125-200cc Eric Gorr 144 kit in an 09 WR125

Hi, what Eric Gorr kit did you go for? mid-top or bottom-mid? I am going to sneak this kit into my wife's bike this summer (red sticker season). She like the bike the way it is, and does not want me to mess with it, but what fun is that.
JS

I think you were talking about her liking to ride around lugging it, so I would go with the low to mid. I went with the third option which is more everywhere. He did very little to change the port timing with this option and it just adds the extra 15% everywhere that you get with the extra cc's. I love it, you will be surprised how well it runs everywhere with this option and your wife will love the low end chug.

You will need to do some modification of the Power Valves when you get them back. When Eric grinds them to give the space recommended between the piston and the valves it widens the sealing edge. You have to raise this a few millimeters to bring it back to the opening height that maximizes your low end.

Walt

Thanks! Yes, she does like to chug around, but more everywhere would benefit the both of us! Haha. Are you still running pump gas with this option?

I cannot wait to see you PV mod procedure.

Thanks for being at the forefront of the WR125 mods. Makes it easier for a novice mechanic like me.

JS

Yep, I didn't have him increase compression so I could continue to use pump premium.

Walt

It will be interesting to see how the pv's with the forthcoming OEM 144 kit will compare to your modded pv's

Norman,

I am very interested myself. I can't wait until someone purchases the kit and reports what they find and hopefully provides comparison pics.

Walt

Here are some pics with side by side comparisons between stock power valves and the reground power valves I am using.

Pic #1: This shows how far the sealing surface was relieved to gain clearance with the 2 mm larger radius of the new piston. I made a dashed line on the stock valve to give you a better visual on the difference.

Pic #2: This is a face on shot of the power valves. The sealing surface on the modded valves is ~.11" wide. The sealing surface on the stock valves is ~.21" which means I raised the effective height of the exhaust port 2.5 mm above stock. When Eric grinds the sealing surface back the 2mm, it actually lowers the exhaust port ~ 1.5mm and I had to raise the bottom edge by ~4 mm to get it to this point. The back side grind on the stock valves is ~ 90 degrees to the sealing surface. I made my grind at about a 35-40 degrees to this grind. The stock grind when fully open creates a smooth exhaust port surface on the way out. I wanted to leave as much of this surface in tact and yet still make the angle to the sealing surface steep enough to facilitate gas movement.

Pics #3 & #4: These are pics to illustrate the difference in width of the sealing surfaces new to stock.

Pic #5: This is a front side oblique angle that illustrates the width differences of the sealing surfaces. I blacked out the sealing surfaces on the ground valves to make it more visible. You can also see the angle differences between my grind and the stock grind of the back side.

If I was going to do anything I would actually raise the height of the exhaust port even further( reduce the width of the sealing surface). Another mm or so would make it as good as it can get with these exhaust valves. The extra cc's make this very doable and it only makes it run better on the bottom/mid than it did before.

Hope this makes sense.
Walt

Man I just hope that is something EG does on his 144 kit. So does EG grind away some of the material on the stock PV as part of his kit?

John,

Eric re-grinds the sealing surface so that you have the proper clearance with the piston. He did not re-grind the bottom side to raise the level of the sealing surface. That is what I did and all I can say is it is fantastic. The valves are made of a soft aluminun metal that is very easy to grind so if you use a die grinder you need to be carefull and take your time or you will remove to much. I used a magic marker and painted the area I wanted to remove and it made it very easy to get the shape and size I wanted. It really is far easier than it sounds. I did no re-touching of Eric's work he got it right and anything I did would make it worse. Die grinders are very cheap and combined with a compressor allow you to do so many things, many probably wrong. I never post a change until I make sure it works well so I keep the OOPS to myself.

Walt

I'm going OEM as soon as it's availible (Late Winter-Early Spring according to Factory contact). I'll report when I get it.

Do you know the price?

JS

How did you know how you wanted it? Why do you think EG does not grind the material the way you did? Nice job by the way. I would have been very nervous to start grinding on my motor parts.
JS

what he said!!
I have an E gorr low to mid top end on my 08 cr 125 sitting in the shed. If I'm lucky I might get to do some indoor moto this winter and find out what its all about .... other wise its going to be a long winter.... I wonder if my valves were cut differently??

I think the whole idea is that with the more everywhere he does very little messing with the stock port timing. With either of the other options he is going to adjust to enhance that area of the powerband. Raising the bottom height of the power valve will enhance low end/ mid-range and not effect the top end at all. With his other options he is going to do some work on other aspects besides the power valves. The great thing about Eric is if you are dissatisfied with the option you chose he will alter the porting of the cylinder etc, for free for 2 years.

I have no problem jumping in with die grinder screaming(as long as I have back up parts). When I tore down the motor to send it off, I was amazed how the exhaust port with the power valves closed was only open a couple of mm above the transfer ports. Very conservative but explains how the 125 runs so well off idle. When I got the cylinder back with the new relief grind on the power valves the exhaust port was virtually even with the top of the transfers and very conservative. I put it together and while it definitely pulled better than the 125 it wasn't significant on the bottom and early mid. At this time I was determined to raise the bottom of the power valves to create a better exhaust flow at lower rpms. Gasserman was giving me the weird look and the don't go more than a couple of mm advice. Well once I got the spare valves and compared them, I just had to try and see if my intuition was correct or just a case of passing gas. It was amazingly better than I could have imagined and that doesn't happen very often.

I also can't wait for your report Norman. I look forward to pics of the stock parts along side the oem 144 parts. This is the best part of the factory oem is you still have all your original parts to re-install when you sell.

Walt

get some studs and join the rest of us "winter riders"!
http://www.werproducts.net/
what I said!!

Thanks Walt and I am not new to grinding or metal work in general. I built machinery for years and have a welder, small milling machine, lathe, saws, grinders, compressors, etc. My problem is I wouldn't know where or how much to take off of what pieces. I haven't done anything with bikes other than a few top ends on my son's small bikes when he was growing up over 15 years ago. I think I am going with the EG low/mid option for my bike. The bike has good pull at the top and I would just like a little more bottom and as much mid as a 144 can put out. I would like to try what you did but I would order some spare parts and make sure I can duplicate exactly what you did before I started. I am just glad we have a pioneer looking and working to improve the power on the Husky 125/144's; thanks.

John,

When you get your kit back from Eric send a face on pic to me of the valves. I can then give you some details on what you need to remove and where.

Walt

Thanks Walt you are the MAN!