Knackered's Project - Highly Modded Mk1

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New Trail Tech Headlight.

Post by knackeredMk1 » 23 Jan 2010, 18:17

Just fitted new X2 headlight (Halogen not HID :cry: ). It is a really tight fit so I had to remove all excess wiring, replaced some connectors, changed ignition switch (£2.99) and changed capacitor (Thanks to KWM_gbr :D ).

Has much better road legal dip and main beam. I have also wired up an 'all on' from the standard Honda light switch.

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Mugen PV Cover

Post by knackeredMk1 » 18 Apr 2010, 10:45

Changeing the look of the Mk1 a little also fitting a Stan Stephens tuned barrel, a Mugen head and the wider gearbox of a Mk2.

New look powervalve cover. Filed flat, powdercoated, mugen sticker and six coats of varnish.

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Retro Look?

Post by knackeredMk1 » 03 May 2010, 11:41

Removed stickers to get closer to the original look. (Bit grubby at the moment :roll: ).

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Max Power Mk1!

Post by knackeredMk1 » 03 May 2010, 13:46

Those who are familiar with this project will know that I have a Mk2 barrel and AR head on the basic Mk1 engine. This in itself gives on paper a little more power than the standard Mk1 barrel which is a bit messy in the powervalve area.

This is a bit of a shortened version but gives the basics of what happened over two weeks at the college workshops. -

I chose as a bit of a project for this year, to rebuild the engine with a fully bored out barrel and a Stan Stephens tune on a Mk3 cylinder. I also planned on swapping the gear cogs for those of a Mk2 so as to make the gears slightly wider and raise 6th by 7%.

In the end I didn't split the crank case as I found the engine responded to setting the powervalve to the point where it was trully fully open when the powervalve servo is fully open, rather than the Manual settings. This is because the raising of the exhaust port in tuning means that the PV needs to have a slightly anti-clockwise starting position to enable it to match the port when fully open.

I did however get a Mk3 barrel bored to 68mm and enduro tuned by Stan Stephens. I will write about the tuning later.

I fitted the new barrel, a new Wiseco piston and a new Mugen head. The Mugen head was to raise the compression ratio. In fact it raises the standard AR CRM from 6.7 to 8.0.

I warmed the engine up and went for a short run. Very short as it only lasted about 600m :!: . The engine started 'pinking' from pre-ignition so I stopped it.

When I took it apart I found many very small vertical ridges all over the exhaust port side of the inside of the barrel. To cut a long story short we found that the piston rings didn't have the required end gap when inserted into the barrel and had to be filed down a little to allow the specified clearance. What had happened is that the rings had expanded but there was no room at the ends so they had cut into the sides and made the scoring.

I then rehoned the barrel, which got rid of the very small marks, and refitted the piston etc. There was no damage to the piston itself. But this time I left out the Mugen head to be sure.

I've changed the jetting by dropping the main to 132 and lowered the needle by one slot. What I've ended up with is more mid range and top end power but below 3,500 rpm the engine is a bit rough on very small throttle openings. As a road engine it is very good but I'm not so sure about trail riding in Winter.

This roughness disappeared after fitting the Boyesen Rad Valve. So was jetting related.

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Forks & Rad Valve

Post by knackeredMk1 » 25 Nov 2010, 11:42

Fittted XR400 forks. They give only 11.0 inches of travel compared to 12.2 from the CR125 forks but they are the same length top - spindle as the original Mk1 CRM forks. They have adjustable rebound damping with less overhang. They are much more tunable and there are springs available. I have fitted 4.5kg springs and softened the compression damping. I have put 5wt oil in. Saves a bit of unsprung weight as well.




I have also fitted a Boyesen Rad Valve which should give a little power increase across the range.

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The reeds for the Rad Valve are the racing version of the Dual Stage reeds -

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Boyesen Rad Valve

Post by knackeredMk1 » 26 Nov 2010, 15:36

Thumbs up for the Boyesen Rad Valve. Seems to have smoothed up power delivery and maybe a little more power :? . Can open the throttle wide at 3000rpm and the bike will accelerate smoothly all the way through to 9,600rpm. No hiccups or misses :D .

Doesn't seem to need leaner jetting as is suggested in the leaflet - virtually no smoke once warmed up.

Also found the answer to why it was hard to start after it had been standing for a few weeks and was very smokey on startup. - I changed oil pump to a newer version (Mk3). I think the old pump was allowing oil to seep into the intake over a period of time due to gravity. I think Skidmark first suggested this elsewhere :? .

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Extras +

Post by knackeredMk1 » 14 Jan 2011, 20:52

Fitted PowerNow Plus - Other side of carb from PowerNow. I know its a bit of a gadget but I think it does work (but not for THE ULTIMATE POWER GAIN :!: ) and the theory is sound. Definitely improved throttle response and maybe a little more torque at low/mid throttle openings. Boyesen make something very similar but not for this carb.

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PowerNow + PowerNow Plus

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Clutch

Post by knackeredMk1 » 20 Mar 2011, 13:19

I've always been a bit dissatisfied with my clutch especially since completing the Mk3 project. It has always been stiff despite the new parts and I was thinking about getting an hydraulic clutch. So I checked into what variance there is between different models amongst the parts I've got lying around.

Starting with the lever and perch. My perch and lever are the ones used on the Mk3/AR and they are the only parts that I can find that go under a CRM product code that were fitted to the CR range - so they must be pretty good.

I then found that the push rods for the Mk1 & 2 are the same (with different part codes :roll: ) but the Mk3 rod is ~ 0.8mm longer. This gives the actuating arm (the one where the cable attaches to) a more efficient position to pull. In addition the Mk1/2 actuation arm is longer than the Mk3 so requires less pull to move. I also noticed that the angle ground into the actuation arm where it contacts the push rod is slightly different Mk1/2 v Mk3. So I reground my Mk1 arm to approximately the Mk3 angle. Finally the Mk2 springs are thinner than the Mk1 springs and so less effort required to the pull lever.

What I've ended up with is a Mk1 actuating arm, ground to roughly the same angle as a Mk3. With a Mk3 push rod and Mk2 springs. Boy does it make a difference :D :!: :!: .

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Power

Post by knackeredMk1 » 04 May 2011, 12:08

Keep getting questions about this -

For the record this bike is significantly more powerful across the range than a standard Mk1 and also a standard Mk3. Both of which it has been tried against. Other than that I can't tell you.

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Re: Knackered's Project

Post by knackeredMk1 » 13 Aug 2011, 09:16

Passed MOT yesterday but had blown a bulb. Headlight has two standard H3 halogen 35w bulbs.

Replaced with PIAA H3 35w D96 bulbs. Vibration resistant and apparently give the light of a 55w without the heat. They are significantly brighter - getting more like an HID setup :D .

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New Photos

Post by knackeredMk1 » 30 Sep 2011, 13:43

Current setup -

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Re: Knackered's Project

Post by knackeredMk1 » 30 Sep 2011, 13:49

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Ignition Key & Barrel

Post by knackeredMk1 » 05 Oct 2011, 15:38

New smaller stainless steel ignition key and barrel to fit on new speedo bracket as have fitted XR400 yokes with the forks. I had to install the old Mk1 steering post on the new yokes as the XR post is slightly longer and doesn't fit. Much better length, sprung and damped than the CR forks.

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Re: Knackered's Project - Highly Modded Mk1

Post by knackeredMk1 » 20 Jan 2012, 14:55

Decided to revisit a Mugen head for my Mk1. So I have got the head modified to take the larger piston diameter and worked the head gasket so as not to get any 'hot spots' using the higher compression ratio. You can see the enlarged head capacity matching the head profile as a ring around the edge.

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Works fine after changing the thermostat (which was no longer working :roll: ). Can't say there is any noticable gain in power but there should be a little at the bottom end at least.

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Re: Knackered's Project - Highly Modded Mk1

Post by knackeredMk1 » 03 Nov 2012, 12:57

Made a carbon fibre clutch cover -

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