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About Doubledown

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  1. Doubledown

    Mikuni BSR36 carb rebuild... extra o-rings

    I know this is older, and I hope that you found them, but hoping this helps others. The rings you are showing are #4 and #49. The kit came with two of the smaller rings you are showing, which I could not see a difference in size on and they are used for both #4 and #13. The larger is used on the choke #49. You will need a pass through ratchet to get the choke out to replace it.
  2. Doubledown

    Keihin fcr mx 39

    Thanks for the reply and reminder. Should have mentioned, I swapped for the manual petcock after the first issue with stumbles and flooded oil. It was on for that short time, but I have done that before with no issues which tells me the new float needle I put in is somehow already leaking or the floats are sticking or cracked (which I checked at the last rebuild). Not that, those potentials aren't eliminated with the FCR, but would like to just start with something brand new, and if I am spending money might as well be an upgrade. I will look into the shorter choke rods. I'll have to see if there are hotstart ones also unless someone says that will clear the clarke.
  3. Doubledown

    Keihin fcr mx 39

    I have an 02' 400s, 3x3, and yosh rs-3 and I do about 85% street riding, the other 15% is riding up the hill to and around in 3700' on fire roads and moderate trails going fairly deep to do some backpack camping. I took a quick trip last weekend to do some shooting and luckily came back to my bike for something to see fuel coming out of the rear air boot to carb seal area, clearly an air leak there but more importantly the floats and one more thing with the carb. Long story short I don't want to get stranded back in the cuts and this is now the final straw on the back of camel who has had countless other straws (hard cold start, stumbling, low speed hesitation, back firing, molten hot head pipe, hard hot start etc etc issues between multiple BSR carbs over the last decade. So I have sold myself, yes several years late and I will pay that price, on the FCR MX 39 upgrade. I see the TT kit, but have also seen the ACV + Hot Start. I have read myself out of the TPS model but haven't seen much of anything on why someone wouldn't want to the ACV and Hot Start outside of the added cost. Maybe its all the issues I have had with the BSR making me want hot start and air cutoff valve, but less backfiring and option of the hot start sounds pretty good to me. What am I not thinking of here with the ACV and Hotstart version of the FCR MX? Another portion of this upgrade I haven't been able to find in search is anyone having gone with the hotstart option having a Clarke 3.9 tank. I have seen a couple posts where the choke on any version of the FCR MX has to be chopped down for the clarke, but the hotstart is lower( may clear) but sticks out quite a bit farther than the choke. Has anyone had the hotstart version on their bikes under a clarke 3.9?
  4. Doubledown

    Xr50 / crf50 suspension upgrade / swap options

    Thats where I started leaning with the dollar amounts for separate parts adding up however I want to keep my xr frame street titled. do you think it is still worth it that way to swap over all the parts without the need for the new frame?
  5. I am bring my stock xr50 out of storage and bringing it back to life with some lights and plastics. While doing so I found that the my forks were bent which prompted me to start the replacement search. Found stockers for $50 or so, and while searching for those I came across some aftermarkets ranging in price which started to make me lean toward some aftermarkets to get the disc brakes and 12" wheel etc. though if I go that route I would likely want to update the to a rear swing arm with a 10" with disc as well. Looking at all the mounting prices for these upgrades I started to think it might just be cheaper to by an aftermarket rolling chassis or used bike and swap the parts to my xr frame though I haven't found anything definitive from searching forums to say what will swap from what makes of bikes right over to my xr, and of those what makes would work for my street riding.. I don't need heavy duty junk as this bike isn't jumped just ridden on the street So my questions to you all is what is the best option for my use? Piece together some cheap Chinese parts? Find a used or new alternate model and swap parts over? If so what makes work (even if I have to cut and weld maybe the rear shock mount or something along those lines. other options? I want o keep the budget at $500 or under.
  6. I have a 1992 WR250 motor I am using in a project and need to find a few things. First, what direction does the coolant flow? I am using a completely different radiator setup than the stock wr250 so I need to know, is the cooled coolant going in through the top of the cylinder and hot going out from the waterpump or vice versa? Second item is I am looking at getting a Trailtech Vapor for my speedo/temp etc. and have the option of getting an inline water temp sensor http://www.trailtech.net/7500-3060.html or a temp sensor that goes between the cylinder and the spark plughttp://www.trailtech.net/7500-3010.html. Which temperature is more important/which sensor should I be getting for the WR motor? If the water temp sensor is what I should use does this need to be installed closest to the hot coolant exit on the engine? In either sensor case, what is the operating temperature for the wr250 motor and what is the danger zone? Thanks
  7. Doubledown

    Swing arm (swingarm) swap help

    haha right on the same page.. I dont have the rm85 brake setup though I will definitely NOT be cutting off those mounts just in case I can come across those cheap to look into making something that will work with the ysr hub.
  8. Doubledown

    WR250 (ZD) Carb boot/mount/flange options

    well here is the before and after.. its cramped though got a filter on atleast. vm38 pwk pwk-aircleaner
  9. Doubledown

    Swing arm (swingarm) swap help

    Thanks again for all the measurements.. ended up with this 2004, seems the same except for the axle adjusters.
  10. I have a wr250 motor I am using for a project. 1)year/make/model: 1992/yamaha/wr250 smoker 2)conditions (elevation,temp,humidity if extreme,type of riding): sea level, going to run summer time so 75 to 95 degrees, street riding 3)modifications (pipe,air box,motor):FMF fatty pipe, uni double layer filter (up4245AST), stock reeds, motor bought used, know 6 hours on top end stock bore. 4)current jetting: - just got the Keihin PWK carb on ebay from an 2003 KTM 250sx Main...175 Pilot…50 Needle… N3CH ??– 5 clip positions, currently on 4th from needle side Slide #65 5)running issue that is trying to be cured: bike is not currently running, looking for a starting point for my location/motor.
  11. Doubledown

    WR250 (ZD) Carb boot/mount/flange options

    well I would say if I were to drop it down a bit it wouldnt be more that about degrees forward. The PWK is for the 92' WR250 engine I bought for my ysr50.
  12. Doubledown

    WR250 (ZD) Carb boot/mount/flange options

    Well I pulled the trigger on the shorty PWK from a 2003 KTM sx250 so its the 38 but doesnt have all the tps or powerjet to remove and fill. That should be here in the next few days. Right now I am working on the engine placement to get the sprocket lined up to the rear.. I dont know enough about these 2 strokes and their oiling system so I am not sure how detrimental the angle of the engine is. Where I have it, unwelded/test fit, it is pretty level. I will tack it for now though depending on if this new carb fits right in with a decent filter or not I am wondering if I could tilt it a bit forward, making more room for the carb, without any ill affects for oiling or anything else for that matter. I will probably make a post on the topic though wonder what your knowledge is. Thanks
  13. Doubledown

    WR250 (ZD) Carb boot/mount/flange options

    No worries, I am not expecting this project to be done anytime soon haha. Just want to get my ducks in a row. Even with this "Short" version of the keihin pwk38 I may still need to look into other boot options. What are the difference in the mikuni flat side and round slide boots? If you come across your camera and feel like snapping those shots it would still be helpful. Thanks
  14. Doubledown

    WR250 (ZD) Carb boot/mount/flange options

    I think this is the thread you are referring to: http://www.thumpertalk.com/forum/showthread.php?t=782718&highlight=1997+wr250+pwk I have found a couple different sites listing different dimensions on these carbs also though the above post is the dimensions I will use for the vm38 carb at 97mm/3.82". I read in other posts about the shorty version of the PWK that is was the same depth as the PWM which is listed at 75mm/2.95". Even with this shorter vm38 dimension I would be expecting about 3/4" gain in space with the difference in the shoty PWK and the vm38 at .87". So you are saying you have a shorty version of the PWK and are ending up with only a 1/4" in over all depth difference in the bike? Can you confirm the measurement of 75mm depth for the shorty? Was PWK measurements from later model YZ carb you picked up?? I also read about the intake boot issue, I found a post of a guy who milled down the diameter of the carb, but I figured I could make it work like you did. Possibly use a head gun on there to loosen things up a bit. I posted http://www.thumpertalk.com/forum/showthread.php?t=983672&highlight= hoping to get some direction in finding what factory bikes have the shorty PWK 38mm, preferably without the tps and powerjet but I am all for filling in some wholes for a cheaper carb. The other post I found http://www.thumpertalk.com/forum/showthread.php?t=978139&highlight=pwk+conversion may also be one you were referring too. This one is saying a 06 sx250 would be my ideal candidate though doesnt list the bore diameter and I am having some issues finding information on the bike.