1974 TX650A Restoration Project

gggGary · Mar 16, 2021

Are both sides getting lube? I'd be checking the LH oil feed tube/passages that side cam and lifters look rough, oil starved?

RustiePyles · Mar 16, 2021

SomervilleXS650 said:
Hahahaha, I was waiting for that.... My stepdad is a retired biologist who spent his career studying birds. He also buys and sells wooden decoys. I had no idea this was even "a thing", but it's a whole world unto itself (probably a lot like pipes Rustie!). If you can believe it....the ones you see in the pic are probably just 20% of what he's got in his garage and basement. It was amazing to see what some of them sell for.

Yeah, decoy collectors are definitely a thing. Some of them can bring a LOT of money. I used to be a pretty avid duck hunter but I haven't hunted in years, Id rather conserve than hunt these days. Also I feel my money is better spent on motorcycle parts rather than ammo now.

Mailman · Mar 16, 2021

Ok I’m seeing the photos now. First of all , thank you for doing this photo intensive write up. I was hoping that you guys who bought that 750 kit would start some up and yours is looking to be a good one!
Rusty beat me to the ducks though! :laugh2:

Yeah I was also noticing that your valve adjuster screws were looking rough. Some of us are running these Yamaha screws, they are used commonly across their V twin line. I’ve got a set and I really like them.
Post#6
http://www.xs650.com/threads/fitted-valve-adjuster-screw.56342/#post-624896

https://www.partzilla.com/product/y...?ref=789656d735561c23e33e3f5ce70f0ea01d2e7450

I also couldn’t help but notice this,

So, does the cam chain adjuster just screw into the back of the barrels and the factory housing goes away?
By the way, I know I’m just a green horn among the pros, but my first thought when I saw that gunked up piston was a leaking valve seal. Just wanted to chime in on that.
Keep it up, I’m looking forward to the next installment! :popcorn:

gggGary · Mar 16, 2021

I like the way you think mailman! I just got two more sets of Jenn-you-whine Yamaha valve seals, n they ain't cheap...

SomervilleXS650 · Mar 16, 2021

gggGary said:
Are both sides getting lube? I'd be checking the LH oil feed tube/passages that side cam and lifters look rough, oil starved?

Thanks Gary. Just to make sure I follow your question - are you saying the LH side of the cam looks oil starved? (i.e. this is nothing to do w/ the carbonization of the pistons). For my own learning....are you saying that because of the streaking/discoloration where it's circled below?

gggGary · Mar 16, 2021

Yup! It might be the remains of rust from long ago but it doesn't look like the nice shiny smooth metal I'd want to see.... You know like the cam and followers on the other side.
That's one of the first things I poke around and check when doing a motor wake up, pull the valve covers flashlight, eyeball the cam surfaces. If those look good the motors usually going to be fine, if not.........

member28833 · Mar 16, 2021

Similar to this. Which turns out is a regrind candidate?
Maybe you will come out ahead with a performance regrind too!

SomervilleXS650 · Mar 16, 2021

Mailman said:
First of all , thank you for doing this photo intensive write up. I was hoping that you guys who bought that 750 kit would start some up and yours is looking to be a good one!

Thanks and no problem Bob. Glad to give something back. There's lots of info here and there on the site about the 750BBK but I couldn't find a thread about an install w/ lots of pics (inspired by @Jim's seminal top-end write up....sort of my inspiration here...trying to do it justice!).

Mailman said:
Yeah I was also noticing that your valve adjuster screws were looking rough. Some of us are running these Yamaha screws, they are used commonly across their V twin line. I’ve got a set and I really like them.

Oh cool - will definitely check those out....I had considered the elephant foot ones last year but I never pulled the trigger (so many other decisions to make, tried not to go down the rabbit hole too much).

Mailman said:
I also couldn’t help but notice this,

Haha, yes, I posted this question a couple places over the last couple weeks and didn't get much of an answer so figured I'd just sort it out myself. Long and short - the BBK doesn't use the 6-hole (or maybe 4-hole on an XS1/2) plate to mount the tensioner. You just thread the tensioner directly into the block. I know the Type D and E tensioner have been reported to work, but I'm not sure yet about the Type C that I have. The 'acorn cap' nuts change to the smaller ones after the Type C, but the Type C still has that long acorn that threads to the 6-hole plate, NOT directly on the tensioner.

OK - you guys have convinced me that regardless of being 'new' that my valve seals need to be replaced. FYI - I used ones that came in one of the Athena gasket kits. I just ordered a new set (these), but have people found there to be differences in quality between the aftermarket and OEM? (loaded question I'm sure....)

Mailman · Mar 16, 2021

SomervilleXS650 said:
(so many other decisions to make, tried not to go down the rabbit hole too much).

What we tell our wives,

5twins · Mar 16, 2021

I've started getting these. They cost no more and may be better. Can't say for sure because I haven't installed any yet, but I will be .....

https://www.ebay.com/itm/YAMAHA-XS6...707615&hash=item3661ef85e6:g:~jAAAOSwgGlepcM1

gggGary · Mar 16, 2021

Might want to be checking valve stem/ guide slop, I mean, clearance.

SomervilleXS650 · Mar 16, 2021

So... before going any further, seems like I should at least replace the valve-stem seals and check the clearances. I will probably take Bob's advice as well and swap my rocker adjusters for the hex-head ones, which seems like would be much easier for adjustment with a t-handle hex wrench. I will also check the oil pump, oil delivery tube (both sides), and rocker arm oil passages to ensure they're free and flowing. There was definitely oil up-top when I opened it, but I don't read that to mean everything is getting what it needs....more just that the pump is likely functioning.

I went back through all my old pics from last year, and (of course) I didn't have as many of the cam as I would have wanted when I first opened it up. But I think some of that discoloration was there when I got it....which wouldn't surprise me actually since I did find that the rotor of the oil pump was cracked.

Assuming I've sorted out any underlying lubrication issues....would anyone have any reservations about using this cam as-is? I really hadn't contemplated a regrind or replacement. It seems limited to discoloration, I don't see any scoring or pits. (I will take some additional photos later today and append to this post)

jetmechmarty · Mar 16, 2021

SomervilleXS650 said:
Assuming I've sorted out any underlying lubrication issues....would anyone have any reservations about using this cam as-is?

Speaking for myself, I'm not sure, so I would source a replacement just because that one would cause me uncertainty.

gggGary · Mar 16, 2021

Might want to measure how much of the lift has worn off the bumps, a comparison to the other side should tell you enough.

Team Junk · Mar 16, 2021

Mailman said:
I also couldn’t help but notice this,

2M and I were discussing this yesterday and came to the conclusion that I needed to find a photo 5Twins posted of the variations of the adjuster. Will look this evening. Looks like any of the post 447 adjusters will work.

More info here.
http://www.xs650.com/threads/1978-x...whining-engine-sound.54000/page-2#post-592533

gggGary · Mar 16, 2021

These images?

SomervilleXS650 · Mar 16, 2021

Team Junk said:
Looks like any of the post 447 adjusters will work.

gggGary said:
These images?

I definitely found those posts and they were very helpful....but they didn't fully have the info I was looking to confirm (which is understandable and I figured worst case I could measure/assess and report back on it).

Specifically...the Type C seems to be the 'in-between' year, where they moved away from the sprocket-type but before they moved to the 'small acorn". So I'm fairly confident that my Type C tensioner will thread into the BBK, but what I couldn't find anything on was the length of it and how feasible it would be to thread one of the 'short acorn' caps right onto the tensioner (i.e. is the tensioner a different length? Would the short acorn bottom out, even with a lock-nut?).

Jim · Mar 16, 2021

SomervilleXS650 said:
Assuming I've sorted out any underlying lubrication issues....would anyone have any reservations about using this cam as-is?

I'll just add my rule of thumb on questionable parts here....

If you have to tear the motor down to replace it....
replace it while the motor's tore down.

There's enough galling there that it's likely the hard facing is compromised. Or put another way.... it ain't gonna get better... only worse.

What do the rocker faces look like?

gggGary · Mar 16, 2021

gggGary · Mar 16, 2021

Jim said:
I'll just add my rule of thumb on questionable parts here....

If you have to tear the motor down to replace it....
replace it while the motor's tore down.

There's enough galling there that it's likely the hard facing is compromised. Or put another way.... it ain't gonna get better... only worse.

What do the rocker faces look like?

1974 TX650A Restoration Project

If not now, When?

"Pocket sand! Sh-sh-sha!'

Hardly a Guru

If not now, When?

XS650 Addict

If not now, When?

Race the wind

XS650 Addict

Hardly a Guru

XS650 Guru

If not now, When?

XS650 Addict

Project collector

If not now, When?

XS650 Guru

If not now, When?

XS650 Addict

Beyond the edge is the unknown. Here be Dragons

If not now, When?

If not now, When?

Similar threads