Author Topic: New XR75 K1 1974 Project  (Read 1679 times)

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Offline alexbrown64

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New XR75 K1 1974 Project
« on: August 19, 2017, 08:30:26 PM »
Well, my sister sends me a pic of this bike today and says her partner picked it up for me..
Checked serial numbers and starts with 11..... she's a 74 K1.

Luckily i have just purchased a full Jane zinc kit and heaps of other goodies to rebuild VMX bikes. She seems to be mostly all original, but the side number plates seem to be painted like a 75.
Lots of time to be spent on this old girl...



Cheers

Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #1 on: August 20, 2017, 01:38:15 AM »
Does anyone have an original 74 with original side and tank decals.  Every K1 XR i look at has either yellow side cover decals and orange wing tank decals or visa versa or both the same in yellow or orange. The blury brochure pics i have show the darker orange yellow for all decals, but some guy put a pic up of his original XR and they all look yellow.  Which combination was it?

Cheers,












Offline Richo52

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Re: New XR75 K1 1974 Project
« Reply #2 on: August 20, 2017, 03:40:30 PM »
Nice score Alex,yes yellow is the colour for decals on the K1 ,my mate is restoring 3 or 4 early XR75s currently.
Regards Richo.
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Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #3 on: August 20, 2017, 04:28:04 PM »
Hey Richo, yep, they are a great project bike.  I think i had my first crash on one of those at the old RKMCC track.
Yep, yellow is the color, but all the decal companies come out with two yellows.  A light yellow and a darker golden yellow.  Re-Mx has both colours in the same kit? Lighter number plate and darker tank.  I have a book i have had since i was a kid and it has a colour pic of the K1 and it looks like it has the darker richer yellow like the brochure i put on here... But then the pic of the original bike below seems to be more bright yellow.
Hmmmmmmm.....

Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #4 on: August 20, 2017, 05:04:25 PM »
Heres a good example of somebody that has got themselves confused by using some of the graphics kits that are out there for XR's



The richer yellow wing or lighter yellow plate decal?  I don't believe you can have both on the one bike.
As for paint, my research is pointing towards Kia Sage Green Metalic paint code EAB. Apparently the K0 and K1 had a greenish tinge in the grey.

Anyone tried the 2k urethane spray cans that are available.  I am looking at spraymax 2k.

Also, the pipe is OEM but hammered.  This is going to give the Pipe King a real workout.

Cheers,

Offline Richo52

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Re: New XR75 K1 1974 Project
« Reply #5 on: August 20, 2017, 09:27:04 PM »
Whatever yellow you decide will look good on your restos Alex.Im in the process of getting bits to complete a yz80d ,obtained everything for my 2nd RM80b but want to make that one an FMF or DG  replicabike depending what head comes up first.
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Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #6 on: August 20, 2017, 09:36:59 PM »
Sounds like your super busy too.  The B's are a great bike to work on. My mint B runs like a Swiss watch, but the boys N runs like a turd.  I have a new carb, new ignition, everything.  Am pulling it back down a bit and adding a new stator side seal, clean out carb, check ignition, add the B stinger instead of the bigger DG one, and fit another cylinder i have with stock new piston and rings.
Hope to get it running right for a VMX meet later this year.
Be good to see a pic of your B's at some stage.
I remember the YZ80D.  It was pretty quick, but didn't sound half as good as the B. I think the C was better than the E, but i reckon the F and N of 79 were pretty much on par.

Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #7 on: August 22, 2017, 04:37:19 AM »
We got the little XR home and the boy loves it. He really wants to ride it, so the plan is to get it going for a few meets later on in the year.
It actually looks better in real life than in the pics.  The patella in the worn tank is amazing. I am going to paint the side panels and mudguards, but i am going to leave the tank with its rust, green and grey hues and knee marks... The tyres are brand new and i think someone had a go at "doing it up".



There is a lot of work to do to the bike just to get it to a meet. Big list keeps growing.  The pipe is coming off and the Pipe King is going to have a look at it but its not an easy job. But thats for the OEM restore in a few years time...may even have to hit GMC up at some stage. There is a nos one on Ebay and guy wants over $1000 US.

In the meantime, i have ordered one of these bad boys complete with the DG decals etc.. This should liven it up and should sound great... i got it on special and he threw in a set of alloy engine mounting plates and it comes with all the mounts etc.



Cheers,




Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #8 on: August 22, 2017, 06:33:27 PM »
The previous owner said he couldn't get it to run.
No wonder.... tank was full of flecks of rust, petcock was full of dirt and leaking, carb was worn out and full of crap, the coil looks like the dog got to it. The airfilter had turned to dust and was just getting sucked into the carb...

I cleaned everything up, got rid of all the dirt and rust, cleaned the plug, wiggled some wires, added some fuel and it started second kick for about 2 seconds.. then died.  Hardly a spark again, fuel dribbling everywhere, backfiring... Mechanically everything is good.  I checked the valve clearances, compression is really good, but the carb and electricals are just too worn out to get the job done, and the petcock is knackered.

We want a running bike, especially before we tear it down and rebuild it ready for a race meeting.  So it was off to re-mx.com and ordering some parts express post to get here asap.

We have ordered a new 20mm carby, new 6v coil, tune up kit with plug, points, condenser, full gasket set and petcock rebuild set.
The original carb and all original parts will be set aside for the complete restore later down the track, but for now we want to get her running right.  Hopefully get the new DG performance pipe on, get all the parts on and get her revving.




Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #9 on: August 23, 2017, 11:01:45 AM »
Massive list (160 parts) of genuine Honda parts coming from Partzilla.
About the only big hurdle at the moment is a broken footpeg mount.  These are actually an alloy block which forms part of the engine cases.  Its snapped where the bolt runs through.
Just wondering if anyone has used this process for case repairing aluminium.  Looks easy, cheap and strong...

https://youtu.be/2rH681CYDgw




« Last Edit: August 23, 2017, 11:53:44 AM by alexbrown64 »

Offline Momus

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Re: New XR75 K1 1974 Project
« Reply #10 on: August 24, 2017, 11:23:29 AM »
Best and really the only sound way to repair the broken foot peg lug is to replace it with a sound case. Those brazing kits are useless for dirty work.

Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #11 on: August 24, 2017, 02:49:52 PM »
Momus, The Durafix HTS2000 rod seems like a great way to fix some repairs.  Just have a look at the first 1 minute of the video.  It also shows you how to do a bolt repair exactly the same as mine.  Pic below of the repair spot. The case has the engine number on it, and i want to keep it original, so it has to be the repair. One trick is to drill and tap a few small studs into the block to give the new material more bite.

https://www.youtube.com/watch?v=2rH681CYDgw

It also shows you how to do a bolt repair exactly the same as mine.  Worst comes to worst, i have had a quote of $150 to tig it all up.

Here is a table of the new rods strength.

Tensile: 45,900 PSI    Therm. Exp.: 15.2 x 10- 6in./in./Fo
Elongation: 10% in 2 inches    Elec. Cond: 26 (% of copper std.)
Impact: 43 Ft. lbs (charpy)    S.P. Grav.: 6.6
Shear: 31,000 PSI    Weight: 0.24 lbs/cu. in.
Melting Point: 380oC - 408oC    Rockwell:  48



I pulled the seat apart and the original sponge was toast.. i have ordered a new one, and another seat cover from re-mx



Here is a pic of the power pipe i have purchased.. its on the way now :-) ...



Another problem i have encountered is the dreaded welded gear lever to the splines.  I ground it off and both the lever and shift shaft are toasted.. no splines at all!!  I found a replacement 4 speed shaft and a new shift lever.. these are on the way too.

I popped into my local Paint Place and discussed the situation.  Walked out with a can of Kia EAB Sage Green Pearl Metallic which is supposed to match perfectly with the K0 and K1.  Also got a rather expensive can of gloss black for the frame.  This system matches up with the two cans of 2k clear coat i got.  The cans have the widget to mix the two parts. 
The idea is to lay down the rubbergray paint, then lay down the 2 pack clear.  Allow to dry, rub and then apply the decals. Apply a few more coats of 2 pack over everything.  This should be really glossy, tough,  and protect the tank from fuel spills.

Well, i have to wait now until the new carb, coil, plug, condensor and points arrive so that i can try and get her running and check out the motor, clutch and gearbox.

Cheers,


Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #12 on: August 27, 2017, 11:01:24 AM »
The little XR is pretty original. Most of the decals are still on the bike in one form or another. I will heat them up and peel them off and keep them on contact paper to preserve them.  When the frame gets 2k coated, i will put repro decals on.

Here is the airfilter decal...



And here is the Shock decal.  Most people get this wrong and put the new decals on the outside of the shocks.. but if your ocd, they go on the inside as per original.



Here is a pic of the steering stem decal. Note that the bar clamps are rubber gray. 



The tank had 4 decals.  Two orange wings and two warning decals.  You can still see the outline of where the warning decals sat on the tank.  I will be removing the dents, prepping, base coat and 2k clear the tank. Then put all the decals on in their exact location and then 2k clear over the top..



The swingarm had an exhaust warning decal. I will be getting one of these and putting it on over the gloss black and 2k clear coat.




Offline alexbrown64

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Re: New XR75 K1 1974 Project
« Reply #13 on: September 05, 2017, 12:11:01 PM »
Parts arrived from Re-Mx and i immediately set about putting them all on.  It all went relatively smoothly and i managed to get a really strong spark with the new coil, condenser and points.  The new carb needed the choke lever bending away from the frame and then it fit well. Power pipe went straight on, but will need longer manifold studs.
I had to jam a Chinese shifter on the worn out shaft and really tighten it up so that i could test the box out.

Fired up beautifully and settled into an idle almost immediately.  Power pipe sounds great.  I snicked it into gear and rode off up the street.  Clutch good, gearbox perfect, engine smooth.. power pipe sounds fantastic.  Got her home and made a 40 sec YouTube video of her running.

She is now ready to be torn down and sorted out properly so that it can be entered in a few events. Even have a Vintage style jersey for the boy on the way..

https://www.youtube.com/watch?v=trVBRjKWtnU

Cheers,


Offline Big Scotty

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Re: New XR75 K1 1974 Project
« Reply #14 on: September 05, 2017, 06:02:11 PM »
Gday Alex
I am enjoying your thread on the little XR,got me inspired to drag my kids old xr80 out of the back of the shed and do a bit of a tidy up ready for the next generation.i also sourced some parts from re mx after reading that's were you got yours,I have to say there service so far has been excellent,answered all my emails quickly,would recommend them to any body restoring a mini,look foreword to more updates
Cheers scotty
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