The XT550 Thread: Info, Stories and Mods Inside!

[netjustin]

Originally Posted by G600

Screwed the plug back in, didn’t really expect the bike to start…. But it did…. And idled just fine.

Like hobie says, you da man!!! Nice work.

Originally Posted by G600

Just need a waterproof box to house it in…
[...]
Now for the big question… to buy a decent CDI or build my own programmable one …. Hmmmm…

Do it! There are so many coolness points available in a build like that.

As far as the box, just wrap your in/out wires in some shrink wrap and make an epoxy time capsule out of the rest. Spray paint desired color, slap a Yamaha Racing inkjet label on and call it good. :)

[Bart]

Originally Posted by netjustin

Call me crazy, but I think valve float should never be an issue if your springs are properly spec'd and still doing their job. Then again you probably know more about this motor than I do. Wouldn't take much. :)

The problem is not so much with set-up, at Really high speeds the valve springs cannot open and close the valves fast enough for the next cycle to come around. I had an early 90's CBR600 with an HRC Race Kit. The HRC Race Kit included stiffer springs for just this reason. It increased the rev limit.

[Zecatfish]

Originally Posted by G600

........
I’m sure the engine will run kind of silly with this DIY CDI, with the timing advance of 12 deg jumping to 36 deg in one step. But I will keep the CDI as a spare part, since it works. Just need a waterproof box to house it in…

Now for the big question… to buy a decent CDI or build my own programmable one …. Hmmmm…

The jump to 36 degrees timing at a the correct rpm should produce a nice hit. . I would suggest adjusting it to the lowest rpm possible without its pinging. To much timing to quick makes detonation, on a side note one rpm will be great on cool days and then higher on hit days.

I've had the stock engine detonate on single track on hot summer days just off idle.

If you decide to toss another together let me know I'd be interested in buying it. My bike is a total mix match anyway. I really like the added power of the TT600 mill verses the XT550 mill.

[G600]

Faulty rectifier/regulator – will the stator be destroyed if disconnected?

My ’83 XT550’s rectifier/regulator is faulty. I don’t know in what way, but there is no voltage over the battery.

If the rectifier/regulator failure results in too low resistance the stator probably will burn (too much current).

If I disconnect the rectifier/regulator the voltage will go up, but how high? Is it possible that the voltage will go high enough to destroy the isolation?

Zecatfish, thanks for the info. I have enjoed reading about your work on your XT, good stuff. I have not yet tested the DIY CDI since I don’t know excaclty how the stator will react if I disconnect the rectifier unit, and since I don’t know how much current the stator is pumping out now, I don’t what to run the engine for more than couple of minutes at the time….

[Zecatfish]

Originally Posted by G600

Faulty rectifier/regulator – will the stator be destroyed if disconnected?

My ’83 XT550’s rectifier/regulator is faulty. I don’t know in what way, but there is no voltage over the battery.

If the rectifier/regulator failure results in too low resistance the stator probably will burn (too much current).

If I disconnect the rectifier/regulator the voltage will go up, but how high? Is it possible that the voltage will go high enough to destroy the isolation?

Zecatfish, thanks for the info. I have enjoed reading about your work on your XT, good stuff. I have not yet tested the DIY CDI since I don’t know excaclty how the stator will react if I disconnect the rectifier unit, and since I don’t know how much current the stator is pumping out now, I don’t what to run the engine for more than couple of minutes at the time….

If you just unhook the reg/rectifier and leave the wires open it should not hurt anything and run it off the battery.

The XT is a three phase stator. You need to keep that in mind if you go aftermarket on the reg/rectifier. I wish I could help there.
PM Big Ed XT Fan he might have one.

[BIG ED XT FAN]

Originally Posted by Zecatfish

PM Big Ed XT Fan he might have one.

Yes, i have one!! Thump-on!!

[Bart]

Originally Posted by Zecatfish

If you just unhook the reg/rectifier and leave the wires open it should not hurt anything and run it off the battery.

The XT is a three phase stator. You need to keep that in mind if you go aftermarket on the reg/rectifier. I wish I could help there.
PM Big Ed XT Fan he might have one.

Just don't rev up the engine. At Idle or slightly above it should be OK but if you rev up the engine it will increase the output and then you will likely burn something out like a head light bulb or maybe something more expensive.

[XTwarrior]

Awesome work G600 I like doing things myself but I don't think I'd attempt to build a CDI, good stuff!


Well, got back from vacation 2 days ago, and ran into 2 problems; The fiance's car has a bad rear main seal failure and then she got laid off the next day Unless they bring her back relatively shortly (if at all) I won't be able to spend too much on the XT.

Last night I did get to torch the frame though. The old man has the torch so he made it nice and red and then I bent it into place. Bent the left peg and right peg to be more in line. One negative to bending the left peg back is that the kick stand was also bent in the crash so it leans very far over. I'll have to work on that.

[G600]

Originally Posted by XTwarrior

...Last night I did get to torch the frame though. The old man has the torch so he made it nice and red and then I bent it into place....

XTwarrior, sorry to hear about your fiancé. Hope things work out OK.

“nice and red”… huh.. You guys are not messing about straightening the frame. That bike sure had taken some beating. Wow…

The regulator/rectifier in my bike seems to be OK after all. After some more measuring I decided to try again with the battery from my EXC400. Bingo, the battery voltage was 14.5 volts when the bike was running. I only tried for a short time, but for now I think it is ok.

So… the point is… a good battery seems to be vital in the XT550, for the charging system to work correctly. If the battery is shot, you will measure some silly numbers over the battery, both DC and AC (at least in my bike). It has a one phase stator (unlike the XT600) so the regulated voltage is more ”uneven”. Maybe that matters…

[XTwarrior]

Ya, I hope it works out too. We were shopping for a new car for her Monday, then she got laid off Tuesday. nice big kick in the nuts for us :(

The previous owner wrecked it in a head on collision so the frame was bent when we got it. Finally got it hammered out so my pegs aren't aligned in opposite directions

Also figured out why my case cover is leaking....it has NO gasket on, just copper sealant I'll just ignore the part where I'm the fool who put the copper sealant on when I lost the gasket and didn't want to order a new one.....

To prep a gasket surface, i want to razorblade and then finish up with alcohol? What type of alcohol?

[XTwarrior]

Got around to doing some more little things on the bike. Put the new gasket on the case cover in hopes that it stops leaking oil. I'm not sure if I did it right but I used a razor to clean off the gunk, then sanded using 400 grit to clean the surface, and finally hit the surface up with some MAF cleaner (leaves no residue supposedly) to take the grease off. Then slabbed some Yamabond 5 on the case and cover metal, and slipped the gasket on. Finally, I finger tightened the case down for drying overnight. The yamabond 5 was liquid instead of thicker/gel like that I've used before. It seemed a bit thin but that's what the dealership suggested and it was very sticky.

Cleaned up a bit:




Also, got pictures of the before/after for the XT footpegs. (Don't know how to rotate but the left peg was caused by frame damage, the right peg itself is bent and I'll have to replace or maybe torch later.)






And about 5 minutes ago I found some new friends!

[XTwarrior]

One busy mouse!

[goodcat8]

just in case you XT fans are looking......

1982 xt550 in LA for sale.

http://www.advrider.com/forums/showt...8#post12451938



Is it really if it's cool?

[Bart]

Originally Posted by XTwarrior

Ya, I hope it works out too. We were shopping for a new car for her Monday, then she got laid off Tuesday. nice big kick in the nuts for us :(

The previous owner wrecked it in a head on collision so the frame was bent when we got it. Finally got it hammered out so my pegs aren't aligned in opposite directions

Also figured out why my case cover is leaking....it has NO gasket on, just copper sealant I'll just ignore the part where I'm the fool who put the copper sealant on when I lost the gasket and didn't want to order a new one.....

To prep a gasket surface, i want to razorblade and then finish up with alcohol? What type of alcohol?

I like to use plastic scotchbrite pads in isoprpyl or methyl hydrate to prep the surface. One slip with the blade and you could score the surface and create a leak. A piece of acrylic sharpened on one end works good as a scraper without the risk of damaging the aluminum mating surfaces. That is what we use in the aviation industry where one slip can ruin a whole wing!

[XTwarrior]

That is one sharp looking XT goodcat! Makes mine look like a junk pile on wheels

Bart, I used a wood wedge to scrape the surface clean, then took 600 grit to it to clean it off and finished up with some MAF air sensor cleaner to remove all oil/dirt. Just took her for a 45 minute ride and beat on it as hard as I comfortably could and she didn't yield. Also, no engine leaks!






Also, this is a handy measuring cup I got from Bed Bath and Beyond (what? they are the only place that I could find something like this!). It measures in ounces, and has a hole with a trigger plug in it that makes it easy to measure out fluids. Works great too!