Inlet Manifold YZ 490 K/L

[80-85 husky]

How hard is it to get one of these items?

how do they run without the YEISS thingy?

I'm sure Sudco will have a standard manifold, not sure about  the bottle fitting

any suggestions?

cheers

[Zakk]

you need to know which model YZ490 manifold you want. the inlet manifold and reed blocks are different between the YZ490K and YZ490L. the YZ490K has the 4 bolt set up while the YZ490L was the first YZ490 to use a 6 bolt inlet.  if you have a YZ490K then i think you'll have to use a boost bottle manifold as the YZ490K's inlet is dog legged slightly to the chain side so the carb misses the rear shock, it should be the same as the IT490K inlet manifold and both of these use the boost bottle set up.
the YZ490L's inlet may be similar to the YZ250 L-N's inlet which don't use the boost bottle set up... but i wouldn't think Yamaha would have made it that easy   

[80-85 husky]

 I will sort out the model. I didnt write down the no's the other day now im on the other side of the country.
it has a linkage with grease nipples, a boost bottle and a double leading shoe brake...

can you still get manifolds as this one had a lot of silicon on it...

[Zakk]

the YZ490K inlet manifolds are easy to find on ebay, type one into the search and you'll probably find them for around $100 for a new aftermarket one in USA. they'll all have the boost bottle connection but you can seal that off if you don't want to use one.

[tony27]

This help?

http://hotfootmoto.net/store/product.php?productid=18296&cat=257&page=1

[maico police]

The best place to start if you're looking for Yamaha parts is your Yamaha dealer (crazy I know). You'd be surprised what they still carry and even if it comes up NLA, if you get them to scout their dealer network they usually can find something at a dealer on the other side of the country who has one.

[80-85 husky]

Cheers for that, solves all issues!

What happens if you dont run the bottle does it have any effect or was it just a classic yamaha gimmick??

[maico police]

What happens if you dont run the bottle does it have any effect or was it just a classic yamaha gimmick??

Pretty sure it was just a gimmick. I don't run the bottle on my 250 H and it runs fine. Billet YZ disconnected his from his
WR 500 (basically a YZ 490) and it runs fine. 

[Zakk]

it's easy enough to see what it's supposed to do, but whether it actually does it or not is another question and strange how Yamaha dropped it from the 250's once they added the YPVS

my IT250J has a boost bottle and there's a noticable 'pop' whenever you shut the thottle at full revs... my YZ250K doesn't have one and doesn't seem to do this