Hi all, Newbie here. This is a great forum and I`m happy I found it, it`s cool to see many others still interested in 3 wheelers.
I have a 1985 Honda 250ES big red, a 1983 185S, a 1984 200S that`s in almost mint shape.
The idle issues I`m having concern the big red and the 185.
The big red will idle, but only for a short time, while it`s idling, it goes up, way up, by ear to at least 1800 RPM or better, then it`ll drop down and idle normal then it gets lower until it shuts off. I installed a carb kit in it, as when I bought it, it had been sitting for a while, the petcock on the fuel tank isn`t in the best of shape, but it doesn`t seem to flood. It has a cobra exhaust and it has great power. I`ve checked for vacuum leaks using carb cleaner and found none. The 185 I bought at a flea market, it`s worn out and I`m soon to be rebuilding it, the carb on it runs pig rich at idle, I backed off on the idle mixture and reset it and it seemed to help at first, then it went back to shutting off with black smoke emitting from the exhaust, the pet **** on this one as well is not in good shape and it too only turns the fuel on when it`s set on reserve. Lastly, can I install a 200X piston in my 200s? I want to raise the compression ratio to the 9.5:1 area the X came with instead of the 7.9:1 ratio the S came with. Also can I bore the 185 out enough to accept a 200X piston? Much thanks to any and all that respond.

 

"Lastly, can I install a 200X piston in my 200s? I want to raise the compression ratio to the 9.5:1 area the X came with instead of the 7.9:1 ratio the S came with. Also can I bore the 185 out enough to accept a 200X piston? Much thanks to any and all that respond. "


yes, yes, and yes.

let me think a bit on your carb issue (haven't had enough coffee yet [img]i/expressions/face-icon-small-happy.gif[/img])

 

I had a simular problem with my 83 110. I'd check the float and float pin.

 

Just wanted to give a update. I fooled around with the big red more, and got the idle to stop going high by adjusting the valves. Now it idles too low and shuts off, also at part throttle it stalls and pops through the exhaust, exactly the same symptoms of a vacuum leak, but I`ve checked all over and can`t find any. The 185 got some what better, sometimes it idles okay, other times it idles too rich and goes dead, but unlike the big red, it has no part throttle hiccups. When I open the 185 up it runs like a scalded dog. So still looking for answers here, where else can I do to check for vacuum leaks? is there anything else that would cause the big red to act like this? Another sign it`s running lean is the exhaust gets hot, so hot it burns my leg, but I don`t know if this is cause the cobra exhaust lacks a heat shield.

 

Another update. I removed the carb`s isolator tube from the big red, cleaned it with carb cleaner, removed the O rings and cleaned them, coated them with vaseline as well as the rest of the flange surface of the isolator. I adjusted the idle mixture 2 turns out, reinstalled the carb, fired it off, problem solved. It idles good, has great power, and no more part throttle stumbles. on the 185s I removed the carb and found everything to be spotlessly clean and in good shape, all passages were clear. Only thing I can come up with is the needle and seat assembly isn`t sealing. How I came to this conclusion was by turning the fuel off and on at the tank to only give the carb a limited amount of fuel, when I did so it idles great with no black smoke, when I turned the fuel on and left it, it idled okay a few seconds then went back to flooding.

 

I had the same issue with my 185S checked everything valves timing
Rabuilt carb Jet carb Vacume leak
Nothing
Found another carb rebuild Jet to engine
Runs and Idles great
I have tried old carb back on engine several times Problem comes back
Some times things make no sense in the mechanical world
But another carb solved my issue
Now I can ride
Thanks
Ray

 

I appreciate the heads up, I finally figured what you was saying was true after many attempts, I still couldn`t get it to work. So finally I took the plunge and found a new 200S carb on Ebay, it`s brand new and Identical to the original carb, except it has a different name. I paid $60 for it. I have my 185 stripped down right now, I mic`d the bore and found it to have way too much clearence, around .008, I did find the piston and rings were new, as was the timing chain. But I knew also it was low on compression, the excessive clearence told me why. So I got a new 200X piston from my nephew that he didn`t use that`s .010 over. My machinist has the jug boring it to size, also ordered a new high performance cam for it along with a cobra exhaust. Hopefully by the time I`m done, it should have plenty of get up. I`m by no means a speed rider, but I like`em to have power when it`s needed.