87 ATK/xr600 Rebuild

[dcarver]

3 or so years ago, on the way to SX races in San Francisco, my buds unmercifully harassed me about failing to complete the ATK project.

"Tell me again how you have a complete rolling chassis and it STILL ain't running?" asked Jack. "Hell it's only been apart for 7 or so years" I retorted. Besides, I'm a busy MoFo".

That's when Jack chimed in; "I'll stuff that engine back in the frame, wire it up with Baja Designs components, fix all the broken crap for you. Toss me a 1,000 bill and I'll make it happen, parts cost only, free labor."

"I'll ask you again tomorrow, Jack, when you aint been drinking" sez I.

Roll onto tomorrow, and Jack is sticking by his story.

So, after spending some time under Jack's tutelage, the ATK is ready to make the journey back home. it should be back sometime August 2010.

The only problem is a nagging ignition issue. After running for a bit, it loses spark. I just happen to have some spare parts laying around the house (I raced MX on this bike 87-91) so I can throw them on shot gun style and see what happens. IIRC I have ign coil, rotor, stator, cdi. But that motor always had weak ignition - although it would always run.

Researching the net, it *appears* that CDI modules are no longer available for 87 and earlier XR's. I hate to think about buying an 88 or newer just for parts, but I can and will if needed..

Anyone have a parts line for new/used CDI modules, 87 or older?

Here's an obligatory pix.

For those wondering, yes it is CA street licensed and even insured...

 

[rushes]

Gotta CDI off a 83 XR350 and a 84 XL350. No ID ifn they'll work.

Yer welcome ta try fer the axin...

BTW...I gotta show ya mine...

I rinsed it off for the first time in prolly 5 years..

 

[rushes]

XR on left..

 

[dcarver]

Gotta CDI off a 83 XR350 and a 84 XL350. No ID ifn they'll work.Yer welcome ta try fer the axin...

BTW...I gotta show ya mine...

I rinsed it off for the first time in prolly 5 years..

406, about what, 92-96 or so? Great bike. IIRC, it had the disc on the countershaft?

XR on left..

Very interesting. I'll go digging in the shop tomorrow for a photo comparison. Thanks!

 

[dcarver]

2012-12-16
Permalink Submitted by dcarver on Sun, 12/16/2012 - 19:04.

Decided to show Ms. ATK some love. Several things I wasn't happy with -

1. The rear fender hanging below the frame rail
2. Wiring routing going to tail light
3. Leaky o-rings at engine outlet to oil cooler..

On the stand, ready for fixin'..



I spent 3 hours fabbing a mount from the right peg to the engine stand. and it bent on the first application of force. Oh well..

I like the FJR headlight reflection in the background. Hey! Let ME in the nice warm shop!

Here is where the O-rings were leaking. New o-rings, and straightening the holder bracket fixed it. Of course, I first had to remove all motor mounts but one, then jack the engine up so those stupid bolts could be removed. What a PITA.



High tech at work...







On to the carbs and leaky float valve. I have both these carbs. The No Fit carb had better main jet baffling, and the needle valve and seat looked identical. So I swapped parts. Made one good one out of both of them. And, apparently, it worked!




More pix later of modifying the rear fender for a better fit..

• edit
• reply

 

[dcarver]

Forum is barking at me - too many pix - so clicky here.

 

[dcarver]

So then, a thread from the past to liven up you dirty bikers....

Re-Routing the Oil Cooler Line - too close to exhaust header
What a PITA this job was.The line running up to the oil cooler was contacting the header.

These pix don't show it, but I had to re-bend the line after pivoting the engine on the front mounts...

While at it, re-wrapped the header with heat tape.
Yes, the Ty-Rap has been replaced. This was a mock-up pix.

I need new rims and exhaust system.



I think the exhaust wrap turned out good.


I need a new silencer. Looking for an oval unit that will provide greater clearance to the rear tire.

x

If you have any ideas on how build/buy a custom oval silencer, let me know?

This is my 'mule' engine. The real motor is being built in La Pine, Oregon, by a fella named Ray.....



Full post here on my site.

 

[Auburn]

DC what about sending the header in to be ceramic coated? I bet fmf will have a silencer that fits. You probably have to call them and talk to them

 

[dcarver]

Well then, been awhile, but for you dirt donks who might be able to help....

HELP!


Parts / Components Identification Needed.

Both rims have cracks and need be replaced. You can see one crack in this pix at about the 11 position.
The trouble is, I don't recall what I have! Back in the day I bought CR250 front fork assembly from a local named Frank Villa.
I also purchased, at the same time, a rear end that had a Honda disk brake.
For some reason, I tend to think the rear end was off a CR500, while the front forks were off a cartridge CR250, supposedly the best available at the time.

My local small independent shop, HiddenPowerCycleClinic has complete hubs/spokes/rim assemblies available for cheaper than buying new rims and spokes. Sounds logical to that route. If only I really knew what I have!~

If you have old school Honda CR/XR knowledge please let me know as the new supplier has a no-return policy.

Here are some pix of the rear end.

75mm spacing between bolts, 6 mounting points.


Concial shape on the drive side.


Views of the disk brake side.


The spacers on the right were to fit the assembly into the ATK rear swing arm.




Now, for part two of the mystery.. this is the front end, obviously. What Honda XR year might it best represent?
I bought the ATK new from Horst in 1987, so I'm thinking 1987.


It has the typical XR front hub speedometer driver mechanism, so the front end is NOT a CR, hub, spoke, rim wise.
I do recall the axle having to be special machined to fit.
Man, this was a loooong time ago.




Brake side.


CR250 forks? XR rotor and caliper? Would you guess 1987 or?

• reply

 

[dcarver]

Must not be too many dirt donks in these parts..

 

[CAJW]

Don, I agree with your assessment of the rear being from a CR500, but the front looks a like my 84' XR front end. Fwiw.

 

[dcarver]

CAJW,

Thank You bud!

If all holds true, the CR250/500 used the same components during the early 90's.

..and the front has been confirmed as 87-88 XR600R