Other need to rebuild a yamaha xl 800 motor,looking for any tips

[WaveDemon]

those carbs are very similar to the sbn and use most of the same parts. the accelerator pump works like on any other motor with one. it'll pump gas withough vaccuume. they're no big deal so don't get too worked up over them. I removed those pumps on my SJ conversion to keep it simple though.

 

[feartheride]

Oh yea ,I'm still going to need a head..

Tom do you have one for sale

What would I have to do to fix mine, I could get away with just recutting the squish surface on both sides and the deck it the same amount.That would keep the squish the same but the compression would be higher,not really a bad thing as long as it is not to high..
just don't know if i can deck the head that much.. The imperfections in head look to be about .060-.080" although some could be high spots...

 

[tom21]

Thanks tom
wasn't aware they resleeve the cyl. ,I do like the nickasil bore..

shipping round trip is 180.00
what's this place like
http://www.pwcengine.com/products/Ya...lt-Engine.html
they say 1000.00 with 2 yr warrant as compared to sbt at 1200.00

I can get hot rods crank for 440.00
cylinder 250.00
wsm top end w/gaskets 160.00 or pro x for 140.00 + gaskets for 70.00
wsm seals ars genuine 20.00 or oem 40.00 (wsm only list ars for inner and outer pto and teflon for mag)

total 870.00

that being said it,s not all about the money,my time is valuable...but if I do it myself at least i get a hot rods crank,better or not ,i don't know
if they were down the street from me I would jump on it...I do live right my buffalo so i ship to the U.S. and pick up from there

Yea I will look at crank when it comes out, so much debris sitting on the top of the case is not good

Hmm what to do

my feeling is they are selling sbt motors. their warranty is almost a cut and paste, could be just a standard warranty and they both use the same one. but honestly I know sbt aggresively bought or put the competition out of business. like pmc. not saying nobody could compete but I have a hard time seeing anyone can compete with them.

I just cant see how they are pricing that low compared to sbt. maybe they are legit? do a search and see what you find.

If you can build it right and know you have covered the issues thats cool. but if you are not so sure what you doing, having that warranty(whoever you go with) can save your bacon!!!

ditch the oil injection and stay away from honda skis.

all 800 are the same

the plastic caps are to clip the bolt onto the allen tool so you can take them off and on without dropping them.

the accel pump is just a diaphragm and spring. sometimes it can get clogged up( there is a little check ball in it- you wont be able to get at this- unless you drill out the plug. best to just not mess with it) at any rate if you work the thottle and fuel squirts into the carbs you are good to go. set it off to the side, or take the four small screws out and clean it up and lube the shaft where it goes thru the pump body. its not complicated.

if you dont find anything wrong- I would go with the oil pump as the problem.

when you open the carbs post some pics maybe we can spot the problem

 

[WFO Speedracer]

One word of advice if you do build it secure the oil lines with the steel clamp kit or premix it, other than that leave it bone stock.

I just got through with one someone put a primer kit on and removed the choke shafts, it would hang at 5000 rpm every time you accelerated, I lowered the popoff, increased the accell pump shot, turned the low speed screws out all to no avail.

These are lean in the midrange already, without the accell pump it would never transition through to the main jet. I had to think on this one a while, what I came up with was really quite simple, on the flame arrestor screen, instead of running one screen , I ran two and oriented them where they overlapped slightly, this put the needed amount of restriction back in the airbox and it pulled to 7000 RPM every time without a hitch.

 

[feartheride]

One word of advice if you do build it secure the oil lines with the steel clamp kit or premix it, other than that leave it bone stock.

I just got through with one someone put a primer kit on and removed the choke shafts, it would hang at 5000 rpm every time you accelerated, I lowered the popoff, increased the accell pump shot, turned the low speed screws out all to no avail.

These are lean in the midrange already, without the accell pump it would never transition through to the main jet. I had to think on this one a while, what I came up with was really quite simple, on the flame arrestor screen, instead of running one screen , I ran two and oriented them where they overlapped slightly, this put the needed amount of restriction back in the airbox and it pulled to 7000 RPM every time without a hitch.

does someone actually sell a kit for it or just buy clamps to fit

 

[feartheride]

And the plot thickens..

split the cases and found a lot of debris in the bottom end ,not sure from what ,thrust washers are ok..center bearing may have lost a bearing cage...I will have to cut bearing off or press apart to find out for sure yet..

The lower case has a hole right through 1/8 x 1" and the upper appears to be cracked..hard to see though, it looks like a hair line, is there a way to tell for sure,can I buy something to test for cracks..

the first pic shows the slotted hole to the left of the bearing surface
Can I epoxy it with jb weld ..On the back side there is a whole pocket between webs that I could fill up...
I would be afraid to tig that it would cause to much heat...

 

[WFO Speedracer]

does someone actually sell a kit for it or just buy clamps to fit

1/4 OD. Mcmaster
52545SS38Gap-Free Pinch Hose and Tube Clamp 15/64" to 9/32" Clamp ID Range, 13/64" Band Width. :sneaky:

 

[WFO Speedracer]

Fubar Call SBT order a motor, install, sell in that order

 

[feartheride]

1/4 OD. Mcmaster
52545SS38Gap-Free Pinch Hose and Tube Clamp 15/64" to 9/32" Clamp ID Range, 13/64" Band Width. :sneaky:

Searched mcmaster carr for this # and nothing comes up...
found these but not in that size
http://www.mcmaster.com/#hose-and-tube-clamps/=dlz1ak

Is this what you mean
http://www.mcmaster.com/#hose-and-tube-clamps/=dlz2ru
52545K38

 

[feartheride]

And the plot thickens..

split the cases and found a lot of debris in the bottom end ,not sure from what ,thrust washers are ok..center bearing may have lost a bearing cage...

The lower case has a hole right through and the upper appears to be cracked..
the first pic shows the slotted hole to the left of the bearing surface
Can I epoxy it with jb weld ..On the back side there is a whole pocket between webs that I could fill up...
I would be afraid to tig that it would cause to much heat...

So do we think I can epoxy these cases

 

[feartheride]

Here are some better pics of the cases,you can see the hole in the top case in pic 5 and the view from the back in pic 6

the bottom case is deffinately cracked in at least two place as seen by the tip of the screwdriver pics 1-5

 

[feartheride]

so guess I am going to epoxy them with jb cold weld

 

[D-Roc]

i have had welded cases before. you surely have someone there to weld them? JB weld may work, i mean we epoxie the intake cases on our 62t and they hold in there. welding cast is very tricky and may need to be done with some cool downs inbetween welds. if you overheat it, it will crack when it cools.

 

[feartheride]

Well after fixing the cases and assembling the bottom end while waiting for the cyl to come back from Millenium technoligiesm i found time yesterday to assemble top end..
This is where the next issue comes into play Millenium screwded up the cyl. where the power valve goes in. they tell me it is common practice to take a handy grinder to the bore where the brass bushing that the power valve slides in goes,due to possible nickasil residue in there..The problem is the bushing is now so sloppy that no matter what I do,when I lock it in place with the bolt, the valve jams and won't slide due to the bushing locking down cock eyed..so I wiped bluing dye on the valve to see where it was binding and filed the side twice and still binding on the same side..
So I have a few choices send it back for another one ( don't want to wait for that ) or try to fix it by either trying to spot face the bottom of the bore,hoping it will help it sit flatter or keep filing the valve..
? is how much can I file off the side of the valve ...valves have lots of play anyway but how much will I have to remove for it to work , I won't know till I do it..

Any thoughts on this

 

[feartheride]

Well I filed the side of the valve down some more and have it moving freely although it's not tightened to full torque, I'm hoping the loctite will hold it..
no wonder I don't like contracting work out ,it's always a nightmare !!!


And whats with ring end gap..The book calls for .008-.016..

the new rings are .025

 

[costellokg]

Well I filed the side of the valve down some more and have it moving freely although it's not tightened to full torque, I'm hoping the loctite will hold it..
no wonder I don't like contracting work out ,it's always a nightmare !!!


And whats with ring end gap..The book calls for .008-.016..

the new rings are .025

I realize this most recent post is several years old, but I'm curious what happened with this engine. I have two XL800s that have both blown out pistons and crankshafts.

 

[feartheride]

Seems to be running fine..

 

[JetManiac]

I realize this most recent post is several years old, but I'm curious what happened with this engine. I have two XL800s that have both blown out pistons and crankshafts.

Have the rebuilt cranks and pistons for your motors.

 

[Waterdawg Kustomz]

Paul,
Give me a call at 541-231-6069. I have everything you need and can answer any questions you have.

Jeff