125-200cc Tuning options for mx

Hi there

I'm currently looking to sell my rmz250 to go back to a 2 stroke. I've found a nice 2010 cr125 with only a few hours and a spare144 kit and so I was wondering what my tuning options might be if i were to buy it? I've done some reading on here about big bore kits, different power valve springs, Kxf clutch springs and exotic sounding carbs but all seems to be related to enduro performance. I was wondering if anyone here has had any experience tuning this bike for mx or if there are any tuners here that might be able to set us strait? In nz we can run up to 250 2st in mx2 so displacement isn't an issue.

Cheers
Max

Hey Max I have a 2008 CR 165 Husky that I purchashed new in 09 as a 125. I then went to a HC 144 kit with FMF Fatty pipe. Now it's a WB165. The WB165 big bore kit comes complete ready to bolt on and sold by a site sponsor; Motorsportz. I also added a modified KTM 200 Fatty pipe thats also sold by them ready to bolt on. I added a SmartCarb to mine but the Lectron is another "exotic" carb you can choose from. I recently had my suspension done and added a Rekluse EXP. I ride MX way more than I ride woods and even stock the little 125 Husky is a winner. They have more power than any stock 125 I've been on and pull way longer making them fairly easy to MX with even in stock trim. If I were you I would bolt the 144 on, pick up a Lectron carb, and go racing! If you feel you need more power then add the WB165 and pipe. I'm 200lbs and this combo really hauls. BTW I'm still on my stock Husky clutch plates/springs and this bike is ridden very hard and by plenty of different riders over the years. The 10 you are looking at is even better than my 08 so I hear.
Cheers
John

Modifying it in what way?

Squish band on the head and grind power valves which Walt does on the 165 kits. Walt can fill in the tec. parts of the work.

most mx guys go for porting on the 144- I believe raising the exhaust ports helps to give them more top end

Thanks guys this is all gold. I'd like to find out a little more about the power valve and head work. I would not consider running race gas so compression would have to be semi consertive.

What is the general consensus on pipes and carbs. Is the original realy that hard to jet and what pipe might I be looking at to get the best overall power spread from the 144? Original, fmf, Procircuit?

Cheers

Good stuff.

Pro Circuit came out with a pipe and silencer for the new models (10-12) last year. I'd go for that one. I haven't heard any bad things about it.

The Pro-circuit will be good, always are. I've heard great things about the Scalvini also, probably will be my choice. I keep waiting for WallyB to chime in, but I have heard from him and Eric Gorr that a good starting point is to massage the head, and match the boostport (rear transfer) to the primary transfers, as it's height gets lowered in relation to the others when the cylinder is brought out to 58mm. (144) Due to it's shallow depth.

I've yet to take a gatedrop with mine but it feels usable-fast, stock. I plan on taking on the fourstrokes with a locked wrist and a raised middle finger.

As for carbs, I have no issues with the stock TMXx. I think it may be inferior at mid-throttle positions, but a smallbore spends little time there in MX. If you are a good b-rider or better, you will keep the motor spinning and won't be down where those carbs are reported to make a remarkable improvement. That being said, I would like to see a full-throttle dyno-comparison, there may actually be HP to be had, especially with the superior atomization and "full" charge distribution of powerjet-type carbs like the lectron.

I've been through them all. I bought a bone stock 09 cr125 and FMF fatty pipe/silencer from the dealer. It never ran well until I adjusted the powervalve arm and installed a Keihin PWK36 carb (did these both at the same time, so I'm not sure which was the true fix). After doing those 2 things it pulled like crazy up top, but had no low/mid compared to other Husky 125's I had ridden.

I then got a OEM 144 kit with WB ground powervalves. This setup (along with the Keihin carb & fmf pipe) was an exact replica of the 125 powerband, but certainly stronger. Especially up top where it was happiest.

Now I have a 165 cylinder w/ high compression head (ran great on pump gas this weekend) along with the Keihin 36mm carb and a modified FMF fatty for a KTM 200. This setup is ridiculous. It still frantic on top, but fills is the low/mid dramatically. I actually added a 11oz flywheel weight to the bike as it was super responsive and felt like it would jump out from under me.

I sold the 125 top end, but kept the 144 and 165. I dont see myself ever going back to the 144, but its nice to have a spare top end laying around for emergencies. Anyway, the 165 is better in every aspect and is so much more forgiving to ride. Even though there's gonna be cash doled out it is worth it in every way IMO.

I bought my 11 CR 150 at the end of last season. I put an FMF pipe on it after a few rides and it made a big difference. Before the pipe, it seemed lazy on the bottom, but screamed on top. The pipe fixed that, and then some, and made it easier to ride. Some of that may have been me getting used to the bike. I have been racing the same 04 RM125 with SST pipe for the last five years. It's fast, and I love it. The Husky blows it away in every possible way. Back to back, I can't believe how much faster, torquier, and better handling the Husky is.