Head Squish Article Questions

[FFRDave]

Will I need a strap wrench and a 20 foot long cheater ?

I made sure the piston was coming up (compression stroke) when I placed the solder on. Then I carefully moved the kicker until it stopped. Then I applied pressure with my foot on the kicker until it completed the stroke through TDC.

After TDC, the piston did rise and fall in the cylinder a couple times. I was a little worried about a chunk of solder being sheared off in the cylinder ports. I think I lucked out because I measured the length of each of my solder strands and compared to the total diameter of my cylinder. The solder strands were all pretty close in length. I was using .125" solder. I think I may want to try the thinner 0.093", as this may bind less.

The tech artical should probably suggest the preferred engine rotation method in order to help the clueless (like me) who try to do this measurement.

[RBD]

Just a quick reply for now.

DO NOT use the kick starter to rotate the crank shaft when checking squish.
Use a wrench or socket on a breaker bar on the flywheel nut and just rock the engine back and forth over TDC.

There is absolutely no need to move the piston any lower than 1/4" below TDC.

Rotating the piston blow the ports is NOT recommended.

I will post more on this at a later time.

Thank you,
Ron

[Eric K]

Originally Posted by FFRDave

Will I need a strap wrench and a 20 foot long cheater ?

I rotated the flywheel by hand to squish the solder. Go slow and apply gradual pressure. It yields quite easily.

[webmaster]

Thanks Dave,
Ron sent me some updates for the article to clarify rotation of the crankshaft while performing this task. I updated the article with his edits. Please take a look and PM myself and RBD if you think it needs further clarification.

I encouraged Ron to put this article together and even helped him write a rough draft to get him going (so you can partly blame me!) I did this because I do think this is a "must do" mod on the bike. It makes it run much cleaner and more efficient. No downside. Given this, and Ron's reasonable pricing and extremely high quality of work - it is a no-brainer...

jeff

[FFRDave]

Yes, Thankyou. I totaly agree.

I look forward to a machine that runs at the top of its game. I am confident that I will like the results.

One huge reason why I post my exploits here is for the purpose of providing a "lessons learned" for others like me. I believe that there are many shade tree mechanics who own a GG and when they find this artical on how to do a Head Squish measurement they will want to try it. In the process of sharing my goofs, I may lose some credability, but I gain the knowlage that someone like me is out there thinking "sure glad I didnt turn that motor with the kicker", even though he will never admit that he planned to use the kicker.


I will try again later tonight when Im off work.

Thanks again for taking my troubles to heart. Now Im gonna tel you about my ex-wife ... Just kidding

[FFRDave]

Thanks everyone for all of your help.

The second attempt went much better.

The engine rotated much easier by turning the 18mm fly-wheel nut. A person could really have grabbed the fly-wheel by hand and turned the engine over TDC quite easily. It takes removing only four 8mm bolts on the plastic fly-wheel cover to expose that 18mm bolt.

I was easily able to rotate the piston up and over TDC both forward and backward to get maximum squish on each of the four strands of 1/8" solder.

Why does it take so much more force to turn the kickstarter lever than the flywheel ?

[(F5)]

Mechanical advantage through Gearing. Or in this case Disadvantage. When you kick the starter it turns the engine over a few times, where as the flywheel is on a 1:1 ratio, . . Funnily enough.

[FFRDave]

I love my Gas gas !!

Now I love it more. I have another post in the Product Reveiw section.

Its well worth the cost.

I love my Gas gas !!