Murray Carbs?

[johnstewart]

I was poking around this morning on the forums trying to debug my XS1100 issue - hadn't run in a year, started up, but then losing the right two cylinders . I'm thinking a fuel issue, since there's no backfiring. I messed with the octopus the last time I worked on it, so I think maybe low fuel delivery or something.

Anyway, in googling around, I came across this:
https://murrayscarbs.com/product/yam...100e-carb-kit/

Has anyone used these? Seems like a great upgrade, potentially. Just two bloody carbs to worry about, presumably lots more room to work in there.

I got a new bike last summer, but I really still love my old XS11 and want to keep her running. I'm afraid if I don't keep it going, it's going to sit forever. $700 is a lot to spend, especially since I ALSO need to work on 2nd gear issues, but maybe it'd give new life to this old girl.

[DiverRay]

If one side isn't running you have a fuel line/feed problem. I know I've had MANY problems with the fuel line kinking on my '79 Special(3&4 going out on the freeway). Took me a while, because the hose was great at first, but after some heating cycles, it kinked! I no longer have the octy on the bike, and have 6mm hoses on it, not 1/4". They are harder to find, but are the correct size for the fuel fitting and slightly smaller outside diameter so they seem to fit just a little better.

[johnstewart]

Thanks DiverRay - I suspect you're right. It was the last major work I did on it, so therefore the top suspect right now. I know one line I couldn't get fed up quite right without kinking; will have to try and see what I can do.

A while back I tried taking out the octopus.... but then without the vacuum feed and a not-great float, it would spill gas out the carb. And while I would sometimes remember to set the petcocks to OFF, they also aren't the most reliable.

So if I had new carbs, at least I could be confident in the float bowls cutting off fuel when stopped!

[LAB3]

$700 seems like a steep price to fix a problem that can probably be remedied by blowing through a fuel line to unclog it.

[steve scott]

I purchased a set about a month ago. The people at Murray’s were great to deal with. The idea of just two carbs was too interesting not to try. Put them on a bike that I could not get to run after several carb sets. Ran pretty good right away!! I am still tweaking and learning them. They are performing better after every adjustment. Love the simplicity of these. Pm me and we can discuss. Not totally satisfied yet but am confident that I will be. Just love this experiment.

[johnstewart]

steve scott - Thank you! I'm curious to hear your continued feedback on these. The two carb setup seems much simpler. Is it also true that with fewer carbs, and presumably without the stock airbox, that there is more room in there to work?

[Bonz]

Interested in the gas mileage as you're starting to work with them.

[johnstewart]

I bought a set of Murray Carbs.

This weekend I got the old ones off. My octopus repairs from a couple of summers ago, and petcock rebuild, weren't cutting it. I think most of my problems is/was getting the fuel lines routed without kinks, with fuel filters, on the old carbs.

But these seem great in that there's plenty of room to work down there now with the airbox gone. I'm hopeful I can get a nice clean fuel line install.

Questions I have:

1 - There appears to be a second line coming from the intake boot to the OEM carbs. Not the vacuum advance that runs to the left side of the engine, but one little tube that connects from the #2 intake boot to the carb. Is this something to do with how the original Mikuni carbs work; they need some sort of vacuum input? It looks like I need to cap this off (right now I just clamped the hose). Anyone know a good source for rubber caps to do that?

2 - I'm a bit confused on the fuel line size (I'll contact Murray, too). What should I be using? I ordered some 3/16" ID Tygon: https://www.amazon.com/dp/B000PHGY3A - I thought all the XS11 fuel lines were expected to be 1/4" ID, so the Tygon would be going on tighter. And that seems true, when pushing it onto the OEM petcocks. But the fuel input on the Murry carbs seem much smaller, so the Tygon slides on/off easily. I'll need a hose clamp, I guess, to keep them on?

[bikerphil]

Use a spring clamp not the screw type. Some pics of the Murray's carbs installed would be nice.

[johnstewart]

I got it fired up last night! I'll take some pics, yeah.

On Q2 - it wasn't a fuel input, it was a vent hole. The Murray carbs some with small pink hoses plugged into vent holes, 3 on each carb! Kinda ugly.

On Q1 I need to figure out the diameter of those vacs so I can find a plug. Looks like vacuum line plugs are something they have at the auto parts store.

[Radioguylogs]

I think MikesXS.net has the plugs

[bikerphil]

Plugs are 1/8" ID I believe.

[johnstewart]

Finally got back to debugging the XS11 this weekend. I did take some video to send to Murray for his input: https://www.youtube.com/watch?v=gZnvnaayrFE

She runs, but not great (yet).

[johnstewart]

After getting it running a bit (roughly), the two middle pipes are much cooler than the outer ones (240F vs 160F, or thereabouts).

Talked to Murray and the first thought is air leak... but I've double checked all the clamps are bloody tight. Next options are possibly ignition coil. I think I saw a post somewhere that made it sound like the pickup coil could be the issue, too. So going to see about checking those out the next time I have time to do wrenching, goodness knows how long from now.

[bikerphil]

Yep, make sure the electrical is ship shape, cylinders 2 and 3 share the same coil and pickup coil. The bike sounded like it was running on 2 cylinders in the video.

What do the spark plugs look like on 2 and 3?