Shocker!! Another Newbie with a laundry list of questions!!

[Yamaha Newbie]

Hey all and thank you so much in advance for whatever help you can give. So I just bought a 81 XS400 Special so the GF can learn to ride this summer. Over the winter I want to take it down to frame and make a Cafe. I know, I know, not exactly original, but it's something I've wanted to do for a few years now, so gotta try.

But I have to say I am amazed at how much information I have learned on this site before I even bought the bike. Must have spent 2 days straight reading every post I could find on here about Carb cleaning/rebuilds, cafe and bobber projects. I wouldn't have bought the bike if this site didn't exist. You guys are amazing.

Now to the relevant s***. I got the bike yesterday and trailered it home. It runs...sorta. Dies off choke, has a hard time with fast acceleration and has sooty black plugs. So I know at least a carb cleaning is in my future. But before I did that I wanted to make sure the timing was set right and adjust the valves. Timing seems to be good, and I took off the covers to get a look at the angle I would have to bend the feeler guages to get in there. Long story short I cracked on of the viewer plug screws. Doesn't matter how it happened or whose fault it was (I F'd up, the fault is mine) No pieces went into the below the cover, i have all the pieces. Question is do the plug caps off a XS650 fit the 400? I found a 400 cap online from Boats.net (go figure) for $21.00 after shipping. MikesXS has em for like 14.

Second question, I noticed i have a small exhaust leak, puffs but no smoke coming from around the exhaust manifolds on both cylinders. Figured the seals were bad. (Actually from what I could see there aren't even any flanges under the collars) Went to take the exhaust off and can't get the collars past the stud bolts. Seems the inner bolts are angles down and towards center line. Normal? Trick to getting the collars off?

Okay I think that's enough rambling for now, save the rest of my questions (parts interchangeability, fork springs, screaming for help with the carb rebuild/cleaning, jetting questions, why am I doing this project, and how come the wrench never fits where you need it to go...you get the idea) for later.

Thanks again in advance.

 

[bcbobbers]

When I first took my collors off they were on there pretty good too, but some persistant wiggling and prying with a screwdriver got them both loose. There is no trick to getting them off that I know of other than wiggling the living hell out of them, but also trying not to bend the studs.

As for the 650 plug ends working on the 400, I'm not entirely sure, some of the parts are compatible since the bs34 carbs are used on both models, but im not sure about the plug ends. Maybe someone else will know and chime in.

 

[Yamaha Newbie]

Thanks bcbobbers, I'll give it another shot tomorrow.

 

[hmusket]

Hello to another Michigander, I live in Marquette, right by the other big lake. I was in Holland about 25 years ago, nice town, similar to Marquette, lakeside tourist trap. Not quite sure about what you are referring to by plug cap. As far as worrying about timing, don't, there's no points on the '80 and '81.

Download the manual: View attachment 3882

Go to page 9 of the PDF.

There must be a Yamaha dealer in Grand Rapids. Sometimes, not very often, you can get some parts at a reasonable price.

I did some checking, went to Yamaha site. Got this Pic, are you referring to part 15? If so, the xs650 doesn't use a part like that. What did you see on Mikes XS site?

 

[Yamaha Newbie]

Hey Hmusket. Hope your side of the state is getting better riding weather then we are over here. It would be nice if I didn't have to take all my rain and cold weather gear with me every time I ride, just a little consistency with the weather would be nice. Have you been getting the sudden thunder storms and constant clouds over there too? I used to live in Detroit and friends had a cabin just outside Marquette that we would go to. Real nice area as I recall, course that was almost 30 years ago.

Yeah Holland isn't so bad, but your right tons of tourists...and most of them are out of state and don't know about Michigan turns, lots of fun on a bike.

As to your response, yes it's part #15 in the diagram. What I found on Mikesxs was a part #05-0080 called a Rocker Shaft Plug, which looks a lot like the piece I broke, but when I just now checked out the diagram for the 650 your right it doesn't use that part. Stealership wanted almost double what I paid at Boats.net and it would take around two weeks.

I was reading this forum two or three days ago and finally saw to my relief the 81s were electronic so I figured the timing was probably good. However, when I bought this bike the PO handed me a aluminum cup and said "it's a cover for that black plastic thing on the side of the engine." He was referring to the ignition module. Someone had removed the cover (reason unknown) and now the cover couldn't be put back on cause a screw and brass plug had been jammed into the large hole and wouldn't come out. Finally drilled it out last night, now just need to find replacement screws, hopefully allen or torx head.

So, since this engine is running badly anyway and I know nothing of the service history, I'm starting at the front of the engine and working my way back checking everything necessary to get it running at least reliably through this summer till I tear it down in the winter.

 

[drewpy]

I've seen cam cap covers on ebay, there was an NOS set on the UK site a few weeks ago and don't forget that xs250/xs360 ones will fit too!