Author Topic: Learning old school the hard way 74 TX500  (Read 8275 times)

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Offline kickstarter

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Learning old school the hard way 74 TX500
« on: December 13, 2013, 11:32:35 PM »


This is my 74 TX500 I bought not running and being told the issue was gas residue in the carbs, so I swapped those out and got it fired up and instantly noticed a backfire (it was an afterfire actually since it was coming out of the exhaust and not the carbs) so I checked the timing and found the left was spot on and the right was way. I set the timing and still had the popping so I checked the valve lash and found that was out of specs so I set that to specs took it for a test drive and the throttle cable snapped.



So I ordered a new longer set of cables and figured I'd throw some paint on the beast



I went with basic cheap rattle can primer and covered that with a matte clear



I found this cool Celtic symbol and had to try so I laid down some tape and started drawing it out



I did all the cutting with a razor blade but next time I might try something different





I put the black down first than tape then white. After that I taped it off again to get a white border from the base color.



Some scallops for some extra flavor



Base color, flat red





And here it is with one coat of the matte clear


So after that I took it for a ride and found the right side isn't firing, I swapped the coils and I'm getting the same thing. I checked compression and got 150psi from the left and 90psi in the right specs are around 140psi. I did wet and dry compression test and the variation was slight and the same on both cylinders so I don't believe it's the rings. The next step is pulling the motor and doing a head job I think.
 

Offline kickstarter

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Learning old school the hard way 74 TX500 Update
« Reply #1 on: December 19, 2013, 01:12:47 AM »
So I pulled the motor and found all kinds of dirty oil on the front







That's the right side of the motor. I know the manual says to break the cam chain so I just have to find a cutter/riveter. I have new gaskets so I just hope the head isn't warped.

Offline Garn

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Re: Learning old school the hard way 74 TX500
« Reply #2 on: December 19, 2013, 06:14:03 AM »
Kickstarter, you are getting to the good part!
My first encounter with excess oil, was on the engine head front, just as you have shown. I wondered if capillary action could have drifted the oil up as high as shown. the leak seems to be from the middle head gasket of the split head, about level with the top exhaust manifold gasket bolt.
Keep us up to date!
RegardZ.
 
Kawasaki Z1, Z1A, Z1B, Z900-A4 and TX500A
    Sydney, Australia

Offline kickstarter

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Re: Learning old school the hard way 74 TX500
« Reply #3 on: December 20, 2013, 08:49:47 PM »
Garn: I thought about the movement of the oil because the bike leans on the kickstand. I think I'm getting a leak from probably all of the gaskets on the top end I'm just hoping the compression problem is a head gasket and not a head. The last picture shows some seepage where the head meets the cylinder. Could I lose compression if the cam case gasket went? How was your cylinder head when you pulled it off?

Offline kickstarter

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Re: Learning old school the hard way 74 TX500
« Reply #4 on: December 20, 2013, 08:51:15 PM »
Oh I forgot to mention the guy I bought the bike from said he had just gone through the engine and I wonder if he re-used the old gaskets. I don't know, as soon as I get a chain breaker I'll have all kinds of answers though.

Offline Garn

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Re: Learning old school the hard way 74 TX500
« Reply #5 on: December 20, 2013, 11:33:37 PM »
Kickstarter, I have a spare head that I'm getting ready for the same type of job you are doing. The previous owner gave it to me and I'm currently doing it up ready to replace and to check ....why the oil leak? As mentioned on another post I'm going with two copper head gaskets (one for main one for split) to see if I can nail this inherent head problem.
 
My compression was down when first did the check cold, however, when it was hot it was good ...140 PSI.
I agree you should not be down on compression if it is just the split gasket that is leaking.
I did find the valve lash specs are pretty critical.
It's not an easy job to torque the head up after 100 .. 500miles, as a torque wrench can hardly fit in with the engine in the frame and those 6mm socket heads are not the easiest bolts to torque. Perhaps this may have been the problem all along! Who want to pull the engine out just to re-torque?

I've been looking at breaking the chain and I think I will just dremel the rivet ends off and carefully punch out.  May need something more elaborate to install the new link, possibly a third hand!

RegardZ
Ps. I like the like clever Medievial pattern on tank....very skillful! 
Kawasaki Z1, Z1A, Z1B, Z900-A4 and TX500A
    Sydney, Australia

Offline James R

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Re: Learning old school the hard way 74 TX500
« Reply #6 on: January 17, 2014, 04:52:53 AM »
Hi,
  I'm just getting things going good with my TX500. I like the idea that they have both kick start and electric.
   I'm still cleaning. The stuff I got in the box looked pretty good but some mice found their way under the tarp where the old owner had it.
  Mice love to eat wire! At least they didn't get inside the engine.

   Feel good about yours.  I'll post some pictures when I'm not embarrassed about what mine looks like.

Offline EJerg

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Re: Learning old school the hard way 74 TX500
« Reply #7 on: January 19, 2014, 05:43:46 AM »
I've been looking at breaking the chain and I think I will just dremel the rivet ends off and carefully punch out.  May need something more elaborate to install the new link, possibly a third hand!

I tried fussing with a c-clamp and doing tricky things at first with my timing chain, but found it so much easier to use a chain breaking tool! Plus when you put the chain back on you have a riveting tool.

Kickstarter- great progress. Any other plans with it?

Offline kickstarter

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Re: Learning old school the hard way 74 TX500
« Reply #8 on: April 27, 2014, 12:07:50 AM »
Hello all, after a long and snow covered Michigan winter Iím back and progress on the bike has been slow but steady. Pulled the motor apart and one of the exhaust valves on the right cylinder had a sunken valve seat due to the badly cracked head. I had pictures but I canít find them, anyway I ended up getting a decent head for a song so I carried on with the rebuild. Currently the motor is built back up I just need to find a link for the timing chain. 

I still have some ends to tie up, I bought a sparto taillight and I have to remount the fender, I took the sprung seat bracket off the seat and cut up a new one out of the old taillight mount. (Which snapped off when I fell into it trying to kickstart the bike one day) Bought some header wrap for the pipes and a couple other little bullshit things that are kinda cool.






As soon as I find a link I'll be back in the wind.

Offline kickstarter

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Re: Learning old school the hard way 74 TX500
« Reply #9 on: April 27, 2014, 12:13:17 AM »
Oh by the way, I ended up buying a cheap chain breaker online, I think I paid $25 for it. It's fine for the tool itself but I suggest if you buy a cheapy one buy some expensive pins. The pins supplied with a cheap chain breaker will almost certainly bend and/or snap eventually. I got mine to work but my idiot friends completely destroyed the link and two of the pins. Needless to say, I know longer need their help, live and learn. 

Offline kickstarter

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Re: Learning old school the hard way 74 TX500
« Reply #10 on: August 30, 2014, 02:10:06 AM »
Finally got the bike back together (Thanx Couchy) and running. There's still some work to do but here it is



Was using it as my daily driver for about three weeks, rode it everywhere. Even strapped a 24 pound bag of ice to my back. Tragically though the bike started acting up, wouldn't cruise below 45 mph and that annoying backfire was still there. Then this past week I was heading to work and she quit halfway. Luckily a guy I work who happens to have a pickup saw me and we loaded it in that and hit the road.



I know I need new carbs, I can turn in the right side pilot screw all the way and still get a backfire which according to the manual turning in the pilot should stop all gas flow and low speed cruising is accomplished through the slow and pilot jet. Also I've been reading Deans post about "Cheap Ass EMGO Filters" and realized I suffer from dumbassness as you can see from the filters on my bike, I'm gonna hunt down some new carbs and put the UNI Pod filters the bike came with back on this weekend and let you guys know how it goes.
« Last Edit: August 30, 2014, 02:13:09 AM by kickstarter »

Offline dean

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Re: Learning old school the hard way 74 TX500
« Reply #11 on: August 30, 2014, 03:15:21 PM »
Popping out the exhaust and backfiring is typically caused by a lean condition ( or of course bad timing) .  Turning in the mixture screws creates and even leaner burn at low rpm.

Are those carbs stock? ( original jetting ) because running with pods and absolutely no mufflers may have been lean   to the point of overheating/  exhaust valve damage.  You should check cyl. compression

Offline kickstarter

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Re: Learning old school the hard way 74 TX500
« Reply #12 on: August 30, 2014, 08:43:42 PM »
The carbs are stock far as I know, the pipes have mufflers welded in right after the curve but I don't know how well they actually work (its really loud). I bought this thing knowing very little about bikes and even less about carbs, I've picked up some here and there but could you elaborate on the lean condition causing the popping? I thought turning in the pilot screw would  stop all gas flow to the engine, and I was thinking the popping was caused by gas hitting the hot pipes. With the engine running as I turn the pilot screw out, the popping becomes more frequent. There is a compression problem though, after I finished putting it back together I did a wet and dry compression test and the right side was almost 20 psi lower then the left but still above the 120 psi limit but just barely. I got a used head but re-used the valves and I think the bike had damaged exhaust valves all along. The motor had poor compression before and after the rebuild. The timing is spot on by the way. 

Offline dean

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Re: Learning old school the hard way 74 TX500
« Reply #13 on: August 31, 2014, 12:43:40 PM »


There are mufflers welded inside the stock diameter headpipes  :o ?
Could it be what you see is the inner pipe of the stock set up ? ( cut off at the ends)

As you have retained the stock side covers in the design, you should install a stock air box/plenum, carb boots, filter and a set of silencers that have proper baffles and are at least 26" long. 

Offline guylr

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Re: Learning old school the hard way 74 TX500
« Reply #14 on: August 31, 2014, 07:23:11 PM »
Did you lap the valves to seat them in the used head?

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"