125-200cc So you want to convert to a 165

Here is the situation I am in. My dealer who is 3 hours from me called to tell me my 2013 WR125 was ready to go. I guess the 144 kits are on back order from Husky for the next three weeks. I was hoping to have the dealer install the 144 kit before I picked up the bike, but I can't wait three weeks. I'm drooling over this bike and want to ride it. So I'm going to pick it up today. I was thinking of just having the dealer send me the 144 kit when it comes and and then having the 144 kit upgraded to the 165. This will allow me to ride the STOCK WR125 up untill the 144 kit is converted to the 165. I was also thinking that by converting the 144 kit to the 165 kit, I will still have the stock 125 kit if I ever wanted it. So here are my questions for you 165 experts:

Besides buying a new piston, what else will need to be purchased? If I'm doing this I wanna do it up right....new pipe/silencer? New carb? Valves? Re-jet? Let's hear it....

Also, where is the best place to have this done? How much does it cost? And what does it consist of doing? Milling out the cylinder, and putting a 165 piston in? Any suggestions on pistons? Or other parts needed for this upgrade?

After receiving the 165 kit back from who ever does this, how hard will it be for someone who has never installed a top end, to put it in themselves? Does it just bolt on? Are their any instructions that come with the kit?

Thanks guys....on my way to CT to pick up the WR125 now....pictures later tonight!

First off, congrats on the new bike!

Second, under no circumstance should you send an OEM 144 kit to be punched to 165 when you have the perfect donor cylinder currently on the bike (the 124cc jug). I know it sucks, but be patient and wait for the 144 to arrive THEN ship the 125 off to the slaughter house. I've had all 3, but ended up selling the 124cc top end and keeping the OEM 144 and Walt's 165 kit. And after putting time on the 165 I'd never go back to the 144 by choice, but I keep it around as a spare.

Installing a top end on these bikes is amazingly easy and somewhere on this site is a nice write-up on how to do it. I'm sure you can find it using the search feature.

I'd wear out the 125 piston first, (cheapskate!) then install the 144, wear that out too and have the 125 converted to 165 or even a ported 144 if you were happy with that.

I did what OLd3 has said but life is short and you may be better off going straight to the 165. Contact Kelly from Motorsportz - check website Walt( Wallybean) does the conversion .Walt is the man .
BTW - I think the website needs to show a bit more information as to what is done etc as they do a lot of work to the cyinder .
I would ride the 125 and keep cylinder for re- sale of bike ( transplant 165 on next new bike ) , dont buy the 144 kit and see if they can provide a complete 165 conversion kit with a donor head and power valves. You will need to update the standard pipe as a must do They offer different pipe options at very reasonable rates .
I think the standard Mikuni will be fine with the 165 kit .

Everything you need to bolt on and go is included in the kit. You should, however, get a new pipe, to really make it run perfecto... Send out the 125, and keep the 144, (or sell it). The 144 is worth more.

I would do this^ why spend close to $1K(kit,pipe,gears) for a perfectly good brand new bike with two cylinders to wear out? If you need to spend money replace the quirky carb with a lectron,get a pipe and then ride the pi$$ out of the bike.

My 144 with the Lectron and Scalvini pipe is amazing in every way. It kicks butt!

I completely agree with you. Wear the top end out and then switch to the other one. If you want to try the 165 send the worn out top end in at that time. I also think that you should definitely go to the 144 directly. It has the same power band as the 125 but with a little more everywhere. While you will have less invested you are still going to have +$500 in the pipe and carb to make the 144 run the way you want. Also for every rider like CelticDude who doesn't like the 165 there are 2 that think it is the best bike ever. I am not unbiased.

PS, I have done a lot of fine tuning since Doug rode my 09 165. The 165 can be made to run very similarly to the 144 but with more everywhere. A number of riders that have gone that route love their 165 with that configuration much more than the bottom/mid/early top motor that I like.

So at MINIMUM what else would I need to go up to a 144?

You might not need anything. My son had a 09 144 done by Eric Gorr and we just swapped the jetting, slide and needle. It was ported for pure top end. It ripped, stock pipe too!

I'm trying to get used to my old fresh 99 125, but it has been along time and our MX track has really changed since I raced 125s there, very SX-ish now because the 250f and 450f bikes make it so easy to grunt over a short run jump. I don't have the timing/faith to launch a big double or 80' table when I have to be sure to stretch 4 gears out of a first gear turn. On my 570 it is a twist of the wrist in 2nd, third or even fourth gear. Shifting is optional.

On natural terrain, no issues. I say ride it first, gear it for what you do and make sure it is jetted clean. If you build some skills and reflexes on the 125, you will only be a better rider when you pop on the BB kits.

I'm confused as to how the bike even arrived without the 144 jug/etc in the box. Is it only the CRs that come with the 144 kit included?

The last time i visited the husky dealer the 144 kit came with both bikes...

My dealer said the last one they got didn't have the kit and they were waiting to hear back from husky to find out why.

I'm not sure either? But I was told that the 144 kit was on back order. The dealer gave me an "I OWE YOU" receipt.....

Yes congrats on your bike . Now down to the answer....Yes send your 125 in to Motosportz for the 165 swap. You don't need but you will want the 200 Fatty pipe they have for it also. While you are at it get the Lectron carb to complete the package. The only thing left to do is enjoy the finest bike and mod combo on the planet! Enjoy.

Well, as promised:









and another of my 99WR250



Did 35 miles today on the 99WR250...the thing rips! Ran great! I'll be riding the 250 untill i have a chance to tear down the new 125 and grease it up/break in the motor. Then looking to sell the 99.

Secksey

Walt how are they achieving that sort of power. Is it something you do with porting or with pipe/carb selection?

hi, I was wondering about boring mines out,is that at wossner 62mm piston?