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Offline ncfrc

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Base gasket or not ?
« on: February 15, 2013, 10:56:58 AM »
I have an 06 KDX-200 that was ported and I know the
exhaust port was raised.
I want to get back some of the low end power and am
considering not using the roughly .020 base gasket.

Any thoughts on this ?
Will you feel .020 port height in the throttle ?

New Here ,,, thanks a lot for any input.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline evo550

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Base gasket or not ?
« Reply #1 on: February 15, 2013, 11:46:38 AM »
My suggestion is keep the base gasket....please.
You will just end up with a seized motor, then you will have no bottom end...or mid range....or top end.
If it's that important, get yourself a second hand, unmolested cylinder and fit that.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline cnrcpla

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Base gasket or not ?
« Reply #2 on: February 15, 2013, 12:56:43 PM »
Always use gaskets. Metal on metal sealing is much less than perfect an not using a gasket is asking for an air leak causing extreme lean conditions and a fried motor. Not to mention, I very highly doubt that the coolant would stay in place (as in out of the motor or inside of the cooling jackets) with out spewing all over the place not using a gasket.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ncfrc

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Base gasket or not ?
« Reply #3 on: February 15, 2013, 01:35:59 PM »
If I didn't use the thick paper gasket , I was going to use a
very high quality RTV like Permatex RT. Stuff.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline moto867

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Base gasket or not ?
« Reply #4 on: February 15, 2013, 02:09:11 PM »
you could just have the cyl base turned down .020" on a lathe
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ncfrc

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Base gasket or not ?
« Reply #5 on: February 15, 2013, 02:30:52 PM »
Do you think .020 in port height would be noticeable in
low end performance ?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ford832

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Base gasket or not ?
« Reply #6 on: February 15, 2013, 04:35:37 PM »
It's not uncommon to eliminate the base gasket on a 2t.If you were going to do it,I'd go with either 1194 or 1211
http://www.threebond.co.uk/PRODUCTS/ThreeBondSealants/LiquidGaskets/tabid/229/Default.aspx
I expect the low end difference would be negligible though.
I see you have a 220 as well.As you are no doubt aware,the 220 runs a smaller carb than the 200 and therefore has better low end.For the couple minutes it takes,I'd swap carbs and see where you're at-with the base gasket in place.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
I'd rather a full bottle in front of me than a full frontal lobotomy.

Offline moto867

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Base gasket or not ?
« Reply #7 on: February 15, 2013, 10:40:14 PM »
yes you'll notice it, but make sure you check the squish clearance.  if someone has been in there before they may have altered it.  i wouldnt go tighter than .045"-.050" with an older crank.  with a new crank i have run it as tight as .030"
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline beaner

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Base gasket or not ?
« Reply #8 on: February 15, 2013, 10:48:53 PM »
  i wouldnt go tighter than .045"-.050" with an older crank.  with a new crank i have run it as tight as .030"

If your piston is moving .015"-.020" because of your crank, you have bigger problems.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Ontario, Canada

Offline ncfrc

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Base gasket or not ?
« Reply #9 on: February 16, 2013, 09:23:45 AM »
It's not uncommon to eliminate the base gasket on a 2t.If you were going to do it,I'd go with either 1194 or 1211
http://www.threebond.co.uk/PRODUCTS/ThreeBondSealants/LiquidGaskets/tabid/229/Default.aspx
I expect the low end difference would be negligible though.
I see you have a 220 as well.As you are no doubt aware,the 220 runs a smaller carb than the 200 and therefore has better low end.For the couple minutes it takes,I'd swap carbs and see where you're at-with the base gasket in place.

I did that a couple years ago when my son first got this bike . The 33 mm carb did improve low end snap but more so it
made the power very linier , no major hit at 2/3rds throttle.
I have a 35 on my 220 and it's great !
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ncfrc

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Base gasket or not ?
« Reply #10 on: February 16, 2013, 09:44:49 AM »
yes you'll notice it, but make sure you check the squish clearance.  if someone has been in there before they may have altered it.  i wouldnt go tighter than .045"-.050" with an older crank.  with a new crank i have run it as tight as .030"

If I do this , I'm aware that I may have to run 2 head gaskets as their basically just a .010 metal shim.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline 2T Institute

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Base gasket or not ?
« Reply #11 on: February 16, 2013, 10:11:05 AM »
First check if the main exhaust and sub exhaust ports open at the same time. If they do kick who ever did the porting in the arse. Dropping the cylinder will help(you can use a gasket cut from a manilla folder and greased if you like)  as will putting a spacer on the KIPS sub chamber and cylinder. The KDX is in a low state of tune to begin with, sorting the cylinder head out and upping the comp works well. Check the KIPS mechanism regularly the low state of tune makes bad carbon build up which spells death for KIPS gears.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ncfrc

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Base gasket or not ?
« Reply #12 on: February 16, 2013, 10:27:27 AM »
Above 6000 rpm's the KIPS system opens the exhaust port and the side exh. ports.
After doing some further homework on the porting done , only the center main exhaust port
was raised. The three ports are at the same height where stock the main port is lower.
I'd like to find a spec on how much lower.
Thanks for your help
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline 2T Institute

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Base gasket or not ?
« Reply #13 on: February 16, 2013, 11:10:05 AM »
Whoever did that needs a kick in the arse opening main and subs all at once gains a tiny bit of top end a looses oodles of mid range(as you have found out). What should have happened is to machine off the base of the cyl and raise the main so it opens first followed by the sub ports. That makes the best mid and most top end. Stock set up is in between the 2. Have worked on a few KDX's and goes miles better than standard.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ford832

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Base gasket or not ?
« Reply #14 on: February 16, 2013, 12:57:24 PM »
Sweet looking bikes Ncfrc.They'll go like a raped ape when opened up compared to stock and are probably the most overlooked woods bike out there.I'm sure the majority of the off road riding population would go faster on one of these than a KTM in the rough stuff.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
I'd rather a full bottle in front of me than a full frontal lobotomy.