Finally put together (need Help) Cant get it to idle properly. (2019)

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If gas is pouring out that means the floats are too high and are hitting the base of the main body. How are you setting them. With the stayups, you gently bend the tab. Keep tweaking them lower until the gas flow doesn't happen. Also check that the tickler is withdrawing all the way up into the carb. Once you have the floats set to where the gas isn't pouring out then check the fuel level. Here's how. Get a spare float bowl drain plug, plastic will work fine. Drill a hole in the center and find a 3/16 hose fitting at a hardware store to screw into it. With the carbs on the bike, put the new drain plug in and attach some 3/16 fuel proof hose to it. Make a gentle bend up the side of the carb and secure it with a zip tie. Turn the gas on and give it a few seconds to stabilize. Mark the fuel level in the tube on the float bowl. Measure from the top of the float bowl to the mark. Should be .21" with +/- .004 tolerance.
 
brian4.2 said:
Thanks for all the suggestions. This bike has only been ridden about 3 miles.


After checking, the float heights were slightly over .080". I did set them to level with the top of the bowls, the gas ran out the ticklers freely, i don't think the Vtip ever closed the valve at this height. I couldn't start it like this. So I set them to .020" below , I think the valve never closes, gas is running out the ticklers again freely. Dont know what I am doing wrong. It is both sides. I have checked the metal frames for the float, seem straight and functioning properly.

The ticklers dont seem to travel their full range, can you damage or change a float height by pushing too far?

Sequence of events. Made the adjustment to .020" below the float bowl edge, put them back on the carbs. Opened the petcocks. No leaks. Used the ticklers and they never stopped running, both sides.

Thanks Brian
Click to expand...

Brian.
A few thoughts:

I too went with new premiers and set the floats slightly lower than the top of the bowls. One thing I noticed with the premiers is that the gaskets could interfere with the stayup float operation, so I relieved them to reasonably guarantee no interference. Bike starts easily and runs strong. Have never had overflowing issues.

If you are still seeing wide variations in idle, it could be a combination of high/sticking floats and a vacuum leak at the manifold/head or carb/manifold connection. All carb screws snugged up properly?

Hope this helps.

Regards,
998cc
 
I thought about the gaskets but I figured they hold the pins tight. The float mechanism is on hinge "barrels" these seem to have plenty of clearance to allow the float to pivot on the pins .

Dont know where the idle is at presently, as the gas flows out the ticklers.

I am going to lower the floats again but I'm heading in the direction I was.
 
Amal now recommends to set the fuel level, not the float height.
I usually undo one bowl at a time, twist them around on the Tygon fitting, maintaining the fuel inside, hold the float axle down with a screw driver and open the fuel.
You can see where the fuel level stops this way. I test it several times until I'm comfortable with the reading. Reinstall, then do the next side.
You can get the recommended range of fuel level off the Amal site. I shoot for about 5mm below the top edge, or 3/16".
 
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The fuel level in the bowl can be a little bit low and still be fine. You'll compensate for the slightly lower fuel height with the idle air screw position. It can NOT be too high or near the highest limit or it will flood. Trying to get it as high as possible isn't all that critical. Making sure it's not too high is critical.

WTBS, some people have had floats hang up on the bowl gasket, so they trim the gasket back so the float rises and falls freely. If a float is hanging up on the gasket, that would nicely explain the surging you are experiencing...
 
brian4.2 said:
Thanks for all the suggestions. This bike has only been ridden about 3 miles.

Ok a little work done. The strobe timing is checked, 31 degrees, it tops out just above 4K RPM. It drops to 20 degrees at around 2K RPM. .Doesnt seem to get much lower

I am working on the float heights. Stay up floats, viton tips in new 2 Amal Premiers. Still on the top groove. Pilot jets are clear. 23o mains. I do think it was running very lean.

Todays Problem.

After checking, the float heights were slightly over .080". I did set them to level with the top of the bowls, the gas ran out the ticklers freely, i don't think the Vtip ever closed the valve at this height. I couldn't start it like this. So I set them to .020" below , I think the valve never closes, gas is running out the ticklers again freely. Dont know what I am doing wrong. It is both sides. I have checked the metal frames for the float, seem straight and functioning properly.

The ticklers dont seem to travel their full range, can you damage or change a float height by pushing too far?

Sequence of events. Made the adjustment to .020" below the float bowl edge, put them back on the carbs. Opened the petcocks. No leaks. Used the ticklers and they never stopped running, both sides.

Thanks Brian
Click to expand...

I believe I asked earlier but didn't see a reply, why are you setting needles in top groove which gives leaner mix off idle? Starting point is middle groove AFAIK.

If ticklers are leaking fuel only after you first depress them, perhaps they are sticking and not popping back up fully? If these are like original amals there is a roll pin within the tickler body that can be pulled up or down slightly to change how much they push on the floats.
 
Thanks for all the suggestions. I am working my way thru each problem.

The slide cutaway is #3 or 3"? Is this the correct slide? Cant remember where I read 3.5". What would happen running the wrong slide?

Jets were tight, 330 mains , 106 needle jets. the pilots I will leave alone because their adjustability. They are clear.

Again, this is a 72 750 combat, JS1 cam, combined head and base gasket are @ .095"

"I believe I asked earlier but didn't see a reply, why are you setting needles in top groove which gives leaner mix off idle? Starting point is middle groove AFAIK.
If ticklers are leaking fuel only after you first depress them, perhaps they are sticking and not popping back up fully? If these are like original amals there is a roll pin within the tickler body that can be pulled up or down slightly to change how much they push on the floats."

Thanks, I had to wait to take the carbs off again. Needle position is now the middle. I can't confirm if this is correct.

The ticklers were not the same, one had .125" more travel than the other, I was able to depress the roll pin to get them closer. Within .010"

Made a bench rig to check the fuel level, this was impossible for me to to do on the bike. Still difficult to get the fuel level under .200" without the floats rising above the lip of the bowl.

Hopefully back together tomorrow to check it out. Would like to get some feedback on the slides before I proceed.

Thanks all, Brian
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Finally put together (need Help) Cant get it to idle properly. (2019)
 
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3 is correct for 750, 230 main, middle position.
You probably have the round spray tubes.
If so, the needles should have the two ID rings.

If you have the stepped spray tubes, the needles should have 4 ID rings. These rings are above the 3 clip rings.
 
brian4.2's idea and set-up is an excellent step in capturing real world data. I have found that this method as well as measuring float height from the bowel rim on the opposite (forward) side yield equally acceptable results.

However. In both cases the issue is that the float pivot pin wants to stay put on the bottom of the channel it rests in; you can stake the pin a number of ways as long as you replicate its' functional positioning. Further, if you choose to go for the .080 measurement be sure that the the float yoke is bearing on the bottom side of the float needle's groove.

Additionally. Bending the metal float tab is common, but is not advised. The correct method is to raise or lower the float needle seat. The first time I did this I had no idea what to expect and wondered if the seat would injured; fear not. Select suitable drifts, you will need 2, secure the bowel and apply heat with a heat gun, a torch is to aggressive. It doesn't take long before the seat can be re-positioned. Do keep in mind that drifting the seat up or down by, say, .010 will produce about a 7x change on the opposite side of the bowel.

I have 2 old concentric bowels that I am happy to send to anyone that would like to practice with before working on their operational bowels; the catch is that the recipient(s) must agree to "pay them forward" if others want to gain the experience; with moderators agreement I will start a post that shows who has the bowels; details to first requesters.

Best
 
After watching the video, I'm going to add one thing I know for fact. The occasional white puff of smoke I saw is caused by raw unburned fuel hitting the hot exhaust valve. Weather it's electronic misfire or over rich fowled plug misfire. Good luck, wish you were closer I like a challenge!
 
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