She is dying while shes reving? UPDATE: now with a miss!!!

Ok so ive restored one of my XJ's (just the bike not the motor) and after doing that when i ride her and give her full throttle when i hit about 5000rpm it starts spluttering? and struggles to rev to redline.

Ive cleaned & synchronized the carbs (made my own tool), changed the spark plugs, checked to make sure the tci is advancing the timing (which it is) but am at wits end to what the problem could be?

It has had pod filters fitted to it (was like that when i bought her) but before taking it off the road two years ago it went like a rocket! now it just doesn't want to go! its not leaning out as the plugs are a nice whitey tan colour, so um yeah???

Any help would be great guys!!!

 

Re: She is dying will shes reving!!! help!!! Please!!!

Oh and i forgot to mention that ive picked the needle up to the max position and increased the idle richness slightly too, to see if it is a lean out issue, but its not the plugs are still a nice colour.
Also she dont like cold starting too much either? Well actually it will start fine with the choke on but won't idle very well and with the choke off it will idle ok but i have to hold the revs on till she warms up. Oh i really should mention she is a 83 (31a).

 

Re: She is dying will shes reving!!! help!!! Please!!!

Sounds like a fuel issue. You say she didn't run for two years? Have you cleaned the carbs? Check for air leaks on the intake boots. Run her up to 5k and hold it for a bit and kill it. See what the plugs look like then (don't let her get too hot, either do it while riding by coasting into the garage or put some fans on her.).

 

Re: She is dying will shes reving!!! help!!! Please!!!

Yeah mate cleaned the carbs to spotless!!!

 

Re: She is dying while shes reving!!! help!!! Please!!!

What about revving in neutral. Same behavior?

If yes, then it's probably an ignition issue, if no, then probably a fuel issue.

If ignition, then it could be a problem with one of your VR pickups. You might want to compare the resistance of the two. Should be around 600 Ohms each.

 

Re: She is dying while shes reving!!! help!!! Please!!!

Nah it revs pretty good in neutral.

Forgive my ignorance but what are the vr pickups?

 

Re: She is dying while shes reving!!! help!!! Please!!!

VR = Variable reluctor

These are the coils under the timing cover that trigger the TCI to dwell and fire based on when the edge of the rotor passes the pickup.

 

Re: She is dying while shes reving!!! help!!! Please!!!

AHH ok thanks mate, so do you just pull the rotor off to gain access to the wires?

Could welding to the frame bugger them up? only reason i ask is i unplugged the tci but that was it. I welded some brackets to the bottom of the frame to fit a belly pan.

 

Re: She is dying while shes reving!!! help!!! Please!!!

Ok so after playing with the carbies AGAIN i have managed to richen up all the cylinders except no,2???

I suspected it was running lean and that was making it miss and splutter at 5000 + rpm as it has pod filters and a pretty straight through 4 into1.

Well its still doing it and no.2 is lean and i can't get it rich. I have stripped and cleaned the no.2 carb about 3 times now :roll:

Im going crazy!!!

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Oh i checked the vr pickups too, they are with in specs according to the manual and the temperature.

When at light load the engines fine, but under hard accel it starts to sputter at 5000 then goes ok briefly then splutters and lacks power too redline.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Have you re-checked your carb synch?

When I synched my carbs, the 3/4 pair was badly out of synch. The synch seemed to drift a bit during warm-up and required a few re-tweaks.

If you zipped through the synch process too quickly the carbs may not really be in synch.

Can you provide some details on your home-brew synch tool?

Have you checked for gas smell in your oil?
Has the oil been changed?

Maybe your main jets need replaced or upsized?

Did you check float height?

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Sounds like it is lean in upper RPM. Are the jets still stock size with the pod filters? Pods filters always require rejetting.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Yeah the jets are still the stock size, i upped the needles but it only helped a little.

The weird thing is that when i first bought it two years ago i only rode it twice before taking it off the road, and it went like a rocket. Now it has this problem???

The only other thing i have done to it (performance wise) was fit a four into one. But it had a straight through twin system on it anyway so i dont think it would have made that much difference.

To answer HalfCentury, yeah i did the floats there spot on (22.3mm)
Ive changed the oil twice in 50km No smell that i can remember.

Here's a link to the yics tool.
http://home.westman.wave.ca/~jbe/YICS.htm
I made mine out of 5mm rod instead of the 1/8 so its stronger used stainless washers and so on, and did the whole thing in metric.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Ok i decided to check the coils and there resistance is...

Primary 7 ohms

Secondary 22 ohms

Is this normal? it way out if compared to my book but does anyone else out there have similar resistance in the coils on a running bike with no problems? that way i can eliminate coils from the equation.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

I have the coils off of my parts bike in a box. I will pull them out tonight and check the resistances.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

If it had the stock exhaust before and now you have a 4 to 1, you will definetly need to rejet. With your current setup 4 to 1 and pod filters you will need about 2 to 3 sizes larger main jet size than stock. Thats a good starting point then its more trial and error, changing jets till it right. Another option will to reinstall the stock airbox if you still have it.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

If it revs good in neutral, but cuts out going down the road, check the fuel filter, and the petcock. Sounds to me like it is not getting enough gas to the carbs. When I bought my bike the fuel filter was covered in rust, and the petcock was gummed up and didn't flow fuel very well. I added an inline fuel filter to mine also just to make sure none of the rust makes it to the carbs.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Unfortunately it was already modified when i got it,

No air box just pods.

4 into 2 into 1 non stock system, no cross over pipe, and dobson mufflers with no guts in them :roll:

So i took the 4 into 1 off my other bike (a stock 31A) and fitted an original system to it (the bike is full original although in need of a restore) then put the 4 into 1 on the the bike of topic. Did that make sense??? i hope so i have a headache now :lol:

I think your right it would be breathing pretty good now and probably always needed a re-jet, i just cant figure out why when i got it it flew now there's just no top end, would the four into 1 make that much difference over a straight through 4 - 2 - 1?

Ill ring Yamaha Aus tomorrow and ask them about jets, although they NEVER have any xj stuff in stock and it takes up to 4 weeks from Japan 8O

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Good thought, but yeah the fuel flows like a fire hose!!!

When i first started the rebuild i learn't that the filter wasn't even attached to the petcock 8O because when i took the tank off i heard rattle rattle rattle??? Hmm whats that??? Maybe just the fuel sender??? so i took the petcock off (was gona give her a clean) and bingo! no filter :roll:

Geez wasn't that fun to get out :lol: But with a carefully bent piece of wire and with the fuel sender removed i could sit a light over the sender hole with the wire through the sender hole, shake the tank to get the filter in the right position and by looking through the hole where the petcock was i juuuuust got the wire through one of the holes and ever so carefully (brain surgeons skill comes to mind ) lift it up through the sender hole.

Anyway stop rambling Flash, sorry, yep got a filter and all is good in that department.

Also,

I would like to make a quick mention of how much i appreciate all the advice and the suggestions of ALL you guys on here, i literally come inside check the computer for replies, read them, then back down to the shed and give it a try

Keep them coming! we will get there!

 

Re: She is dying while shes reving? UPDATE: now at wits end!

this might sound stupid but it might get ya pointed in the right direction
add some restriction to the intake (stupid part) cut up some old socks and stretch them over the pods, the mixture has to get richer if that helps the problem your half way fixed
best done at night so nobody sees

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Ok so i changed the muffler from the low pressure aluminium one to a spare R1 Titanium unit i had lying around so she has some more back pressure...... still no good :roll:

Here is some photo's of her if anyone is interested, its my street fighter XJ version, i call her "THE BLACK"

http://xjbikes.com/Forums/viewtopic/p=1 ... tml#119724

 

Re: She is dying while shes reving? UPDATE: now at wits end!

I like Polock's idea of adding socks to the filters, If it makes a difference that means you need bigger jets. Everytime you change something like exhaust or airfilters from a stock arrangement the flow through the engine has changed. Therefore the carb jets will need to be changed to account for the change in airflow.
Here is a example, I changed the airfilter on my XJ1100 to a K&N style. The exhaust pipes started turning blue from the extra heat(sign of a lean engine). The bike had 15k miles and a near perfect exhaust. That little change made the bike runlean, I had to richen the mixture.

Nice bike, we'll have it running soon

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Follow this link to XS11.com. It give good starting point for jets

http://www.xs11.com/forum/showthread.php?t=382

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Thanks mate your a legend Ill check out the site to figure out sizes

I rang Yamaha today, they said they have an upgrade kit which has main & pilot jets and different needles for $150. Might be the go i think. or there is a up grade set on ebay but its just both (pilot & main) jets no needles for around $50. Suggestions anyone? should i just get the ebay set then shim the needles if i need to?

On another note; i pulled the clutch cover off tonight as it has been a little jittery. Couldn't see much except for a little bit of milky oil on the inside of the clutch cover :roll: far out!!!. Ive done two oil changes in 50km and no milky oil has come out of her :roll: maybe it has a blow head gasket and is leaking coolant? (joking )

Anyway so i pulled the pressure plate off to notice all this heavy silver crud in side? Hmmm? pull out the centre pin to find NO thrust washer! just a empty casing with about 4 rollers!

So it looks like the new R1 exhaust and belly pan is coming off so i can drop the sump and see whats in there and in the oil pickup. Hopefully i can account for all the roller bearings, if not then? I really don't want to pull the whole engine down to look for a little roller.

I'm really glad i only did about 20 km before pulling her off the road for a freshen up.

Is it just me or are my post getting longer 8O hopefully its keeping someone entertained :lol:

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Oh sorry, yep ill be trying the sock thing as soon as i sought out the lack of bearing issue. Hay i might start a new trend here? ill get some hip & funky socks on them, it will be the new 'IN' thing :lol:

Ok, so where's my sisters sock draw.......

 

Re: She is dying while shes reving? UPDATE: now at wits end!

So your thinkin your lean @ 5,000+ ???
Emusion tubes are spotless right?
Is the diaphram or needle binding somehow?

Upping 2 Mains, and 1 Pilot would work on my 750 if I has the same setup you got, I'm not sure about the 900's
I am near sea level btw.

Flash you need to pick up some socks from Shooter's Sister

 

Re: She is dying while shes reving? UPDATE: now at wits end!

if your feeling frisky
back in the day we used to drill out jets to whatever size we needed
a set of #drills is way less than 150$
solder them shut and redrill smaller if you go too big

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Hmm drilling aye???

How do you know what size to drill? is a 120 main jet 1.2mm or something?

Ass.Fault,

Yep emultion tubes are 100% clean, diaphrams go up & down no problems. Do you have a address for shooters sister? maybe some photo's so i know what im in for :lol:

 

Re: She is dying while shes reving? UPDATE: now at wits end!

http://shopswarf.orconhosting.net.nz/drills.html
there may be a relationship there somewhere but i don't know what it is
find one that fits then go the chart and see if the next size up seems reasonable
remember a drilled hole is slightly bigger than the bit that made it
http://www.use-enco.com/CGI/INSRIT?PART ... XNO=945609

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Just a thought- - you ran with the factory filter unhooked. That thing is just a screen, and we're running a second paper in-line filter.
You are only running the factory screen-type.

Having the second filter of the screen type is a waste of time, IMHO.
(I also don't care for the sintered metal type)

Now go clean your carbs

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Sorry mate but the carbs have been off, worked on, and cleaned so many times ive lost count, trust me when i say you could eat off them (as long as you don't mind the smell of fuel )

Im not exactly sure what your saying, but it does have the standard in tank filter fitted. It is also spotless.
I tried a paper filter on the fuel line but it restricted the flow from the tank considerably, but it was a large paper filter so i will go to the local bike shop when i get the time and see what they have. But the tank has been flushed and cleaned as well and every time ive had the carbs off there has not been speck of stuff in them.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Have you checked your valve clearances, and then your engine compression? Just to ensure there is nothing amiss there, possibly from running too lean? Making things more free-flowing almost always requires re-jetting. Some will say no, I will only comment on my experience.


My 1100 has pods and a Suprtrapp 4 to1 exhaust. Main jet had to go up 4 sizes and pilot jet 1 size. I am talking about the fuel jets. You must get proper fuel delivery at wide open throttle before you can even think about trying to adjust the mid range needle position. You could try bigger jets right off, but if there are problems in the motor, you are just chasing a ghost.

Don't make any assumptions, check everything yourself. If you do decide that larger jets are needed, Chacal on this site has them, and he ships everywhere. I have found him very reliable.

I do not know everything, but I do understand frustration, and have found sometimes it is better to just get back to the basics. Many times the problem ends up being some small detail that was overlooked at the very begining.

I hope this helps, as the problem sure sounds like a weak fuel issue. Sorry to be so wordy. Good hunting, Mike

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Thanks for the sugestions Mike,

The comp is ok, not great but at around 120psi on all cylinders.

Valve clearances aren't too bad either, i think it is definitely a fuel issue. I have bought a small drill bit kit and will be drilling the jets out bit by bit to get the right size. Through research and help from the guys on this site i have found a starting point so will go from there and keep everyone posted on my progress, which has been slow at the moment due to Christmas.

 

Re: She is dying while shes reving? UPDATE: now at wits end!

Ok well i got the jets pretty close and the bike revs great now but is a bit over fueled on light throttle to about 1/3 throttle.

So i pulled the carbs again to do a slight adjustment on the mixture screw and take the needle back to the halfway point from having the clip set 1 lower than standard.

Now it has a miss?????? ive checked all the plugs and they have spark, compression is good, what could it be??? Would a carb issue manifest itself as a miss?

 

change the plug on the bad cylinder, what did you come up with for jet sizes ?

 

Could you still have a fuel to carb delivery problem? I have a small gas tank I had to strap on mine and go for a quick ride to figure my problem was in the petcock. I rebuilt it but not sure its still not somewhat restrictive. Just a thought. I'm going to do some mods to my petcock and see if I can get it to flow more fuel under full throttle. I like my 1100 because it has two petcocks 1 for two carbs Vs 1 for 4 carbs.

Thats also strange the fuel filter you had installed was not letting enough gas through. I picked up one at NAPA that worked well.

 

Thats the thing though, all plugs are firing A ok.

I ended up with:

Main jet drilled to 1.2mm

pilot drilled to 0.4mm

 

With the carbs on the bike i undid the drain screws on the bottom of the carbs and the fuel flowed out of the drain holes no problems, for a good while so i doubt its a supply issue. Float heights are perfict too.

The fuel supply from the petcock pours out, but with the paper filter inline it was barely a trickle. So i removed the filter and now only have the one in-tank.

 

Go with the stone type of filter.
When you see what it catches you'll be thankful.

 

Could still be a bad plug, though. It is common for a plug to look like it's firing fine, in the air, but once back in the engine and under compression, the spark shorts through the body of the plug rather than firing across the tip. Us snowmobilers are really used to that. Put a new plug in, regardless, and see what happens. Heck, it's just a plug, so why not try a new one.

Another thought, too, (my first thought was "plug')......check the rubber boots both from the airbox to the carb, and from the carb to the head. You may have crack or leak that has been opening up with all the on/off stuff.

keep trying, and keep asking..............we'll get you straightened out.

dave