New bike

[john69]

After determining I could no longer bring my 1966 triumph to life with the outdated and archaic means of gaining ignition (kick start) and the difficulty in using the spring loaded clutch, I decided on a 650 Yamaha SX 650 for a replacement. I purchase a 1981 SX650 the other day from a gentleman who had acquired it at an estate sale. The bike looks to be in very good condition and has 1365 miles on the odometer.
I believe he replaced the battery, drained and refilled the tank and attempted to start the engine. He was able to get it running and go for a very short ride but it runs very rough.
Having never owned a 650 Yamaha I am not sure how to proceed. Any and all thoughts would be greatly appreciated. Are there any good manuals available for this model of motorcycle?

 

[fredintoon]

After determining I could no longer bring my 1966 triumph to life with the outdated and archaic means of gaining ignition (kick start) and the difficulty in using the spring loaded clutch, I decided on a 650 Yamaha SX 650 for a replacement. I purchase a 1981 SX650 the other day from a gentleman who had acquired it at an estate sale. The bike looks to be in very good condition and has 1365 miles on the odometer.
I believe he replaced the battery, drained and refilled the tank and attempted to start the engine. He was able to get it running and go for a very short ride but it runs very rough.
Having never owned a 650 Yamaha I am not sure how to proceed. Any and all thoughts would be greatly appreciated. Are there any good manuals available for this model of motorcycle?

Hi john and welcome,
if you just did a typo and your bike is an XS650, this is just about the best site to be on.
Haynes XS650 manual is OK for most stuff. The factory manual is better but (IMHO) insanely expensive.
Use the search button and the TECH section to find stuff on bringing a dormant XS650 back to life again.
My personal tips:-
1) Check if the EPA-mandated brass plugs over the carbs slow-running needles are still there and rip 'em out if they are, then triple-clean the carbs.
2) Check the mfrs date on the tires. If they are more than 7 years old fit new ones because old tires got no grip.

 

[Downeaster]

Pretty much everything you ever wanted to know about bringing an XS650 back to riding status is on this site somewhere.

Check out the Tech Section and it's various topics, particularly the carb section. The HUGE majority of problems with rough running and hard starting can be traced to dirty and/or mal-adjusted carbs.

The electrical section makes for very good reading as well.

Helpful bunch here too. If you can't find it via search or don't quite understand what you did find, ask and somebody here will jump in.

 

[ThatXS650Guy]

Welcome. You'll feel right at home on an XS650.

 

[Uhlaf]

Post pictures for our viewing pleasure please.

 

[Superjet]

Welcome! Check out the tech section for troubleshooting any areas. Pics too if you can, we all like to see other bikes especially if its got very little mileage.

 

[Jim]

I'll add my welcome to this wonderful forum!! Has anyone mentioned we like pics....

 

[Downeaster]

Pics...right...forgot to mention pics. Thought I'd better mention that in case everybody else forgot...

(To OP: there's the odd wiseass here too. All in good fun)

 

[john69]

Hi john and welcome,
if you just did a typo and your bike is an XS650, this is just about the best site to be on.
Haynes XS650 manual is OK for most stuff. The factory manual is better but (IMHO) insanely expensive.
Use the search button and the TECH section to find stuff on bringing a dormant XS650 back to life again.
My personal tips:-
1) Check if the EPA-mandated brass plugs over the carbs slow-running needles are still there and rip 'em out if they are, then triple-clean the carbs.
2) Check the mfrs date on the tires. If they are more than 7 years old fit new ones because old tires got no grip.

 

[john69]

Thank you for your response. Can you please tell me the benefit of removing the brass plugs? How do I locate the slow-running needles? Do these neeles have another name?

 

[MaxPete]

Welcome John, from Canada’s sunny southern coast in Windsor, ON!

A really important first step is a manual and also, search for the XS650 Carb Guide. It is downloadable for free and contains a great deal of information about the likely source of most of your difficulties. Once you’ve gotten any issues fixed, you will find the XS650 to be a delightful bike which is reliable, a ball to ride, great sound and a total chick magnet.

OK, it’s fun to ride, it sounds great and it will be reliable.

Cheers,

Pete

PS - photos are very helpful for us as you and your old gal go through the wake-up process.

 

[Jim]

Brass plug hides the mixture screw (EPA mandated). Removing it allows you to adjust the idle mixture. Helps a lot.

 

[MaxPete]

There ya go!

Pete

 

[650Skull]

Welcome, hard to answer questions when you don't have a manual to reference to.........here are some threads.

the PDF, (bottom of post), is a comprehensive BS34 carb, (should be on your bike if original), dismantle and rebuild..... these are from a Suzuki but the same carb...........

Did anyone mention pics........Pics also help us identify if there has been any swapping between years/models........common to have on these bikes and because the production dates spans 2 years the models are often misdiagnosed when sold.

An 81 has a production date between Aug 80 to July 81, also there were 2 models produced in 81. The main difference was that one had Mag wheels and the other had spoke wheels...........


A link to online manuals........scroll down to the manual for 81H/SH or a manual that includes that model........lots of good XS 650 information on here as well
https://thexscafedotcom.wordpress.com/tag/manual/

Jean Aker's XS site some good reading and info
http://biker.net/
Link to his parts manual PDF files
http://biker.net/650parts_index.html

Carbs....Caution....do not immerse in carb cleaner for cleaning......Rubber seals will be destroyed
Read the first link in this thread for the holy grail of carb tuning.....
https://www.xs650.com/threads/carbs-carburetors.43/

A bit wordy but well worth the read
http://www.xs650.com/threads/carburettors-from-the-grave.34737/#post-551097.

Good tips and common problems and solutions BS34's
http://www.xs650.com/threads/carbs-carbs-carbs.52014/#post-548423

Electrical
http://www.dansmc.com/electricaltesting.htm
http://www.xs650.com/threads/what-happens-when-you-turn-your-key-on.9625/
http://www.xs650.com/threads/wiring-harness-musings.18925/
http://www.xs650.com/threads/grounds-so-important.41775/

Charging........probably one of the first things that needs to be checked for problems.
http://www.xs650.com/threads/expanded-charging-system-guide-in-progress.10561/

Enough for you you get going for a bit...........Use the search feature for Threads and Tags and the Tech menu as well........There is enough information on here, some people have rebuilt their bikes just using the information without posting any questions.......then posted a thanks........ask any questions and help will be offered........

 

[fredintoon]

Thank you for your response. Can you please tell me the benefit of removing the brass plugs? How do I locate the slow-running needles? Do these neeles have another name?

Hi John,
the green arrow on the photo in Jim's post #12 shows the slow running (idler) needle access hole.
The EPA Nazis had the hole filled with a brass plug to stop owners adjusting the needle's EPA-mandated super-lean setting to make the bike idle nice.
The plug also stops you from removing the needles to clean the slow running passages in the carb body.

 

[5twins]

Yes, the slow running needles have another name. Most of us call them the "mix" or "mixture" screw. They are a screw with a tapered needle point, so I guess that's where the "needle" name comes from.

Note all the little parts that go with (and on) the screw. You want to remove all that stuff when cleaning the carbs. The little o-ring is at the bottom of the hole and often mashed into oblivion, needing replacement. The screw won't meter fuel/air correctly if that o-ring is shot.

 

[Bushyeyed1]

John welcome to the forum. You made a good choice in purchasing a xs650. Lots of good info in the tech section as well as threads on the forum. From what little experience I have with my xs650; I can tell you the best thing to start with is a tune up per the instructions in a maintenance manual such as clymer. You will probably end up fixing some of the issues after following the steps. Then if still not fixed dig into more technical things such as rebuilding carbs. With the bike being almost 40 years old when you remove something you will most likely find a surprise. And better get a gasket, seal, or o-ring to replace where ever you are entering.