Carb Help

[New2Me]

I finally got around to opening up my carbs which are 78-79's. Besides needing a real good cleaning something don't seem right. The mains are all 135 and the right carb has a 180 pilot while the rest are capped off with brass screws. What angle could the PO been going for here? Many of you already know I dont know what I'm doing myself which is why I keep bother you guys but this seems really wrong.

Any ideas? I'll get a pic up soon.

[crazy steve]

Better do some detailed pics.... you might have a 'mixed' rack that the PO tried to compensate for. You're right, that ain't right...

[New2Me]

[IMG][/IMG]

I'm not sure what pic's to take exactly.

[natemoen]

Looks like someone lost the screw and just put a jet in there instead. Is there a regular pilot jet under that one?

[DGXSER]

Exactly Nate, looks like someone lost the screw for that and put a pilot air jet in there instead! You are correct, it ain't right!! Get yourself the correct screw to put in there.

[New2Me]

That's good news actually! What would I call that screw? I'm not sure how to search for it and nothing is popping out in the linked stores.

Ya know what I might just stop at Ace and grab a brass screw that measures out.

[crazy steve]

Worst case, solder the hole in that jet closed. It's just a plug....

[New2Me]

I'm confused as usual. I was shopping for rebuild kits and see there are different kits for 78' & 79' so I checked this http://www.xs11.com/forum/showthread.php?t=73 to see where I should go with the jets and got stumped.

My carbs are 78-79' with 135 mains 45 pilots and a bag with (4) 120 mains that came with the bike.

[natemoen]

Stock for the early carbs was 137.5, so your 135 would be too lean with those carbs. Start with the 137.5 and work from there.

Stock for the later carbs was 110-120's.

[New2Me]

Stock for the early carbs was 137.5, so your 135 would be too lean with those carbs. Start with the 137.5 and work from there.

Stock for the later carbs was 110-120's.

That's where I got confused because why would the PO have 120's in there then swap them out for 135's? Even more conserning is why did someone go from the 137.5 to 120.

The question I should have asked last night was is there a serial number to indicate which year my carb body is? I think someone posted 2H? for a UK carb the other day, maybe there is a list somewhere.

I tried to pull the needle jet last night because that seems to be a difference by the year but my cir-clip pliers were not long enough. It seems like between 78-79 they have 1 mm difference and then 80-81 has the screw type.

[natemoen]

What do you mean "screw type"?

2h9 was the UK type 2h7 is the early us type. It is sort of printed on the body, not very well though and may not be there anymore. By your pic it it looks like you have the early us type with the later plastic floats. With those floats you need to uses the later float height of 23 mm rather than the normal 25.7mm.

And if you don't know for sure that you have uk carbs (i doubt you do) then go with the 137.5 as your base jet number.

[New2Me]

What do you mean "screw type"?

2h9 was the UK type 2h7 is the early us type. It is sort of printed on the body, not very well though and may not be there anymore. By your pic it it looks like you have the early us type with the later plastic floats. With those floats you need to uses the later float height of 23 mm rather than the normal 25.7mm.

And if you don't know for sure that you have uk carbs (i doubt you do) then go with the 137.5 as your base jet number.

Don't the 80' carbs use a threaded needle and the 78'-79' use an adjustable clip? I am going to tear down the carb completely today and document everything inside that thing. Probably what I should have done to start with.

[CatatonicBug]

Don't the 80' carbs use a threaded needle and the 78'-79' use an adjustable clip? I am going to tear down the carb completely today and document everything inside that thing. Probably what I should have done to start with.

Nope. The needle in the later models simply lack the extra notches for adjustment. Switching to a Dynajet kit gives you back those notches.

[New2Me]

Nope. The needle in the later models simply lack the extra notches for adjustment. Switching to a Dynajet kit gives you back those notches.

Ah! Are you happy with your dynajet? Now you experienced that kit would you try something different next time?

[motoman]

That's where I got confused because why would the PO have 120's in there then swap them out for 135's? Even more conserning is why did someone go from the 137.5 to 120.

Simple.........cause they or a shop was clueless..............us oldies see that and worse here.......nutin' unusual.......