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Discussion Starter · #1 ·
Has anyone ever set their timing wrong by accident or on purpose on one of these machines? I'm getting a large amount of fuel stand-off coming out of my carb, it runs, it runs decent at idle it runs decent SOMETIMES at high RPM but it develops an issue after it's been run for a bit with the airbox on. it's pushing a pile of raw fuel back out of the carb and

I've set my valves and done a ton of other tests to try and determine why i'm having issues revving out, I'm about to start swapping jetting despite having the same jets functioning for a long time, I'm curious if I set my timing off by 10.5 degrees by accident is there some way to test this without pulling the head again?

I do know the problem is intermittent, I wonder if part of that is that it loads up on fuel and starts causing issues getting richer and richer then after some time it clears it's throat sitting off...

does anyone have any experience setting the timing advanced on these by 1 tooth?
 

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I think you can put a timing gun on the timing marks in the inspection hole.
Have you checked the diaphragm in the carb?
Float level?
 

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One way to test is remove the tappet covers and see how much the valves move before and after TDC. Not sure how much difference 1 tooth out would make on the proper clearance if cam was off either way. The two I have done I made them dead on. If it's too hard to tell how much they move and when, you may just have to remove head and verify cam placement at TDC.
 

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Discussion Starter · #4 ·
Checked my float level, checked my diaphragm 3x now, checked diaphragm spring (new last year, only clipped 1.5) This only started happening after I did timing chain, wet clutch, starter clutch, and most of the bears and seals associated.

I'll see if I can find a timing gun that will work for single cylinder wasted spark system. I don't believe my ignition timing is off, I think it's my valve timing if that makes sense? would a timing gun be able to show valve timing off? I think my intake valves are hanging open just a small bit after BDC so the piston starts coming up just before the valves close and is causing the excess of fuel to shove out of my carb and backwards into my filter. with a few high RPM rev dumps everything in the path of my carbs intake side is soaked in raw fuel.

there are 34 teeth on the cam sprocket, 360 degrees/34 teeth = 10.588 degrees per tooth, so if somehow I ended up 1 tooth off i think it might create my issue, but I'm not sure.
 

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Did you thoroughly inspect the camshaft before you installed it. I changed mine on my 400 when I couldn’t get rid of the tick after any adjustment. Turns out my rockers were shot with the exhaust one the worst one. One lobe on the cam had wear on the lead side. The other was worn on the back side. I installed a new cam and rockers from Suzuki.
 

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Discussion Starter · #6 ·
I didn't thoroughly inspect the cam or the rockers, my theory was "it was running fine when I took it apart, I took it apart to change unrelated parts (starter clutch squealing, wet clutch slipping) timing chain was a "just cause I'm here" change.

I'm hoping it's not cam/rockers, if it is, it may start looking like a new quad next year and my season being over. overspent like crazy on it this year ($2k and counting in parts)
 

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I’m thinking you should double check the cam position at TDC. It’s not like you need to buy a gasket. When you think about it more, 10 degrees is a lot to be out. What it does being out, I’m don’t know for sure.
 

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Discussion Starter · #8 · (Edited)
I think what it does being out is instills an awful false rev-limiter between 3300 and 4800 RPM and chuffs tons of fuel backwards through the carb making a nasty mess all over everything causing it to flood out at high RPM. This false rev limiter I've been having.

I've swapped coil, cdi, inspected stator, unplugged voltage regulator, cleaned and inspected carb 4+ times now, set valves, pulled stator cover off again to check stator and flywheel AGAIN,

I'm thinking the same thing, I've got a tube of that nasty goop already on my shelf, might as well pull the 8 bolts and have a look. It is frustrating because I spent 2 hours the other day setting my valves to be just perfect, and when I replace the liquid snot and make a massive mess I'll need to do it again. My friends all say "there is no way you are 1 tooth out or it wouldn't run" but I think on these old tractors the tolerances are pretty loose, and the machine will run on hopes and dreams most days. (it ran with piston slap for... 3 years.. 2100 miles..)

The only thing I can think of that could be causing so much fuel to be shooting backwards out of the carb, valves sticking open, or valve timing delayed slightly so they close after the piston has started it's up-stroke.
 

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IF and that’s a big If, you are out a tooth, you have set the valve lash in the wrong position. It’s frustrating but you gotta pull it apart just for peace of mind. If it’s dead on, then we have a whole other issue to deal with. Makes you hope it’s a tooth out lol!
 

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Discussion Starter · #10 ·
Yeah, if I'm out a tooth I need to reset my valves anyways because the rocker arms mounted in the rocker box vs the valves set in the heads, the thickness of liquid gasket effects the valve setting and adjustment. the first time i put it back together and realized I had wet fuel spraying inside my airbox I re-set valves because the thickness of gasket maker was different. I really wish Zuki/Cat would have just spec'd a gasket for that rocker box.
 

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Discussion Starter · #11 ·
Wheel Tire Automotive lighting Automotive tire Tread


Just a little bit out of time... But still ran
 
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Discussion Starter · #12 ·
Thank you Suzuki for not making interference fit valves
 

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So is it back together and running like a charm? Hopefully you fixed the issue.
 
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Discussion Starter · #14 ·
Mostly back together, far enough for a test run before bed last night. Fired up and idled way higher, will adjust that tonight.

Put a long skinny screwdriver down plug hole, pulled valve covers and turned engine over by hand to realize the intake valves were opening before tdc exhaust, exhaust was opening before BDC compression.

Pulled rocker box, fixed timing, bolted up, realized I forgot to bend tabs on cam gear retainer, opened, bent tabs, closed, bump start, bed.
 
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