Removing Fly Wheel (rounded hex bolt!?)

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tizdaz

tizdaz

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hi guys, best way to remove this bolt to remove flywheel?

Screenshot 2023-08-01 081626.png

Tried to loosen it, but the hex key slipped rounding it as the hex bolt was that tight!

Also im guessing i should apply some heat to the bolt 1st?
 
So first, they key is just there to set timing, the crank and flywheel are a tapered interference fit, thays what holds the flywheel to the crank.
Second I'd suspect it wasn't tightened properly, or over tightend, leading to your issue. Many times making the bolt too tight will crack the flywheel and give the same results as it being too loose.
Now as far as getting the nut loose, I find a 3/8 impact works just fine. If you don't have an impact, then you can thread some pull cord down through the plug hole to make a piston stop. Not a preferred method on these engines, but in a pinch it will work just fine. Other option would be to hold the clutch in place. There are various tools foe doing this, but normally you can rig something up to hold it.
 
Seandonato73 said:
Other option would be to hold the clutch in place.
Click to expand...

Bad idea. Problem is you put all twisting motion through the crank pin area which is small and sometimes not much press fit on them. Which means twisting or possibility of twisting crank. You want to do any loosening or tightening on the end you are working on of the crank.
 
The nut that holds the rotor(flywheel) is 112 in lbs, that's 9.333333 ft lbs. Its not much so I cannot see an impact tool causing the crank to come out of phase/balance/line. I personally stuff a rag down the exhaust port and have at it. Pretty sure grown men shake hands with more force than needed to jar that nut loose. I tried knocking the crank pin out of a g320 crank once, I stopped because my snap-on punch shot a piece into my hand, I get the point and my harley crank is the same as this g320 crank and its runout is just fine.
 
Rep732 said:
The nut that holds the rotor(flywheel) is 112 in lbs, that's 9.333333 ft lbs. Its not much so I cannot see an impact tool causing the crank to come out of phase/balance/line. I personally stuff a rag down the exhaust port and have at it. Pretty sure grown men shake hands with more force than needed to jar that nut loose. I tried knocking the crank pin out of a g320 crank once, I stopped because my snap-on punch shot a piece into my hand, I get the point and my harley crank is the same as this g320 crank and its runout is just fine.
Click to expand...
agreed 100% (y) (y)
 
ah sorry guys, it isnt the fly wheel bolt, its the otherside, the clutch bolt that rounded, not the 2 that hold the clutch but the carrier bolt, will get a pic when i take the clutch cover off next week
the bolt that goer in center of this part which is rounded, engine was pretty much brand new so its not been taken off before but its stupidly tight, enough to round the hex bolt on the inside!
Screenshot 2023-08-02 031827.png
 
Rep732 said:
, I get the point and my harley crank is the same as this g320 crank and its runout is just fine.
Click to expand...
We worked on tons of the harley stuff doing machine work on them and we know about them well. But keep in mind it has more surface area with the bigger longer pins in it and are tapered. Zen style cranks as they kept moving the pin outward they did not make the wheel bigger like CY did to keep a good fit. Stock strokes good but once you go up from there they got worse because of pin being closer to edge of wheel so fit is not as good. Cy marine crank takes a pretty good amount to seperate it. Take same Zen 2mm crank stroke and it about falls apart when you touch it. That is why I warned on twisting cranks. Some guys know when to say OK something not right here and stop, but others are "let's get out the 4 foot breaker bar and get this nut lose" with one side of crank locked while working the other end. All twisting now goes through that little crank pin that has no support except for the two main bearings which will not stop it from twisting.
 
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tizdaz said:
ah sorry guys, it isnt the fly wheel bolt, its the otherside, the clutch bolt that rounded, not the 2 that hold the clutch but the carrier bolt, will get a pic when i take the clutch cover off next week
the bolt that goer in center of this part which is rounded, engine was pretty much brand new so its not been taken off before but its stupidly tight, enough to round the hex bolt on the inside!
View attachment 88585
Click to expand...
To get the rounded clutch carrier bolt out you can smash a torx bit in there and it'll come right out, I'm a bit out of touch as I've not touched my rigs in a couple of years but iir the bit you need is a torx T20👍🏼
 
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