NEW MEMBER I NEED HELP!

Hello everyone I'm a new member to the group! I own a 1985 Yamaha XJ700 with aprox 21k. So I need help I was able to get the motorcycle running, it'll start no problem, however it has a very! High idle. I turned the mixture knob( center knob in-between all the carbs) to the left fully. Put all 3 of the starting mixture screws all the way in and backed them out 2 1/2 turns. Still high idle. I'm thinking the idleing jets are clogged with gunk. And the main jet is the only one working. Another issue I'm having is I believe I over filled the motor with oil since oil does come out of the breather on the left side of the crank case. At this second I am thinking it's either serious blow by or an over fill. When it is idle the filter doesn't spew and oil out. When I reach 6-7k or full throttle I realized that if I over fill it'll pour out. Aprox how many qts would I need in the engine, also what kind of filter do you guys run. I feel that if I get the idle correct like around 1100k it'll be fine. Should I put a new jet kit in it since I have it? Will that solve my breather crank case oil problem? Oh I forgot to say I am not burning any oil or smoking any colors of smoke.

 

Welcome to the Forum . First the "Knob" your turning is not a mixture knob per se it is the idle adjustment knob this will slightly move the butterflys open or closed depending on which direction it is turned. You are probably going to need to pull carbs and do a full rebuild ( seal /gasket replace) Go to the Church of Clean link . Go to xj4ever catalog click on upper rt corner . Chacal has all the parts you will need, I did mine all new shaft seals/washers , gasket and upgraded to allen head float bowl drain screws (recommended) this was not cheap , but bike runs soooo much better. Previous owner claimed carbs were "professionally " rebuilt ...2 different size jets and miss matched hardware, float levels were not the same etc . Your bike should take about 2.5 qts of oil you should have a bubble at the top of the gauge with bike on center stand . If you have to much oil go to Dollar store get a turkey baster and pull some oil out though the filler neck till you get level you need, you might need a short piece of hose on baster to get it to work . Good luck

 

Okay so I'll pull the carbs off and put in all the new parts. The jets say it's for a xj650-750 are the jets the same in the 700 model? Should I purchase a bench sync?

 

Bench sync is pretty simple. Here is a link I found on how to do it. It uses a paperclip, but others recommend using a business card instead to ensure you don't cause any damage to the butterflies.

http://www.xjbikes.com/forums/threads/how-to-bench-synch-your-carbs.6366/

 

You guys are so helpful, thank you hopefully it'll idle correctly after I do this. On the jets is there a specific depth they need to be, or just totally screwed into place so they are seated. Also is over filling on the oil to cause a bad blow by issue and over pressure the left side case with the breather in it. And cause it to push excessive amounts of oil out even if it is at the right level of oil, also it being on the kickstand should that cause the oil to spew out of the breather? I have a cheap little oil breather air filter on it. Does that really matter? Also the carbs seem to have "fuel/vacuum" lines off of the carbs, could that be a issue? I do not have the stock air box so I am confused as where all of those lines go to? Do they go to the air box? Any direction or pictures of fully working carbs and the adjustment screw positions would be absolutely appreciated!

 

Aha now I know ...I hate to beat a dead horse, but the stock airbox is the magic trick to get these carbs to work right. Pods may look "cool" but you might have a time getting jets right. if your running a filter where event tube went to the airbox this is why your getting a mist of oil.. IE the stock airbox have a tube going into it the usual mist of oil gets pulled in to normal combustion it is usually a small amount it is same on cars . Please read some of the posts on carbs , you will be shocked at some of the posts and most lead you back to stock airbox. I don't mean to sound like I'm the total expert , but I'm a 30 year aircraft mechanic and been wrenchin on cars, motorcycles in my spare time for more years , Kawasaki's, and Honda's , and of course Harley's don't seem to mind pods as much....YAMAHA not so much. There are some posts on here that people claim they had no problem with Pods ..So what do I know this was just my 2 cents or maybe 5 cents.

 

Read the Church of Clean, and The Information Overload Hour before starting ANY work. You need to understand what you are doing before you begin doing it or you will not be successful.

You most likely will not need any new jets, but you will need other parts (the symptoms you describe may require new throttle shaft seals, but there is diagnosing to do first). Most often the only parts needed will be new float needles and seats, new idle circuit o-rings, and new float bowl gaskets.
The most imortant part is going to be realizing that you must work slowly and methodically to get your machine back where it needs to be.

Now for the diagnosing. Get a can of carb cleaner and slowly spray some in several areas: the throttle shaft seals (the throttle shafts are dead-center on each side of each carb), the intake boots (rubber part between each carb and the engine), and around the base of the intake boots (including the vacuum port caps). If the idle increases shortly after spraying a particular spot, you have a vacuum leak at that location and it will need to be fixed.

 

Overfilling the oil can cause it to come out the breather vent. As Jetfixer said, check the level with the bike not running and suck some out if it is overfull. Check if the oil smells of gas; if it does that means fuel is leaking past the needle valves in the carbs and flowing into the engine.
If the oil level is OK and still blowing a lot out the vent, then you have a problem with your top end - rings most likely.
Regarding vacuum lines. Each carb manifold has a little nipple on it. 3 of the 4 should be capped and the fourth one should have a line to the fuel petcock. If any of them are open, plug them. That could be causing your high idle.

 

2-1/2 turns out from a light seating

to much oil can cause it to blow out the breather valve. the breather you discribe wants to be up high not crank case level, about air box level

I think on your carbs most of the lines are overflow lines 1 per carb

 

I tried removing the carb. No go. I literally pulled on it with plenty of force. Still not coming off I loosened up all of the intake clamps still nothing. Checked to see if there were intake screws holding the carb into the intake. Nothing. I also took off the choke and throttle cables. Still nothing. I am officially stumped.

 

Yea but how the hell did you remove them from the god damn intake

 

use a wooden hammer handle its shaped end makes a perfect nudge tool.
I use a tack hammer . little wiggle here and there. some spray lube. work both ends at first when you get them all moving out. roll the left side out first.
you did remove the air box boots first?

 

Yes it's all removed at the moment I don't have it so I guess I'll try the easy way and just remove the Allen bolts.... f*** they are positioned so bad.

 

I used a ratchet strap. Just route the strap behind all four carb bodies/float bowls on the intake side. Then attach both ends of the strap to the grab bar or frame at the rear of the bike and slowly ratchet the strap. I've done this several times and it works great for me. Also works great to put them back on!

 

Ratchet strap huh? Okay ill try that I feel like the previous owner glued this shit in hahaha

 

I was going thru that too and then I read about the strap from someone else on here. Don't remember who. Tried it and boom! They popped right off! If you do it to put them back on just go slow because they can go on too far into the boots and you just have to pull them back out a little. Let me know how it goes. Good luck!

 

Okay I'll give it a go with that idea I'm gonna try it tomorrow thank you guys I will let you guys know how the carb rebuild goes

 

Warm the boots with a hairdryer first. Once they are pliaboe from the heat the carbs are easy to get off, no strap needed.

 

I had to use the strap even after warming the boots but whatever

 

Besides all the suggestions here, you need to use lots of patience. I have only taken mine off once, and put them on once and it took me nearly all afternoon. I am sure I could do it a lot faster now that I have gone through it once. If you get frustrated, take a break.

 

Patience is SO critical when working on all things mechanical, but especially old motorcycles...when you get in a rush, you make mistakes and cause more problems. The same goes for getting angry or frustrated. Sometimes you can solve a lot of issues and save a lot of headaches down the line by knowing when to put the tools down and walk away for a while. Go have a beer, make a sandwich, throw the ball for the dog a bit, have a smoke, etc. Walk away for an hour or more and then come back refreshed with a better frame of mind. I have found many times that the thing I was fighting previously will cooperate effortlessly after such a break.

 

I just saw your comment about removing the intake boot bolts. Don't. They like to snap off, so only do that if you intend to replace the intake boots with new ones (there is a procedure for that to reduce the risk of bolts snapping).

 

agreed... needs to sloooooow the heck down and do much reading before diving into all of this.

 

I saw my mechanic do that, it was a duh moment why didn't I think of that

 

I had to drill and tap 2 of mine, stupid things I was a nervous wreck for a few hours

 

got it out!!! Wouldn't come off the motorcycle tiedown so I just took my time. I definitely need intake to engine gaskets. It looks like there is fine minerals by the drain valve. Purchased carb cleaner and going to clean them realllllllllllllll good. Also have new float needles it says xj650/750 carb repair kit. Also what is the numbers on the bottom of the slow and main jets please.

 

If you search, it's here on site. Not meaning to be hard, but you gotta do some reading first.

 

Also those look fairly clean... But new bike to you, I'd still break the rack, dip each carb, replace all rubber

 

I'm going to definitely do my research before most of my parts come in or before I purchase any. I need to definitely have them synched and flow jet tested. Maybe the idle jet isn't working. Also I'm curious, off of the gas tank does it go to a splitter to both fuel rails or just to one

 

You will see when you break the rack
And you synch them after the rebuild

 

Will do, thank you

 

Agreed

 

Cleaned and bench synced. I'm not sure why but 1 Carb doesn't have a adjustment screw there are only 3 adjustment screws and the lean to rich knob. Does that mean that that one carb is preset to that spec and can't be adjusted?

 

So here is my major 2 questions. Am I able to bench sync that one carb that doesn't have an adjustment screw, or not? My second question is can anyone give me the possible spots where all of these "fuel/vacuum" lines go.... I can not find any information where they go and what they do or control. I know that the fuel line off of the gas tank goes to the fuel rail right under the lean and rich adjustment screw/knob. And the vaccum line off of the gas tank to the (#1) intake nipple. That is all I know! Please help me solve this issue of where these lines go, I'd like to eliminate any possible vacuum leak. Thank you.

 

#3 is the baseline carb and is set by the idle screw.
The procedure for a bench synch is to match #1 to #2, then match #4 to #3, then to match the pairs with the central synch screw. Have the idle screw touching the idle screw plate on #3 so the butterfly valve is not bound/stuck to the carb throat. I like to use the idle air passage (the rearmost small hole) as the gauge to set the throttle plates to, with the throttle plate partially covering the hole. Others use strips of business card as a feeler gauge between the throttle plates and the carb throat. Small paperclips can be used in the same way.

This is an excellent writeup on how to Bench Synch your Carbs.
Any comments by RickCoMatic should be paid attention to.

 

That knob on the bottom you keep referring to has nothing to do with the mixture (lean/rich). It is simply the idle adjustment.

 

Missed that in his post. Thanks for catching it.