my new project/ first bike/81 xs400h

ahale2772

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Hey guys, (just posted this on yamaha club too)

Just picked up a cool xs400h. Bought it not running but got it to run this weekend. Ive got a few issues with it. At first it would not idle but gradually came down to a steady smooth idle at about 1200rpm. I took it for a quick ride and It has a high rpm studder that seem like a revlimiter at about 6200rpm. Timing? carbs?

few things to note here...the timing was really screwed up and I had to turn the tci pickup untill I got the bike to fire. The bike has been all apart so im guessing the guy that put it back together didnt know what he was doing. That being said how do I check the timing? or more specificly where do I shine my timing light when I hook it up to the left side cylinder? (cant find a clear answer in the manual)

Next up...the inside of the tank is quite rusty. I have a clear fuel line and a small inline filter on it now and I can see im getting some serious rust out of the tank. Its not scaling rust or anywhere neer rotting through but patchy light rust on a an otherwise bare metal surface. I hear many tricks can be used to clear the rust out of the tank...are there any that work best? I hear yamaha sells a chemical kit that nutralizes it?

Lastly, the bike has 2 to 1 ehaust with a small muffler and UNI pod filters, can any one advise me on what I should do to re-jet the carbs...or should I wait and see what the spark plugs tell me? I have not ridden the bike much but if I need to clean the carbs to get rust out I'd like to rejet while im in there.

this bike will be a dailiy driver/commuter this summer and im hoping it will treat me well

thanks in advance for any advice!
 
Hey again....got some pics,

Picked her up with 5530 original miles, it was quite a bit more take apart but I got a ton of parts and put her back together to this..... (made that seatpan this weekend)

My plans....get it all back together, mold some led directionals into the stock headlight bucket and the new seat pan/tail. Then it all gets ripped apart again, tank and other body pieces are getting flat black with red and white pinstriping and the frame is gona get a coat of shiny lipstick red

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looking good. welcome to the site

start with the basics;

ignition timing using a stobe lamp
valves checked
fuel getting to carbs

all else fails... carb clean
 
thanks for the welcome, seems like a good forum with a bunch of talented folk.

thats exactly how im going to do it, once I get marker lights rigged up it will be on the road and I can really work the bugs out of it.

drewpy, where is there a mark to shine the strobe/timing light on?

I know fuel is getting to the carbs and I've had the bowls off and they look exceptionally clean.

this weekend im going to do the bb's and diesel fuel method to clean the tank.

Made a little battery box today IMO it came out killer :)

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front of the box mounts through the bolt for the gas tank, rear mounts with two bolts going thro a big crossmember bar I welded on to replace that cheesey sheetmatal strap

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cant wait to get it out on the road!!!
 
that's not a box, its a swimming pool :D

only joking, everything can fit in there, and that will keep the bike fresh, is it welded in? why not get it brass plated?

for timing, you have the RT and LT marks need to line up. once you get the strobe going you'll see it more clearly! :thumbsup:
 
Thanks Drewpy,

its a bit bigger than I want but thats because the seal pan I made sits down in the frame about an inch (I want to keep the seat foam low)...but like you said it will keep all my electronics neat.

see what I mean

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Its not welded in, you can almost see the two bolts i have on the rear crossmember tube and in the front there is a tab that lines up with the tank mounting bolt hole. fits great

I LOVE the idea of brass plating it...do you have any more info on how to get it done? Isnt it just one of the steps in getting a piece chromed?

one of my favorite bikes is one of the chopper/bobbers that jesse james made out of copper, with the tank rivited together

I think I may very well do that...might get my headlight bucket done as well, believe it or not I allready had that idea but I thought the copper looking plating that is a step in chroming was zinc...

good idea though, all the credit is yours
 
That flasher should work but you should also be able to buy an electronic unit that looks like a stock flasher from most any auto parts store - unless you want that one to conceal in your magic electronics box!
 
cool, you would have to talk to a plater to see about brass plating, maybe it has to be put on in sheets (hence the rivets). copper is used under chrome, so its an easy step to make.

you will need an LED flasher and that seems to do the job
 
yup I think the flasher will work. Im planning to use 4 small red 1/2inch leds in the back two dedicated to marker and running lights and 2 strictly for brakes.

In the front im going to mold 2 one inch amber leds into the stock headlight bucket, going to try to make it real street fighter looking

also considering doing some hammering on my tank to make some knee dents, but not looking forward to the loss of fuel capacity. I hear these bikes are about 100miles to empty...is that true?
 
I was quoted 175bucks to get the batt box, headlight bucket, clipons and some other bits and pieces to get plated in copper, I think when it comes time for paint im going to do it :)...guess ill have to get good at polishing and keeping stuff tarnish free

any votes on paint for the bike? Im definently going to do a gloss red frame (have a quart allready) the rims will stay black...

seriously thinking about doing some knee dent's in the rear of the tank, not full length but like the first tank "skillsman" did ...although I think im going to cut swap sides and weld instead of hammer
 
cutting and welding...should save on filler..provided its TIG welded ...if you decide to go that route do awrite up for the site and we'll all be happy to check it out.
 
yeah skillz, I would like to do the whole deal without filler besides if it warps a bit.

the question is.....how do I cut the pieces out? plasma is way too messy, cutting wheel may work with thin blades taking my time but there are some sketchy corners there...
 
Not really sure....I would say thin cutoff wheel....but making the patch pieces and getting them leak proof welded presents other problems.....you would likely want to tank seal it afterwards to be safe.
Those thoughts and the lack of a TIG setup is why I went the hammer route....about 5 hrs worth of work to get it in primer...pretty quick considering the weld route.....and 95% of the world couldn't tell you the difference in the end between a good job either way.
 
yeah I know what you mean, its just that im good with a grinder and not so great with patience for body filler work....BUT the tank needs filler anyways for the botch job someone did hiding the yamaha emblem so If i cant find a good cut method ill start hammering

5hrs isnt bad if that includes body filler...
 
another question for the guru's...

whats the best way to firm up my front end? I can bottom out my fork pretty easily, it dosent seem to have much dampening.

I have read that draining then refilling with 20wt fork oil "6inchs from the top" will get me better feel...is this true?
 
I read that old springs can also start to sag eventually. People are saying going from 10w to 15w might produce a huge change. Someone also mentioned a pre-load spacer on the spring could be modified and made longer thus increasing pre-load on the springs. Some people have even just cut pvc to use as a spacer.
 
Not really sure....I would say thin cutoff wheel....but making the patch pieces and getting them leak proof welded presents other problems.....you would likely want to tank seal it afterwards to be safe.
Those thoughts and the lack of a TIG setup is why I went the hammer route....about 5 hrs worth of work to get it in primer...pretty quick considering the weld route.....and 95% of the world couldn't tell you the difference in the end between a good job either way.

You can start your cut with a cutoff wheel, then use a jigsaw with a metal cutting blade: good for tight turns as long as you can keep the foot down on the tank you are good to go.
 
bcware where is epsom NH? I work in salem NH

I have herd about the pvc thing but I dont want to get that deep, looks like my fork seals are semi leaky so im guessing the 30 year old oil is halfway gone.

the springs feel ok, but there is very little dampening going on, think Im going to try 20wt



crush, yeah I have thought about that but the smallest saw I have is a sawzall, I will look in to it though and see if I can borrow a saw, that would probably be the most accurate/ smallest cut width
 
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