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Posts: 4
Reply with quote  #1 
As a new season is approaching quickly, my understanding is that to keep a 206 running at peek performance a valve job should be performed after every season.

My Motor has just about a complete season of (Sprint) racing and lapping on it and I would like to know which parts should be checked and changed, and what special Briggs tools will be needed. Should valves be changed or just lapped, should springs and or sleeves be changed, what are visual indications of wear? Are there any pitfalls or potential problems that someone should be aware of before beginning a valve job on the LO206?

If there an online manual or video for this process, that would be great.

I have reviewed the Setting Valve lash video, which is great for fine tuning but does not contain the information I am looking for.

Thanks for any help and advice.


Posts: 182
Reply with quote  #2 
The valve guides should be checked for wear and repaired if necessary before anything else is done to the valves or the seats.
I am not a fan of lapping valve and seats.
If you lap the valves you will put a groove in the valve. The depth of the groove is going to depend on what grit of lapping compound you use and how many times they have been lapped. I have seen these grooves be significant enough to reduce the flow past the intake valve and seat. Air flow is what makes power. More air flow = more power less air flow = less power.

In addition to the grooves in the valves lapping often will not remove a dish that often appears in the face of the valve seat. It may look good to the naked eye but when using special tools to test the valves and seats things like this become very obvious.
To get rid of any dish in the valve seats i would suggest that the seats be re-shaped either with carbide cutters, professional quality valve grinding stones or both.

If the valves have been lapped or show any signs of pitting or grooving  under a magnifying glass they should be replaced.

The valve springs should be replace if for no other reason than it's cheap insurance.
If you want to do this right be prepared to spend hundreds of dollars on very specialized tools. You might be better having a professional do this for you. However, be careful who you choose.
If you just want to lap them go to you local auto parts store and buy a lapping stick and some compound.
Quite inexpensive.

tel 920-207-9180

Posts: 4
Reply with quote  #3 
Thanks for the response Faster,

Your information is good and appreciated, but I was hoping for a little more detail about the process and what specific tools or technique would be needed and what pit falls may be encountered. I was very intrigued/ worried after checking out your article about oils brands and their reluctance to mix, I have changed oil brand without flushing the engine, what type of problem might this have created.

My specific questions about the process are how to remove/replace/inspect the valve guides, is there a special Briggs tool to complete this or can another tool be substituted? I also heard that the little retaining clips can be an issue, is this true?

I have a leak down tester and the Briggs valve compressor, and I am not worried about spending a couple of more dollars on tools to be able to learn and do the process myself but this is not something I have done before and need some instruction. I am sure that there are other LO206 runners out there who would be interested in the process as well.

My understanding is that the biggest loss or gain in performance from the LO206 is in the valve train and I would like to have my motor running at its maximum performance within the Rules. That being said I would also like to be guided so that If something needs to be reamed or cleaned, I don't exceed the "no Go".

I was a hoping Briggs would consider an instruction sheet or Video like the Valve Lash one.
What do you think Briggs Racing?

Any more info or help is appreciated.

Thanks, RJ



Posts: 4
Reply with quote  #4 
To Anyone who is interested about Valve Lapping and engine prep,

I did find a great Motor Prep/LO206 Dealer here in Eastern Canada. KDM Racing, from Eastern Ontario, were extremely helpful and prepare a really strong, LEGAL LO206. They offered me the option of Refurbishing my existing motor, a Prepared base motor (no exhaust, pulse, catch can...ect), or a prepared complete motor ready to bolt on to the kart and go. Kelly was extremely helpful and gave some other tuning tips as well.
I can't thank him enough for all his help. I am now running 2/10ths or less off Pole and running with the front runners in my class. (the rest is up to me I guess[smile], my motor can no longer be used as an excuse.
Briggs makes a fantastic package that levels the playing field, but there are small things that a good tuner knows that can help maximize the already great performance, this is what I think KDM does. 

Here are KDM's coordinates right from The Briggs & Stratton dealer page. 

Kdm Racing

17012 Headline Road West Rr#1

Long Sault, On

613 933-2552

I hope this provides a starting point for anyone else who may be looking for a good motor guy.

A great racing season to all!

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