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Author Topic: 81xs400-questions about jetting after installing pods?  (Read 1098 times)

Offline jmj166

  • Posts: 62
Hello, I was wondering if i could get so much needed help. I'm pretty new to working on bikes but have a few basics down. I Currently have an 81 xs400 that i got a couple months ago and have decided i want to convert it to a cafe. Anyways, after i installed a new battery i decided i'd clean the (stock) air filters to help the bike run better. Upon taking the air filters off the bike and opening up i found that they basically disintegrated and were very patchy in spots(they also had a smell of petrol and felt moist). I went ahead and cleaned them and ordered some bulk uni filter foam to replace it, I only wanted to use this solution as something more temporary because i want to eventually put pods on the bike. Anyway, while waiting one weekend (i work two jobs M-F, so i have all weekend to stare at my bike just sitting...i gotta do SOMETHING) i decided i'd go ahead and take the carbs off to clean them since from what i've been able to tell so far, the PO did very little...to nothing to keep the bike in good shape. I was thinking about going ahead and ordering some pods to install on the bike....

So my question(s) is/are
1. i'm assuming the jets on the bike are all stock, so what sizes would i need to go to if going to pods, such as main jet, air jet, pilot jet.
The owners manual i have says the xs400 has main jet=142.5, air jet=45, pilot jet=42.5. But the manual covers more years than just the 81, so are all xs400's stock with these(this makes sense, but just want to make sure)
I've read mixed opinions about only increasing the main jet and not the pilot, and some that say to increase both.
I'm assuming its been running rich(haven't checked the spark plugs yet), since the filter smelled of gas, but is that because theres less air flow feeding the stock settings so naturally it would richen the mixture because of this.

and

2. Where do most people relocate the breather hose to, i've seen a valve on mikesXS that i'm assuming you can put, can you just put a smaller filter there as well?

i know thats a lot, but any info on the matter would be very helpful.

thanks

Offline Big Rich

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Re: 81xs400-questions about jetting after installing pods?
« Reply #1 on: Sep 08, 2010, 17:27:14 »
Any years with the same motor / intake / exhaust / carbs should have the same jets.

I would experiment with going 2 sizes up on the mains and tube from there. Thing about the pilot jet is at idle, the engine is using ABOUT the same amount as air regardless of filters - so you may or may not need to change it out.

Offline jmj166

  • Posts: 62
Re: 81xs400-questions about jetting after installing pods?
« Reply #2 on: Sep 08, 2010, 18:11:41 »
I was kinda thinking the same about it being the same jets, but i'm not a very mechanical person (yet :P) so just wanted to make sure. I just want to make sure before i order everything.

also, what do you mean "tube" i think i may be missing something obvious and later feel dumb about it

Offline crazypj

  • Posts: 13199
  • Split personality, I fake being smart
Re: 81xs400-questions about jetting after installing pods?
« Reply #3 on: Sep 08, 2010, 18:27:03 »
Have a look at keyboard, 'B' is next to 'N'. should be tune not tube  :D

PJ
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline jmj166

  • Posts: 62
Re: 81xs400-questions about jetting after installing pods?
« Reply #4 on: Sep 08, 2010, 18:37:25 »
hahaha, like I said, i would later feel dumb...as far as tuning goes would that go as far as screwing in/out the mixture screw, or more along the lines of adjusting how many turns for the jets

Offline Big Rich

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Re: 81xs400-questions about jetting after installing pods?
« Reply #5 on: Sep 08, 2010, 20:07:35 »
Have a look at keyboard, 'B' is next to 'N'. should be tune not tube  :D

PJ

Absolutely correct - im on my phone so it tries to "guess" the proper word. Also why it types "im" instead of I'm.

Jets get screwed in all the way (snug, but dont strip the threads), the mixture screw gets turned in and out a certain amount of times.


Offline jmj166

  • Posts: 62
Re: 81xs400-questions about jetting after installing pods?
« Reply #6 on: Sep 08, 2010, 22:31:08 »
Absolutely correct - im on my phone so it tries to "guess" the proper word. Also why it types "im" instead of I'm.

Jets get screwed in all the way (snug, but dont strip the threads), the mixture screw gets turned in and out a certain amount of times.



this is exactly what I needed to know. I have the manual and it mentioned turns but wasn't specific about if jets should be screwed in all the way or not. I'll probably be ordering everything shortly. When ever i figure out how to load pictures on here i'll make a post (in the appropriate spot) on my building progress. Appreciate your help!!!