Author Topic: JETTING Advice IT400D  (Read 514 times)

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Offline ozadvntr

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« on: October 30, 2017, 09:46:35 AM »
Hi all,
I am having issues with my IT400D leaning out at higher revs and running on. I am riding it mostly doing VMX at the moment and have been up and down on the needle and up on the main with no luck.

I intend on changing the needle and nozzle as the needle is slightly bent. I only discovered this yesterday.

Any successful specs appreciated including nozzle and needle recommendations as well as MJ size and Pilot Jet size.

IT400D, IT250G, IT200N

Offline mboddy

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    • Vinduro Penrite Team
Re: JETTING Advice IT400D
« Reply #1 on: November 01, 2017, 07:17:34 AM »
First make sure your crank seals are good, no leaks around head gasket or base gasket and no cracks in the inlet manifold.
Is the ignition timing correct? Do you just have the one original head gasket?
Is it all still original IT400D; pipe, silencer, piston, air box cover?
What two stroke oil and ratio are you using?
Vinduro Penrite Team
1980 IT125G, 1979 IT175F, 1984 IT200L, 1977 IT250D and IT400D

Offline ozadvntr

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Re: JETTING Advice IT400D
« Reply #2 on: November 14, 2017, 08:04:25 PM »
Thanks for the reply.

Inlet manifold is fine, new one fitted. New base gasket and head gasket. Crank seals are fine.

Ignition timing is also good. One head gasket.

It has the original chamber but has a GMC silencer, not 12 months old. Piston is fine as are rings and bore. Great compression. Original airbox cover no damage.

Motul 800V at 40:1
IT400D, IT250G, IT200N

Offline twohcrew

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Re: JETTING Advice IT400D
« Reply #3 on: May 15, 2019, 10:13:20 AM »
Have you checked your float height?

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