1998 Steamer Restoration

[ram33]

I'll get my hands on a morgan carbtube!

From the sounds of it, it's running too lean so i'll turn the screws out to 2 turns and work out from there. Fixing the airbox, fine, i need to find more screws as it was missing a load.

Valves i'll need to do more reading, but sure i'll do them, i'll try that after having a little play with the carbs first as I fancy turning the idle out to 2 turns like recommended and seeing what happens, i'll also shim the needles for good measure.

i think the screws are air screws?, if so screwing out more would let more in making it weaker not richer
i maybe wrong though and it wouldn't be the first time

[GavD]

Depends where the screw is,
If it's engine side of the carb it controls fuel and screwing out lets in more fuel(richer).
If it's airbox side it controls air and screwing out will let in more air (leaner).

I think

Or is it the other way round

[Joshorilla]

Fiddled with the carbs a bit, she now starts on the button, idles nicely around 1krpm, throttle is quick to respond and it rides like a double sprung bed with a rocket tied to the underside!

Valves need doing, sounds a bit tappy at low RPM's, job for next weekend!

[nickjtc]

I'll get my hands on a morgan carbtune!

You will not regret it.

[Joshorilla]

Ok!

I've been thinking (dangerous).

* The bike is running rich, too rich at 1 & 3/4 turns, so i'll lean her out to two turns and see.
* The carbs need syncing, since the middle cylinder is fixed and the other two are tune-able, after popping her out to 2 turns on the air screw i'll make a manometer out of a couple of hot dog jars (really tall jam jars) then balance 1 to 2 then 3 to 2 then check 1 to 3 to see if we're all go, rinse repeat.

As much as the morgan carbtunes look good, the springs and rods will have slight differences in friction and compression which i've seen by people hooking up one cylinder to the three morgan ports and getting different readings every time! Physically, a liquid vacuum level is far more accurate.

So, how easy is it to get to the two screws to adjust the butterflies with the tank off and bike running from a res tank?

I also need new hose clamps for the carb boots, B&Q I guess it is!

I am also also painting her this weekend and fitting new seat vinyl!!!

She's coming along, pics on the monday.

[Mustang]

You need to go to less turns on the screws to lean out the idle mix

[Joshorilla]

Really? I love and hate the internet as for anything you'l find someone for and against, but I trust you Mustang!

I was working on the basis that this being airbox side, and being a tapered needle that screws in to reduce the hole size and out to increase the hole size and given this is an air screw it's letting in more of less air.

Turning it out increases the hole size, allows more air, more air to the same amount of fuel = leaner.

Where have I gone wrong with this logic?

[threepot]

Carbtune worked OK on my tiger,and easy. Placed tank to side of bike and used a length of pipe join to fuel line. Adj screws easy to reach with longish Philips. Try doing a zx9r!

[Joshorilla]

I'm not saying they don't work ok threepot! I'm sure they are fine, fast and accurate enough.

I'm just saying that measuring pressure relative to each other is going to be more accurate, and cheaper.

Think of it like standing on three pairs of weighing sales, each scale may be out by a pound or two from each other, so while it's accurate it's not mega accurate, but if you were to build a highly accurate seesaw and counter your weight with an arbitrary small item like sugar cubes, you could tell your weight relative to sugar cubes down to a grain of sugar. It's more effort and it's harder, but it's cheaper and more accurate.

[Mustang]

Really? I love and hate the internet as for anything you'l find someone for and against, but I trust you Mustang!

I was working on the basis that this being airbox side, and being a tapered needle that screws in to reduce the hole size and out to increase the hole size and given this is an air screw it's letting in more of less air.

Turning it out increases the hole size, allows more air, more air to the same amount of fuel = leaner.

Where have I gone wrong with this logic?

the needle is engine side of carb not air box side.
The mixture screw controls fuel flow.

[Joshorilla]

That makes more sense! Thanks for the explanation Mustang!

[Sin_Tiger]

you could tell your weight relative to sugar cubes down to a grain of sugar. It's more effort and it's harder, but it's cheaper and more accurate.

Unless you're diabetic 

Someday you need to treat yourself to a Morgan Carbtune set, trust us, if you are at all mechanically inclined you will use them, sigh in a contented fashion and believe there is a God of engineers   

[nickjtc]

I'm just saying that measuring pressure relative to each other is going to be more accurate, and cheaper.

Cheaper for sure. Yes, the Carbtune may not be exactly accurate as to the precise mmHg of vacuum, but it does do a good job of showing the balance of vacuum in each carb.

I was pleasantly surprised at how easy it was to use it.

[Joshorilla]

Yeah i'm sure they're great, but for £70 (inc delivery to Channel Islands) or $190 for our cousins, I really can't justify it over making something for free that does the same thing, but at the cost of taking more of my time and being more effort, as I enjoy making stuff like that, it isn't an issue for me.

And aside from the Tiger I only own twins (er500 and exr250r), and the two bottle manometer seems ideal.

[nickjtc]

as I enjoy making stuff like that, it isn't an issue for me.

I agree with that. Before I got the Carbtune I used the set up with two lengths of clear plastic hose made into loops with little ball bearings in them. Worked just fine, except you are only able to work on one cylinder at a time as well as the standard one.