'80 XS400 whiteout

I have access to a blaster at work. Unfortunately we only paint not powder. Am just wondering if it's worth investing in the powder equipment. I want to do my carbs like yours but with black instead of the red. They look so nice and would look good on my build.
 
Well I'm just using a cheap Chicago electric gun and for most stuff a toaster oven. Picked up a full size oven for 20$ on kijiji for bigger things. Powder is from emerald coatings/powder365.ca which is here in ontario and ranges mostly from 12-25$ a pound for most powders.

Have a look at the prices. Depends on how much you think you'll powdercoat. 1 pound of powder goes a long long way.

If you want them done without buying the equipment Im sure there is someone local to you who will do them. Or I'm in Ontario, could ship them and I could do them. Have plenty of black (gloss flat and satin) and white.

Just remember the rack needs to be taken apart so you'll need to re-sync afterwards.
 
Well I got the steel but my oxy regulator is leaking at the tank so I haven't been able to bend the new downtube or sidetubes yet.

I'm removing the triple backbone in favor of a single .120 1-1/4" DOM backbone and I'll be re-bending some sidetubes out of 1" .120 DOM to tie into the new backbone. The rear section will also be extended to tie back into the backbone as well. This is to fit the new tank.

I tested the compression and only have 30 psi in both cylinders dry, wet test did bring one cylinder up somewhat on the first test but was somewhat erratic after that. The kicker doesn't spring back so it was hard to really test it. I'm going to make a leakdown tester, hoping it's just the valves but I'll be tearing it down anyway to have a look at the rings. The oil that shot out during the wet test was very dirty so I imagine the walls don't look good.
 
Started disassembly.

Lots of dirt in the cylinders and valve seats it looks like. Exhaust port is full of scaly rust and dirt. Haven't taken the valves out of the head yet to see the seats. The walls of the right cylinder look okay. Haven't saw the left side yet.

The exhaust valves have what look to be scaled rust on the faces of them. It's quite hard, wouldn't brush off or scrape off really. I'm hoping the low compression was from some really gummed up valve seats or stuck rings.

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Yes, it's all smooth on both cylinders with no cross hatching left. Some marks up and down the cylinders but no scores or scratches. The rings are completely stuck in the pistons and so are the wrist pins. I'm going to try and pull them out with a homemade pin puller and then soak the whole piston in atf and acetone. There is not much of a lip at the top of the cylinders, mostly just seems like some carbon built up.

If I can get the rings out in one piece and the end gaps measure in spec can I just re-hone it and re-use the rings or will I need new ones? If the rings are out of spec does that mean I need to bore and get oversize pistons and rings or can I still get away with a re-hone? Just checking out my options.
 
If you can get the rings out and the ring gaps in the pistons (and bores) are good, a hone and new rings should be all you need for them. If not then it's new oversize pistons and rings:doh: I would replace the pins and clips regardless as they are still around for cheap.
 
Well, I'm making little to no progress with the top two compression rings on both pistons. I got the oil rings out with a little flux and some light heating from the inside with a propane torch.

For the compression rings i've tried breaking off even a piece of the ring with a punch and chisel, acid flux, soaking in atf paint thinner mix for days, boiling in water and also boiling in ATF, all of which has yielded only a slightly burnt finger and possibly destroyed pistons. I'm going to try a jig to hold a dremel with cut off wheel and the piston to see if I can get a piece out and see if the pistons are even salvageable at this point. If not, some new ones are $50-ish on ebay that look to have the rings all loose so I may have to just go that route.
 
As long as my heating attempts haven't destroyed them and I can get the rings out I don't see why they wouldn't work with some new rings? Unless I am missing something?

My only thing with buying new ones is I don't want to buy some just to find out that I'd need oversize pistons and a bore. I'd like to be able to get these rings out and measure to see if they're in spec or not.
 
I would measure your bores first. If they need an aggressive hone to clean them up you may need an overbore to get a good seal. I have seen this with a few guys that thought a hone and new rings where all they needed and the bikes smoked like crazy. That was with rings that where not seized in the pistons to start. With the potential cost of fixing yours, a donor motor that runs good maybe an option.
 
I've been using the manual for specs but wasn't sure how much honing would remove, was just hoping you would know off hand. A quick search showed that deglazing removes very little. So after looking at the xs360 part of the manual for a while and scratching my head at the 66 mm specs compared to my spot on 69 mm bores I figured it out. Oops. Make sure you're looking at the right section.

Anyway, machine shop measured dead on 69 mm. So I just need a set of pistons, new standard rings, deglaze the bores and lap the valves.

Next is to fix the kickstart return, think the PO installed it wrong.
 
I have installed it wrong, only thing worse is breaking the aluminum journal, where the shaft lines up into. Good luck
 
Yep, I've read the horror stories so avoided trying it without the side cover on. I got it installed correctly fairly easy. Just have to take a look inside to see how they all go together. I did notice however that the journal didn't look that great, scratches and scores. Oh well, it's rarely used and in 1 piece so I can't complain.

Although I can see how easy they break, there is a lot of flex to it even if you just push the shaft without the sidecover on.

I'm now looking for spoke and brake replacements.

I'm confused by MikesXS spoke listings when it comes to the 400's so any help is appreciated. Will any of them work for the xs400 front and rear 18" spoked rims?
 
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EBC, are what are out there, here a example from Amazon, I am sure Ebay, and other online sources are available.
http://www.amazon.com/BRAKE-SHOES-Y...8&qid=1426205234&sr=8-5&keywords=xs400+brakes

What I noticed from Mikes XS site, is that there is a mention of 18 or 19 inch selection. My bike has Mag's, so never thought about it. Some of the mentions seem to be universal,
https://www.mikesxs.net/product/19-0050.html
Spoke Set - Rear 36pc.+ Nipples - Bright Cadium Plated Finish
Fits: XS650 TX650's (1970-84) with 18" Drum Brake Rear

Can be used for XS400 18" front with our 18" 36 spoke rims. The spokes are about 2-3mm shorter than the stock XS400 front spokes, but work.

OEM Reference #
• 256-25304-01-00
Double check a website with OEM #'s, (any yamaha parts site, like partzilla, boats.net, ...) verify if that number is close to yours. Then do a couple more googles afterwards to make sure.
 
I was mostly having trouble because I didn't know what the rear rim came off of but I believe it's a 78 or 79 xs400 rim so thats easy.

Yea I saw that on Mikes site, that is what confuses me because it says:

"Can be used for XS400 18" front with our 18" 36 spoke rims."

It says it can be used with their rims. Is their rim different than the factory ones? I can get a set off ebay that is for the xs400 but Mikes is cheaper if they will work. I'll have to send them an email.

And the other spoke listing is for a 19" rim but in the comments it mentions the 18" xs400 rear.
 

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