1st gear sputtering

Hi, Guys, I'm back with another question. The bike is an 81 xj650 maxim. It has a 4-1 exhaust and pods. I know, I know Pods suck. That's the way I bought the bike. When I got the bike, I cleaned the carb and noticed it had not been jetted for the exhaust and pods and ran like shit. I followed the formula on the information overload and stepped up the fuel and air jets from a #40 to a #42 and from a #110 to a #116. I had also stuck in new spark plugs. I have had a significant increase in both power and less backfire although I do have some backfire. I have noticed when I am at a complete stop after the bike has warmed up it occasionally will start to sputter once I try to take off in 1st gear. After about 2 or 3 seconds it will roar back to life an accelerate with no problem. I suspected a vacuum leak. However, I checked both pod and carb boots for leaks with propane but could not get the engine to pull any gas into it and make it the engine race. I have not done the valve shims yet but have a kit coming. I have not checked the float levels yet and suspect that it is either float level, valve shim adjustment or improper jetting. My question would be what order I should trouble shoot? Do The valve shim first then see if that fixed it or should I pull the carb and step down in fuel or air jet size. Would the fuel level cause an intermittent low-speed sputter? Also would throttle shaft seals which were not replaced be a cause? I pulled the plugs and seen that 2 of the four plugs were carbon fouled. I pulled the tank and resynced the carbs but they were all pretty close. I am not very experienced with bikes and have learned most of these techniques on this forum. I am not sure what I should do to address the carbon fouling issue. Should I mess with the fuel air screws if the carbs are synced? thanks for the help in advance

 

Butterfly seals can be cause of vacuum leaks , question why did you order a "kit " for the valves...measure with metric feeler gauges..if out of tolerance pull the shim see what number is on bottom of the shim .. check chart see what size you need good chance you may only need a couple and sometimes you can move around in different cylinder position. I know when I did mine I only needed 3 bought them at local dealer for 9$ each. I hope your kit is only the valve cover gasket and bolt seals not a bunch of shims =$$$. Another possible thing your synch could be off this can cause sputtering at idle if you hear a low kind of pop in the exhaust this is usual indication . Good luck

 

The kit will be a valve shim kit. a friend of mine has a Vmax and a xs750 were going to split the cost of the kit. Just to have the extras in case someone needs it. What really has me wondering about the sync is the 2 plugs that are carbon fouled already. If those cylinders are too rich and I backed down on the fuel air wouldn't it throw it out of adjustment?
When I cleaned the carbs I had the racks apart because of fuel supply oring leaks. I followed the Church of clean (or possibly another forum which indicated where the fuel air screws should be set as I had no idea if they were correct in the first place. (bike ran like shit) So when the carb was reassembled and reinstalled with the recommended fuel air screw turns it was out of sync. Yes it was bench synced however I was not able to get a good sync without adjusting the fuel air screws during sync. (I could not get all butterfly adjustments to give me a proper sync) So those fuel air screws were turned during the sync process just not sure if that's what caused the carbon fouling. I suspect it might be though. Why else would some plugs be good and some fouled.

 

I use a 4 vacuum gauge set up as long as they are all even this is what you want, what many seem to miss is yes there are 3 synch screws >>>BUT>>>> the idle adjustment is what it takes to even out ,The first go with adjusting synch on mine I got good readings on 1,2,4 but 3 was no reading ...got these cylinders to read 5hg and turned idle knob a half turn and all 4 read 5hg and idle at 1100rpm and no popping in exhaust . Now granted I run stock airbox so it is easier to set up than with pods at least in my OPINION ( sorry don't want to offend Pod lovers) . The other thing if you don't have gauges you can do it with one vacuum gauge ..more time consuming ..or make a Momoter out of baby bottles ( kinda messy) Sounds like you broke the rack ,but if you did not replace butterfly seals there is no other way to replace but pull carbs apart...butterfly plate has to be removed and shaft pulled to get to inner seals. If your carbs are out of synch adjusting mixture will not really solve a rich cylinder fully .. Have to ask did you soak carbs with without tearing down carb? If so the seals are toast and the idle mixture screws have tiny O rings that will parish in cleaner too. When I do a bench synch I use 2 business cards cut in two take and place one in each carb , adjust synch screw until you get a slight drag on card ( and do the same with idle knob) Hold carbs up to light you should see a slight smile on bottom of the plates . Set mixture screws turn in soft set and back out 2.5 turns this is good start.
Ok sorry if I've overloaded you just want to help you out with this , I know it can be frustrating , but sure K-Moe or Stumplifter, XJ550H, Fiveofakind, Chacal may have a take on this too .. Cheers

 

No that just might be it. I did soak the rack in carb cleaner about 2 hours. actually 2 hours on one side and 2hours on the other. I do have the carb vacuum gauges. And all carbs are really close to perfect in sync. I've checked them twice the loss of power is very sporadic. It never happens when the bike is cold and usually starts after about 5 to 10 miles from home. It just has no throttle when i roll on from a complete stop. it might do it and a block later be fine from a complete stop. I can show a video if you want of the first sync. but if what you say is true it could possibly be a vacuum leak on the throttle shaft activated when I roll on the throttle. Might as well add throttle shaft seals to the job right? Orings for the mixture screws too

 

My experience says that you're still jetted too lean, AND the throtle shaft seals are suspect as well.

 

I think it is bad news for your shaft seals and mixture screw O rings...get with xj4ever and order new seals . This could be cause intermittent vacuum leak at shaft seals as it heats up could leak.

 

Agreed thanks. Ill get it ordered

 

Seals replaced would be wise ^^^

Recommend you do the valve clearances first.
Then float levels. Then a colortune and resynch. The colortune would help with the air fuel mixture (which to my untrained eye is what it sounds like) -BUT (and that's a big but) {Captain Obvious voice} -running pods throws a bit of snake oil into the picture and finding the silver bullet may not come easy.

 

Ok, I just checked all the clearances, and everything was extremely tight. My feeler gauge goes down to 0.02 mm, and all of my intake clearances were tighter than that. All my exhaust side were between 0.03 and 0.06mm. I have the Haynes book and do have my chart for corresponding clearances. My question would be with everything being so tight is there a possibility of anything being damaged and should I do any further inspection?

 

Unlikely. Preceed to fitting shims to nring it back into spec. The valves with the cleaances so tight that a feeler could not go in will need to be deal with by either guessing, or buying a thin shim from Chacal that is used for that situation so you don't have to guess.

 

When you broke the rack, did you take apart the 3 fuel pipes between the carbs and their o-rings before soaking in carb cleaner......if not...those o-rings are probably like mush....

Replace the fuel o-rings as well when you are replacing the throttle shafts seals.......unless you already replaced those.....

Following "In the Church Of Clean " is critical.

Cleaning carbs is of upmost importance.....taking shortcuts will only lead to frustration down the road......hence pulling them back off and re-doing

I know first hand.....I was guilty myself at one time

Like Chacal says "Do it right the first time, do it once"

 

when the rack came apart it did not get soaked. all fuel line orings are new and have not been soaked. I originally soaked the carb before I knew of this forum. which was late last year. I have new replacement throttle shaft seals and mixture screw orings coming from chacal. I will send him a message about thinner shims. thanks Kmoe.

 

Hogfiddles runs a shim pool.
Send him a PM of what sizes you need. The idea is, he sends you what you need and you send him what you no longer need.

First you need to have a condition where you can get an accurate measurement with the feeler gauge so you understand what sizes you need. Then you write down:
1) the existing shim in that position
2) what the clearance is
3) what shim you need to bring the clearance back to spec.
Having everything written down you can observe the whole shibang and sometimes you can do the shim dosey-doh.

 

Here is what I had:

Clyinder# Intake
Installed Shim Size---Clearance---Shim needed(according to chart in Haynes)
#1 280 0.00 270
#2 285 0.00 275
#3 280 0.00 275
#4 280 0.00 270

Exhaust
#1 265 0.03 250
#2 255 0.06 240
#3 265 0.04 250
#4 265 0.04 250

I used the same procedure that has been detailed with pictures on this forum by Fritz I believe. I used a zip tie to keep the valve in position. I would then rotate the lobe so that it was pointing away from the shim. I would then insert or try to insert the feeler between the shim and the back side of the lobe. bascially 180 degrees away from where the lobe would be pushing into the shim. so the pointy end pointing away from shim. Sound right?

My question is, and Kmoe kind of alluded to it, is with such tight clearances especially on the intake side if I get the Haynes chart manual of suggested shims I wonder if when those go in if I will still be out of spec. I sent a question about it to Chacal

 

Intake : Seems to me you need to go down 3 sizes on each one

Exhaust: 3 sizes smaller on each one of these as well

 

Here's a bug in the ointment... "0.00" is not really a reading. So you need to get some thinner shims to allow for a feeler gauge reading, then work from there.

I thought I recall someone mentioning that there are plastic shims available just for that purpose (not for running - checking clearances only).

 

I agree "0.00" is not a reading, but I would start off with 3 sizes smaller.....as a minimum

 

Did I understand correctly that you inserted a zip tie in the cylinder when you measured the clearance? That would ruin your measurement because that is supposed to find the distance between the shim of a fully closed valve and the cam (position of the lob seems OK by the way). The zip tie would pull the shim away from the cam, increase the clearance and give a false reading.

 

Hopefully, he was using the zip-tie method to keep the valve open, so that he could pop the shim out......

You are correct, hopefully he did not do this when taking measurements......

 

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What did you mean by the zip-tie statement above......it has nothing to do with taking measurements.......only used for taking shim out & assisting in keeping value open to take the shim out.

 

With the lobe pushing down on the shim I stuck a zip tie with a slight bend in it, to catch the valve and prevent it from fully pushing up against the bucket. I only did that when it was time to remove the shim. Not when checking the clearance.

 

Ok thanks guys. I'm gonna try the 3 sizes down and see where that gets me. I will report back on what clearances are then.

 

Also I did type the process incorrectly. I did not have zip tie when checking clearences only when trying to remove the shim. Sorry for the confusion

 

Thanks for clarifying....you did it right....

 

Ok so if we are going to go 3 sizes down: on the intake size I have 3) 280's installed. On my exhaust side, I have 3) 265's. I Could technically just move those over right? But you cannot remove a shim and then rotate the motor without reinstalling a shim correct? Damage to the valve if it does not have a shim when the lobe moves back down correct? I am trying to figure out if that's possible or if I just need to new 265's

 

cut a strip of two liter pop bottle to slide under the cam, and rotate away.
i believe chacal has sets of plastic shims if you need to take them all out at once

 

Interesting. I see how that could work

 

I also am having Chacal send a couple very thin shims to use a baseline for clearance measurements. Man I dont know what I would do without this forum

 

It is great to be your own mechanic.....this forum is making motorcycle mechanics out of everyone.......( for the most part )

 

Ok one more thing. I just got finished reading the thread valve clearances exhaust side. I had not read that before and wished I had. One thing it says in there is that you cannot leave your wire tire hooked on the valve and then go to rotate the engine to do another one as it will bend a valve. I definitely did leave a wire tire in and rotate the motor 2 or 3 times to find a good position to get a shim loose. I did not have multiple valves with wire in, only one at a time but I did rotate a couple of them completely around a few times. Wouldnt you have to do that to get the wire loose? or is that speaking to simultaneously working on more than one shim?

I would get a zip tie hooked on a valve, rotate it till there was enough clearance, Then I would try to get the shim out. If I needed more clearance or didn't think I had the lobe right I would rotate the motor again without removing the zip tie. Once again I only worked on one valve at a time. Did I screw up?

 

I would only call myself "the Reluctant Mechanic"...but this site has been a Godsend to keep my old bike running. Locally there are no mechanics qualified to work on old bikes, and I couldn't afford it if there were.

 

you would have known if you did. if the valve was held open far enough to contact the piston as it came to TDC, you would feel the crank stop as the piston hit the valve. i never did it, but i think it would be obvious

 

Ok tell me there is an easier way to get these damn shims out. I am working too long to get them out. there is next to zero clearance I cannot get enough space between the cam and the bucket to get the shims out. I have the valve blocked open this time with a wire which seemed to get others more clearance. I just worked an hour to try to get a shim out. I can get it started loose but it wont fully unseat out of the bucket. Will the yamaha tool get me more clearance or is there any loosening I can do on the cam strap mounts. I keep getting stuck in this position. I need a break otherwise Im gonna damage something

 

I do have the lobe t=rotated to give me the most space as well.

 

Small forceps or an offset needle nose.
Glad you walked away while being frustrated.
Get a beer or two and then go back to it... it always helps to have a dog laying by your feet (it did for me the first time I did it). Then you have someone to talk to about your situation.

It'll get easier.

 

Went back out and got it loose unable to get it pulled out just kept popping back in. Loosing the bolts that hold the cam down just a little on tge very end for some play is a nono right?

 

you need to get the valve open farther. with zip ties, use the big end or maybe a bigger zip tie. with #14 wire twist 3 or 4 pieces together.
don't loosen the cam
this is why you could spin the engine and not hit a valve, they weren't open far enough. be careful this time

 

Well, I am getting there. I started the throttle shaft seals tonight. They were in terrible shape. I did pick up a telescoping magnet which helped with one of the shims to remove. I tried it again on another shim, and I know that I for sure stuck the magnet to the cam a couple of times. I know that is a no no so I wone=der if there is anything I can do to de magnetize it? I ordered a valve shim tool from chacal today, so hopefully that solves my shim removal dilemma. any idea on a way to de magnetize the cam?

 

Use a length of 12 gauge house wire instead of the zip-ty; the valves simply are not open far enough. Using a magnet to remove the shims is perfectly fine. It takes quite a lot of effort to magnetize steel. Merely touching a magnet to it will not cause an isue.

 

Yep it is working much better. I am still not finished. I have 3 of the 4 intake shims in spec. I also have 2 of the 4 exhaust side shims in spec. need a couple more shims I should be getting there. All my Throttle shaft seals were soft and I am sure the cause of my vacuum leaks. Were getting there!

 

The valve retaining tool makes it a LOT easier, but there's absolutely a "knack" to using it correctly. Make sure the tool is positioned centered on the cam completely - there's a little metal bit at the end that holds the bucket down, and it needs to be right centered or the bucket will slip off the tool.

It's really easy to do once you understand what you're going for. Should look like the attached photo. It's way, WAY easier to do than fiddling around with zip ties, IMHO.

As is noted in the how-to, be REALLY aware of which way you rotate the engine when the tool is in place, as the cams will push the tool through the cylinder head with little physical effort. Leverage, yo.

 

I have the tool coming tomorrow I think thanks to Chacal. I have made significant progress using 2 wires inserted next to each other to hold the valve open. I have all shims in spec except one now. I hope using the magnet to pull shims free hasn't caused me any future problems.

I did get carb reassembled last night. I have had the rack apart before but never removed the butterflies. I felt pretty comfortable putting everything back together but I went back to church after everything was getting ready for bench sync. Long story short I didnt know the difference between vasoline and white lithium grease. I read in the church of clean says never use it...too late so now Im stuck with determining if I want to tear it all back down or run it for a while and get new seals and at the end of the season do a complete teardown on carb again.. recommendations? I know r"go back to Church!"

 

that's what kept me from even thinking about that thing

 

I was nervous at first - hell I'd never opened the engine up before - but really, the cams rotate in the same direction you rotate your wrench, so it's pretty foolproof so long as you make a point of look-think-turn-watch cams when moving the engine. I feel a lot more comfortable with it than I do with zip ties, but to each their own. Whatever one is most comfortable with =)

 

they always make better fools, and i'm signed up for automatic updates

 

Ok, all valve clearances are in spec. It does make sense to use a micrometer to measure the thickness of the shims. I had multiple shims that were off. They are all on the high side of allowable clearances. That was some work. However, I have everything recorded and next time will be a snap now that I have the proper tools. I set my Cam end plugs last night with RTV and cleaned off my gasket surfaces. Now I am ready to do the valve cover gasket. Am I correct, I put a thin coat of RTV on the valve cover surface then set the gasket on the RTV? No RTV on the motor itself. Do I use a little vaseline on the motor or no?

That's one thing done now, I need to get the carb un-racked, nd my new orings cleaned of the lithium grease and then reseated with vaseline. One thing came up when I replaced the fuel air mixture screw orings. There was no washer between the spring and the oring. Only the needle, spring and oring were in all 4 fuel/air screw slots. I know that in the church of clean it says there is a washer. The bike has been running for I suppose a long time without them. any thoughts?