getting into it

[joshua]

Well, I've started. I took off the air box (wich had plenty of fuel in it) and I'm taking the carbs apart. I took off the gas tank and checked the plugs too. Plug one and two are black and wet. 3 and 4 are white and dry. When I took the carbs off there was fuel in the bowls of 1 and 2, but 3 and 4 were dry. I've only gotten as far as looking at the jets. 37.5. The floats didn't seem to have anything on them. That's as far as I could go without checking here now to see what to do next. Anyone have pics of what to do next? I don't know what I'm looking at or what to look for next. I'm hoping to get the Bastardbike going by this weekend, but I don't know. Wish me luck!

[mason79]

http://www.xs11.com/forum/showthread.php?s=&threadid=39

click on forum and scroll down to maintenance, mods, under fuel and carbs and read read read

[skids]

Re: getting into it

I don't know what year or model your bike is, but if you just rolled it out of mothballs, consider pitching out the old fuel and get some fresh. The carbs are filled up with the use of the PRI (prime)position on the petcocks. I wouldn't run it too long if the carbs (1 and 2) have leaked a bunch of fuel into the cylinders and contaminated the crankcase oil. Also, if she hasn't run in a while, (more than the winter) consider misting the cylinder walls with oil before you start it.

Originally posted by joshua
Well, I've started. I took off the air box (wich had plenty of fuel in it) and I'm taking the carbs apart. I took off the gas tank and checked the plugs too. Plug one and two are black and wet. 3 and 4 are white and dry. When I took the carbs off there was fuel in the bowls of 1 and 2, but 3 and 4 were dry. I've only gotten as far as looking at the jets. 37.5. The floats didn't seem to have anything on them. That's as far as I could go without checking here now to see what to do next. Anyone have pics of what to do next? I don't know what I'm looking at or what to look for next. I'm hoping to get the Bastardbike going by this weekend, but I don't know. Wish me luck!

[skids]

OK, rereading your post... I would say that you HAVE been running the bike. OK. There is a chance that the petcock is not releasing fuel while in the run position if you have a standard. You can prime it to supply fuel. Check for kinked fuel hose also. If your air box has fuel in it it can fuel foul the plugs, especially the ones that are getting fuel.

[DiverRay]

Joshua,
As your bike is a '78, you NEED to pay attention to the vent and fuel lines off each pair of carbs. There are two "T" fittings on each side, upper and lower. The upper fitting is the VENT, and the line should go to the airbox. The lower fitting is the fuel line, and goes to the petcock on the OPPOSITE side of the bike. Carbs 1&2 feed from the right petcock, and 3&4 feed from the left petcock.
While you have the float bowels off the carbs, use a LITTLE compressed air to blow INTO the vent. You should be able to feel air on both carbs. Do this for both sides, to verify you do not have anything blocking the vent.
Check the condition of the needle and seats, reset the float level to about 1 1/32", or 26 mm and then BENCH TEST the float BEFORE putting the carbs back on the bike.
If in doubt, spray some carb cleaner into any passage you think may be blocked. DON'T forget the safety glasses!!

[joshua]

Thanks for all the advice. DiverRay, I only have one petcock running the whole bike. The PO had one feeding the whole bike. I'm debating on getting another.

[DiverRay]

One should be able to feed the bike. I ran mine on just one for about three months with NO problems. Check for kinked lines, and watch the lines as the tank goes on. sometimes it's that last inch that causes the problem.

[joshua]

So I've gotten it all apart and I'm cleaning the parts that are supposed to be cleaned. One of the aluminum posts holding the floats was broken by the PO. Is there a good fix that doesn't involve welding, or am I going to need to take it to the shop?

[Ken Talbot]

Use the search button at the top of the page to look for 'broken float post'. Lots of guys have had this problem, and there have been a couple of no-weld fixes.

[John]

Originally posted by joshua
So I've gotten it all apart and I'm cleaning the parts that are supposed to be cleaned. One of the aluminum posts holding the floats was broken by the PO. Is there a good fix that doesn't involve welding, or am I going to need to take it to the shop?

Is the whole post broken, or just the hole where the pin goes through? I tried to repair one that had broke off at the pin hole. Half the hole was still in the post, but the top half of the hole was broke off. I tried to repair it by building up a new post with JB weld, and drilling a new pin hole, but that didn't stick to the orginal post very well, and I just finished trying another trick... I drilled a very small hole through the post below the pin hole in the post, 90 degrees to the pin hole, and used some safety wire to secure the pin into what is left of the pin hole. It works wonderfully. I just took it for a test beating and all is well.
MRO, if you read this, this is how I repaired the #2 carb with the broken post. If this doesn't work, but I believe it will, then I will try drilling down through a post in a sacrificial carb, then cut it off the donor carb, and then drill down throuh the keeper carb, and pin the two together like dowelling two pieces of wood together. and use a roll pin to secure the two pieces to

[joshua]

It LIVES! I got it all together again finally and it started on the first push of the button. Only thing is now I have a leak in the #2 bowl. Oh well. I'll be pulling it all apart and trouble shooting. It runs a LOT better already though. Real test will be when I take it out on the road. PO had it on the wrong clip settin, floats were all out of whack, butterflies weren't lined up....I could go on. Thanks for all the help and advice! I'll hopefully be out enjoying the Tucson sun in a day or so! Happy riding!

[joshua]

HELP! The *&$#%@ air box is not playing fair. Turns out I'm missing parts to keep it together and in place. Not only that, but it's the most painfull part of working on the carbs. I'm currently bidding on some individual filters. Anyone know what size jets/mains I'll need when I change the box out for individual filters? And also, where can I get them and what kind of wallet damage am I looking at for new jets/mains?

[TopCatGr58]

Hey Joshua,

Why bother with Ebay, the pods are available from several sources, PartsnMore, BikeBandit, etc..

I just double checked the set of 79SF carbs, the intakes are 54mm. PNM says for the 78-79 series to use the 52mm, but I'm pretty sure they are 54mm, but wouldn't hurt to measure yours to be certain!

The 52mm's are only in the round style, but the 54mm come in oval as well as round.

The Main jets can be gotten from MikesXS.com for $6.00 a pair, pretty cheap! But unless you can't find anything else to buy to bring your total to $35.00, you'll pay a modest shipping charge, it's FREE with $35.00 or more order!

The round ones from PNM and bikebandit are the EMGO brand, and they have a prominent lip on the mounting that has caused some folks problems with air flow and the ports in the inlet bells. One person who got the oval ones said that the lip wasn't much. I was able to use the Bikebandit ones without any real problems, but I made some homemade velocity stacks to mount them, there's a thread I posted a while back that shows them.

With OEM exhaust and pods, the jetting guide states 2 sizes up, so from 137.5 to 142.5. YMMV, monitor your plugs!-
-------------------------------------------------------------------------

Main Jet - Large Round Type
#142.5 Main Jet - Large Round Type - N100/604 Mikuni type - Fits:1980-84 Stock
XS650 Mikuni 34mm. CV carbs and aftermarket Mikuni TM 36-68 Flatslide carbs.
Sold in 2's.


Part #48-0122 $6.00 USD /Pr

BikeBandit:
[quote]
Home Aftermarket Parts - Street Fuel & Air Air Filters (EMGO) - Yamaha Yamaha XS1100 1980-1981

Name: EMGO Clamp-On Air Filter, 54mm (Yamaha XS1100 1980-1981)


Price: $8.95 Our Price

$9.95 MSRP

Manufacturer: EMGO



PartsnMore

CHROME CAP AIR FILTER
Fits: XS1100 (77-78).
52mm opening. It is advised that you measure your carb to ensure that this will fit.


$10.00US EA.

Part#15-0032
********************************
OVAL CHROME CAP AIR FILTER
54mm Fits XS1100 (79-81)


$12.00US EA.

Part#15-0035

[joshua]

Thanks TopCat. I'll look into that once I can get the gas to stop pouring into my airbox. It's rediculous. I've cleaned the carbs, replaced seats and o-rings, set float hights....but when i hook the gas up and turn it on to prime I'm getting a pretty decent flow of gas right into the airbox. My garage stinks, my hands stink, my bike stinks....I'm getting pretty fed up with this.

[randy]

Joshua,

One of your floats may be hanging up on the inside of the bowl. When you have the carbs on the bench, clear of gas, blow into the fuel line while tipping the rack upside down. The floats shold cut off the air pressure, if they dont, then a float is hanging.

Do this for both pairs of carbs.