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Resurrecting Yamaha 750 Sportbike

1811 Views 28 Replies 8 Participants Last post by  enos
Whats up, Im Chris and am wanting to get my Grandpa's 1978 Yamaha 750 Sportbike up and running. He passed about 5 years ago and his bike is sitting in the garage rotting away. I need to do something with it.

What do you suggest for a bike that has been sitting for 10 years? Battery, tires, plugs, oil, carb rebuild? Is there a way to see if it is worth the money and not locked up? Throw in a battery and some oil with a bit in the plug holes and fire away? What kind of oil and how much do they take anyway?

Sorry guys, Im a car man. I just getting into the biking scene. Help me get this thing back on the road!
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carb cleanup picture guide in excruciating detail:

no, you can't throw the whole carbs into the cleaner because there are rubber parts in there that will get eaten by the cleaner. You basically have to take those out. There are pics in that series that show which parts you dip. It helps to blow the passages and jets out with compressed air to make sure there's nothing blocking them. You can buy canned air for like $7, or just use a tire pump with that needle attachment for soccer balls.

Since you got to this point i'm assuming you know all about the wonders of penetrating oil.. and i don't mean the rubbish that is wd40.

oh, do you have a shop manual or just the owner's manual?

either way, it's looking pretty good.. you're gonna love that bike..
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A friend of mine had an XS triple years ago. Had a Kerker exhaust, that thing sounded sooooo kewl...
Thanks for the support. I only have the owners manual.

Another question I have is how can I clean the gas tank without hurting the paint?
it's like car paint (no clear coat). so you can use a regular car wax on it.
Check out this site:

It's a pretty cool site that teaches you some fundamentals of bike repair, and some advanced stuff... at least for me :)
enos said:
it's like car paint (no clear coat). so you can use a regular car wax on it.
I was talking about the inside. Just flush it with water and dry it out?
no, don't use water. You risk rust. Rinse it with some gasoline.

If it's already rusty, then it will be hard. There are rust removing/sealing kits. POR15 comes to mind, though you can get acid at home depot (forget the name, though) that will clean it out. I was too chicken to do it, though.
Well, the project is coming along fine except for the no spark. The ponits seem to be fine except for one of them. I jumped them with the screwdriver and could feel the coils actuating. Then I felt the plug caps and they were also (I dont understand why, but I could feel clicking in them). Then, I took a plug (new) and put it to the wires and looked for spark once again but saw nothing. Remembering that the plugs were about 1 kilohm over the standard, I put the plug to the end of each of the coils (without the plug wires) and saw spark at two of the three coils. The one that I was not getting spark to is the one that would not spark when I jumped the points...hmm. I assume new wires will solve the problem for the two cylinders, but what do you guy think about the third?
Look up Dyna. They make electronic ignitions for those old bikes. Basically get rid of points altogether.
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