"new" Yamaha xs750 project

So, I'm pretty new to the site, but I figured I'd check it out since I got this sweet deal on a 78 xs750. I paid $60 for it, yes $60, that is not a typo . Obviously, it does not run but it has everything I need to get it running again except for a battery but I'm sure it needs new plugs, lights, etc. Has about 25k miles on it. Anyone have any suggestions or pointers about these yamaha triples and what a look for when I tear into this thing? I am pretty knowledgeable when it comes to working on cars and I am a jet mechanic by trade, but this is my first bike that I've owned and really want a cafe. Any advice would be appreciated.

I have an xs750 project I'm working on as well. Fair warning, pulling the engine apart is kinda a bitch. You need to break the cam chain to even get the cylinder head off. Other than that, 2nd gear is known to pop out often on higher mileage ones. Check out www.yamaha-triples.org, great forum, lots of information. Here's a link to my build thread: http://www.dotheton.com/forum/index.php?topic=21399.0


Its obviously not complete yet, but I'll be updating it as i get the chances. Let me know if you have any questions about anything.

Another one! Go away! There are too many yam triples on here.

Before you go heavily modifying the beast check out www.yamaha-triples.org and check out the workshop section and read over the "So you acquired a triple" thread. Excellent info.

Things to really go over:
-Electrical system
-Petcocks ;D Leads to "gas-oil" lots of info at the site
-If it has points I highly recommend a transistorized ignition swap. Can be done for under $100...best mod I have ever done
-Swap out the middle and final drive fluids with fresh
-Carbs should be rebuilt. $100 for the kits and Boiling them in lemon juice is the best method. Smells dreadful though.
-Check the carb to engine boots for cracking this causes a surging idle. Also replace the butterfly valves in the carbs or your bike may sound like an angry cricket.
-When you pull the points be careful to not push in the crank timing pin.

I've wasted countless at work learning about this bike and have acquired a lot of knowledge short of rebuilding the engine. If I haven't done it I can usually find the info in short order. Check out my build thread and the other 750/850 yam builds. There are about 5 in progress currently. The xs1100 is similar and their forum is great as well to give you some ideas.

Good luck.

Thanks for all the help. Yamaha-triples.com is great, I'll def be on the lookout for a transistorized ignition kit. Just ordered a service manual so that should help too.

Do the manual petcock conversion, youll be glad you did. It'll run you about 100 bucks and is totally worth it. Here's a link to a thread on yamaha-triples that has all the parts you need for a turnkey solution:


http://www.yamaha-triples.org/forums/thread-view.asp?tid=13793&mid=94984#M94984

Cool.. I just bought one tonight! ha ha

Swapmeet Louie said:

Cool.. I just bought one tonight! ha ha

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What?? Even more reason for me to come over Saturday!

Sorry no thread jack, welcome to the site Koconut. The people on this site kick ass.

Sorry for a thread hi-jack, guys....but I have a question for you XS750 types. I've got a standard XS750 tank that I'm using in my XS650 cafe build. It was missing the petcocks and gas cap....I figured out what petcock to order from Mike's to take care of that problem, but does he have a gas cap to fit a XS750 standard tank? I know better than to ask Mike's.......Welcome to the site!
Thanks and good luck with your builds!

The cap they have on their site looks almost identical to the one on my tank. If you want to be sure, you could always order it from an OEM parts website: http://www.yamahapartshouse.com/yamaha-parts.aspx?aribrand=YAM#/Yamaha/XS750F_-_1979/FUEL_TANK (item 11) although it looks like its about 2.5 times the price.

ldordai said:

The cap they have on their site looks almost identical to the one on my tank. If you want to be sure, you could always order it from an OEM parts website: http://www.yamahapartshouse.com/yamaha-parts.aspx?aribrand=YAM#/Yamaha/XS750F_-_1979/FUEL_TANK (item 11) although it looks like its about 2.5 times the price.

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Thanks for the quick reply! You're talking about the chrome flip-up cap at Mikes, right? I figured the OEM route would probably cost me more than the tank did! LOL!

Gas Cap and Ignition with key
http://cgi.ebay.com/ebaymotors/78-Yamaha-XS-650-Key-Set-Gas-Cap-and-Ignition-400-750-_W0QQcmdZViewItemQQhashZitem43a4d682b4QQitemZ290528330420QQptZMotorcyclesQ5fPartsQ5fAccessories

Gas Cap, Ignition,and seat lock
http://cgi.ebay.com/ebaymotors/77-xs750-xs-750-yamaha-key-ignition-lock-set-gas-cap-_W0QQcmdZViewItemQQhashZitem3a5f210df1QQitemZ250704104945QQptZMotorcyclesQ5fPartsQ5fAccessories

Gas Cap with key $40 BEST
http://cgi.ebay.com/ebaymotors/YAMAHA-GAS-CAP-FUEL-CAP-XS360-XS500-XS650-XS750-XS850-_W0QQcmdZViewItemQQhashZitem5888c06b0cQQitemZ380251433740QQptZMotorcyclesQ5fPartsQ5fAccessories

Gas Cap with key $45 new
http://cgi.ebay.com/ebaymotors/NEW-YAMAHA-FUEL-CAP-ASSY-XS360-76-77-XS750-77-79-_W0QQcmdZViewItemQQhashZitem19b9b1c969QQitemZ110489618793QQptZMotorsQ5fATVQ5fPartsQ5fAccessories

Juggernaut said:

Gas Cap and Ignition with key
http://cgi.ebay.com/ebaymotors/78-Yamaha-XS-650-Key-Set-Gas-Cap-and-Ignition-400-750-_W0QQcmdZViewItemQQhashZitem43a4d682b4QQitemZ290528330420QQptZMotorcyclesQ5fPartsQ5fAccessories

Gas Cap, Ignition,and seat lock
http://cgi.ebay.com/ebaymotors/77-xs750-xs-750-yamaha-key-ignition-lock-set-gas-cap-_W0QQcmdZViewItemQQhashZitem3a5f210df1QQitemZ250704104945QQptZMotorcyclesQ5fPartsQ5fAccessories

Gas Cap with key $40 BEST
http://cgi.ebay.com/ebaymotors/YAMAHA-GAS-CAP-FUEL-CAP-XS360-XS500-XS650-XS750-XS850-_W0QQcmdZViewItemQQhashZitem5888c06b0cQQitemZ380251433740QQptZMotorcyclesQ5fPartsQ5fAccessories

Gas Cap with key $45 new
http://cgi.ebay.com/ebaymotors/NEW-YAMAHA-FUEL-CAP-ASSY-XS360-76-77-XS750-77-79-_W0QQcmdZViewItemQQhashZitem19b9b1c969QQitemZ110489618793QQptZMotorsQ5fATVQ5fPartsQ5fAccessories

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Thanks, Juggernaut......very helpful! That should take care of my cap problem.

Just disconnect everything....you should tag each piece with what it does...i.e. left turn signal, to make reassembly or replacement of the wiring harness easier......

Got it, I've been labeling everything I disconnected from the bars i.e. throttle cables, speedo/tach cables. Waiting on my maintanence manual. Hopefully, it will have some more in depth info on this harness. Might just make my own or find a new one, though. This one is pretty old and haggard.

The clymer manual I have has a full wiring schematic for all xs750 models in it. Its definitely a good idea to label everything, but the the manual schematic is very complete (even includes wire colors/etc). The xs750 has a "reserve lighting" wiring system in it. Basically it means if your lightbulb burns out, the reserve lighting system kicks in for a brief period of time until you can replace the main light. Most people who do mods to their wiring harnesses end up removing it.

sooo....checked the mail after work just now. Saw a package in the shape of a manual, opened it up and....its for Honda XR dirtbikes. They sent the wrong one, pretty lame.

KOCONUT said:

sooo....checked the mail after work just now. Saw a package in the shape of a manual, opened it up and....its for Honda XR dirtbikes. They sent the wrong one, pretty lame.

Click to expand...

Welcome to the site I have a 76 I am working on and they are unicorns on this site but looks like the trend is picking up. Shoot me your email I have a scanned copy you can use mean while you wt the right one.

cant, email is having issues. If you could send it to me through this site I would appreciate it!

The PDF. Is pretty big don't know if I can post it. I will try.