XS500 single carb manifold, jetting?

here is the 34 (36 slide) and the one that measures 35 with a 38 slide
ill take some pics of the 38 and show it next post
 

Attachments

  • 044.JPG
    044.JPG
    868.1 KB · Views: 226
  • 045.JPG
    045.JPG
    846.5 KB · Views: 214
  • 051.JPG
    051.JPG
    858 KB · Views: 216
  • 046.JPG
    046.JPG
    911.5 KB · Views: 214
here is the 38 510 model code 1975 yamaha mx400b
 

Attachments

  • 054.JPG
    054.JPG
    245.7 KB · Views: 220
  • 056.JPG
    056.JPG
    218.1 KB · Views: 215
  • 057.JPG
    057.JPG
    856 KB · Views: 230
  • 055.JPG
    055.JPG
    840.4 KB · Views: 210
  • 053.JPG
    053.JPG
    853.4 KB · Views: 217
They look good, we just gotta now if the 38 jetted right would be good for a 500 with a single carb manifold, i read that overcarb could be worse than undercarb! If one of those works ill take it!
 
better chance me finding a good slide with 36 gimme till tomorrow ill be garthering parts and what not
 
it can be counter intuitive larger carb has less venturi velocity so may need larger jets

where do you live?
 
I used to be station at Ft bliss but i got out of the army and now im in PR, temp is usually 85-95, at sea level and very humid
 
so far good news :D
i have a good 3.0 slide for the 36 8)
lots of times these old carbs off mx bikes have had a steady mud diet and the slides get worn down badly
ill gather up the jetting, float bowl (gonna use the bowl with floats on posts)and choke plunger and all the etc and post up a pic of the lot this evening
 
now all we need is some one to lend or sell me a cylinder head cheap so i can make you a manifold
 
That would kick ass!!! You guys have no idea how much i appreciate your help!
For the manifold, i read the xs500 blog from a guy named jimmer that was using a 40mm flatslide carb and a boxed style manifold, ill attach a pic, but i dunno if that style manifold would work for me since his bike was heavely modded and was for track use, the cool thing about the xs500 is that it doesnt have the back bone in the middle, so i can put the carb in the middle with a good filter!
 

Attachments

  • image.jpeg
    image.jpeg
    131.8 KB · Views: 221
  • image.jpeg
    image.jpeg
    145.1 KB · Views: 220
not the way i would do it that manifold will have some weird midrange issues i have tried them

i build a lot of these i would build it like my 4-2 intakes and do away with the factory isolators

and bolt it on to the head with viton rings
 
Yup that was the first thing that went in my head when i wanted the manifold a single piece to bolt to the head aomething like this:
 

Attachments

  • image.jpeg
    image.jpeg
    212.7 KB · Views: 299
  • image.jpeg
    image.jpeg
    23.2 KB · Views: 292
Bringing this thread back from the dead as I’m looking to go a similar 2 into 1 carb manifold on my xs500c. Largely because certain BS38 parts are becoming harder to find and I like the idea of a single carb setup - no syncing, cheaper in the long run etc.

So what I want to know CXman is if you could make one remotely for me as I live in Australia? Also keen to hear about the ideal design. I’ve seen one made for another XS500 owner by Dean Speed Customs but it is quite a long design which I would think harms the low end response?

I’d be looking to run a Mikuni VM36 as my carb.

Any opinions advice out there much appreciated!
 

Attachments

  • 88BE5C63-EF83-4396-874E-FC0188636715.png
    88BE5C63-EF83-4396-874E-FC0188636715.png
    6.5 MB · Views: 182
I’m guessing the problem in getting a shorter length is radius coming from the cylinders. I’m thinking maybe it would be possible to do mitred cuts or a log style manifold. Open to ideas here anyone?
 
Back
Top Bottom