Modified Stage 2 Predator 212 Hard to Pull Start and Mikuni 22mm Running Rich

J

JackJ217

Member
#1
#1
Hey all, I have a Predator 212 with a header, billet flywheel, billet rod, hot-265 cam, 22mm Chikuni from gopowersports, and 22 lb valve springs. The flywheel has 34 degrees advance timing. I just put together the engine a couple days ago, rode it for about 30 minutes, went inside, and then when I came back out later it wouldn’t start. I checked the spark plug, and it was black. I know that means that it is running rich. I don’t know know much about Mikunis so any help would be appreciated. So I got it to start again by raising the clip on the jet needle by one spot. I tried revving it a bit, and white smoke came from the exhaust and it stalled. I checked the oil and it was a little low, so I put a bit in and now the pull cord keeps recoiling and ripping out of my hand. I drained a bit of oil and tried it again, and the same thing happened again. The card that came with the valve springs said to put the lash for both at 0.003. If somebody could help that would be great. Sorry if this is all over the place lol.
Thanks in advance.
Some pics of my ride are included :) image.jpg image.jpg image.jpg
 
J

JackJ217

Member
#5
#5
Alright, so it's not the flywheel key, valve lash, or head gasket. I got everything put back together and realized that air/exhaust was coming out of the Mikuni air filter, and the pull rope is still extremely difficult to pull, so there is still a compression issue. The rubber that attaches the air filter to the carb looks intact, but I don't know for sure. Is this a common issue? And does anybody know how to fix it? I already contacted GoPowerSports about this but they haven't gotten back to me yet.
 
ole4

ole4

#6
#6
Is it hard to pull over with the iginition off? IF it is then it is the compression that is pulling the cord out of your hand. Unless your cylinder is full of oil or gas and is hydrauliced then either your compression release is broke or more likely your exhaust lash is loose and not leting the compression release work. You MUST set the piston a few degrees past TDC to insure you are at least at TDC or past before setting your exhaust lash. Set it at a tight .002.
 
J

JackJ217

Member
#7
#7
ole4 said:
Is it hard to pull over with the iginition off? IF it is then it is the compression that is pulling the cord out of your hand. Unless your cylinder is full of oil or gas and is hydrauliced then either your compression release is broke or more likely your exhaust lash is loose and not leting the compression release work. You MUST set the piston a few degrees past TDC to insure you are at least at TDC or past before setting your exhaust lash. Set it at a tight .002.
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Yes, it is hard to pull even with the ignition off. I know the valve lash is correct because I spent a long time making sure I got it right. I can hear air coming from the air filter and I’m pretty sure that’s not normal, correct me if I’m wrong.
 
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SAS289

SAS289

Well-Known Member
#10
#10
You said you spent some time with the valve lash. Did you notice the exhaust side rocker opening slightly and closing around TDC?
 
ole4

ole4

#11
#11
If you pull it over slow on compression you should feel resistance if you try to rotate the exhaust pushrod up until about 10 degrees BTDC. This is because decompressor is holding exhaust valve open. If pushrod spins freely early in compression stroke either CR is not working or lash was adjusted while CR was active. Hope this makes sense. Make sureex pushrod is not bent.
 
J

JackJ217

Member
#12
#12
ole4 said:
If you pull it over slow on compression you should feel resistance if you try to rotate the exhaust pushrod up until about 10 degrees BTDC. This is because decompressor is holding exhaust valve open. If pushrod spins freely early in compression stroke either CR is not working or lash was adjusted while CR was active. Hope this makes sense. Make sureex pushrod is not bent.
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How do I know when I’m about 10 degrees below? Will the exhaust pushrod just barely be up or halfway or somewhere in between? I heard that you should be able to move rockers back and forth a little at TDC. Is this true at 10 BTDC as well?
 
ole4

ole4

#13
#13
If you watch carefully you will see ex rocker close just before TDC. This depends if you set the lash when lifter is on base circle of the cam After it is off the cr tang. the cr lifts the lifter about .010 but they all vary a bit.
 
J

JackJ217

Member
#14
#14
Okay so I let it sit overnight and now the compression seems fine although I have no idea what changed. But it's just not starting. It's turning over just fine I think. It has enough oil and gas so I'm stumped.
 
SAS289

SAS289

Well-Known Member
#15
#15
Compression is one thing, compression release is another. When Ole says cr he is talking about the compression release. Have you verified that the compression release is working? With the rocker cover off you should see the exhaust rocker move up and down if you move the crank back and forth in the TDC area of the compression stroke. And remove the spark plug to make spinning the crank around easier. If you take the blower housing off you could spin the crank with the starter cup by hand.
 
J

JackJ217

Member
#19
#19
Studeman68 said:
Sitting overnight the compression now ok? I'd seriously look at possible hydro locking.
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No it’s not possible that any water got in the engine. It’s only been ridden once after I got it all put back together and since then it’s been in my garage, and no water has been near it.
 
Studeman68

Studeman68

#20
#20
JackJ217 said:
No it’s not possible that any water got in the engine. It’s only been ridden once after I got it all put back together and since then it’s been in my garage, and no water has been near it.
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Hydro locking is fluid build up in the cylinder.. either fuel or oil, or both. You mentioned pulling the needle up in the carb, that only richened it up further. I'd pull the plug and investigate further to see whats getting in there. being able to let it sit for a period of time, and then it pulls over is a big red flag pointing towards hydro lock.
 
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