Lost power

Went for a drive today, in town was fine went and picked up my buddy drove over to the highway, once I got on the highway it felt like I lose all my power, I had the throttle wide open and 60km was all I got then my buddy said a big poof of black smoke came out of my muffler, so we pulled over it was ideling fine nothing was smoking nothing leaking , so I said let's go for a bit and see what happens and when I pulled the throttle it accelerated really awesome like a brand new bike and had lots of power and it was fine the rest of the trip, I recently switched to premium gas if that helps,

 

All my spark plugs looks like this, my adjustment screws are all 3 turns out, is this a sign of to much fuel? It only made that one poof of black smoke then it was over

 

1) that plug looks normal to me.

2) you should keep all your questions about your bike in ONE thread. It's easier for the smart people around here to see the entire history of the bike

 

Ahh that makes sense I thought new question new thread,

 

My front brakes won't open got a few mins down the highway and smelt burning my rotors were so hot coulda fry a egg on em, gonna take the pistons out and clean and replace the o rings, my question is are these o rings specific to these calipers or can I find these rings at a auto parts store

 

They aren't o-rings. The seals have a rectangular profile, and are specific to the caliper. You will not find replacements at a hardware store. You should also rebuild the master cylinder, and check the date codes on the brake lines. If they are rubber and more than 4 years old they should be replaced as well.

 

O ok, I did replace the diagram in the cylinder and clean it out, I looked at my brake line but can't make out any of the numbers there all faded off so I'm guessing there more then 4 years old

 

Just curious, my brakes weren't leaking at all and I didn't wreck the o rings when I took them out, if I just clean all the crude out of the hole and off the pistons can I just reuse the o rings? Or are the o rings what made them not open properly to begin with

 

Which one of the small holes at the bottom is the one that release the pressure from the calipers?

 

Both need to be clear, and the piston seal should be replaced, and the piston bore should be cleaned and lightly polished.
HOW TO: Rebuild Your Master Cylinder

 

The brake piston seals haren over time, and will eventually cause the pistons to bind. They are inexpensive. Reusing them is a false economy that could lead to taking a trip in a fancy van.

 

Ok thanx

 

New rings are on the way, cutting it close my road test is on the 29th and they said my parts will be by the 20-22 hahah in the mean time I'll clean out other stuff and hope like hell thats it

 

So bikes been running awesome but 1 thing I noticed and I've read though some threads but didn't find my answer is hard hot start, cold start super easy but after I ride of the bike sits for say 10-15 mins I gotta do 1/4 throttle and crank till it catches, I've tried starting it with the gas tank open to see if vent was blocked and same thing I also tried turning to prime and same thing, I've also read that this is a normal operation , dos anyone else's bike do this normally?

 

valve shims in spec?

 

Yup I did those about 2 months ago

 

my seca doesn't do that but i've had other bikes that did.
there's dirt bikes that have a "hot start" lever that's like the opposite of a choke

 

Interesting ok thanx, maybe that's just how it is

 

I have the same issue and just like you the throttle has to be opened slightly - I don't know the exact time but it seems like it will start very easily up to about the 15 min mark when hot. I did read an earlier post where member CDS1984 solved his issue by lowering the wet set level by about 2mm below spec, and theorized the heating of the carbs was causing a slightly flooded condition. The XJ550's actually have a sheet metal plate to shield the carbs from the crankcase, perhaps it is for that very reason but everyone seems to suggest you can just throw those away?

 

So I'm trying to bleed my front brakes I used a vacuum pump on each caliper about 37 times lever still isn't firm so I'm gonna do the old manual bleed through the calipers, the process I was told by a couple people was squeeze the brake then loosen and tighten the bleed screw, but on a bunch of forum on here I read crack the bleed screw first then squeeze the brake tighten bleed screw release brake, so to end this fustration should I do it there way or the xj way

 

With the system closed or in normal operation mode, can you get pressure? Made sure the little holes in the bottom of the MC are clear and clean of gummed up stuff or old caked on bake fluid. My old go to method is vacuum on bottom nipple with a wrench on the nipple. Pump MC handle and hold it to the bar. Release the pressure with the wrench and the bleed nipple and see if there is fluid coming out going to the vacuum tube. There should be some movement. This will not happen very well if the MC is not clean to work as designed.

 

Please clarify which model of XJ you have. There are variations that require some special care for bleeding the brakes thoroughly.

 

Yamaha actually stopped fitting those shields during the production run.

 

Bleeding the XJ750 Seca Front Brakes this may help you

 

I've got a 82 maxim 750, when the system is closed it will gain a little bit of pressure but not much, and I did make sure the holes were clear at the bottom of the mc, I used a guitar string to clear the tiny one

 

the seca info will work for you.
edited for maxim

3. Break loose 2 bleed fittings (be sure to put down cat litter or drip pans).

4. Tie the brake lever to the grip.

5. Fill the master cylinder

6. Wait overnight (or at least a few hours)

7. You should now see brake fluid coming out. Close the bleeders, and untie the brake lever.

8. Bleed the brakes as normal, keep filling MC

9. You aren't done yet. There will still be some air in the system. The next step cures that, no matter what method you use to fill and bleed the system.

10. Use a vibratory sander (no sanding pad) and slowly run it along the brake lines, calipers, and distribution block from bottom to top. This will move any remaining air bubbles up into the master cylinder. Tap (or vibrate) the master cylinder to get the air bubbles to come out of the return hole. This process can also be done with a box-end wrench or other similar tool, and tapping the calipers and lines (it just takes longer).

11. Do one final bleed normally, just to be certain that the calipers are fully bled.

 

my maxim was a little spongy/soft on the test ride. when I kept the lever pulled at the light but slightly released the rest of the air i missed came out. 2 sets of lights and it was perfect. I guess the motor vibration and pulled lever took out the rest of the air.

 

Thanx I'll try that tonight, that sanders a good idea

 

So when all bleed, where should the brake fluid level be at? Between the lower line and top of glass? Want to avoid this hydro lock you speak of

 

There are two lines cast into the master cylinder. A fill is to the top line. Between the lines is fine, but generally you want it at the top so you can easily notice pad wear, or if there is a leak.
If your master cylnder does not have an upper line, just leave a bubble showing at the top of the glass.

 

Ok thanx, I opened my brake and bleeders like in the directions and my mc drained in about 5 mins so I closed the bleeder and I'm sanding my lines now and pumping the brake so hopefully I'm close

 

Well I think I got it, go for a test run tomorrow after work, they still feel loose but this is my first bike so I don't really have anything to compare it to and I'm pretty sure they weren't working properly before cause I just unclogged that tiny hole, before I drained it the brake lever was super tight but my calipers were also sticking and not opening fully, maybe this is how there suppose to feel and I've been screwing with it for nothing, when the lever is pulled as far as I can get it it's about 1/4" away from the handle bar there is some pressure there but pulls back fairly easy

 

Test run went pretty well, bikes running good now just in time for winter, now it's time to get started on my goldwing

 

So I'd like to get rid of the original gauge cluster, 82 maxim 750, I'm looking at this it says it takes a 12mm cable, so is this a fairly simple process, when I take my old gauges off if I just open them up and see what wires go where and match them up to new unit is that it? Also to find a new tach I know mine is electronic right now, what should I look for in a new one, is there a certain gear ratio or number or anything

 

here is a thread on removing the atari cluster

Here's the wiring mods to remove the rectangular instruments

you cut 5 wires ,splice the headlight wires to 3 of them and jump 2 others together from what I see

has photo and wiring diagram

 

Cool thanx

 

the tach will have settings for cylinder count

 

O ok so if I get a tach that's a 4 cylinder one and electrical I should be fine then eh? Just connect the wires

 

yes it will have a way to set it for 4 cylinder yamahas, it may be that it is set to 2 cylinder . our bikes have a wasted spark ignition so it fires 2 times in the 4 strokes.
some work by wraping around spark plug wire some hook to coil

 

Ok thanx

 

Depending on what you get for a speedo, you might not need a cable for the front. I put an aftermarket on my BMWR1100GS Brat build, works fine. Just had to mount a magnet and then measure the rotation of the wheel. Love that gauge...

The RPM is easy but take your time matching up the rest of the lights. It will work great, just have fun doing it.

 

So I’m doing some bike Reno’s this winter, my speedo cable is disconnected right now and I noticed when I spin the front wheel forwards the cable doesn’t spin but when I spin the wheel backwards the cable starts spinning, I didn’t notice it last summer cause I just used my gps for speed but my new speedometer requires the use of the cable so I gotta fix it now

 

Hate to be naggy but any thoughts?

 

Once you remove the speedo from the front wheel, you can pull the cable out of the sheathing. This will allow you to look it over, clean it and then lube it up. Inspect it to make sure the wheel end is in good shape and non of inner cable is rusted or has issues.

If this is all good and you are still having issues, you will have to pull the front tire off. The speedo gear fits into the front wheel only one way. It has slots on either side of the axle hole that the speedo need to contact with to make the inner cable spend. If for some reason one of those slots is damaged, this could be the reason why the speedo is not working one direct when the tire is moving.

The simple fix could be that the inner cable is not making contact with the great in the wheel portion, so it is not spinning as it should. When you put it back into the back of the speedo gauge this would take care of that, pushing the inner cable into place.

Some of the wheel drives have a screw or bolt that holds the cable in place, make sure that is in place and installed as it should be. The screw/bold slides by the shoulder of speedo cable on most systems.

 

Awesome thanks dude, it’s a brand new cable and I’m pretty darn sure The piece that drives it on the wheel was installed on the wheel correct, but I’ll give all that stuff a good check, I’ll try and plug it into my new speedo and see if it helps,

 

750J parts

CLUTCH, METER 3.40 to 5.49 to maybe tabs are bent
341-25149-00-00



RETAINER, CLUTCH 2.90 to 4.35$
341-25846-00-00


OIL SEAL 5.81$
93105-45017-00

GEAR UNIT ASSEMBLY Not Available
4H7-25190-00-00

get a used one click part number to see what bikes you can use mostly 650 and 750 fit

gear unit is sealed so you would have to use a needle to grease it

 

Ok I’ll try and squirt some grease in there, the ears on the wheel were bend found that out last year when I changed my tire, I did bend them back and when I put the drive gear on I spun it by hand and I could see the little turny thing that moves the speedo cable turn so I assumed it was all good, but never really tested it cause my old speedo didn’t work when I got the bike

 

I’m pretty excited for this year, I think I got the bulk of the issues dealt with last year, just been doing cosmetic stuff over the winter, I’m doing rear brake shoes, I got new rear spring shocks, new speedometer to replace old Atari, new round headlight, and I’m getting a sissy bar welded up out of chain, it looks so bad ass haha , and new mirror and hand grips, wanna have it all done ready to roll by April kinda wish I took a before pic but I’ll post an after pic when I’m all done

 

So I’m mounting my new speedometer on the bike and have discovered that my cable is like 6” to short now, is there an extension I can buy? Certain size of cable wire I should look for

 

xjforever sells some extentions

6 8 and 10 inch he also lists cable lengths incase there is on that will fit

HCP17702 Aftermarket drive cable EXTENDER CABLE, extends the length of your stock speedometer or tachometer drive cable (at the gauge end) by 6", just the thing when using modified handlebars or re-located gauges! Saves you the expense of having to buy a completely new drive cable. Correct end fittings allows you to screw this cable "in-between" the end of your current cable and the gauge head fitting.

HCP17703 Aftermarket drive cable EXTENDER CABLE, extends the length of your stock speedometer or tachometer drive cable (at the gauge end) by 8", just the thing when using modified handlebars or re-located gauges! Saves you the expense of having to buy a completely new drive cable. Correct end fittings allows you to screw this cable "in-between" the end of your current cable and the gauge head fitting.

HCP17704 Aftermarket drive cable EXTENDER CABLE, extends the length of your stock speedometer or tachometer drive cable (at the gauge end) by 10", just the thing when using modified handlebars or re-located gauges! Saves you the expense of having to buy a completely new drive cable. Correct end fittings allows you to screw this cable "in-between" the end of your current cable and the gauge head fitting.