Review of some parts purchases from MikesXS

2M, I know you like to tinker so I think you might like experimenting with shimming some of that .020" endplay out of your advance rod. It's an easy, cheap mod (less than $10). I did mine years ago, shimming it down to .005" or .006". Near as I could tell (measure), it was around .016" to start. It made the bike run a bit smoother. I think it stabilized the timing and advance curve some. Details are here .....

http://xs650temp.proboards.com/thread/1372?page=2
 
Thanx, 5T, you know me well. Yes, I remembered your mentions of tightening up that endplay, but chose a different method. Didn't take pics, since this is somewhat unorthodox, but I chucked up the points cam and shaved a 12.5mm dia recess into the backside of the cam, 0.010" deep. The endplay is now just under 0.010"...
 
I recently installed Mikes advance springs. They were rumored to be looser than stock, but my batch must have been fine. Had quite a bit more "snap back", or my stocks were really bad...haha
 
Advance springs. Another area needing research.

The OEM springs are an open wind, meaning that they don't have the tightly closed windings with the "initial tension" common to most tension springs.
256-81654-10 OEM02.jpg


This open wind would make these springs have a straight, predictable, linear spring rate, even down to minimal displacement.

What I could see of the springs on the MikesXS advance unit, shows them to be close wound, with an unknown "initial tension".
MikesAdvSpring.jpg


This "initial tension" would put a step in the spring's rate curve.

The MikesXS replacement spring kit may have the same springs, with the same feature. Dunno what the advance curve is with these replacement springs.

However, since the stock advance curve puts the ignition timing at full advance around 3,000-3,500 rpms, and most folks may not be riding below 3,000 rpms, this could be a moot point. Not as critical as period Chevys, with their amalgamation of distributor advancer options...
 
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Rebuilding my early petcocks.
XS1B-PetcockRebuild01.jpg


Acquired 2 MikesXS petcock rebuild kits a couple years ago.
XS1B-PetcockRebuild02.jpg


The oval body o-ring is the correct thickness, at 2mm.

But, the fuel selector "whizzer" valve gasket has a problem.
XS1B-PetcockRebuild03.jpg


The OEM valve is 3.0mm thick.
The MikesXS valve is 3.5mm thick.
If it's greased-up good, it'll eventually press in there.
But, the selector lever (even with a polished face) is quite a bit stiffer to turn.

The MikesXS valve also has a grainy appearance compared to an OEM valve. The OEM valves also have a number embossed in the center of one side.
XS1B-PetcockRebuild04.jpg


Also acquired 2 MikesXS petcock mount screw and washer kits.
XS1B-PetcockRebuild05.jpg


The OEM screw has a flange face, and uses a fiber sealing washer.
The MikesXS kit has metal washers, and metal-cored fiber sealing washers.
Don't know why the steel washers, they'll just leak.

An edge-on view of the metal-cored sealing washers, compared to the OEM washer.
XS1B-PetcockRebuild06.jpg


Ordered OEM whizzer valves and sealing washers from boats.net.
Should be here in a few days...
 
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Interesting. I have a set of those MikesXS tank screws and with the metal washer installed, they definitely do leak like mad. I stared at the ass’y and realized what was happening, removed that steel washer - and the leak ceased.

I wish these folks would either test their products or respond to critiques from the user community.
 
I tried everything for those washers from Mikes. Made sure the screw was properly tightened, cleaned the tank mating surface, ect. Nothing. Still leaked. I got OEM from boats.net.....fixed.
 
An addendum to the sealing washers:

6.2mm ID, 12mm OD, 1.5mm thick.

From the original factory parts manuals:
178-14766-00 - The original fiber washer, '70-'75, still available
90202-06010 - Updated washer, '76-'83, don't know anything about this one

90202-05187 - Final revision, appeared after '83, used on other bikes, revised/modern/current XS650 parts manuals show this one, the notorious steel-cored washer that both Yamaha and MikesXS will sell you, has a smaller 5mm ID that has to be opened up...
 
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I had the same problem. Yamaha were at fault in the first instance by not making the thread insert in the tank a blind hole. Had they done that an ordinary screw would be fine. Makes you fume.
 
I also used the rebuild kits from Mikes (for XS1b). Didn't use the steel washers with the screws provided, just the fiber ones, no problems with leaks. Yes, the petcock is stiff to turn, didn't realize there was a thickness issue. Also, Mikes kit was missing the fiber washer for the drain plug, found them at Ace hardware.
 
Are these the ones that ‘should’ work as good as OEM?

From boats net.
90202-05187-00 WASHER,PLATE


666F1951-F935-46CB-81BF-9CC3DFA91C9D.png
Here’s mine: they look similar but the boats washers look a little fibrous to me. Mine originals are hard solid rubber.

0DD1108A-0A49-4700-AF7F-EC7916DA836B.png


 
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