Carb jets

[crazy steve]

....Then I figured I might as well check the valves since the bike was this far apart and the valve cover leaks anyhow. I don't know what spec is but they look very even. front valves are .007, .007, .007, and .006 and the rears are .004, .0025, .0025, and .0025. I did notice the cam chain seemed pretty loose. I have the factory adjuster on it.

Some questions I have is: What's valve specs?

Does anyone have a part number on the auto adjuster that fits this bike and has that turned out to be a good upgrade?

Here's the auto-tensioner mod..... http://www.xs11.com/forum/showthread...111#post358111. Everybody has been pleased with this so far, and some of these have been run a lot of miles.

Yes, you need to adjust your valves, although not desperately. All but one are too tight, and that one is at minumum spec. Exhaust clearance should be .008-.010", and you have a choice on the intakes; the 'early' spec of .006-.008", or the late spec of .004-.006". Different schools of thought on the adjustment; run them 'tight' and have a quieter motor (which was the only reason for the change), but less time between adjustments. 'Loose' = longer time, more noise. Either will work, I'm lazy so I run mine loose...

[natemoen]

You like em loose don't ya Steve? ;p

[copracr]

OK, as I run the bike will the clearance grow? or will it eventually hit 0?

[natemoen]

The clearances get smaller as they ware. Eventually it will get to 0 and then the valve will no longer be closing and will be held open.

[crazy steve]

One reason I like to run the valves loose is that gives them more time on the seat, and that's how the valves dissipate heat. I personally think that running them with less clearance helps accelerate wear, and anything to improve longevity with all the unobtainium parts these things have is a good thing...

[Nubian]

Marty, the FSM shows 110s across for the '80 Special, 115 outer/120 inner for the '80 standard. Clymer matches for the standard, but shows the 110/120 combo for the Special, so which would you trust....

My FSM shows 110's & 42.5 all across and that's what I found in them during my rebuild. That's how it's running now @ 2 3/4 turns still getting some backfires, but wasn't running right @ 3 full turns. I have 45's on standby, when my colortune arrives I'll see if I should use them and maybe also move up to 112.5

[mjpxs11sh]

carbs

the factory manual says 80-81 BS34 III 3J6 00 Special carbs have the same mains. ive just been thru this. my 81 has 110's in alll four, the floats were set at 23mm and the fuel level ck with a hose attatched to the drain on each carb was at the 3mm spec below the top of the bowl. the idle mix i set at 2.5 turns after some trial testing, which is where they were before removal. i pre synch'd them before i installed em, and thats where they remain. no carbtune or colortune, and it runs excellent. thats about 2 weeks of hands on carb work experience. id like to synch em and vacuum adjust the mixtures, but im pretty satisfied with where they're at for now till i get a guages or a stick. ur carbs are exactly the same. hope this helps.
Max

[Nubian]

the factory manual says 80-81 BS34 III 3J6 00 Special carbs have the same mains. ive just been thru this. my 81 has 110's in alll four, the floats were set at 23mm and the fuel level ck with a hose attatched to the drain on each carb was at the 3mm spec below the top of the bowl. the idle mix i set at 2.5 turns after some trial testing, which is where they were before removal. i pre synch'd them before i installed em, and thats where they remain. no carbtune or colortune, and it runs excellent. thats about 2 weeks of hands on carb work experience. id like to synch em and vacuum adjust the mixtures, but im pretty satisfied with where they're at for now till i get a guages or a stick. ur carbs are exactly the same. hope this helps.
Max

Which setup do you have with that, stock airbox and exhaust?

[skids]

Well, if it aint broke, dont fix it. The synch is really more for the low range anyway and if you color a set of plugs at idle or just off idle and they are good, just go with it.

[copracr]

I'm doing this valve thing and I want you guys to double check my math here.

Exhaust L to R:
.007 with 290
.007 with 290
.007 with 280
.006 with 285

Intake L to R
.004 with 265
.0025 with 275
.0025 with 275
.0025 with 285

So for exhaust Ill aim for .009 and I'll need : 280, 280, 270, and 270
The intake i'll aim for .007 and need 250, 250, 250, and 260

Sound about right? Sucks I only have one of those but maybe the local bike shop will do some swapping with me.

[crazy steve]

I'm doing this valve thing and I want you guys to double check my math here.

Exhaust L to R:
.007 with 290
.007 with 290
.007 with 280
.006 with 285

Intake L to R
.004 with 265
.0025 with 275
.0025 with 275
.0025 with 285

So for exhaust Ill aim for .009 and I'll need : 280, 280, 270, and 270
The intake i'll aim for .007 and need 250, 250, 250, and 260

Sound about right? Sucks I only have one of those but maybe the local bike shop will do some swapping with me.

Each shim size equals .002", so you're off... exhaust should be 285/285/275/275. Intake 255/265/265/275. This will put your exhaust (in the same orders as you have them above) at .009, .009, .009, .010, the intakes at .008, .0065, .0065, .0065. Personally, I'd go down one more on the last three intakes (giving you 255/260/260/270) putting those at .0085. A tad loose, but they'll wear into spec rather than out of spec. That's your call, either will work.

You'll only need four shims....

[copracr]

Oh, nice math I had there. How long do these motors go between need ing adjustment?

[DGXSER]

Recommended is every 5000 miles or 12 months. Most folks will double those figures realistically. Some of these engines like yours perhaps may still have the factory valve cover gasket, never been opened.

[Joab]

Recommended is every 5000 miles or 12 months. Most folks will double those figures realistically. Some of these engines like yours perhaps may still have the factory valve cover gasket, never been opened.

I know mine probably does...that might explain those funny noises...

[copracr]

Some of these engines like yours perhaps may still have the factory valve cover gasket, never been opened.

Could be original, I have 33k on it but the VC and oil pan gasket were pretty crusty.