Great now a other issue

[MrOzz]

Well. Since the mysterious electrical issue somehow has not happened again. Now I have another issue. These bikes are fun, lol.

I went for a ride with my brother-in-law. We were riding for a good hour or so. Then my ride would not launch. It would hesitate, then catch. It would run normal until I stopped again.

Got home spent the last day and 1/2 going over the bike. All the connections are good. Coils test good. Getting fuel.

Now the odd part. I checked the sync on the carbs and noticed the vacuum is much lower. I am talking from around 24 cmHg originally to now about 10cmHg. Any ideas on this? My carb tune is fine.

I pulled the carbs. Cleaned them. Checked float levels. They are at 23mm. Pre synced them.

Idle screws are set to 1 1/2 turns out.


Put the carbs back on. Sync carbs. Vacuum still around 10cmHg.

Went for a test ride.

Same Issue. Failure to launch. The only difference now is the RPMs hang when I come to a stop. Will Stay that way for 10 seconds or so. Then will calm back down.

As always I am looking foward with your help.

Thanks in advance,

Ozz

[tarzan]

Actual vacuum reading is not important.You just need all four carbs to have the same reading.
Idle hang is usually a sync issue.It could be a vacuum leak though.I would start there.

[TopCatGr58]

Hey Ozz,

I'm with Tarzan, suspecting vacuum leak. It can be small, but enough to reduce the ability to draw the proper fuel air mix thru the idle/pilot circuit under low rpms...starting/launching from a stop, but once you get going and the rpms are above 3K, then there's enough air flow to activate the mains and it runs okay as far as you can tell/feel until you slow down or stop again, and then you need to rely on the pilot circuit again!?

Check the rubber caps on the synch ports, and the ports themselves to make sure it hasn't worked loose. ALSO check the intake boots where they fit against the head, the bolts can work loose, or the rubber gets hardened and can crack, etc.! Start the bike, use an unlit propane or bic grill lighter to blow around those areas listening for rpm changes!
T.C.

[MrOzz]

...Check the rubber caps on the synch ports, and the ports themselves to make sure it hasn't worked loose. ALSO check the intake boots where they fit against the head, the bolts can work loose, or the rubber gets hardened and can crack, etc.! Start the bike, use an unlit propane or bic grill lighter to blow around those areas listening for rpm changes!
T.C.

I checked the vacuum ports on the carb manifolds. They are good.

On the propane test. Adjust flame to 1". Blow it out. Then run the leaking propane around the Carb manifolds?

Thanks for the ideas.

Ozz

[XJOK2PLAY]

Hey, Ozz...

What's your rpm @ idle?

If mine gets higher than 1100 (which is where the XJ's are supposed to be) it will take about 10 seconds to drop, as you describe.

Mine will stall on launch occaisionally, even though it begins to take off just fine. Dies deader than a hammer after 4 or 5 feet... about the time you just put your feet up on the pegs... It always restarts, though...

I can't remember what all you've done to your carbs besides cleaning...

I'm going to invest next in a Dynojet kit. I think that will resolve some of my carb issues... because I suspect worn jets /needles...
And I hope to see my MPG's increase the way it has for 2 of my friends on their XS's has. For them, they gained right at 10 mpg! (Low 40's now, from low 30's.)

It might be something worth checking in to for you as well. JAT

[tw1980]

I say look at you slide diaphragms real close.You may have developed a small hole or tear.

[MrOzz]

XJOK2PLAY,

My RPM @ idle is approx 1000 RPM.

Nothing with the carbs besides the cleaning, float level check. That was preformed after the issue started. stock carbs.

tw1980,

I will double check the carb diaphragms again to be sure. They looked good when I cleaned the carbs.

Thank all,

Ozz

[MrOzz]

T.C.

I did the propane check. No change in RPMs. Not even a slight change.


tw1980,

I looked at the slide diaphragms. Rubber is still soft. No holes or tears that I can see. All looks good.


I pulled the plugs to double check them. Gaps good. A little on the dark side. Prolly cause of the low rpms I have been runing due to the testing. I replaced them to be on the safe side. Still same issue.

Im still at a loss. SWMBO is getting upset. Spendig more time working on my ride than with her. lol.

I am going to step away from my ride for a little bit. Have a beer or two before I loose my mind completly. Ha! maybe its too late already.

I am unsure of what to check next.

Thanks for the help so far.

[bikerphil]

Ozz, what coils are you running? I had a MikesXS coil go out on me and it gave the same symtoms, stalling on launch. It tested fine on the bench though. Also, might check the coil's double red/wht wire plug for fraying. On mine, half of the strands were broken, probably helping the coil fry out. JAT

[MrOzz]

Ozz, what coils are you running? I had a MikesXS coil go out on me and it gave the same symtoms, stalling on launch. It tested fine on the bench though. Also, might check the coil's double red/wht wire plug for fraying. On mine, half of the strands were broken, probably helping the coil fry out. JAT

I am runnig the Mikes XS coils, $35.00 ones. I justed tested them. They seem good. What ones did you have? Also checked the wires they look good.

Thanks for the idea.

Ozz

[bikerphil]

Yep, I had the $35 ones. I don't run them anymore. I think Dbeardslee had one go out on him too.

[MrOzz]

Bikerphil,

What are you using for coils now?

Ozz

[bikerphil]

I'm using stock XJ11 coils (free). On my other scoot, I have the Accels. Don't know for sure if a bad coil is your problem, but a few of us have had the symtoms you describe, hesitation or stalling from launch, and it did turn out to be a bad coil. They will sometimes check out OK with a multimeter, but fail under load.

[MrOzz]

Thanks. I will keep that in mind. Any way to test the coils under load?

Ozz

[MrOzz]

Ok. After stepping away from the bike I have 2 quick questions.

Could the timing cause this issue if it is off?

Also does anyone one know what the Ohm reading is suppose to be on the plug side of the coils. I am talking about the Mikes XS High output ones. Seen here.

I dont think they are the same as the stock coils at 15k ohm. I am getting a reading of 24k ohm on each. This is with the NGK 5 ohm caps.

Thanks again all for your help on this.

Ozz