Posts
11
Joined
8/1/2016
Location
Georgetown, TX
US
benclimbing
8/2/2016 6:47am
8/2/2016 6:47am
I have a 1985 CR125 that I’ve completely rebuilt. All new bottom end seals and bearings, rebuilt crank, new Hot Rods con-rod, Wiseco piston, properly gapped ring, resurfaced head, new reeds, rebuilt carb, new stator, new coil, good cdi, good compression, passed leakdown test great (held 6lbs for 20 min). It will fire but once it starts it won’t rev at all (see video link below), it will just sit and idle. It seems to dump fuel too, both during starting and idling, so much that I had to empty the crankcase at one point. The ATAC chamber even fills up some and starts to leak. The carb has been completely cleaned multiple times, fuel passages blown out with compressor, floats work, level is correct, needle stops flow properly (I bench tested), jets are new, and tank petcock flows good. No rags in airbox etc, all the basics have been checked. It’s got fuel, spark, air, and good spark timing, or else it wouldn’t even run. It just won’t rev, only bogs every time you crack the throttle. I can’t figure out what the hell is going on here, so I’m looking for help. Any opinions appreciated. Thanks
https://youtu.be/RYsDvZEuaso
Build pics: https://drive.google.com/open?id=0B64HLi9uAU6edTNQcWI4aWZ4VUk
https://youtu.be/RYsDvZEuaso
Build pics: https://drive.google.com/open?id=0B64HLi9uAU6edTNQcWI4aWZ4VUk
I need to find a loaner carb to try, don't have an extra for that bike. I just don't understand how it could dump fuel if the needle seat is new and works fine on the bench. I even leaned it out quite a bit via float, needle and jet adjustments, no change. I understand orifice obstructions causing lean, but a lack of obstructions causing rich, I don't get it.
The cdi is one I just bought off ebay ($80), thinking the old one might be suspect. Same outcome.
Stator and pickup are brand new too ($90). Getting tired of throwing money at this thing; I've built a lot of bikes/motors and just can't bring myself to take it to a repair shop.
The Shop
are you 100 percent sure its got the rite one?
As far as the carb issue; My buddy had a similar problem on his '98 YZ250. He finally replaced the carb and it solved the problem. He could only assume the casting had a hairline crack somewhere inside and the gas was being sucked through while the bike was running.
Good luck ben.
Pics of my 1985 CR125:
https://drive.google.com/open?id=0B64HLi9uAU6edTNQcWI4aWZ4VUk
And pics of my 1986 CR500:
https://drive.google.com/open?id=0B64HLi9uAU6efll2QTJkbnZ2ZHVQdExjUGk3V…
Pit Row
Brian riv187
The problem is solved. I bought the bike from Ben. When I got it, it tried to run when kicked but died immediately. I suspected timing. Bright blue spark easily seen in daylight. I checked pulsar gap first,,noticed it was new aftermarket and gapped a little wide. I tightened gap, but only minor improvement.. Then I checked flywheel part number, also that crank had a key. I saw the aftermarket stator too. Ben was thinking on right line. Double checked wires. Then swapped stock stator plate with stock pulsar off my bike. Started and ran 1st kick ! Yippeee. I was believing the Pulsar was culprit,, so I put the aftermarket one on my stock stator plate...and back to not running more than 1-2 seconds.
I know these aftermarket places,,many with Chinese import stuff, say one size fits all...but they are wrong. The Pulsar can effect timing and did on this one.
There are now several ruts and turfs stripes up and down my yard
This bike will receive this Mugen top end from a rusty crusty swap meet Cr I have. The crusty chassis wasn't worth fixing with all the bad stuff. Thanks to Ben, I have a nice bike to marry my top end too...
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