1. 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    WR = 2st Enduro & CR = 2st Cross

250-500cc 250 engine tuning

Discussion in '2 Stroke' started by roost, Jan 4, 2009.

  1. roost Husqvarna
    B Class

    Location:
    USA
    Hi all!
    I'm new 'here', and to the Husky 2 strokes...but I've gotten involved with 'race prepping' a new, leftover 2008 WR250. I've done lots of 'net site' research, in the hope of not 're-inventing the wheel', and ended up here (very nice site :applause:). I'm looking for some experienced tuners to help guide my efforts; we're looking at sending the head to RB Designs, to fix the squish band..any good/bad experiences with this?
    Already have a PWK carb, and we're looking at upgrading the reed block from Vforce 2 to the Vforce 3...anyone done this?
    Overall, the bike looks to be of great quality, and I'm just trying to 'tweak' the performance, mostly with the aim of smoothing the power delivery, with emphasis on 'bottom to mid'; I'm looking at the right side power valve chamber...has anyone tried to increase to volume of this?
    I also am curious as to anyone's experience with adjusting the stock engine timing ...
    BTW, in my searching, I've found links to 4 stroke shop manuals(with very good tech info) but can't seem to find a 250 2 stroke manual link, anywhere...can anyone help??
    I'll be very glad to post our results, of this project, both good and bad (and worthless 'wastes of time' :banghead:); I know I can contribute to the site's knowledge base (I look forward to answering similar questions in the future), and THANKS IN ADVANCE !!
    I really appreciate any of "Cafe Husky's" resident experts here, in lending their experience to us!
    Roost :thumbsup:
  2. NWRider Husqvarna
    AA Class

    I had RB do the head on my 125, no complaints and the price is good.

    If you go to the thumpertalk 4t section and search for "manual" you will find at least a few links to workshop manuals. You might not get an 08 one but that motor hasn't changed much.

    I've ridden a 07 with a PWK and thought the motor was fantastic. I also tried it with a Recluse Pro and that is the way to go to really smooth it out.
  3. Zim Husqvarna
    A Class

    The factory blokes or so I read have an adjustable power valve,although there pricy,there was a thread on this in Thumpertalk Husky 2 stroke section
  4. robertaccio Husqvarna
    Pro Class

    Location:
    San Diego, Ca
    Husqvarna Motorcycle:
    2021 Husqvarna TE300i
    Other Motorcycles:
    99 HusqvarnaTE610, 94 Husaberg FC501
  5. Motosportz CH Sponsor

    Location:
    Vancouver WA
    Husqvarna Motorcycle:
    2021 TE250i, 570 Berg, 500 KTM, 790R
    Other Motorcycles:
    many
    DO THE SUSPENSION

    This will be your single biggest gain in performance on that bike. the forks are horrible and the rear is good. Send it to LTR, Ace, House of HP, or the likes and get it dialed. Will make life much EZer. Also play with fork height settings for your type of riding, makes a lot of difference in how the bike turns and behaves.

    Might try a carb divider plate if you looking for smooth roll on power. I think the motor on these bikes is very nice and does not need a lot. Soft flexible bottom end for technical stuff and ripping top end for getting it on. Factory pipe seems one of the best performers but is EZ to smash. Eline pipe guard is a must IMHO.

    reinforce the muffler bracket before you snap it off.

    I like this model much better with a damper. transformed my buddies bike. He is running ours (Motosportz) but I'm sure any brand will help. Not a twitchy bike but just feels so much more planted and EZ to ride with it.

    - Welcome to the Cafe.
  6. Yanni23 Husqvarna
    AA Class

    Location:
    Waynesville, NC
    I hand-delivered my 50mm Shivers (not stock on WR250's, but got 'em on mine) to www.motocd.com. Respring and revalve up front, with just a respring out back. .45 up front with Woods valving and .48 out back on the stock Sachs. $300 total with free revalving. Now that's service! 5'9 165lbs. A/B woods rider.
  7. crb345 Husqvarna
    B Class

    The adjustable power valve sounds like a great way to go if you want to smooth things out but the price is a little hefty.

    Would the poor mans fix be to get an adjustable cam throttle tube?

    I have some friends who run them on their Yz 450 for the woods and love them.
  8. raisrx251 Husqvarna
    AA Class

    Location:
    Virginia
    I have spent the last year and a half tinkering with the my '07 WR 250. I think you are on the right path. Squish height is very important and I think the WR's come with too much. By setting it correctly you are going to get a better running motor with more pull. I have retarded my timing a hair meaning one hash mark which helps smooth things out and give a better bottom to mid. I am running the PWK carb and can give you my jetting specs if needed, not sure where you are located. I am running a 50 tooth rear sprocket for the east coast. I have the FBF 50mm forks and suspension set up by Les at LT racing which I highly recommend. Not sure if the V-Force 3 is adjustable but on the 2's you can adjust when the reeds open, high or low. I have run just about all the pipes out there, the Doma pipe (one on ebay) may give you a little more bottom/mid, stock pipe is excellent though. I also liked my HGS as it seemed more smooth in the mid to top. I run either a FMF Power Core or a stock CR silencer with the smaller opening. I have not experimented with a little longer head pipe but did buy a few extra washers to try. Jetting plays a huge roll in changing the Characteristic of this motor in my opinion. Usually when people have a violent experience with a WR it is due to being too lean. My next experiment may be with a CR ignition. I am interested if I can keep the traction but yet be able to get it to bark a little more. Keep a eye on the kick start nut as even with Loc tite Blue I have had it come loose. It is a very reliable bike and like your thinking with more volume on the power valve cover. hmmm....
  9. roost Husqvarna
    B Class

    Location:
    USA
    Well, i really want to Thanks Everyone!, for their advice and suggestions. :thumbsup:
    So far, the 'prep' has gone well, and we're just waiting for the last couple parts to 'come together'... Got the head back from Ron, at RB-Designs, and it was 'spot on', for the requested clearance (.040"), and as usual, the work looks of excellent quality (as expected!). We did a 'lot' of teardown and rebuild, so as to failproof the bike...and to minimize future wear, from the upcoming riding season. So far, we've got a PWK jetted for 'COLD" weather (MN), at 180/50, with a #7 slide, DDJ #4, A.S. at 1&3/4 TO. Anybody have any better ideas on this setup, for 0-20 degrees (1000' alt)? We set the PV per recommendations of Steve, aka 'Huskydogg", and shimmed the governor 1mm, with an extra stock washer...thanks again for sharing your experiences with this! BTW, that handle "huskydogg" seems to have a few too many gg's on it...perhaps there's a 'closet' GasGas rider lurking there??? :D
    As 'Raisrx251" pointed out, we'll be playing with the basic ignition timing, too, as soon as the Husky 'phase' tool (it looked 'handy') shows up, but we need to establish some 'base settings', so we need to test ride this bike...see what we've got. We'll keep the V2 reeds, for now, and we did adjust for the low tension position, loctited everything (scary stories of loose screws, and damages...!). Gearing for now will be 'stock', as we have no experiences yet, and I am interested in what we'll find with the 'tune' of the OEM pipe... I'll let you know on those PV spacers, again, we need some test time! BTW, what's the difference/benefit between WR vs CR ignitions? And has anyone ever wondered about how 'puny' that stock CDI box is ?
    'Motorsportz', I appreciate the suspension advice, but this is an area I can probably work through myself (lots of GG experience with Zoke Shiver 45's) BUT your comment reinforce the muffler bracket before you snap it off has me wondering...which bracket were you referring to ? On damper, we're running an older Scott's, and just waiting for a new 'ProTech' bar/damper mount (really nice stuff !) Thanks, too, for the caution, re-pipe guard, that's something not yet handled...Looking at a HYDE brand skid plate...another great product!
    Other stuff... Rekluse clutch, OFG rad guards, Trelle spikes.
    Greased chassis (pretty good from factory ! way to go Husqvarna :thumbsup:), rebuilt wheels (not so good :thumbsdown:), cleaned out calipers, greased shafts, cleaned rotors/pads, flush/bleed, checked/tightened a bunch of bolts (thanks for the heads up, here!), sealed air box, ignition stator, lapped rotor to crank, probably a bunch more stuff that we can't recall :doh:
    Anyways, Thanks to everyone for all the help and ideas...it's really helped us to a good start on this bike !!! :applause::applause:
    We'll report back with testing/ride results
  10. Bench Racer 117 Husqvarna
    A Class

    Location:
    Oregon
    Husqvarna Motorcycle:
    2007 WR250
    I read through this thread with intent of head mods with rb-designs. I wanna know what you found and if it was worth the money and effort. I want actual bottom end power and have heard this is the way to go.