In about 2-3 weeks ill be breaking in my new top end

motofox2006 · Post by **motofox2006** » 07:19 pm Mar 10 2007

Last week I put my bike in the reconditioners for new piston and rings and a sleeve put in due to a big scratch in the bore, Im also getting the head moded at the same time, at the moment my jetting is a 158 main and 45 pilot, I do believe the main is to rich and the pilot is too lean.
Is it bad if I break my top end in with this jetting because I can hardly rejet at the same time as breaking it in.

Has anyone had their head modded just by itself, does it increase power much.

And my power valves are being replaced because they had all snapped and werent working at all will this make me notice much difference. I cant wait to feel the results.

KillDozer · Post by **KillDozer** » 09:08 am Mar 11 2007

With just your power valves working you will notice a huge difference.

motofox2006 · Post by **motofox2006** » 01:09 pm Mar 11 2007

It felt powerful as it is not as powerful as dads yz400 but it felt powerful.

crazyaboutriding · Post by **crazyaboutriding** » 01:19 pm Mar 11 2007

it will definately help. once i had gotten mine fixed after not working it felt like a whole different bike. as of now it has almost NO low end.

motofox2006 · Post by **motofox2006** » 10:00 pm Mar 11 2007

How often do the powervalves need replacing?

Does anyone know about the break in
at the moment my jetting is a 158 main and 45 pilot, I do believe the main is to rich and the pilot is too lean.
Is it bad if I break my top end in with this jetting because I can hardly rejet at the same time as breaking it in.

motofox2006 · Post by **motofox2006** » 10:05 pm Mar 12 2007

can someone answer my question please

Post by **Indawoods** » 10:07 pm Mar 12 2007

I have never replaced my power valves on either my 92 or 95 KDX.

So how often depends on how often you manage to break them.

motofox2006 · Post by **motofox2006** » 10:52 pm Mar 12 2007

Does anyone know about the break in
at the moment my jetting is a 158 main and 45 pilot, I do believe the main is to rich and the pilot is too lean.
Is it bad if I break my top end in with this jetting because I can hardly rejet at the same time as breaking it in.

Post by **Indawoods** » 10:58 pm Mar 12 2007

A question is usually followed by a question mark my paisty friend...

You should get it in the ballpark for your elevation and temps... and you haven't given any info on that....

motofox2006 · Post by **motofox2006** » 01:35 am Mar 13 2007

My main is one size rich, I think, my pilot is one size lean I think, is it bad to break in my top end with slightly off jetting? because I cant jet it why breaking it in

hart125 · Post by **hart125** » 01:51 pm Mar 13 2007

I just caused a bunch of trouble with my new piston and cyl by having it too lean. tolerences are the tightest when new so if there is a little too much heat that will be when its the most dangerous. Just be sure your too rich for the first 5 gallons of gas or so. then lean out. Id consider a 48/160 for breakin unless thats too rich to run.

motofox2006 · Post by **motofox2006** » 10:03 pm Mar 13 2007

Thats alright what you said there but ive heard that you shouldnt have to richen the fuel mixture to break it in all i was asking if it is bad to break in the top end with a lean pilot/ rich main

tha_reids · Post by **tha_reids** » 10:49 pm Mar 13 2007

I would be patient. Make one change at a time. You can end up with a poorly running motor and not have a clue as to why or what upgrade had what effect on how it ran. If you want to be thorough save that for when your checking tolerances.

I don't think you'll have any issues with your jetting. Save that for after you break-in.

motofox2006 · Post by **motofox2006** » 12:22 am Mar 14 2007

Ok thanks mate

hart125 · Post by **hart125** » 03:58 pm Mar 15 2007

motofox2006 wrote:Thats alright what you said there but ive heard that you shouldnt have to richen the fuel mixture to break it in all i was asking if it is bad to break in the top end with a lean pilot/ rich main

most of my damage in the past wasn't from too lean main,, its been too lean on the pilot.. the damage is less at lower rpm but it still happens and it's a lot harder to tell when its happening, thats why I would at least go to 48 on the pilot

motofox2006 · Post by **motofox2006** » 05:58 pm Mar 19 2007

So when you break in an engine do you richen the jetting or not?

Post by **Indawoods** » 06:03 pm Mar 19 2007

No... should be exactly how you would ride it.

hart125 · Post by **hart125** » 08:47 am Mar 21 2007

yes, exactly as you would ride it if its jetted perfectly as you ride it.(most people dont know) If your not sure,, and it could be lean, error on the rich side! especially if its cold out when your breaking it in

motofox2006 · Post by **motofox2006** » 08:47 pm Mar 21 2007

My jetting is a 158 main and a 45 pilot with 1172n needle in second from top clip position. Can someone give me the ballpark for my jetting for my elevation, and temp. my temp is 10 to 25 degrees celsius, my elevation is 0 - 600 feet above sea level, I ride mostly sand.

Post by **Indawoods** » 10:11 pm Mar 21 2007

What exactly do you have? a 200, 220, 240? What size carb? I tried looking for what you have without any luck....

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In about 2-3 weeks ill be breaking in my new top end

In about 2-3 weeks ill be breaking in my new top end