1982 XJ325J, ok XJ650J with issues

1982 Yamaha XJ650J

24,000 miles

Name - Rick
Age - old guy
Place of residence - MN burb of MPLS

Hi there, its been over 20 years since I had a bike and I like to work on things so I figured I pick up a used 1980s bike and I like the look of the XJ650, not too big, not too small. I even got a 1981 XJ650 parts bike and a tub full of parts. I paid $400 for the whole mess.

I knew this would need some work, but I think I got one of the rare XJ325Js. I’m sure it is related to the carbs from everything I have read so far on your site/forums.

I would like your all’s thoughts and opinions.

Before I even took the carbs off the bike it was dumping gas from the #3 carb. I took the carbs off and just popped open the bowls and the things were spotless. I put the bowls back on and the carbs back on the bike and the leak from #3 was gone, but then it was dumping fuel out of the muffler. I opened up the carbs and sprayed what I thought to be all the holes, tubes and surfaces even though they looked brand new. The diaphragms looked new as well. I did not make any adjustments to floats, jets or screws. I did check the floats to make sure they did what they should (float) and none of them had fuel /fluid in them. I reinstalled the carbs and I can see clean fuel running through the clear fuel line to the carbs, however the bike wont start at all. I did replace the oil and filter as the oil was full of gas. The spark plugs looked carboned up (except for #3, that was clean and dry). I cleaned up the other 3 plugs and made sure the gaps were all correct according to the service manual. I checked all plugs and they all showed spark, but not as strong as I thought they should be. I finally/briefly got the bike to start for a minute or so, I felt the exhaust manifold pipes and cylinders 1 and 2 were hot but 3 and 4 were cool to the touch. I took off the carbs and sure as you know what, #3 carb bowl was dry as a bone.

I like techie kind of crap too so I thought what better way to see inside some of the innards of the bike then with an endoscope. Take a look at my short video of what I filmed and throw your thoughts my way.



Thanks for your time. Oh yeah, I have printed off the Church of Clean 70 pages! Glad I did it a work.

 

Hey Rick, I like the write up. Nice tone to it. However, this might be better suited to the Technical section of the forum. If any Moderator were to browse by, perhaps they could move it for you. On to the troubles. The overflowing fuel could be due to a stuck float, or leaky needle needle attached to that float. If the leaking has stopped, I'm leaning to a stuck float which all your fooling with unstuck. I can't help you with the no fire on 3 and 4, that's above my pay grade. Welcome to the club. Here's some light reading.
https://www.xjbikes.com/forums/threads/read-this-first.110898/

Really read the Information Overload Hour link, it's EVERYTHING to do with XJs.

 

Hi Matti. Thanks for the message! I was debating where this should go since it was going to be an introduction of myself. My ADD took over and off I go. Lucky I finished where I started to be honest with you.

 

Carbs need to be pulled off and at least inspected.
The float needles on at least one carb are not sealing, or the float is hung up/set incorrectly.
Often a PO does a halfassed job and does not consider how old the internal rubber parts are.
Do not attempt to start it until you fix the fuel issue.

Read This First

The Information Overload Hour
IN THE CHURCH OF CLEAN

THE SECRET LIFE OF CARBURETORS
Inside your Carbs
Setting the fuel levels
Replacing your Hitachi throttle shaft seals


I'm moving this to technical chat. Please make this thread toe one that you use to help us keep track of what problems you have and what work has been done. Multiple threads make it much more difficult to provide good help.

The spark looks weak, but isn't. A TCI system has a weaker-looking spark, but the spark has a longer duration (for a reason) which can be confusing to someone who has only worked with points or CDI systems.

 

Thank you for moving this over. I’m not real sure about working on bikes, but that’s one reason I bought a fixer upper. I like learning some new skills and it’s even better when I reap the rewards of a job well done. I have a couple neighbors with bikes, but have no clue how to repair anything so I’m on my own that’s why I’m going to be driving you all nuts. I took the carbs off and checked things out, cleaned what I could, although they looked like new and clean, I tried a couple of things, got them back on, made sure the plug wires were making a good connection to the boots and got the bike running. I’m sure I have to some adjustments as it revs high with the choke but stalls out without the choke. I know all three carbs get fuel, but the #4 exhaust is still not burning hot like the other three. I was able to ride it around the neighborhood a few times, but I know I can do better. It bogs down when I hit the gas unless the choke is on, but when the choke is on a bit and I give her gas she wants to move quick! I’m taking that as a good sign so far.

 

What you descrine makes me suspect that the person who did the carbs did not know exactly what he was doing.

I'll (or we'll since others will chime in soon) take a think and see about writing up something to get you started with a proper diagnosis without overwhelming your skillset.

 

Thanks K-Moe and all!

 

Although every thing looked good in the carbs, would it make sense for me to get the rebuild kit and redo them? What are your thoughts on swapping out the petcock for one without the vacuum assist? I would really like to have this bike road worthy and safe to drive, my wife thinks I should get a newer bike, but I like the looks of this one. Thanks again for your help.

 

In my opinion it is totally worth it to order a deluxe rebuild kit from @chacal, break the rack and give them a complete overhaul that way you know for certain everything is done right. Meticulously follow the church of clean, wet set the fuel levels, check/adjust valve clearances, sync, colortune, and ride

 

The vacuum peacocks are awesome IMO. Rebuild it too.

 

This is where I’m at.

 

Make sure that that throttle and choke cables aren't switched around at the carbs.
It's a common mistake, and even some of us experienced people have done that to our own bikes.

 

Holy crap, if that’s the problem I’m gonna kick my own $@!. I haven’t gone to look yet, if I remember correctly the choke lever lifts up the little button plunger things on top. I’ll look tomorrow. Thanks man!

 

Correct. The "choke" lever lifts up the enrichment plungers on the carbs.

 

@RJ C, consider dropping by Diamond's Coffee Shop in NE Minneapolis on the second Monday of each month. It's the monthly meeting of the Vintage Japanese MC.

 

when you pull the lever towards the grip it pulls the cable, lifting the plungers(right) or adding throttle(wrong).
but pulling yours back seems to slow the engine, i think the idle knob is set way high and by pulling the lever to the grip your adding enrichment
and flooding it, making it slow down and finally killing it

 

Making progress. Was going to remove the carbs...again, but decided to put some sea foam in the cylinders for a bit. I removed the tank, disconnected the choke cable, blocked the intake vacuum port and kept the throttle connected. I decided to try and run some fuel straight to the carbs just to try to warm up the engine and the bike started right up. I manually controlled the choke on the carbs, once it was warmed up I let go of the choke and the bike kept running, throttle worked fine. I pulled the plugs and put some sea foam in the cylinders and left it in for 24 hours. I removed the excess sea foam and started right up, smoking a bit but running. My thoughts are, something wrong with the choke plungers and or petcock problems? I now have torn down the petcock and looks good, but the elbow part that the fuel comes out of will not stay snapped in the carb. What do you all think. I have not reinstalled petcock, tank or choke cable. Thanks for all of your input guys.

I did dial down the idle knob when it was warmed up.

 

Thanks for the invite!

 

Thanks m gonna have to save up for the colortune, wife’s car just lost the timing chain and the diagnosis is bent valves and hosed up engine. The vehicle was great except for that. Selling it for a thousand and putting it towards a newer vehicle.

 

Common enough of a problem.
You can get a new petcock, or clean the outlet and the bore for it, then reinstall with a thin coat of 2-part epoxy.

 

I’ve seen them from 12.00 to 80.00+, I think I’ll start with the epoxy. Thanks as always!

 

Making progress, leak fixed in petcock, starts fine then seems to bog down on moving the throttle. I removed the vacuum line and capped off the petcock and carb nipple. Once warmed up seems to run great on the on position . Do I need the vacuum line?

 

I'd replace it. Be sure to get vacuum ilne and not somehting else. Any other type of hose that size will collapse when warm.

 

until bike warms up a little using the throttle can cause it to bog.
your petcock in on or prime position with out vacuum line and running?

4mm id on the vacuum line.
using the vacuum line is to keep fuel from filling your crankcase up if you develop a carb leak issue also stops fuel from flowing if bike is dumped and the motor is off

there is a thread on converting vacuum petcock to manual petcock.

 

The vacuum line was new and very ridged so I know it’s not collapsing on me. I even tried different intake positions. Rainy and cold yesterday so I didn’t go out.

 

I only used Pri to fill the bowls then changed to On, weird thing wouldn’t start with the vacuum line connected even in on position. I removed the vacuum line and choked the crap out of it and started right up. It hits about 4K rpm then settles down after a few minutes and I back off the choke till 2k rpm then I’d take off with sputtering for a little while and kill the choke and it seems to be fine. I’ll have to try letting it warm up a few minutes longer. Thanks for the help you two, it’s much appreciated!

 

vacuum line on/off, whatever. just so your plugging the nipple after you take the line off, don't run it with that nipple open very long

 

Short clip of my ride! Woohoo!

 

sounds like you have a chicken or something stuck in your wheel

 

I haven’t ridden the bike since this video. I was moving it in the garage and noticed a rubbing sound once in a while. The PO had put a 110/90/19 on the front wheel and guess what... .

 

You dirty dirty YICS.

 

Dude, you are the man!

 

I’ll have to agree with you chacal. Thanks.

 

Ok ladies and gentlemen...I suck at numbers so I am hoping that you all can review my numbers for my valve clearance and confirm that I have this all correct.



If my numbers are correct, I need to rescue 5 "new" shims from the pool and I have 5 shims to toss back in the pool. @hogfiddles I see that you are the lifeguard at this pool, do you happen to have the shims I "think" I need?

Looking for 2-270, 3-285, 1-260
The five being swapped are 1-280, 2-290, 2-275

I know riding season is just about over for me so I am trying to fine tune things before -20 hits MN.

As always, I appreciate all of your help.

Rick

 

Yes, your calculations are correct!

 

Awesome! Thank you for double checking my work, much appreciated.