Bike before rebuild ran ok, looking for suggestions on what to check
don’t have the resources for a leakdown
cylinder resleeved, new piston+ring, new carb, new seals and bearings, new rod
compression cold and no oil was 120-130.. but a cheap tester, it could be off..
sparks fine and ignition timing seems to be good.. what did I miss? It seems to be getting fuel..
I would, and did, try myself, just don’t know if I’m overlooking something.. bikes can run with 110 compression even.. so it should at least run…? I know a desired rebuild is 160+ (preferably 170+) but it’s cold, not run yet, and well kinda dry I guess. It does seem to get fuel though..
even an airleak should allow it to run? I was thinking it’s the new carb, pwk 38, oem is 36mm tmx ss
I tried to fiddle with the jetting, I think I started with 170 ish and tried a 160 or so, and smaller pilot. Didn’t work
it does turn over ONCE, once every.. 10 kicks? Like you can hear it combusted a single turn, that’s about it. Even if 170 would be lean it would still turn over right? Putting in a 185 or something, would that…? Time is very very scarce for me recently so I figured I’d post, I only have a few hours every month.. so..
Top of anyone’s head, anything I might have overlooked? The boot is a little rigid but didn’t seem to leak before, and even a leak, small one, should allow it to run, what did I miss? Could it be possible a seal, even though I installed them correctly for what I know, is .. or .. it makes obvious compression I’d think if a seal was installed wrong (all parts used are oem, piston too, seals bearings etc) it wouldn’t make any compression or at least turn over?
anyway all tips are welcome, I tried it all (also put gas in the cylinder from the spark plug) also changed a plug, replaced head gaskets just incase I installed em wrong .. (they were oem and brand new of course, I only use new oem parts!) and also to no avail!
thanks in advance
Morning fella,
There all likely far far more knowledgeable people that will respond, but my initial thoughts are;
You say it ran before? Ran well? Started easily (hot and cold)? What led you to rebuild just maintenance?).
As you've eluded to - Jetting and then timing would be the first thing to validate, if she has compression, fuel and a spark. You mention the timing seems to be 'good', but worth validating the timing against a manual etc (simply timing tools are readily available). Remember too that jetting for a bike that's worn will not likely work for then the same bike following rebuild.
Your not getting proper juice/jetting. Squirt some pre-mix in the hole and LMK.
Check to ensure the little woodruff key is in the crankshaft, keeping the flywheel in the right location.
The taper holds the flywheel, not the key.
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Thanks for the tips. I’ll check out the timing and the ignition, seems that’s where you guys all guess where the problem is. I’ll post a reply when I get to it. Thanks a lot
When I said juice I mean go go juice, not spark. If you feed fuel directly into it and it runs it's not the ignition.
Could be a stuck ring. I had one after I rebuilt my yz125.
If i recall i think people were drilling one or two holes where the exhaust bridge is on these. Do some research on it before you dive in however.
To start I would try to start/run it with the old carburetor to eliminate that as the problem.
You're right. Perhaps I shouldn't have said "keeping" it in the right location, but instead "ensuring it's in the correct location during install". Regardless, taking a good look at ensuring the flywheel is in the right location and tightened to spec (so the taper holds it there) is a prudent and easy thing to do with these symptoms.
If the key isn’t in there the bike will have spark but at the wrong time therefore it won’t start.
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