NEW ITEM!: IDLE MIXTURE SCREW SPRINGS

Just introduced, in stock date 2/10/08:


ims6) Aftermarket carb idle mixture screw TENSION SPRING, brand new reproductions exactly replace damaged, rusted, or missing originals. High-strength carbon-steel coil springs have a baked yellow-zinc plating as original.

HCP6573 Aftermarket reproduction idle mixture screw Tension Spring, fits all Hitachi HSC32 and HSC33 model carbs as used on all XJ650 (except Turbo), XJ700 non-X, and all XJ750 models, each:
$ 3.50

HCP6573SET4 Aftermarket reproduction idle mixture screw Tension Spring, fits all Hitachi HSC32 and HSC33 model carbs as used on all XJ650 (except Turbo), XJ700 non-X, and all XJ750 models, set of 4:
$ 10.95


HCP6574 Aftermarket reproduction idle mixture screw Tension Spring, fits all Mikunii BS-28, -30, -33, -34, and -35 series carbs as used on all XJ550, XJ650 Turbo, XJ700-X, XJ750-X, XJ900, and XJ1100 models, each:
$ 3.50

HCP6574SET4 Aftermarket reproduction idle mixture screw Tension Spring, fits all Mikunii BS-28, -30, -33, -34, and -35 series carbs as used on all XJ550, XJ650 Turbo, XJ700-X, XJ750-X, XJ900RK, and XJ1100 models, set of 4:
$ 10.95


All of the above and more at:

http://www.xjbikes.com/Forums/viewtopic ... t=135.html


Thanks!

 

Chacal, how I order parts from you? I don't have paypal, would consider setting it up if that's the only way to do it...

 

Do what I do: send him a money order.

/won't touch paypal with a ten-meter cattle prod

 

Hey Oak.....you can pay via credit card or check/money order thru the mail.......I've sent you a PM with the details!

 

how necessary or worthwhile are these springs? i coat my screws with a dab of oil to hydro-lock them in place.

 

Hey Fonz, well, they're only necessary if the originals are corroded/rusted excessively or distorted from previous overtightening.....I've seen quite a number of them that have been rendered useless. Also, in comparing LOTS of used originals to NOS versions, I notice that even the "good" used ones have lost tension to allow them to be almost 1mm less in overall length....that's about 12% shorter than original.....so the springs do lose their tension over time (as expected). Since the screws are normally run at a 3-4 turns out final position, the lack of proper spring tension could allow the mixture screws to "walk" a bit from vibration, heat/cool cycles, etc.

All that being said, unless I was doing a complete carb overhaul, I wouldn't be changing these, but while you're in there, it's kind of cheap insurance to replace them while they're easily accessible.

As far as NOT using the springs at all, again, I think that with the vibration and heat cycling issues, that the screw will tend to move on its own over time, requiring more frequent attention to re-tuning the carbs. The factory put them there for a reason!

 

Hydrolock only stops a screw from going into a blind hole. They'll back out just fine. If you do get enough oil in there to hydrolock them you'll break something.

That spring also holds the o-ring at the bottom of the hole.

Get some springs and put them in.

 

i've never seen any o-rings neither. either im missing them or the PO really screwed things up.

 

Yes, many of the used or "rebuilt" sets that I'v come across have no o-rings....another reason so many people have tuning difficulties! The original o-rings can easily disintegrate over time, and many people fail to replace the originals during a rebuild. Trust me, they ARE necessary!

 

do the o-rings go on the mixture screw or sit in the bottom of the hole? i tried finding them and the springs in a parts diagram but none of the ones i saw had them listed.

 

Hey Fonz....well, the o-rings END UP sitting in the bottom of the bore, but when installing them, you simply put them on the bottom of the idle mixture screw----once you install and tighten the idle mixture screw, the o-ring ends up in their proper place.

You won't find them on many parts diagrams, because they weren't sold as "parts" over the counter, since Yamaha didn't want customers messing with them for emissions reasons. If you look on on the Yamaha factory parts diagram for an XJ700-XS or -XSC (Mikuni-equipped) model (1986), you can see them there----but those are for Mikuni carbs, which, while similar, are NOT the same as for the Hitachi carbs.