New here and could use some help!!

Hey everyone, new to the forum and also new to the motorcycle world! I just picked up a 1984 yamaha xj650! I just love the look of the old school bikes!
I'm hoping to gain lots of knowledge here and I would like to start off with this: bike wasn't running when I got it but owner said it ran when he stored it 2 years ago. First thing I did was pull the carbs and gave it a thorough bath, I then set the floats/fuel level to spec. Petcock is functioning fine and compression is 150, 145, 150, 153 (which I was happy to see) with all this it still won't run, funny thing is after it sits for a few hours it will actually turn over and chug a bit but wont stay running and won't turn over again till later! I've not yet changed the plugs but there is spark and plugs are bone dry after all the attempts starting! I'm a little stumped at this point and not sure what to look at next! Any help would be greatly appreciated! !

 

Welcome to the forum, you will find all the information and help you may need in the forum.

The first thing you may want to do especially with a bike that clearly has not been maintained properly is to check the valve shim clearances. Once that is done you can move on to setting up the carbs properly.

When you say a bath to the carbs what do you mean? Did you replace any parts? There are a lot of passages that must be spotless to ensure proper operation including the enrichment well on one side of each carb bowl.

Best wishes,

 

I had to disassemble and clean these carbs thoroughly.. There are some passages in the float bowls that are very important to clean .. They are part of the choke/enrichment system.. Also would be wise to take the entire enrichment system apart and clean it.. There is a write up that is very thorough on this site.. ATM I only have my phone so hopefully someone else can find the link for ya.. Welcome to the site...

Oh yeah .. Almost forgot.....


Valves valves valves.... Get a feeler set .. Take the tank off..and the valve cover .. Check the clearances ... Very important.. Also there is a write up somewhere on this site..for that too



Where in ont are you ?

 

I didn't replace any parts cuz tbh it didn't really look bad inside there but I took every single piece out and cleaned thoroughly using carb cleaner and compressed air! Also triple checked every pin hole to make sure it was free!
Thx

 

I've not checked valve clearance but I guess I should check this! My gut is telling me that it may be some sort of electrical issue!
I'm in whitby which is on east side of Toronto! You?

 

Kingston

 

Cool, not too far! Where do you get your parts from?

 

Make sure you have a fully charged battery. Having the bike idling won't charge the battery.

Do you have the original fuse box? they tend to be a weak point on the electrical system as the terminals deteriorate with time even if they "look ok".

The same goes for the carb parts that wear out. The float valves may seem ok but the rubbing and moving up and down will wear them out ever so slightly that you may not see it but they sure will.

Best wishes.

 

Ya I'm constantly charging battery as multiple attempts at starting drain it pretty quick! I'm currently inspecting all the wires to see if there's anything visible going on! So far I don't see anything obvious! Here's a question, I've not changed the plugs yet but haven't thought it quite necessary yet as after all the attempts at starting they are still bone dry! If it was a spark plug issue they would be wet would they not? I'm also trying to find out if there's anything electrical that could cause this! If I let it sit for a few hours it will turn over and chug once or twice and that's it till I let it sit for awhile again!

 

How clean are the plugs ? What do they look like.. Black sooty ? Etc

 

They were a little black, came that way when I got them! I am gonna replace them just to rule that out! Just trying to limit the amount of $$ I spend till I know I can get her running! I haven't replaced yet cuz I figure that if it was that they would be wet. I'm thinking I'm just gonna change anyways!

 

Take a small wire brush to them clean em up.. Check the electrode... Some wire brush shed so make sure there are no wires on the plugs.. .. Also if you have a spark gap tool check the gap make sure its in spec...0.7-0.8 mm or 0.023-0.032 inch. If I remember right

 

I did this exactly! Is there anything electrical that could cause this?
Also, in the birds nest of wires in the headlight I found a couple wires that lead to nothing but don't see anywhere for them to plug to so not sure what they are for! I have a manual but with electrical it might as well be written in Chinese to me! Lol here's a pic

 

Electrical... I don't have any ideas ... I haven't looked in my head lamp... I doubt there is something in that location related to ignition.... Will she fire with quick start fluid.. If you don't have a bottle of staring fluid head down to crappy tire or princess auto and get some..
I found it helped me when I couldn't get mine to fire.. If it fires on starter fluid... Chances are its carb related... There are way smarter folks on here that might point you in right direction

Also check for spark pull spark plug re onect the ignition wire.. Hold it against the engine and turn it over... Bes to do this indoors or at dusk .. The spark is hard to see if the light is too bright

Spark mixture compression.... All three needed to run


Also I would change you thread title to something that says your have no start issue.. It might get some attention from the gurus on this site... Ie help bike won't start can't figure it out... Or some such... If you where closer I would come by and look... Maybe after I get back from vacation.. whitby isnt that far...Leave on sat night

 

If the bike is not starting and they are bone dry then no gas is being delivered, that sounds like carbs are not fully clean. Just like anything in life, if you kinda do it, it kinda work. Once you thoroughly clean them and replace all the parts that wear out then your carbs will work like new.

 

You need new spark plugs; put the petcock on PRI (assuming fresh gas) and unless you need a new battery it should fire up.

If the battery is soggy, it will spin all day and never fire. If there's no gas in the carbs, it's possible there's an issue with the vacuum operated petcock; that's what "PRI" is for. However, if your floats aren't right, you could end up filling your motor with gas so be careful with "PRI" it's like turning on the faucet.

Shortcuts will only lead to heartache. Follow the above advice.

 

I took every piece apart and cleaned very thoroughly! Used compressed air and did it a couple times just to be sure! And tbh there wasn't a spot of anything in these carbs, I was quite surprised! I've got them off again and going through process again to be sure!
Thx for input!

 

You need to WET-SET the float levels. It's critical: http://www.xj4ever.com/setting%20fuel%20levels.pdf

Then do an accurate bench sync before you reinstall them.

 

Im gonna pick up new plugs so I can rule that out! At first I was unable to get fuel in the bowls and when I went back in to check the floats I noticed that someone had been in there and floats were way off and upside down to boot! So I fixed them and set them according to spec and checked fuel levels and everything was where it needed to be! So I now have confirmed fuel in the bowls but I'm assuming now that the fuel is not coming out of them! I did put petcock on prime for about 20-30 seconds and switched to on and nothing! I have confirmed spark but not convinced fuel is getting to plugs as they are bone dry! I've also confirmed that the petcock is functioning as it's supposed to be! I've got the carbs off again and am gonna check them out again, not sure what else to do at this point!

Thx for the input!