic functions only, with a speedo bolted to the rear cylinder.. not ideal. That said its all very neat with most of the wiring hidden inside the frame tubes. I want to replace the old speedo and idiots lights with a new up to date tacho/speedo with built in idiot lights, and completely replace the wiring, taking advantage of the latest tech from the German company Moto Gadget, which wasn't available when I built the bike all those years ago.
 
Lets get started by making new mounting plates for the forward controls, which moved the pegs an inch or so closer and a little lower. Luckily I was able to re drill and cut down the original plates which saved a lot of time.

Next the old one off risers were replaced with these new ones I made, they are as low as I could get them, while now moving the bars back an inch. The old risers and their mounting bolts were drilled to allow the wiring for the bar end indicators to pass unseen through the bars and down throught the risers.

I'll be losing the bar end indicators, as that'll made the bike six inches narrower at the bars. Handy when filtering through traffic, which is legal in the UK.
 

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Here's the risers polished with the new speedo/tacho on the bike, its mounted to the risers is a bit different, but it kinda works. Since I took this pic, the cap head bolts have been changed for domed head bolts which look better imo.

If you want to hear it being run up on the dyno, clicky here https://youtu.be/s2Jo-fipEAM
 

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Improving Ground Clearance

This was the mod I was most concerned about, there's a chance it could all go wrong, which would be an expensive mistake to fix. My plan is to move the Swing arms shock mounts back 20mm, doing this means the swing arm will need to rotate further down before the shocks can be bolted to the swing arm. This change should (in theory) lift the back end of the bike up around 45mm. However, if I get it wrong, the swing arm could hit the frame at full extension or the shocks may not reach the changed mounts on the swing arm.

Oh well, nothing ventured, nothing gained...

My first problem was that I had no room to work on the bike at home, not enough to safely remove the back end anyway. Thankfully, my mate Tim owns the local bike shop and kindly allowed me to work on the bike in the corner of his storage unit. Its not what you know, but who you know....

As usual things didn't go according to plan... they never do lol... but got there in the end, the photos below show the difference before and after. And since I went to the trouble of filming the process, you can see how it was done here..

https://youtu.be/cOmDXLuC1NM
 

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With the swing arm now powder coated and a new battery, I installed the back end and fired up the engine for the first time in more than 18 months. Surprised it started ok with only a stuck float to show for its long sleep. The mods to the swingarm have worked out well, giving more than two inches of extra ground clearance and changing the stance of the bike more than I expected. I quite like its new look.

The final phase of this update is to wire in the new tacho/speedo and clean up the wiring using Moto Gadget parts.

And here it is running sans silencers after I couldn't resist firing it up

https://youtu.be/CrqCoUlsZU0

Here's two pics.. before and after
 

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That torque figure sounds fun... what a beast I bet it sounded like a cannon with straight headers. Honestly not a fan of drop seats and what they force the rear fender to do, but yours is well executed. I'd do a swing arm mounted rear fender and hug it close to the tire. (you are gonna need a chain.... ;) )
 
Had to split the chain to remove the swingarm, hadn't fitted it when I took those pics. Sadly the change to the rear end height meant the old chain was no longer long enough, so had to buy a new one. Pity as the one I removed wasn't that old.

When it was first built it had V&H pipes which when I dynode the bike later, proved to be crap. Had to run them without baffles to get decent power. But doing so made it super loud and ruined the low end power, hence I ended up making my own exhaust. Here's an old vid of the bike running on the dyno with its unbaffled V&H pipes... its so loud the camera mic cuts out at high revs as it cant handle the noise....

https://youtu.be/gJq4fZk--jI

While coming up to date, here's a short vid of the bike this weeks, with new chain and 'silencers' fitted..

https://youtu.be/yCrT2m5H9yM
 
The bike will be at my mates workshop over the new year, as one of the modules from Moto Gadget is on back order. Not a problem as it'll not be ridden till the spring anyway.

But that hasn't prevented me from making a start on another upgrade which is a mini-project in itself. One issue I have with all Harleys is their weight, a standard Evo Softail is getting on for 650lbs with fuel, something I've attempted to address on my bike. Cant do much about the mass of the engine / transmission (around 300lbs), while an OE frame and swingarm tips the scales at 100lbs (60/40), the aftermarket HPU frame is a bit lighter, but not much. Despite these hefty components, my 131 Merch is a lot lighter, having got the weight down to 515lb dry and around 540 lbs wet.

When the swing arm was off the bike, I found it weighed 33lbs, not bad for a Harley, but that's heavier than the frame kit of my Norley, so surely I could lose some weight here, particularly since its unsprung weight.

A few years ago I asked one of the UK's best frame makers how much they'd charge to make a replica of my swing arm in alloy... the answer.. £3000 ! I didn't ask them to justify that amount, as I suspect it was a job they didn't want.

I forgot about it, until last month, when the swing arm was off the bike for a couple of weeks... when I had an idea... why not make a replica? Therefore we took careful measurements of the arm before it went back on the bike, and went through various options of how to actually make a lightweight replica in alloy. Much head scratching later, we had a plan, and I went ahead and ordered the billet alloy we'd need.

Now this replica wont be made the way most alloy swing arms are made.. ie from square section alloy extrusions welded together with cast / machined sections added where required. Instead the whole swing arm will be constructed from several sections made solid billet alloy, which will be bolted, pegged and welded together where appropriate. Doing so would result in a swing arm even heavier than the original, except that each part of the jigsaw which will makeup the whole, will be milled extensively to lose a huge amount of weight. Fingers crossed we'll end up with a cool looking part much lighter and stronger than the steel original.

Below you can see a start has been made on the 'jigsaw pieces', some having been line drilled to give a basic shape and marked, before going on the miller to be shaped accurately.
 

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The electronic parts we were waiting for have finally arrived from Germany, so I was asked to pop into my mates workshop to discuss options as to where various components were to go, and which buttons I wanted doing what.. The Moto Gadget stuff is clever, you can program it so one button does more than one task.

It was odd seeing my old bike on the lift, with its entrails hanging out, as I'm the only person whose ridden it or touched it with a spanner since it was built. I had to resist the urge to grab a cloth and start cleaning it lol. Fingers crossed the next time I visit, it'll be back together and running as good as ever..
 

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What a beast you have there. I recently rode a 110TC" Bourget chop that was a straight line white knuckle ride. You are so very correct that 100+ft/lbs of torque really opens your eyes!
 
Yep, also sitting so low to the ground makes it feel faster than it is. This one makes over 100 lb/ft torque from 1500 rpm to the redline, peak at 145 lb/ft. Looking forward to riding it again after a two year wait.

Also hope to have a go on this Sportster I've had a small hand in (its not mine). Started out life as a early 90's XL883, but now has a 1250cc Hammer performance kit, flowed big valve head and lots of mods including revalved USD forks from a GSXR750, alloy oil tank in front of the motor, 17 inch alloy rimed wheels etc..
 

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Luugo86 said:
How much did you punch the jugs out and what type of heads are you using ?

Its got a Hammer performance 1250cc kit, while the heads were flowed and given bigger valves .. cant recall the valve sizes.

Here's a before pic of the engine and new barrels, pistons etc..
 

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Slight thread detour, since folks like the look of the XL Scrambler project, here's a vid I posted today of progress on its final assembly..

https://youtu.be/JZh7TL4uQ84
 
Back to the Merch131... The switchgear from Moto Gadget has been fitted, they make a few different options... black, polished alloy, standard or mini buttons.. I went with the polished / 3 mini button option (the bike only has 3 buttons on the bars for the horn, high beam and starter) which at around £120 isn't cheap. But they do feel very well made, so hopefully worth it..
 

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While the mini sub project to make a replica swing arm in billet alloy is making slow progress, with the front side plates and the cross pieces having been milled now..

And here's a short vid of how its coming together so far..

https://youtu.be/FkbKCfGSpbg
 

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