my new project/ first bike/81 xs400h

get some Gasgacinch gasket sealer,made to be used as a gasket on cases of 2-cycles.Gotta be tough stuff,used it on my dirt bike,but don't know as I haven't finished for going to Dr.s for tests,feel like a pincushion that's been drained of blood! If a gasket is going to be under stress,I'd use something to hold it. lha:bike:
Ughh, why she's ah no run good?!

I've checked for air leaks around the carbs boots, fuel flow is good, idle mixtures are both about 3 turns out, carbs are super clean, and yet she dosnt idle very well :(

I've checked the vaccume readings at the ports on each carb/intake rubber, they seem about as good as it gets. When the carbs were off I checked the butterfly adjustment linkage screw and got the butterflys adjusted as good as possible to the eye

What else? Float level? Any way to check the float level with the carbs off or do I need to speand way too much time ripping them out over and over and over.....?
What year is your engine? I think some later carbs need the floats checked with a tube outside the carb. Mine ('79) require removal of the carb, but I can do that in 10 minutes tops....plenty of practice.

What is it doing at idle?
At idle is seems to not want to keep a certain rpm, I can keep it running at about 2000 rpm if I feather it but if I get under that its doddgy and will die if it gets too low. Ill have to check the bowls.

Thanks for that link:bike:
How's your battery? Sure you sure both cylinders are firing? Water sprayed on the headers tell the tale without burns to your hand.
Yeah I should probably check, im gona do more once I replace that pesky clutch pushrod seal.

The battery is decent but I need to check how she is charging again.
hey folks!

got the bike running pretty good!, ive been through my carbs like everyday for the last week tweaking and adjusting drilled out my jets with a 1/16th drill bit, according to a chart online thats about a 150 main jet.

also backed my idle mixtures out to about 4 turns out thats seems to be where she idles best, yet she still dosnt idle well

running kind of funny when its on the road, its geared WAY too low so ill have to find a 38-40 tooth sprocket for the rear. seems like when the engen gets hot with sustained load on the highway it breaks up, BUT if I take the rpms higher a bit it seems to do better.

still need to fix a oil leak on that pushrod seal, it is back ordered so I have just been watching the level.

ive considered selling the bike a couple times lately. Im mega buisy with school and trying to get some cash so ive put the bike up for sale or trade for a more reliable bike. I know ill regret it if it does sell but im getting killed driving through boston traffic everyday in my diesel.

anyways im just gona keep riding it, got to redesign my rear pegs, keep scraping them off in the twisties, the bike does handel like its on rails :bike:

as she sits now with my "for now" ducttape seat :D

looking good Ahale, keep at it. It took a lot of tweeking on my standard xs to get right, never mind a modded one.

I am going on a rolling road dyno to dial in the tracker, can't be arsed taking the carbs off and on etc, get a fueling readout on the dyno!
That thing is just sick man-what a great build, I cant believe shes a xs400, Im staring at my bike and then pics of urs kinda droolin, gotta say!
thanks guys, :) im definitly happy with how it came out, one of those deals where I wouldnt change a single aspect of it because its just how i want it too look.

the seat with get some professional treatment sooner or later, but im out of money so for now its ductape and sme cheep foam.

selling...kind of.... but not really. Im entertaining any offers but not trying hard to sell it. Im just nervous about trusting the engine/electrical system if I really want to ride it often. I dont want to be in the carpool lane coming home at 5pm when the bike dies and leavs me stranded...but we shall see for now im just riding it.

ordered a 40t sprocket for the rear yesterday, that will get me down to 17/40 instead of the 17/43 im running now...thats really killing the speed of the bike.

on the subject of timing, if the bike gets hot when I load it on the highway and starts to sputter, would that be too far advanced or retarded? I dont think its fuel because it only seems to happen when I put a sustained load on the engine...not in normal blasting around.
I eliminated a lot of problems by adding more fuel to the bowl. The brass floats on my 78 should be at about 26mm when stock; this was causing me to still have a hanging idle when the bike was hot. I lowered them to 23mm and I have not had a problem yet. It is also possible you're still running lean.

I threw in 160s and the bike still ran great. Right now I am using 142.5s, but I can definitely go bigger. Still squashing some bugs and wanted to make sure I was not too rich before I increase the mains again further.
good work!!!
could you give me directions on that air filters?
diameter that is?
how they were assembled?