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1981 Virago 750

Discussion in 'Other Motorcycles' started by Timbox, Feb 1, 2021.

  1. Timbox

    Timbox Well-Known Member

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    Brent,
    I hope it does, I could not see the shape of the top yesterday. I have a tool made for doing other forks so I will try that today and see what happens. Nice out this morning -14, ya, I will hold off going to the shop for a while.
     
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  2. Timbox

    Timbox Well-Known Member

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  3. Timbox

    Timbox Well-Known Member

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    Mother nature has won today. I attempted to get the lowers separated today. Between how stubborn the bottom bolt is being and just how cold it was to work with those solid steel forks, I had to give it up. I tried finding a nut to fit down inside to stop from turning. I ran out of size at 24mm and that didn't work. I tired the handle down the inside trick, I broke 2" of the wood inside the lower from the impact hammer. Next I guess I will have to drill it out, but that had to wait on another day, too cold out.
     
  4. Fuller56

    Fuller56 Active Member

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    I seem to remember doing a set of forks, maybe the Seca 750 and using a spark plug socket to remove the damper rod. The spark plug socket has to be 1 with the hex on the top. Fit the 3/8" drive extensions from the spark plug side so that the hex can fit into the damper in the bottom of the fork slider. If you have enough extensions you can get your breaker bar on the top and allen key on the bolt in the bottom, add a little heat to the bottom if possible and you should have enough leverage the get it apart. Of course in your neighborhood any heat is just going to be sucked away so quickly it won't matter right now.
    Good Luck!
    John
     
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  5. Timbox

    Timbox Well-Known Member

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    Nice weather again today, but chose to get this fork thing done. Ended up having to drill both of the bottom bolts out. Not hard once you just go for it. Once I got the first one apart I measured the top of the internal fork and it looks to be a 26mm.
    [​IMG]20210213_131950 by Tim Brown, on Flickr
    As mentioned by Fuller56 above ^, one of my old motorcycle tool kit wrenches did fix okay. Not a perfect fit, but for future reference I might try it once before I drill the bolts out again.
    [​IMG]20210213_132021 by Tim Brown, on Flickr
    This is how I had to hold the inside so it would not spin as I drilled. I think this wold work better as a two person job. I did use the vise the second time around to hold the stick and work my way up to a 9mm drill bit.
    [​IMG]20210213_121517 by Tim Brown, on Flickr
    If you chose to drill out the bottom bolt on these older bikes. Take it slow, work your way up on the drill bit size and use a center punch once you are down 1/4" or so. You do the measuring yourself on another bolt but not that far. Breaking the bolt off at the end with a center punch will make sure you don't damage the fork lower. You will have to drill over an inch to get to the internal lower part.
    This worked on this fork.
    [​IMG]20210213_132339 by Tim Brown, on Flickr
    Good luck if you are rebuilding the forks and for those of use in the cold snap, stay out of the wind and stay safe.
     
  6. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Yamaha (among others) used Threebond to secure the damper rod bolt in place. They don't always come out easily, even with the proper tool to hold the damper rod.

    Also, if you need to drill the head off, use a left-twist drill. The damper rod is less likely to spin on you, and sometimes you get lucky and the bolt twists itself out.
     
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  7. Timbox

    Timbox Well-Known Member

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    Worked on the lowers on the forks. Got all the old stuff off them and have them put back together with new seals. End bolts in the mail to finish the job. Installed the newly painted exhaust on the 750. Inspected the rear break shoes and put back tire on. Carb gaskets came in the mail so once the temps get above 0, head back to the shop. Hope to hear the 750 run today. Need to hope the shop doors for that so need some warmer temps. Next will be getting to the bar switches, starter button, headlight and gauge reinstall.
     
  8. Timbox

    Timbox Well-Known Member

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    Have the gas tank sitting with evaoprust i it just to make sure. I have ordered the on/off/res non vacuum petcocks and will have to do the mod on one of them. Removing the fuel nipple from the petcock, drilling through and then steal weld epoxy the original side. I like the full on and off type petcocks just to be sure.
     
  9. Timbox

    Timbox Well-Known Member

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    Finished modding the new fuel petcocks. The 750 has two of them so had to remove the output fuel nipple, drill through the petcock fuel hole, steel epoxy the original end then reinstall fuel nipple on the other side. I found a link once but not right now, I would share it.

    Got the 700 running but the front carb was not working right. I took the carbs back off and sure enough some fuel line rubber had blocked the bowel fill jet. That was a first for me. New fuel line, cleaned carbs again, nothing else found. Installed carbs and ready to put AUX fuel and start it again. Live is getting in the way again.
     
  10. Timbox

    Timbox Well-Known Member

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    Front cylinder issue was the float level. Always remember the basics when you are trouble shooting. It will keep you from second guessing what you know and have tested. The compression on both cylinders was 150. They had spark and still the front cylinder would not run. Pulled the carb boots off and put my hand in front of the opening of the front cylinder and it started to fire and then run.

    When I fixed that the carb gasket on one of the carbs broke. Back to waiting on the mail. I guess I will take the ignition out of the new project bike and make a key for it.
     
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  11. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Are you member at
    viragotechforums.com ?
    The members there were very helpful when I was refurbishing a 920 for a friend and the 920 project that I had to sell before moving (still annoyed that I didn't have room to take it with me)
    It's not as active a forum as we are, but there are tons of great articles and threads.
     
  12. Timbox

    Timbox Well-Known Member

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    Yes I did get in over there. Thanks for the heads up. Once of the folks over there is active and tries to help out. Lots of links and data to sift through.
     
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  13. Timbox

    Timbox Well-Known Member

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    The 4 brush starter came in, need to take the time to put it in and see of this bike runs. Really hoping I can save the left side cover gasket.... Need to get this bike down the road and find it a good home. Spring is in the air and lots of folks looking for bikes.
     
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  14. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    If you can’t save the gasket cut one from a cereal box and spray it with gasket dressing.
     
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  15. Timbox

    Timbox Well-Known Member

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    Took me over an hr to get that side cover off! Wow was that thing more or less rusted on. The two dowels were more or less frozen in place. Took another hr to get the gasket off the cover, I am sure it was OEM.

    New 4 brush starter in, shaved the teeth on the starter clutch gear with dremmel. Got her all buttoned back up and tried to start it....my jump start battery was not charged, so I will have to wait till morning.

    Changing out the gasket on the 700 s well, have that sitting overnight with some gasket removal stuff on it. I don't know if that will really work but have to try. Going to put the new and improved starter clutch gear in the 700 and hope it work well.
     
  16. Timbox

    Timbox Well-Known Member

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    The 750 has a bad rear head gasket, so she will not run. I did get the starter figured out and it wants to start but not enough compression on the rear cylinder. I will wait maybe till the end of summer to pull the motor our again. Oh well when you see bubbles coming out of the head that is not good....lol.
     
  17. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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  18. Timbox

    Timbox Well-Known Member

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    Yes just as the fuel was being squeezed out of the cylinder head. I just say one, not like a bubble bath or anything going on. There was also a tell as it was oily or dirty in that area as well. Just never know on the rear cylinders as they always seem to be dirty. Once I catch up on other projects and move some of the winter bikes on down the road, I will get back to this bike and make her work.
     
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  19. Timbox

    Timbox Well-Known Member

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    Found a donor bike for cheap, going to pick it up tomorrow and hope to swap the engine out. The donor bike also has a nice back rest that looks nice. So this will be the second motor swap out to a title frame for this 750.
     
  20. Timbox

    Timbox Well-Known Member

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    Pulled the donor engine this afternoon. Looks like the back cylinder is also low on compression. No gasket leaks and the engine only has 13K on it. Older engine was 26K. I am hoping it is a held up rings and will take care of it's self. If not, taking the engine out does not take the long. I will pull the engine out that has blown head and see what can be done to that one. I would hope I can pull the head off and replace the gasket. If nothing else, I can hone and see if the rings are still in tolerance.
     

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