armyofda12mnkeys
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Posts posted by armyofda12mnkeys
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As i said all sohc's will fit.
if the contacts can be upgraded, then i assume the reverse is true
cool, I shall give it a shot.
I'll definately have some questions for you and kmac on setting up the wiring when it comes down to it as it would be my first time doing anything with wiring (probably in a week or 2).
A lil intimidating
Thanks!,
Arian
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its got the electronic ignition trigger which is usually a later engine (circa 1980) and the engine off a special/heritage type bike due to the rounded barrels.
there is a thread in the sticky to convert to electronic ignition if you want to go that route, otherwise sell the trigger mech and revert to contacts!
4G8 engine #?
Here is a larger pic:
Looks like a 4R4 engine number on there. cool, i can just easily put my contact assembly in there?
Maybe I'll work out electric ignition later ... or not, debating how easy it would be to do since im not good with electronics
PS i guess since its probably a 80/81 xs400 engine as you said, will work out on a 78 frame? or will some modification of the engine frame need to be performed you think?
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sweet!, thanks drewp!
Hey drewp.
i noticed the engine he's selling has a module for contact lead wire instead of my split wire one (here is a pic of
). also the contact breaker box looks a bit different on the right side...Do you know what year his XS400 is from? he claims 1977
heh maybe he used a 78 xs500 contact breaker lead wire as it looks closer to that, or maybe it is an xs500 engine lol
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So my first question of my xs400 engine disassemble is that when i was taking off the oil pan, it seemed like previous person tightened the oil pan way too tight.
the screws mostly made a snap sound right when i got them to loosen up, the kinda sound as if I was tightened it too much and screw breaks inside (but Im pretty sure I was untightening counterclockwise as they did thread out easily right after I got it 'loose')...
Anyway, 3 of the 6 screws broke off in the hole ( and the other 3 looked like they were about to break in the middle of the screw).
the oil pan doesnt come off, i guess maybe cause the screws inside are holding the pan to the engine still maybe (i was hoping it broke off on the pan side versus engine, so I could take it off then figure out a way to get the screws out but guess that wont work out doh hehe).
Anyway is a screw extracter the best way to get them out?
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If anyone ever needs links to these stock parts, aka wants to pay $3 for a 5 cent part
...Im in the same boat as you, leaking somewhere back there so I'll order those parts n' try em out ...
Pain to find exact source cause there is SOOOOO much GUNK from the chain throwing stuff back there which gets 'oily' also from the chain lube it seems.
PS here is my gunked up area lol:
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So I'm at a loss now. The idle mixture screws being turned anticlockwise make the mixture richer (more gas)? If this is the case then I must have to go the opposite right? Screw them clockwise to make the mixture leaner? But wont this cause the RPM's to go up?
yes, screwing it clockwise will make it leaner... (if its a carb with the mixture screws towards engine versus back of the carb which i believe it is)
hmmm not sure about rpm's. i dont think it really messes with the rpm's when i mess with the idle screws. it just stalls if i goof on the setting.
Get a Colortune 14mm spark plug to play with if you got $50 to spend...
I like it as you can literally see whats going on in there (spark plug has clear casing you can see through). and get the mixture correct when it turns burnsen burner blue ... then mess with the throttle-stop screw to optimize rpm's at idle.
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good to go mate, all sohc's fit!
sweet!, thanks drewp!
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i found a good deal on a rebuilt 77 xs400 engine that Im debating buying, and while i am working on rebuilding my engine, I want to swap the 77 in so i can ride
... Is there anything i need to look out for?
I'm asking as I bought the 77 carbs off this fellow before, and i noticed the carbs are a lillll different (throttle stop screw at the bottom, different float style 'plungers'). but even that seems swappable so I assume the engine is fine too.
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interesting you posted this cause I just got an Xs400 from some sketchy guy..
and I noticed he had the hose from the carb capped with a double a battery
and the hose connected to the engine was a 2ft long vinyl tube that ran to the bottom of the bike and
was just left open. I removed it the other day and hooked it up the way its supposed to and everything
still seems to function ok like it did before.. but I haven't really got to ride it around for long.
Im curious, can you get gas in your engine through that breather tube?... like if your petcock is accidentally left on prime, and the floats get stuck, and gas is overflowing and going into the airbox and it goes in the middle tube into the engine?
Just trying to think theoretically if it can happen and maybe just buying one of those crankcase breathers is a better option
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those jets will fit as they are standard mikuni jets.
as to the sizes, it all depends what you are trying to do.
always best to go richer then down from there.
cool, i just wanted to have backups in case i try anything
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I saw MikesXS had BS34 carb parts (for their 1980-84 xs650 models though).
And was just curious if they are interchangable since my 1978 xs400E i believe is the same Mikuni carb model?
Here are the links to their main/pilot jets...
http://www.mikesxs.net/products-38.html#products
http://www.mikesxs.net/products-39.html#products
Also Do you guys usually buy 1 jet size smaller and bigger so you can jet? or it isn't unusually to get 2 sizes bigger/smaller if you re-jetting.
Thanks,
Arian
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cool, I'll buy some and try it out.
Thanks guys!,
-Arian
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I went ahead and purchased the stock replacement filters. However, my local shop suggested I use K&N oiled foam and wrap it around the stock filters, after removing the fuzzy fur. Apparently others have done it with good results.
Good luck.
PS, The EMGO/'pod' filters on ebay that they claim fits 77-81 XS400 is 48mm diameter on the inside rubber and didnt fit my '78 and '77 XS400 carbs I had which diameter was about 55mm i think.
Anyone else have same problem?
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cool, but may just do mikesxs if i need to get other stuff in 1 order.
Anyway, what exactly do i need to buy in addition to the coils to make them work?
Im guessing:
2 "Non-Resistor NGK Spark Plug Cap"
and
1 set of "Spark Plug High Tension Wires"
Also would the "XS Performance Ignition Coil" (there are a few of them, but Part #17-6807 says there is no danger of frying it compared to others) be a plug-n-play upgrade?
i see it says you need couple "5K OHM spark plug caps" and the "Spark Plug High Tension Wires"... says the performance ones has a 3.3ohms primary resistance. Think XS400 stock ones are 4ohm.
eh maybe i be better off getting the regular xs650 coils.
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k thanks guys. got the part #. I work at an ace hardware so I'm gonna try one of our o-rings first and see how well it works.. if it doesn't
i will order the right one.
I know the ones we have our made from Nitrile Butadiene Rubber which is oil and chemical resistant but not surethe ratio of nitrile (more nitrile the better apparently).
Is that the same o-ring Part# for a 1978 xs400?
mine leaks in same 2 places I think hehe.
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Hey guys, I posted in an old thread bout other coils, but thought I'd create new thread as no one responded....
Saw someone bought mikesxs coils to replace their old 78 XS400 coils, which is my bike (think mine and mikesxs coils are both 4ohm resistance so think they should work fine?) ...
Product 17-6805 here:
http://www.mikesxs.net/products-27.html#product-17-6805
... What wire and cap from that site should I buy to make it work?
I saw some 5K Ohms and 1K Ohms caps there and I dont got a clue about the electronics aspect.
Also the stock 78 xs400 condensor is fine with those new coils?
Thanks!,
Arian
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So I was going to take my junky MAC 2-1 exhaust off and go back to 2-2. I have some xs400 mufflers but need new headpipes/headers...
Would these work perfectly (they are from a 77 xs400 and mine is a 78 xs400... part#'s seem to be different so I been hesitant to buy)?
Let me know if you see anything on ebay/etc that is better condition (if you got some in yer own garage and willing to sell, lemme know as well)
Thanks,
Arian
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I was wondering the nut #12 and turns into the thing to the right of it (not sure term to call it, its called a Bolt Stud in pic below ... I guess its kinda like a bolt without the top hex part)...
http://www.boats.net/parts/search/Yamaha/Motorcycle/1978/XS400E/EXHAUST/parts.html
Think its labeled as #30 here in the pic as well:
[img width="200"]http://www.boats.net/images/diagrams/yamaha/02/0720/0002.png
Part #: 90116-08046-00 BOLT, STUD (823-13558-00)
Anyone know where to buy that? my bolt stud/nut are pretty rusted so i was going to replace them with something new (only saw the nuts on boats.net).
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yeah sonds like your carbs need a good clean but i cant help you with a manual/step by step
I think this is pretty close to xs400 but 4 carbs for xs650:
http://cycles.evanfell.com/2008/09/how-to-clean-a-motorcycle-carburetor-the-right-way/
I was gonna put some video up of taking off my 77/78 carbs so peeps can see the parts before they do it themselves, but post in the Classics forum next few days.
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Sounds good. Did you have to change any of the bike's wiring or were they plug and play?
So when you bought the mikesxs coils for your 78 XS400...
http://www.mikesxs.net/products-27.html#product-17-6805
... what wire and cap from that site did you buy alongside it to make it work?
I saw some 5K Ohms and 1K Ohms caps there and i dont got a clue about electronics.
Also the stock 78xs400 condensor is fine?
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Have you changed the oil? If not, do it and use the proper weight motorcycle or diesel engine oil.
The pictures are directly below the clutch actuation rod. That is a frequent source of oil leaks. Take the sprocket cover off and see if the oil is coming from that high up. If so, the seal is cheap...but can be a challenge to change. Oil could also leak from the neutral switch.
hehe i leak a bit from there as well. Those 2 wires on bottom are always a bit oily after I ride.
If you want to get engine gaskets (not sure if that seal is included), here is a link for cheap engine gasket kit
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Like Noah was getting at, go down to an auto parts store and find a small air filter that will fit that hose. You con't block it off and you don't want dust to be able to get in there. They are even called "breather filters". You should be able to find one that fits. If you are sure you are not going back to stock air boxes, you could cut the hose off a little lower.
cool thanks, I was just curious. prob keeping my stock boxes
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That is the crankcase breather. This allows excess air pressure in the crankcase to be vented and any fumes are burned in the engine.
I guess my next question is, i bought some new replacement air filters, POD style. which would fit onto each carb ... but there wouldnt be a shared intake line anymore...
What to do with that black hose if i were to install them (i realized the 48mm xs400 filters sold on ebay are a realllly tight fit and just pop off since the outside diamter is 55mm and not 48mm... so going back to old aircases, but still wanna know for curiousity)? Think my friends newer bike has something that almost looks like a mini air filter instead of a line that goes into the intake, saw one that may fit xs400.
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cool thanks Alex!
). also the contact breaker box looks a bit different on the right side...
... 
I know the ones we have our made from Nitrile Butadiene Rubber which is oil and chemical resistant but not sure
1980 XS400 leaking oil.. pictures .. how screwed am I? lol
in Classics
Posted
curious, can u just pull out that clutch gasket? without dismantling engine?