Carb needles and cam work

[borjawil]

Been a while since I've been on here. A few years or so back there was someone who made carb needles that were left and right side dependent due to one side running leaner. Anyone know where to get a set of these?

Possibly the same person, there was someone who did cam work for relatively cheap to help on the vibrations.

 

[gggGary]

You are thinking of XSJohn, RIP, there are threads that conglomerate much of his wisdom and ideas.
Here's one http://www.xs650.com/threads/a-collection-of-xsjohns-mods.2426/

 

[weekendrider]

You are remembering XSJohns needles. The only way to acquire some would be used from someone.

 

[gggGary]

Canadian needles are an option. I have a BS34 carb kit with adjustable needles from ebayer cruzinimage_co
http://www.ebay.com/itm/80-81-Yamah...702783?hash=item2122ad49ff:g:VggAAOxy-gBR-4HK
Just putting together a set of BS34's now, will do a comparison to stock needles and if they seem to be in the ball park will try them and report. Ride report may not happen til later in the month or sometime in May, bike is a serious "project".

 

[weekendrider]

gggGary have you looked at it yet? Wondering how the mix screws compare.

 

[gggGary]

That kit does NOT include the idle mix screws.

 

[gggGary]

Somewhere I have a file that has all of XSjohn's needle specs, station by station along the length.

 

[weekendrider]

That kit does NOT include the idle mix screws.

Hmmm when I click the link it clearly shows the tension spring, metal washer, and o-ring for the mix screw, BUT it also shows a blunt end screw I assumed was a representation of the mix screw. Maybe I haven't had enough coffee yet.

 

[gggGary]

The spring and screw are the idle adjust for the throttle plates. OK you made me look, will report back soon.

 

[gggGary]

Details, the three needles top to bottom are marked;
Y265 1 of 2 in kit
5HX12 (stock USA model)
Y267 2 of 2 in kit
The kit needles appear to be solid brass (checked with a file) the factory needle, some sort of aluminum?
Anyone know what the canadian model needles are marked?
bs34 heritage special 1980 1981 1982 1983 1984 needle jet jetting
The factory emulsion tube (needle jet) is marked 270 Y-0
the kit needle jet is not marked.
I'll let you decide if the other jets are genuine or forgeries......
last pic is the stock needle with a mcmaster car SS washer above the nylon donut this raises the needle a smidge and cures the off idle stumble often found on stock USA BS34 bikes

 

[borjawil]

Oh Damn. Sorry to hear. Guy new his stuff. If you can get the specs that would be great. I do machine work and maybe? Able to recreate them.

Anyone 've other ideas on getting the right side to match the left side of the engine? If I remember correctly the right ran more lean

 

[gggGary]

um

Oh Damn. Sorry to hear. Guy new his stuff. If you can get the specs that would be great. I do machine work and maybe? Able to recreate them.

Anyone 've other ideas on getting the right side to match the left side of the engine? If I remember correctly the right ran more lean

um see above? that kit has needles with slots so you can raise one side.
PS :washer mod if you raise the needle more than "one washer" you have to shorten the spring or it binds the needle causing problems

 

[5twins]

I don't have a functioning set of BS34s to play with (yet, lol) but if I did, I would be experimenting with these needles. The Y267 is a close match to the '78-'79 5O2 needle. The Y265 matches the stock 5HX12 in length but it's taper is more like that of an XS400 5Z1 needle. It would be my first choice .....

The Canadian needle is a 5IX11. It measures 50mm long from it's top slot to the tip. The stock 5HX12 is 50mm long from it's (only) clip slot to the tip. That means running the Canadian 5IX11 in any of it's lower clip slots would make it a step or more richer than the stock needle. A single needle clip change can make a big difference so this may seem like a lot, but keep in mind that this Canadian needle is supposed to be paired with it's matching Canadian needle jet. That needle jet appears to be leaner. Even though both are numbered a Y-0, which would signify the same jet hole size, the Canadian version (Y-0 336) has more air bleed holes down the side. So, the combination gives a richer mix than stock, just not as rich as the needle alone would.

 

[5twins]

It's not that one side runs leaner, that cylinder runs hotter. Richening it's carb mix slightly is an attempt to equalize the running temps between the cylinders.

 

[Bushyeyed1]

Revising an old thread here. I have been researching and dabbling in some different needles for my BS34s. I had a needle left over from an xs750’s BS34s and it had me wondering. So come to find out the emulsion tube is the same Y-0 on the 1978 750s as the American bs34s. I think the XS400 is the same too, but I’m not sure about the needle. So instead of buying two emulsion tubes and getting a Canadian needle you could just get two of the Y140 needles. They are slightly shorter than the stock needles and adjustable. The Y140 needle to me looks similar to the Y265 in post above from @gggGary. In the picture I posted from left to right is the Heiden tuning needle, stock needle , and then the Y140 needle.

My 2-into-1 exhaust. always keeps me busy adjusting my carbs for new changes. So of course I am chasing a new spot @4500 rpm since my recent performance upgrades. So since I’m lean @4500 now I’ll be trying the Y140 and if I get the rich stumbles then I may shave down the Heiden needle one notch so it fits in under the cover. Since I’m waiting for the Y140 I through back in the stock needle and I’m going to see what happens first.

*one more thing to note the slightly shorter richer profile of the needle seems like it would be similar to the xs John mod of a richer needle possibly for the right carb to keep the cylinder cooler.

 

[5twins]

Is that Y140 needle from some aftermarket rebuild kit?

 

[Bushyeyed1]

Yes it was from a rebuild kit for an xs750 from niche cycles. The matching one I just ordered didn’t come in a set though. The original mukuni needle is 5HX6 for the 78 model xs750.

https://www.ebay.com/itm/172159337230
https://www.ebay.com/itm/351369018620

 

[5twins]

Interesting. That 5HX6/Y140 needle looks like a very viable alternative for our BS34 carbs. The taper looks more similar to the stock needle than the Y265. The way the Y265 starts it's taper and gets fatter lower than the stock needle would seem to indicate it may be leaner. But, maybe one could compensate for that by raising it. I have that needle and I do now have BS34s to fool with, but I haven't tried it yet. So far I've kept the stock needle and just changed mains, pilots, and air jets. The carbs seem to be tuned quite well with no stumbling, break-up, or flat spots anywhere in the RPM range. I'm not sure I need or want a leaner needle profile in there. But, I guess the only way to find out what would happen is to try it, lol.

 

[Bushyeyed1]

From what my calibrated eyeball can tell is the Stock and Y140/5HX6 have the same taper. The Y140/5HX6 is about one clip shorter; so if installed on the middle clip it would be one clip richer if you could raise the stock needle. The Heiden needle worked for my two into one exhaust until I added the Shell#1 cam to my xs650. It starts out leaner, but the middle section doesn’t lean out until later. It is longer though so not sure the engineering behind it. To be honest I never liked how much I had to richen up the idle and pilot jet to run the Heiden needle. This being the main range I usually ride around in and rarely pushing it WOT over 4500 rpm.

 

[joebgd]

I have a small shim washer to raise my right side stock needle, the shim is so small I'm going to go a bit thicker next time I take the carbs off. My bike has an 21,000 miles and the emulsion tube is visibly out of round at the top.