1983 XJ650 Maxim bringing back to life

I don't follow the "in spec is in spec rule" because if the gap is on the lower limit it will become out of spec before the other valves do and possibly in a shorter amount of time than the inspection interval. I go for the middle to high end of the range if possible considering the small range of high to low limits. It is tricky no matter how you do it. Conversion is easy, SAE x 25.4 = Metric.

 

I go by whatever the EXACT measured clearance is.
And
In-spec is in-spec.

If it’s in-spec but just barely..... it’s still in-spec, and it may stay there for for the next 10 checks, too. Of course it may be out by the next one...... but the same is true for in-spec to the high side too ...it may be in spec for the next 10 check, but it can also be out by the next one. That’s why they are CHECKS. If it’s out, you change it. If it’s not, leave it til next check.

 

I read that gaps tend to get smaller over time due to valve wear. Is this what you all have experienced?
Its interesting how most of them ended up the same gaps but one in particular ended up REALLY tight.

I was thinking to not change much if in spec and to inspect again next winter. Now that I have done this once, its going to go much faster next time.

 

The gap decrease is due to the valve receding into the head from the constant pounding of the valve against the valve seat. As the valve recedes, the end of the stem gets closer to the cam which reduces the clearance. Thinner shims are installed to re-establish acceptable clearance.

 

So, went back to check in 1,2,3 again by stacking a .07 & .04. First stacked a .07&..03 and verified it passed under In 3. Then tried .07&.04 and it also passed In 3.
Went to In 2 and .07&.04 passed, but when I went back to In 1 which previously passed a .10 no longer did and I had to go down to a .06 to get it to slip in.
This was with the cam pointed 90 degrees to the surface of the shim. I then moved the cam some and kept checking. Turns out I can get up to .10 with the cam about 80 degrees
So wondering if I should Change In 1. Well, I won't have a 280 right now so will have to do that at another time if I do.
other shims coming in today

 

Today's winning post on the Internets!

 

The raised portion of the cam lobe should be pointed 180* away (directly opposite) from the flat plane of the shim.

 

In vernacular... exactly perpendicular to the shim plane

 

Exactly

 

Yes, when I say 90 I mean straight up. I was comparing the cam lob to the plane of the shim. So 180 degrees from maximum compression.

Shimming is all done
Going to sync carbs and colortune this weekend, hopefully put tank back on and let a friend who is an experienced rider take it for a ride in the neighborhood.
If all is good, I'll be ordering some brake lines and rebuild the brakes.

 

Shims done
Colortune and re synch carbs done.
Put tank back on, could not fit a filter unless I ran the tube off to the right then back to the left. Had I known I likely would have been better off putting the Fuel inlet between carb 3/4 instead of stock position of 1/2.
Put new petcock in and tank on bike.
Running and idling good now.
https://www.youtube.com/shorts/7KQrDTa23aQ

 

Fuel T belongs between 1-2.

glad you got it running, but it still sounds like there is a lope to the idle.

 

If you mean the moving up and down in RPM at a rate of about 1 cycle a second, yes, what do you think is the cause of that?

 

Not synced right yet

 

Or rich.

 

I'll have to double check Synchro. I color tuned it about 1/4 in from turning blue to yellow.

 

You want adjust all four individually to be “Bunsen-burner” blue.
Balance/sync screws are the vertical ones on the butterfly shafts between 1-2, 3-4, and 2-3.

sync 3-4 with screw between 3-4, and 1-2 with the screw between 1-2, then sync 1/2 with 3/4 using the screw between 2-3.

 

New plugs (only found resistive) and leaned out 2 carbs, re sync and lope is gone.
Its cold up here so I'll likely need to adjust in the spring I guess.

 

Yaaaay

 

So, buddy (former Police officer that spent time as a Motorcycle officer) took it out of the neighborhood for a ride. Here were the take aways:
Speedometer was humming. Did not hum when he left but was humming when he came back. When I rode it myself to the top of the street and back it would humm only in motion and even at low speeds.
I live at the end of the court and did some circles and started to work on figure 8's (I'm rusty and don't even know what I used to be able to do in HS and college cause HS riding was a little Honda SL70 dirt bike and college was a 250 street bike I think.

For the speedo, I started by searching for threads here:
Mine sounds just like the video in the first thread
https://xjbikes.com/forums/threads/noise-and-vibration-while-riding.130364/#post-663911
https://xjbikes.com/forums/threads/speedometer-humming-needle-jumping-and-then-died.126154/
Any other suggestions on the Spedo Humm?

He got it up to 70mph and in 5th gear, as he was entering the neighborhood after the about 10 minute ride, it was beginning to starve for fuel.
I'll have to look at the petcock as that is my first suspicion. Petcock is new and same model that was on the bike but not original part. I had it in reserve. I am going to have to do some garage testing of the petcock.
Suggestions on petcock/fuel flow testing I can do that does not initially involve riding the bike (Cold here and I still am on a learners permit)

He felt that it rode smoothly. He lent me a jack to get the front wheel up and when we were looking to see how the bearings were, we noticed that it looked like the front brakes were tight. I am already next going to be working on a caliper rebuild and put new stainless brake lines in but wanted to figure out what I should be looking at for the brakes as is. I'd like to see what would make the brakes so tight. Suggestions on tight brakes?

Its about 40F outside right now.