1974 TX650A Restoration Project

Google "micrometer camshaft" brings up some handy videos...

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Thanks for all the feedback everyone. I went dark a couple weeks ago, but have been chipping away so thought I'd give some updates.

So - I spent some time looking at options and trying to figure out what the best path forward was with my cam and followers... (all the while watching the lively "unreamed holes" discussion in the 750 BBK thread). The one piece of advice I couldn't get out of my head was
"If you have to tear the motor down to replace it....
replace it while the motor's tore down."
(expensive advice...thanks a lot @Jim !! :cautious:)

So I decided to bite the bullet and opt for a new cam, performance valve springs, and new rocker set. I figured one of the aftermarket ones with a good reputation was probably a reasonably safe bet, and seemed like it would complement the 750kit nicely. I went with the WebCam 59a and springs from yamahaxs650.com and a set of rockers from Mike's only because I could find no other options.
Last week they showed up so I thought I'd take some pics. The cam came with a data sheet and and documentation from WebCam.
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The rockers also looked pretty good and were all within the specs listed in the manual. One benefit was they came with the hex screw adjusters, so I saved myself one purchase.
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Started putting the rocker box together last week:
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And dropped the cam in:
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And just like that had all these new bits installed and (hopefully) ready to go. Double checked the oil feed pipe to ensure it was clear and reinstalled it as well:
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Ok....that was last weekend. Next post will cover this past weekend....
 
Yeah... Im'a bad influence.... :rolleyes:
You can bet when I was telling my wife about the few hundred bucks this little detour cost you can bet your ass "Jim the aircraft mechanic from the forums" was brought up IMMEDIATELY :laughing:

Are your cam bearings fully seated?

Are your cam endcovers fully seated?

Thanks 2M, good looking out.
Short answer - I followed the procedure as outlined in Jim's top end thread.
Longer answer - when I took the pic of the cam I had not yet centered it....maybe I did it slightly out of order...I put the rocker cover on (light on the head nuts), then installed the cam endcovers and snugged down to center the cam/bearings, then loosened the endcovers, torqued the head to spec, and retightened the endcovers. Also installed the 4x tappet adjuster covers per the suggestion from 5twins in said thread to ensure those were all oriented just-so.

So I feel pretty confident the cam bearings are centered, but your question about the endcovers being completely seated is making me worried, so I'll plan to double check that. I'm hoping what you're seeing is an artifact of the angle of the photo, but I appreciate that note and will check it out.
 
So, after getting the new cam, rockers and valve springs installed and top end buttoned up, I took the opportunity to install the 8-disc clutch pack I purchased from @gggGary. Didn't take many pics here, wasn't really too much to see.
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Since I had the RH side open I figured I'd fix a nagging issue from last year and tighten the wishbone spring on the starter gear. While I did replace this last year, and pre-tightened the replacement spring, I don't think I did a great job and would get the occasional garbage disposal sound when using the starter. I used @toglhot's trick and slipped a 3mm piece of stock in the 'top' of the wishbone to ensure the clamping was directed towards the legs of the spring and not just overcompressing the 'top' bit.

I had posted a couple questions on this in various places including back in this thread earlier, but I was trying to figure out if I could use my original "Type C" tensioner. As many surmised - it didn't work great. (See pic below). The tensioner bolt can thread in just fine but it's just far too long and when threaded in to the recommended spec (end of rod flush with bolt) there is way too much of the assembly sticking out. While you could probably put some additional lock nuts on here to fill all the extra rod, I found a "Type E" on ebay for about $20 and grabbed it and a replacement acorn nut. This assembly works perfectly in the BBK kit. (Of course I didn't take any pics of the new one)
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So motor ready for install, but a little detour. I had bought a new set of Vesrah pads for the front brake. Since I wanted to remove the rotor to give it a sanding prior to installing the pads, I decided to drill the rotor as well. I found some good threads on the forum and used one of the templates I found (word of warning - need to triple check the dimensions....for some reason they don't print to scale automatically, I don't know why). But in any case, I printed a template, used a center punch to mark the holes and then a 1/4" carbide bit, a little oil and a shitty Harbor Freight drill press to get it all done in about 90 minutes. It came out pretty good, although some of my holes were just slightly off. I realized this towards the end when my center punch got super dull and started to skid a little.
Pics of the process and rotor installed:
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Back to the main event....at this point I reinstalled the front wheel, added a lot of protection wrapping to the frame, and carefully willed the motor back into the frame. I was a little worried this was going to be an awful process, especially since last time I laid the frame over the motor, but I was pleasantly surprised; it wasn't that bad.

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Oh - probably should mention that my engine mount HW had started to show a little surface rust which was driving me nuts, so they went on a trip through the toaster-oven powder coater to get a bit of silver. Not perfect, but better than they were.
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Now to try to get my new headers and Commando exhausts installed, along with the carbs, airboxes, etc. Worth noting that I took the carbs apart to clean them a few weeks back and double checked all the jets. Turns out my pilot and main were both off by one. Based on all that I've been reading about the 750 and carb tuning I knew I wasn't going to change much. I decided to just up the mains by one (to 130) and use the stock pilot.
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At this point, last bit was to set the cam chain tension, set the valves per the WebCam spec sheet (0.005" exhausts, 0.004" intakes) and give everything a double check.

Took this video at 8pm last night:

That is a GREAT feeling when it first starts up.... :cool:.
FYI, I was purposely keeping the idle high as per the WebCam instructions (recommends no less than 2000 rpm for first 15-20 mins of operation).

So - 750BBK and new exhausts feeling like a success so far. Obviously the whole thing could still blow up (lol) but cautiously optimistic. I was very worried changing so many things at once but it runs and sounds pretty good so not a bad place to be starting from!

Few more pics with the side covers more or less fully together. Very happy with how the exhausts look (and sound) so far.
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Yes, that old style Commando is a wonderful muffler. As I've mentioned before, I think it's about the nicest muffler available for the 650. Looks good, sounds good, and performs well.

One tiny little fly in your ointment you maybe didn't notice - one of the swirl patterns on your disc only has 6 holes while all the rest have 7, lol.
 
When I say I speak for the forum......

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It is really a sharp bike! Y
Thanks guys, appreciate all the feedback and guidance from you both.

Yes, that old style Commando is a wonderful muffler. As I've mentioned before, I think it's about the nicest muffler available for the 650. Looks good, sounds good, and performs well.
For sure, you have definitely been vocal about these, and have to say I hadn't seen your posts about the 'old style' repros I probably would have ended up with Emgos, so I definitely give you credit for that!

Your front disc came out great, what was your technique for surfacing your disc?
Ha, thanks Bob. "Technique" feels a strong description for 100 grit sandpaper in a palm sander, haha. That was it.

One tiny little fly in your ointment you maybe didn't notice - one of the swirl patterns on your disc only has 6 holes while all the rest have 7, lol.
@5twins DAMMIT what the hell man!! :banghead: hahaha uggggh :doh::doh::doh:
 
Your bike sounds great with the commandos. They look very much like the OEM TXA pipes but sure sound a lot better.
Thanks for being the canary in the mineshaft for the BBK. And thanks for clearing up the tensioner quagmire. Saves me the trouble of trying the original tensioner.

Go out and ride.
Jack
 
Absolutely GORGEOUS!

Of course, the '74 TX650A is the ultimate expression of the genre. Not that I'm prejudiced or anything...


I love my 1974 TX650A as well...I just have to get it and my sidecar out of my greenhouse and finish it . I have been sidelined by: Life (all good) two BSA 's and a Honda 250 Elite scooter. Taking my time just retired.
 
Thanks everyone. I'm really excited as well and looking forward to getting out on the road to test "Version 2.0" of my bike.

So, I was down with my bike last weekend in it's winter storage home when I took the first start-up video. Tuesday I had to come back to the city for the week. I can't get back down there this weekend (which isn't too much of a loss considering it SNOWED here all day yesterday :doh: and not likely to get back up into the 60s until next week). So will probably head down next weekend to finish out my planned winter projects before a road test.

Remaining on the list:
  • Need to flush and bleed the front brake
  • Even though I replaced the fork seals a couple years ago when I first got the bike I didn't flush/clean the forks well and I think the gunk in there chewed up my replacements. I have a new set of all-balls to install and going to give the forks a nice cleaning inside and out.
    • Personal point of irritation for me at this point is the fork lowers; want to give those a once over and see if I can't polish up a bit more, they've started to oxidize a bit and currently holding the "shittiest part on the bike" title.
  • Grease the swingarm; centerstand bolts
For those following the "Mr Riggs hydraulic clutch" thread, I'm also looking forward to installing that, but don't have any expectation I'll get that unit before I start riding the bike again, so that will be at some point over the summer. I will, in the meantime, start to break in the new one-piece Alu pushrod I snagged from GLJ.

Any way for you to do a ride-by video?
I had not considered it, but glad to oblige! I'll figure out some way to do it.

One question for this group (i'll also do a bit of reading today).... I replaced the stock air filters with repros and powder coated the airboxes, so they're like factory. But boy are they a PITA to pop on and off and I know are probably not optimial in terms of filtration efficiency vs resistance. If you were me.... would you consider swapping for a set of UNIs?
Convince me! lol.
 
The Unis, should definitely breath better, might eek out a little more power. Might have to up the jetting a tad?
On your ‘74, would removing your air boxes affect your side cover mounts at all?
 
On your ‘74, would removing your air boxes affect your side cover mounts at all?

It shouldn't... you can see the attachment points here, (with no airbox installed):
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And you can see here when I was mocking up the tins without the airboxes installed:
3NRMb4b2A_njOPdVypRZnUy-SErACV_Axta7rNJU6mIgwoCo6QlZhN1rFSihjvVyqfk7wOFHKd9ZAAumvr_1WOuVJ4lq1LTItaanSGRkOGuJVjxl4VmkYdvfKQopvEKncPZOfF1mln8sK9ZIsd968gg7xzq1j-CjPs5WugoAgQ1vwRjOdPibnZZt4_kDWg8GwTlUFYh11cCbmC9IU1PvuDlg4OevkW09ku8Y5o1Y5OHh3eGv1clboz7ZOd7OjEvZaRCowQ67A3L2jstgyf3h4nx4fzk4MrqqBUkuVeMCzeyAeLEkfBDCzuXwtxGPpxIM4j7KDhUv_eQ-hkwRgk5erWz2-NBZmlsVoDnna6oo9U4ZzhgY7lx6_NphSjsCAsXDyKjUPDuMlKw_Ky5HRUItzj0nR7dQNKGEJoiqrJBWwoXlAc-bE5PJ-SoXNkSiAOeSKqs4w2bwhPHs0wU1pSivD8OdlMnkmS9zq9MgZHRS_p2saY_z9nE6Vjr_BsOMJRLZ4-EiCNgZhWrvLOWfu1h5YzC_RKeWtZVhXUucrKp0eObNUj1WIb8nu7mzvHYNs2MPsBo5VtInMC0STH6LyGW836cpWHfLYyZ6yv8ldFz_c-POEp2Z_xQGRypzNEjmVidENzD7-d6cQNYiiWoLriH1Uw_8fqbp0ug3IVB1zuUy6nWZeN8Q7GDF-8IP51B-HVbc7LH1WzCrk9HmVXFND_L5QZs4=w1204-h903-no


So I think the only question, which @Machine 's picture seems to help answer, is if the pods can sneak behind the tins. Seems like yes, but not sure if there were subtle changes in fitment through the years. Anyone have any insight into this?
 
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