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Post by royldoc on Apr 15, 2011 12:44:06 GMT -6
I'm thinking it is an 80 just stamped backwards. It is a 19mm Jing Rong cvk carburetor. This is the carburetor I pulled of the trike when I did the bbk.
Roy
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Post by royldoc on Apr 15, 2011 1:22:58 GMT -6
I was going to change the jets. The main jet I took out is marked JR08. Does this indicate it is a 108 jet?
Roy
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Post by royldoc on Apr 14, 2011 11:25:09 GMT -6
It does sound like a fuel problem. When was the last time you filled up and do you use an additive? quick test, pull the fuel line off carburetor and put in glass jar let some fuel run into jar and check for water. This may not be the problem but it is easy test. I like to eliminate the easy stuff first.
Roy
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Post by royldoc on Apr 14, 2011 9:29:37 GMT -6
I also put a big valve head on. I had to take the valves out and mill it down because when I got it it had a big gouge on the gasket surface all the way across. I milled about .010" off the head. Did you check to make sure the valves don't hit the piston? I put some modeling clay on top of piston about 1/8" thick. I assembled every thing but the valve cover. I did not use gaskets and didn't torque it down just snugged it up good This is just a test fit. You can do this with the gaskets just don't tighten the bolts and compress the gaskets. I don't use the gaskets because when I reassemble it gains that much more clearance. I set the valves to .004" intake .005" exhaust. then turn crank 2 full turns back to top dead center. I then disassembled it. If the valves hit the piston it will be easy to see. I very carefully peeled the clay off the piston. I sliced through the clay where the valves made an impression and measured the thickness. I cleaned every thing up real good and reassembled with gaskets.
Roy
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Post by royldoc on Apr 13, 2011 23:07:59 GMT -6
Are you using a stock head or did you replace it? I just did a 50mm bbk and don't have any problem. I would suspect camshaft timing or valve lash.
Roy
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Post by royldoc on Apr 12, 2011 18:12:21 GMT -6
Finally got the 83cc bbk, big valve head,24mm carburetor on. Started it and let it warm up. it was idling about 2 grand so brought it down to 1600. it was idling good and sounded good. I gave it a little throttle let of it went back to idle and died. I started it up again let it set and idle a little bit, give it throttle it responds good. I let off the throttle it went back to idle and died. If i slowly back off throttle it goes to idle and purrs.
Roy
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Post by royldoc on Apr 7, 2011 0:57:32 GMT -6
I have to agree with alley. bad rings will cause low vacuum and low compression.
Roy
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Post by royldoc on Apr 7, 2011 0:43:11 GMT -6
You are right alley. I didn't catch the part about the reed valve. Its late and I had a real bad day today. Any way even if it is a 2t if it appears to have good compression but no vacuum at intake it's sucking in from some place else. Just not sure where. I could be wrong again.
Roy
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Post by royldoc on Apr 6, 2011 23:41:01 GMT -6
The wind in your hair and the bugs in your teeth. ;D Oh what a feeling.  Roy |
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Post by royldoc on Apr 6, 2011 23:18:16 GMT -6
I had s similar problem on a different type engine one time. took me a while to figure out. It appeared to have good compression but not much vacuum through the carburetor. turned out it was the exhaust spring was to short and weak. On the intake stroke the exhaust valve would drop open slightly. On the compression stroke it would close up. This engine didn't back fire. I even tried the paper at the exhaust tip trick. Hold a piece of paper at the outlet of the exhaust and plug up the intake while trying to crank it. If the paper tries to get sucked in the exhaust valve is suspect. I'm probably wrong but never know. Good luck.
Roy
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Post by royldoc on Apr 5, 2011 12:05:38 GMT -6
Hey guy's thanks for the input. This is a new jug so I don't need to hone the cylinder. Whenever I do a ring job I always hone the cylinder to break the glaze and put cross hatch pattern on the cylinder walls. This helps new rings seat properly.
Roy
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Post by royldoc on Apr 4, 2011 10:55:29 GMT -6
Yes robb you are correct the bevel goes up. but my problem is when I look at the edge of the rings I can't see the bevel. I even used a very large 8x magnifying lens.
Roy
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Post by royldoc on Apr 4, 2011 10:19:33 GMT -6
I'm doing a bbk upgrade and the set of rings I got have no marks on them at all. one is a copper color one is black and the oil ring set. Now I have installed many sets of rings on various types of engines. So I know that rings have a beveled edge and they must be installed with the bevel in the right direction. They are usually marked on the side that goes up. I'm guessing the copper colored one is the top ring. As I look at the edge of the rings I can't determine which way the bevel goes.
Roy
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Post by royldoc on Mar 31, 2011 1:32:53 GMT -6
I do love my trike. I got the 50 so I wouldn't have to go through the registering and tag thing. I knew it wasn't a speed demon when I bought it but it ain't garbage ether. I keep up with 35mph traffic on level but slow down on hills. I got it as a tinker toy so to speak and to ride around my neighborhood. most places I need to go are only a few miles away from me. I enjoy riding a little slower sometimes. and let me tell ya this little trike gets a lot of lookers.
Roy
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Post by royldoc on Mar 30, 2011 12:14:31 GMT -6
Hey alley, mine resembles that remark. ;D
Ok both of them are manufactured by ice bear. don't know if they are tagged by a different company.
The red one is a ace (pst50-12)
The blue one is a mojo (pst50-8) gotta be slower than mine because its blue ;D
Roy
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