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Author Topic: Project Shinjimei- 73 TX500  (Read 103963 times)

Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #380 on: Apr 12, 2015, 01:00:36 »
First picture worth posting in quite a while.... But I got a couple hours out in the garage tonight, and this was the result. I might even have her running again before Rockerbox!
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new

Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #381 on: May 25, 2015, 14:28:41 »


You ever have one of those moments when you said, "Shit, I wish I hadn't done that..."?
Yep. This is one of those moments. How much you wanna bet I have 4 bent exhaust valves?

Seems running a late head on an early motor has some issues....
« Last Edit: May 29, 2015, 13:13:29 by two-smoker »
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new

Offline SrgtBear

  • Posts: 843
  • The arsenic has oddly shaped feet...
Re: Project Shinjimei- 73 TX500
« Reply #382 on: May 25, 2015, 17:11:42 »
Yikes!  Sorry for your loss on this one. I guess someone had to try what you did eventually. Just sucks you were the guinea pig.

Id probably search for a new motor at this point. Finding replacement parts will be a bitch.  Especially if your cylinder wall is scored from the particles, then you will need a fresh hone and new rings. Not to mention those Pistons are now done. It will probably cost you more vs getting a donor engine.
Ted

Kawasaki Kaiju (怪獣) - 79 KZ650 - 700cc Bore Cam Rocket - http://www.dotheton.com/forum/index.php?topic=39748.0
75 Yamaha XS500B Cafe - Completed - http://www.dotheton.com/forum/index.php?topic=14392.0
74 Honda XL 125 - Original - http://www.dotheton.com/forum/index.php?topic=25706.0

Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #383 on: May 25, 2015, 18:16:07 »
The funny thing is, I got a 78 bottom end from Dean j already (i really thought the whole issue was a rod knock, which may still be the case),so the bottom end is taken care of.... The issue is, now I need another replacement head. Or at least 4 exhaust valves and a skim.
As an aside, the reason this happened was at least partially my own damn fault. I'll explain later....
« Last Edit: May 29, 2015, 13:14:42 by two-smoker »
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new

Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #384 on: May 29, 2015, 19:56:12 »
So, the reason the exhaust valves contacted the pistons was at least partially my fault. I had issues timing the exhaust cam. No matter what I did, the timing marks wouldn't line up. Either the mark on the cam was on one side of the pointer or the other. I picked one, buttoned it up  and never bothered checking if there was an issue. Mostly because I only had one had gasket and couldn't afford another one at that time. So.... I'm thinking I picked the wrong side of the pointer. Better luck next time?
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new

Offline DeanJ

  • Posts: 421
Re: Project Shinjimei- 73 TX500
« Reply #385 on: May 30, 2015, 19:45:39 »
 :o ouch!

Although the casting process improved for the one piece head and improvements were made over the years ,such as the round port E exhaust , the actual cams and valves are the same parts on all of the TX/XS500's heads '73-'78. The the higher comp 2F1 pistons in that E motor are also a common upgrade when rebuilding the older 371 engines.
 
With the timing pointer at the "V" on the plate and all of the cam chain slack to the exhaust side with full pressure on the tensioner, the dots on the cams "pretty much" align with the arrows on the caps. "pretty much" means they are not precisely aligned, however if they are off a tooth either way, it is absolutely positively obvious it is incorrect.


Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #386 on: May 30, 2015, 19:47:55 »
Yeah, I had it on the exhaust side of the mark, so I thought for sure it was right.... Guess that wasn't the case this time.
Either that, or trying to put a 76 head on the 73 bottom end isn't the hot ticket.
Just to clarify, it's taken me this long to remove the head from my old motor- this isn't the 78 bottom end I got from you, Dean. That's still waiting to go in.
« Last Edit: May 30, 2015, 19:52:55 by two-smoker »
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new

Offline DeanJ

  • Posts: 421
Re: Project Shinjimei- 73 TX500
« Reply #387 on: May 30, 2015, 19:59:13 »
I'm far less freaked out then  :P

Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #388 on: May 30, 2015, 20:12:25 »
Lol yeah, I probably should have mentioned that.... I do know that the 73 motor was the only year that had compression as high as the 78s.... And I had some interesting issues with fitment. If, as you say, the slack should be towards the exhaust side, I had had it right after all... So maybe it's an issue with deck height...
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new

Offline two-smoker

  • Posts: 1026
  • I reject your reality, and substitute my own!
Re: Project Shinjimei- 73 TX500
« Reply #389 on: Jun 15, 2015, 00:00:47 »
Some closer inspection has revealed what caused this debacle..... I mentioned someone had been inside this motor before, right? Seems they knew to fit the'78 pistons. The bike had 1mm over '78 pistons fitted already. The addition of the late model head to that is what caused the valve-to-piston contact. The valves are indeed bent. Even worse, it looks like the exhaust cam journals are worn out from the extra pressure, as well.

Anyone looking to part with a Suzuki GS500e motor, cheap?
"I suppose I'd say.... BOLLOCKS! But that's pretty much a reflex for me."

http://www.dotheton.com/forum/index.php?topic=21144.new#new