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Help Yamaha SRX250 oil cooler addition

Discussion in 'Yamaha 250cc Singles' started by GeorgeT, Nov 22, 2021.

  1. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    If I remember correctly after reading multiple threads on these cooler adapters the original guy who was mking them... (no longer with us unfortunately) did a heap of testing in the Desert... or somebody did but I dont remember the outcome...
    As for Oil coolers and belly pans... Australia did get them... but only as accessories, not as standard equipment.
    I dont believe anywhere got them as standard equipment, they were listed as Optional Extra's. Price is always a consideration in a competative market.
     
  2. Alumascoupe

    Alumascoupe Member Premium Member

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    Yeah I cannot find the source either but do recall seeing the XT225 was shown to have oil temps approaching 300f /150c at times ! If thats the case a cooler is a must. Yet as many have stated yamaha known for its reliability never included one stock so results must "vary"... Maybe they were crawling along at 20km/hr at near redline going up an active volcano !
    I have a cylinder head temp sensor coming to test before & after results, & might look into one of the oil drain plug temp sensors also. Will be interesting to see the results, if any, adding a cooler will make.
    I got my spare oil cover yesterday, immediately started comparing to 2valves images so I know where to add ports & I noticed a difference, the air bleed hole is actually moved over a bit on the cooler housing to make room for the oil cooler outlet hole. You would think bleeder would be at top dead center/12 o'clock on both, but it is not.
    Not wanting to mess around moving the bleed hole I just moved the planned upper/outlet bung location a touch (the lower inlet hole is the critical location luckily)
    So heres what I have made thus far, it did not weld as clean as the engine case I did, lots of oil boiling out of porosity causing problems, but once I could lay down a decent pass of weld after "floating" the contamination up & out after several passes it was OK. Its ugly for now, still just a raw block of material waiting for a sculptors touch but should have plenty of material to drill holes & add t 20221202_062420.jpg he AN fittings once they arrive :) 20221202_032752.jpg
     
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  3. Alumascoupe

    Alumascoupe Member Premium Member

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    20221205_023832.jpg 20221205_023803.jpg well a few hours of filing & careful measuring & drilling later I have an oil cooler cover nearly finished. Just waiting on weld on fittings coming next month :)
    In hindsight would have been faster & easier to just go with hose clamp type nipples vs. AN fittings like I am, the low pressure doesn't need high pressure fittings & an overall smaller nipple fitting would need far less material added to the cap. Could almost just weld 2 barb end pipes on to the cover vs adding giant bungs to fit fittings in. The only truly critical part is the drain return hole that needs to be lined up to the hole in block once an area is built up in the cover to make the o-ring recess in.
    I will enquire if the guy making CNC xt225/tw200 coolers has any interest in copying the part over the winter for production. I kinda doubt there is enough demand but maybe if he has a pattern already made for free he will.
    Otherwise if anyone needs a cooler cover, a local welder with aluminum experience should be able to add the spots of weld needed to add the bungs & drain hole. Everything else can ( & was) finished by hand with good files & a handheld drill. So if it remains impossible to buy, at least it is still possible to make for the cost of a used cap, perhaps a welders fee, & plenty of elbow grease :)
     
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  4. Alumascoupe

    Alumascoupe Member Premium Member

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    20221231_220732.jpg 20221231_220916.jpg 20221231_155225.jpg 20221231_220916.jpg 20221231_155225.jpg 20221231_155225.jpg 20221231_220916.jpg View attachment 53791 20221231_220824.jpg Finally got all the pieces on hand to DIY a copy of the OEM SRX250 cooler :) Still need to get some clamps to brace the bottom of the cooler to the frame with some rubber bushings, just using the one top center factory mount with some rubber grommets for now. I decided to route the inlet line inside the frame to stay clear of the hot exhaust & keeps the cooled oil return short & far from any exhaust heat. The cooler location closely replicates OEM & most of the heat extracted should pass over the top of the valvecover leaving the engine cooling airflow near original.
    Total cost : $94 (w/o weld cost)
    Used oil cover $12 (ebay)
    Oil cooler $36 (aliexpress)
    AN6 Fitting Kit w/hose $35 (ebay)
    AN6 weld on fittings $2 (aliexpress)
    AN6 adapters for cooler $9 (aliexpress)

    If you can find a decent aluminum welder to weld a used oil cover the project can be done even more frugally by using much cheaper hose clamp style lines (its low pressure) & just welding a more basic nipple on the oil cover vs. the time it takes to weld & hand shape large bungs for AN fittings like I did.
    Will be testing the cooler in a few months when spring arrives, if it works properly & as expected without issues I will inquire to see if a machinist is willing to do the work to make copies for us SRX250 or XT350 owners...if not, the determined among us can simply seek out a used cover, a handy TIG welder, & a handful of cost effective bits & DIY them :)
     

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    Last edited: Jan 2, 2023

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