Author Topic: Mainjet adjuster? Doordie please explain  (Read 3565 times)

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Offline demographic

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Mainjet adjuster? Doordie please explain
« on: September 16, 2005, 10:25:41 PM »
While looking through the gallery I spotted this....



Also I spotted this picture...


I can't see it that well from the pictures but it looks like you have used O rings to seal your cylinder head, am I right?
and the port in the back of the piston? to lubricate the small end bearings?

Any chance of a port map to show us the location of that?
And a longer explanation cos I am very interested by that and as I now have two engines I have more bits to play with :wink:
What carb modifications have you made?

I can see the bit on the bottom left of this picture (have seen them advertised but can't remember what they are called :? Maybe an Airstriker wing?) but how well do they work?


And I take it that the mainjet adjuster is the part on the bottom right of the picture and it replaces the standard plug from the bottom of the carb?
If so it looks different from the other mainjet adjuster that you have, whats the difference?

Regards Scott

Offline doordie

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RE: Mainjet adjuster? Doordie please explain
« Reply #1 on: September 18, 2005, 02:50:01 AM »
Demographic,
Many questions there,but I`ll try to answer them!

1)Main adjusters in different size only,one I have made(the big) and one better made found at internet and copied.
2)Sealed with o-rings is old mods, but works very well IF you want to open head often and check.
3)Piston port it?s good for lubricate small bearings and to COOL pistontop(more power for long straights) and make piston a little bit lighter.(A Wisecopiston and a stock modified pistonpin make a huge different,oops a tuning secret). :shock:
4)Ovalbored Kehin PWK 39mm carburator.(Maybe a Lecron 40-42mm in future).
5)Powerblade (KTM 125/200cc use Kehin PWK 39mm)makes faster gasvelocities at part-throttle=more lowend power. :wink:
6)Sorry, no portmap from me. :twisted:

//doordie
Iceroad champion 2006,still 2007,even 2008 without a single race!

Offline YUNGGUNNAZ

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RE: Mainjet adjuster? Doordie please explain
« Reply #2 on: September 20, 2005, 05:54:17 AM »
doordie,you have mail.thks

Offline doordie

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RE: Mainjet adjuster? Doordie please explain
« Reply #3 on: September 21, 2005, 08:13:25 AM »
YUNGGUNNAZ,

No received mail,try again! :wink:

//doordie
Iceroad champion 2006,still 2007,even 2008 without a single race!

Offline YUNGGUNNAZ

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RE: Mainjet adjuster? Doordie please explain
« Reply #4 on: September 21, 2005, 10:09:08 AM »
sent pm again.thks

Offline demographic

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Re: RE: Mainjet adjuster? Doordie please explain
« Reply #5 on: September 24, 2005, 10:22:55 AM »
Quote from: doordie
3)Piston port it?s good for lubricate small bearings and to COOL pistontop(more power for long straights) and make piston a little bit lighter.(A Wisecopiston and a stock modified pistonpin make a huge different,oops a tuning secret). :shock:


I knew from THIS thread that Wiseco KX 500 pistons are 30 grams lighter than the stock pistons which seemed to me to be a significant amount on a reciprocating part.

Offline doordie

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RE: Re: RE: Mainjet adjuster? Doordie please explain
« Reply #6 on: September 25, 2005, 03:38:18 AM »
demographic,

Yes, you can see a big difference about  weights between stock and Wiseco. :wink:

This is a post from another forum (ATM):

Standard: (Wiseco in brackets)

All in = 489g (471g) Wiseco 18g lighter.
Pin = 80g (86g) Wiseco 6g heavier.
Rings = 14g (18g) Wiseco 4g heavier.
Piston = 395g (367g) Wiseco 30g lighter.

I use the best from this worlds! :twisted:

//doordie
Iceroad champion 2006,still 2007,even 2008 without a single race!

Offline demographic

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Re: RE: Re: RE: Mainjet adjuster? Doordie please explain
« Reply #7 on: September 25, 2005, 05:53:04 AM »
Quote from: doordie
demographic,

Yes, you can see a big difference about  weights between stock and Wiseco. :wink:

This is a post from another forum (ATM):

Standard: (Wiseco in brackets)

All in = 489g (471g) Wiseco 18g lighter.
Pin = 80g (86g) Wiseco 6g heavier.
Rings = 14g (18g) Wiseco 4g heavier.
Piston = 395g (367g) Wiseco 30g lighter.

I use the best from this worlds! :twisted:

//doordie


Would that be a Wiseco piston, standard gudgeon pin, and standard rings then?

I am guessing that the standard gudgeon pin is thinner than the Wiseco one, am I right?

Offline Johnniespeed

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RE: Re: RE: Re: RE: Mainjet adjuster? Doordie please explain
« Reply #8 on: September 25, 2005, 06:13:23 AM »
Wow, I havent heard the words "grudgeon pin" in thirty years,  I used to be an MG mechanic.  Thanks for the trip down memorylane.  The words "sparking plug"  "boot""bonnet" and "gaiters" just came back to mind also.
  Back to the reciprotating weight thing,  is it possible to reduce the reciprotating weight to the point of the crankshaft assembly being off balance?  I know when having car engines balanced, the reciprotating weight was figured into a percentage and bob weights were added to compensate. then the crank was spun and balanced.  Is that how a one cylinder is done?
Spring is here and the Mighty 500 wants to ride.
 2004 KX500 E16
 Michigan has the best groomed and mapped trail system, check out the Cycle Conservation Club of Michigan trail maps.

Offline demographic

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Re: RE: Re: RE: Re: RE: Mainjet adjuster? Doordie please exp
« Reply #9 on: September 25, 2005, 06:32:52 AM »
Quote from: Johnniespeed
Wow, I havent heard the words "grudgeon pin" in thirty years,  I used to be an MG mechanic.  Thanks for the trip down memorylane.  The words "sparking plug"  "boot""bonnet" and "gaiters" just came back to mind also.
  Back to the reciprotating weight thing,  is it possible to reduce the reciprotating weight to the point of the crankshaft assembly being off balance?  I know when having car engines balanced, the reciprotating weight was figured into a percentage and bob weights were added to compensate. then the crank was spun and balanced.  Is that how a one cylinder is done?


I am English and over here we still use words like Gudgeon pin, Boot and Bonnet and the only Gaiters I know of are the bits that cover the fork stanchion chrome on right way up forks and the ones that walkers wear at the bottom of their trousers and go over their boots, same thing?

I would have thought that to balance out the piston weight loss you would have to drill out some of the crank web? maybe?

Offline Johnniespeed

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RE: Re: RE: Re: RE: Re: RE: Mainjet adjuster? Doordie please
« Reply #10 on: September 26, 2005, 01:29:17 PM »
Yes those are gaiters!  Also the rubber boots on a cars rack and pinion were referred to as "gaiters" on the new car prep we were supposed to check the Gaiters  for "security and chaffing"  Another word used in reference to English cars was "trunion" .
 I  believe you are right concerning the drilling of the crank web to compensate for piston weight loss. ( if we were doing it perfectly)
Spring is here and the Mighty 500 wants to ride.
 2004 KX500 E16
 Michigan has the best groomed and mapped trail system, check out the Cycle Conservation Club of Michigan trail maps.

Brett

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RE: Re: RE: Re: RE: Re: RE: Mainjet adjuster? Doordie please
« Reply #11 on: October 12, 2005, 10:05:53 PM »
Changing crank balance to suit a 30g piston weight change is a crock of s**t, cranks are only ever perfectly balanced at 1 speed and so a tiny 30g change would only change the perfect balance by 1 or 2 hundred rpm.