It fires up quick with full choke,takes several minutes to warm up, RPMs climb so you have to gradually reduce choke to keep engine speed down. When finally warm, throttle response is barely OK, then engine quits around 4500 or 5000. If you let up on the throttle it begins running again. A quick float level check with a clear line indicates floats are way low, so I will attack this first. Is the number I keep seeing ...36mm... to be used like other carbs as the distance from the gasket surface(not the gasket itself) to whatever the highest surface of the float? is this the right measurement for an 83?
I have read about the rev limiter wire but I don't want to start cutting wires...this thing is in too nice a shape to start butchering it..........
Thanks
You can disconnect the rev limiter wire at the back of the gauge cluster.
The service manual has a specific method of checking float level by connecting clear tubing to the carb drain tube. Not a fun job.
Thanks for the tip about the wire to the guage cluster.
I have done the float level check with the tubing. What I'm looking for is ..What do you do when you are obviously way off on float level? I am going to pull the tops off and reset the floats, but without a benchtop measurement it's just poke and hope, and I don't think the experts on here would accept that. There must be a measurement one can use to get in the ball park, that's what I'm looking for.
Whatever you do, don't attempt to remove the float pin from its' pedistals. Breakage of one of the pedistals is almost a certainty. The Haynes manual has a float highth setting. I don't remember what it is.
Quote from: pullshocks on September 11, 2011, 11:14:46 AM
The service manual has a specific method of checking float level by connecting clear tubing to the carb drain tube. Not a fun job.
naw, not that bad to do. adjusting valves..now that sucks! lol
i'd call it 90/10 that they won't break. i've done dozens... my technique is, using chanel locks, press the small end of the pin to the post by carefully squeezing the pin into the post with the ch-locks (one jaw behind the post, one on the pin) then pry the pin the rest of the way free with a small flat screwdriver under the head. use care & caution, & all should be good
Fuel level in the clear tube should be 20 mm (.79") below the bottom of the gasket. If it is not you have to take the carb apart.
First verify that it is not a sticky float valve.
If that's ok then you are faced with the trial and error (or poke and hope, as you said) process of gently tweaking the float assembly and re-checking the fuel level disassembling the carb each time. There is a little tab that bears on the float needle--apply a very gentle bending pressure. I think it took me about 5 tries on each carb. I had the carbs removed when I did this, and rigged a little fuel reservoir connected to the fuel inlet. As they say, do this in a well ventilated area.
I pulled the carbs for the 3rd or 4th time. Set the floats to 36mm off the gasket surface. Also discovered I had the adjustable balance bar between the butterflies on backwards which keeps them from opening more than about halfway. Also this stops the accelerator pump from spraying down the throat. After fixing these items, it runs quite well, still very cold blooded. My son rode it for a half hour tonight with no problems other than the tach died. Any suggestions?
Quote from: pullshocks on September 11, 2011, 04:28:53 PM
Fuel level in the clear tube should be 20 mm (.79") below the bottom of the gasket. If it is not you have to take the carb apart.
First verify that it is not a sticky float valve.
If that's ok then you are faced with the trial and error (or poke and hope, as you said) process of gently tweaking the float assembly and re-checking the fuel level disassembling the carb each time. There is a little tab that bears on the float needle--apply a very gentle bending pressure. I think it took me about 5 tries on each carb. I had the carbs removed when I did this, and rigged a little fuel reservoir connected to the fuel inlet. As they say, do this in a well ventilated area.
I know this is an old thread but starting another to ask a question just scatters info around.
I searched but could not find a reference to static float height. This would be when the top of carb is inverted and gravity holds the float against the valve. Then the distance from the top of the float to the gasket surface is measured.
If this dimension was captured then the number of attempts to get the float height correct can often be reduced to 1.
Checked in the service manual, info on page 106:
Setting the float arms so they are parallel to the body of the carb top should get you very close.
Quote from: George R. Young on November 06, 2021, 09:12:03 PM
Checked in the service manual, info on page 106:
I would but I have misplaced my service manual. :(
What is the point of reference for those measurements?
Download the service manual from POD's postings. There are links for lots of technical stuff whenever he posts. :)
Thanks for the reminder. :-)
And the info.
-Mike O.
1. To measure the float height, you do this with the carb top off and at a 45 degree angle. Measure 36mm from the top of the float to the gasket surface
2. To measure the fuel height measure fully assemble with the clear tube. It should be 20 mm from the upper gasket surface of the main body
If you get 1 right, then 2 will usually also be correct. Too high and you have a valve issue, too low and you have a float issue (or rarely the overflows are pressed in too low). Better hope for too high because floats are impossible to find. Both measurements are in Haynes - see links in my sig.
I'd advise not to use Lucky's method or the Haynes method. You might get lucky but if you snap the leg you are looking for a new carb. Support the leg on a wooden block with a hole drilled so the pin has somewhere to go. Knock the pin out with a pin punch or even a nail narrower than the pin - it will work every time. There's no friction on the end you tap from.
Also while you are working on carbs:
make sure the accelerator pump jets are squirting properly
For 82s swap to 120/120 air jets
Replace the float valve o-rings
Quote from: Prophet Of Doom on November 18, 2021, 04:17:14 AM
Also while you are working on carbs:
make sure the accelerator pump jets are squirting properly
For 82s swap to 120/120 air jets
Replace the float valve o-rings
Check.
Check.
And, check.
I inscribed marks on the carb body to measure the fuel level. I was thinking about taking a queue from some of the 60's and 70's carb by installing a site-glass in the side of the float bowl. Drill a hole. Install a very small lens/crystal at the correct height. My son's RX-7 Nikki carb has windows on the float bowls. Yes it would be unnecessary but may be fun. :-)
I managed to get the engine running after a full charge on the battery. It is now backfiring and occasionally spitting/firing through the intake. :o :( >:(
Never thought of a carb sight glass. What an excellent idea !
Now to find one - such things are hard to find in New Zealand
I have seen watch crystals used as a sight glass for brake fluid reservoirs.
In this case I am thinking of a small lens of some type. Maybe a diameter of around 5mm for laser stuff. Lots of them out there and inexpensive.
https://www.ebay.com/itm/254646545224?hash=item3b4a1deb48:g:RFkAAOSwDlxfBEE9
That sort of thing.
And what adhesive would you use to hold the new lens in place? It would need to withstand continuous contact with fuel.
My granddaughter would say, 'if you can't say something positive, zip it', however. Are you planning to mount a camera to view this sight glass?
Quote from: Walt_M. on November 22, 2021, 06:54:47 AM
My granddaughter would say, 'if you can't say something positive, zip it', however. Are you planning to mount a camera to view this sight glass?
Why would you need to?
The sight glass will tell you at rest if the levels are correct. Enough to see you through your next ride
Quote from: fret not on November 22, 2021, 12:12:26 AM
And what adhesive would you use to hold the new lens in place? It would need to withstand continuous contact with fuel.
Any of the fuel tank epoxy putties would do just fine I'm sure.
I'd prefer something screw in like this
Holley 26-112 Holley Sight Plugs | Summit Racing (https://www.summitracing.com/parts/hly-26-112?rrec=true)
Price is OK, but shipping cost to NZ is 10 times what it actually costs
And it would need to have a lip to sit on so simply drilling a hole would not work. Perhaps drill a hole and then ream out the sides to create a 1mm lip?
POD, a range of watch glass sizes are available in NZ from the "Time Centre" watchmakers supplies in Auckland. Alternatively, as cheap as noodles from Aliexpress from China.
I have used JB Weld Tank Weld epoxy on all sorts of fuel system repairs.
I'd probably use it to seal the crystal in place.