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So wth is the problem now? Not starting

6K views 51 replies 8 participants last post by  morgan 
#1 · (Edited)
07 450er. - New starter and new start clutch. Did I put something back on wrong or forget something? Just turns. Tries to back fire if I turn too long so I know it's getting fuel. Tried with choke on and off. Battery charged for 8hrs. Attached short vid link
 
#3 ·
Could the decompressor be too tight, seem to start strong, but I don't hear a whole lot of compression

Did you try to turn the engine both ways, sometimes you get a reversed sprag and it locks both ways, then the starter drags the engine down.
Changed mine yesterday, that would be the 4th I change on 06-07 models
 
#5 ·
Did you mean the valves? I know it's doesn't always mean anything. But before I changed the starter clutch I could get it to start and run good. But the back firing could have threw the valves off huh. I'm new to small engines. I normally work on automobile motors. I have noticed the mechanics on the two are about the same. Thanks for your help. Your information last time was a big help.
 
#6 · (Edited)
It's the arm on the cam tower with a 8mm bolt and a flat screw that bleeds the compression to allow the starter to trun the engine, must be right exhaust clearance (0,011 typical) + 0,010 in so around 0,021 depending of the ex clearance measurement.
It's not related to the work you have done, unless the valves have been adjusted.

The engine will turn both ways, but the starter and gears should turn only counter clockwise not clockwise (from the clutch side of course).
 
#10 ·
Measure valve lash first, no bacfires can mess valve clearances and decomp, but it's the most common cause of no start. It must be done anyway.
Make sure you have spark, fuel and that the starter is not dragging while the engine turn clockwise by itself.
 
#12 ·
I'm going to check my valves. But this idea about my gears being turned clock wise has me thinking. When I put the starter gear bolt back on and because I used a impact and I didn't have the gears jammed. It turned clockwise quite a bit at First. If that's the case. How do i fix that?
 
#14 ·
Valves need shimming
 
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#16 ·
O7 should have auto decomp... It's ur cables look up ur specs and re shim
 
#20 ·
Yes but different in thickness, you need a 9,48mm diameter shim set, you swap for thinner shims, they are in0,05mm increments, in this case intakes can go down one size and exhausts 0,002 about 4-5 sizes less and the 0,005 about 2-3 sizes down, a caliper comes handy to identify the older shims, for this, make sure you measure with the lobes facing away and decomp away too.
Keep the old shims they are just as good as new.
 
#22 ·
Needed shim = Actual shim - ((Target clearance - actual clearance) *2540)
Needed shim= 205((0.011-0.005)*2540) = 189,76

or

that would be Clearance difference : 0,011-0,005= 0,006

Multiplied by 2540 : 0,006 x 2540 =15.24

Actual shim - 15.24 : 205-25.24 = 189.76 rounded to 190


That confirm my guess lol
 
#26 · (Edited)
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