Instant start and poor idle and function

Hi all XJ lovers

So, I have a small problem with the XJ650 Seca.
From the start:
I have cleaned the carbs acc. To all suggestions in this forum.
But, I cannot start the bike without instant start when cold and I will not run properly on low revs without the choke set to mid, which gives around 3500 rpms.

I have new spark plugs, but it will not run as expected, but again only on low revs.
Above 4000 it shoots off like a rocket and the motor seems to ignite even and it is really powerful, but as soon as I lower the revs it starts to bludder and I need to use the choke or it dies.

What would you suggest?
Valves?
Sync carbs? Is that even possible without the YICS tool?


I appreciate all the help I can get.

Thanks from Sweden.

 

First and foremost, I'd go ahead and check your valve clearance to start. When you said you cleaned, did you replace anything? Diaphrams, seals and such? Did you make sure that all the tiny passages are cleared and clean? Did you wet set your carbs? Check your fuel levels? Bench sync? Lots to poke at before we can really start to dial in to help you. Once your valves are set and all the previous is done and confirmed you can try to sync as best as possible without a yics tool.

 

Okay, you should have checked your valves before you did anything to the carbs. This is number 1! Next you must have the floats set properly this is number 2 and then you sync the carbs.
I keep my bike on the charger 24/7 to keep the battery at its top peek performance.
My bike is very cold blooded so if it sits more than 3-4 days then I will open the petcock so that fuel feeds into the carbs for about 20 seconds then I put the petcock in normal mode, set the choke, then hit the start button.
This seems to work well with my bike but the other issues you are having is probably do to the first things I had mentioned.
Hope this helps....

 

Are the carb and air box boots good? Is the air filter in it?
Try squirting some easy start around the boots when it is running to see if it speeds up indicating an air leak. I have found these bikes to be very sensitive to air leaks. Just an idea. Hope it helps

 

That's an interesting thought. I will try that.
Just can't understand how this bike can be so sensitive compared to my other bike.

 

Because it is over 30 years old!!!

 

Is your 650 Seca a YICS-motored bike? The ones we got here (only '82) were pre-YICS.

That being said, carb tuning is futile if your valves aren't in spec.

 

So is my other bike

Thanks for all your suggestions and tips.
Guess I tried to take a shortcut as I was so lucky with my 1981 Honda that practically started at first try?
I realise this Inge will need some more live before it starts to live me back.
That's what she will get.

Starting with the valves.
I will keep you posted if my findings

Thanks for all your help so far.

 

Yes YICS it is…

 

I had about 4 litres of oil in the motor. I think this made the motor to stahl.

 

Was it oil?? Or was it oil mixed with gas?

 

Yes, it was mostly oil plus fuel from after my first attempt to clean carbs.
Third carb was still stuck so I had to redo them again.
How ever, I made a mistake when replacing the oil as well. I just loosened the filter, so i still had oil in the motor when I filled it up again with the aprox.2.65 L that I was supposed to after filter replacement.
No wonder I could not see the oil in the level window. I thought it was dirty, but I must have had like four plus litres in there.

That's corrected one but I will need to replace the air filter that was soaked in oil/fuel.

At least now it starts again..same mystery with idle though. Needs choke to stay alive, and when I use choke I sort of need to adjust it as the revs varies between 1500-4500..
I guess i will not have the break through as I hoped for, and I have been thinking about selling it and use the Honda, but today I went for my second ride on it, and I really like the bike.
Nice revs in 70km/h and still it can kick off from there with noticeable power.

I guess I will need to fix it cause it really is kind of nice to ride..

The plan is to
1. Adjust valves -do you know where to purchase tools and shims?
2. Remove the carbs for the third Time this time I will have them micro cleaned
3. Bench sync and sync.
4follow your suggestions on this forum as I really want to ride this bike.

Thanks for all your support..

 

Once your valves are in specs and your carbs squeeky clean, do yourself a favor: install an inline fuel filter to keep these carbs as clean as could be.

 

Sounds like an terrific idea..

Thanks

 

Alright,
So I did the float level test with the carbs still mounted on the bike, just to get an understanding of the actual status.

I showed that all four was way below spec. Around 25-35 mm below.
Now, I would assume that is at least one factor that makes the bike not idle without choke, as the carbs just cannot provide fuel to the mix, as the mixture is too lean or in fact non-existing.

As I am working on being infamous as the "short-cut guy" I find it a little sad that the bowls cannot be removed with the rack still mounted but a positive thing is that I will get the opportunity to bench sync after I have adjusted the float level.

You can rest assured that I will come back with results when I have done this, to let you know the difference.

Also taking the opportunity to pop a question:
As my mistake with the oil any fuel in the engine gave my air filter an oily bath, I assuming this needs to be replaced as the air filter is a part that affects performance? yes?

Thanks!

 

When you check float levels with the carbs on the bike you still need to make sure they are level.

That being said, 25-35mm below spec is an almost empty bowl, so that is the cause of your idling issue.

And yes, you will need to replace the air filter.

To get fuel into the oil you need to have a failing or mis-adjusted float and a failing petcock/fuel tap. Get these fixed before you change the air filter or you'll be doing it all over again.

Also, have you checked those valves yet?

 

So, when adjusting the tang for the floater to get the correct level, are we talking about micro meters or what?

 

We are talking if you "bend" it enough to know you bent it, you went too far.

Think "nudge" or "persuade."

 

This may help.

http://www.xj4ever.com/setting%20fuel%20levels.pdf

 

Sorry I'm Swedish, and don't understand persuade in that sentence., but I guess the boxing gloves has to come off for this action.

Thanks again for all support! I am planning to do this during tomorrow. And I hope it will make a difference.

Can't get the link to work though?

 

The link is to a .pdf file, you may need to install a pdf reader to view it.

 

Right, thanks!
I will open it from my computer.

 

Gentle and slight might help: "mild och lätt"

And "knuffa den något"

 

Now it makes sence!
Amazing that you speak Swedish! ;-)

 

Google translate :wink:

I actually speak a little German, so I am good at looking for better English words to translate and get the point made

 

Aber naturlisch!
Danke…

I will set my carbs straight tomorrow and I am really excited about the result.
Hope not to get too disappointed.

 

So my dear fellows, and XJ bike fans.

I would like to thank you all for your input to help and solve my disaster.
I was really close to sell the bike actually just because the energy needed to go through the carbs a third time just was not attractive enough, and as I have a bike already I thought, watta hell – sell it and sleep at night.

But you guys with your energy got me going again, and I discovered that the float level was really low when testing while carbs were still mounted on the bike. And that sort of gave me a hint of the reasons for why the bike was running crappy/almost not at all on idle and low revs.

Removing the carbs for the third time made me realise that it’s actually not a big deal, as I have learned from the other two times 
Aligning them to be in level, and filled them up, found that carb 1 was a little low, removed the bowl….And there it was…Some stupid had mounted the floater upside down!! What an idiot!!
So, that gave me the thought that the idiot who done this mistake must have made it in all carbs, and my assumption was correct.
Changing all floaters to the right position and mounting the bowls on all carbs, made the measurement for level and BOM! There it was! As if it was taken from the book. All carbs on spec.
Took the opportunity to make a bench sync and that was beautiful and fully synced. Just as if someone just synced them. Could be the idiot, but sure as h*ll wasn’t me! (Even though I have to admit that the idiot and me is the same person, but I am sure you all figured that out by now).

So, a small nugget of hope raised inside of me when re-installing the carbs.
When done, ignition On and full choke. Hitting the start for 10 seconds, nothing!
No choke – hitting the start for 10 sec. Nothing. Dead as a pile of poop.

No choke –ether and BOOM! 4000 rpm's idle. Turning the idle adjustment and got it down to something in between 1000-1500.
Solid idle and acceptance of gas without stalling or dying.
Added a little choke to warm up for a couple of minutes, and took her for a ride – Runs like a charm!

Again, thanks for all your support and interest to help me out with this!

 

Congratutations!
Did you check your valves? If you did not, you will be back in the forum sooner than you want.

 

Probably just needed for the fuel to get drawn through all the Carb passages and into the cylinders.

Congratulations on your first job!

Dave

 

So, that will be my next mission..at least it's now worth working on

 

Great discovery, finding someone else's small error then fixing it!

 

Just wanted to get back to you to tell you that the bike still runs so well.
Smooth run over the whole register, at least up to 8000 rpms. No need to push it
Again, thanks for all support in my getting the bike to run journey.

Jr.