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Help Yamaha SRX250 oil cooler addition

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

  1. GeorgeT

    GeorgeT Member

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    Has anybody successfully added a non-original oil cooler to an SRX250 or any other bike by modifying a factory standard oil filter cover. I am thinking of doing this. What I think will work is to fit a spigot into the cap so that it is connected to the oil-pump-flow circuit. I then connect a hose including a non-return valve and tap up to a cooler. On the other cooler connector, I fit a hose back to the oil filter cap including, again, a non-return valve, to the engine-block circuit. This would allow the cooler oil to passively flow back to the oil filter while preventing the cooler from filling in the opposite direction assuming that both circuits in the oil filter chamber are under pressure. The tap on the oil filter to a cooler line is so that I can disconnect the cooler from the circuit in extremely cold weather while the non-return valve on the other line is so that no oil goes to the cooler when it is disconnected from the oil-pump-flow circuit. To ensure the motor is always safely receiving oil I would add the cooler volume to the total oil as per the manual, e.g., add ~90ml to the oil change. Am I thinking this through correctly?
     
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  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I've been thinking of making one from an oil filter itself which is modified - shortened and capped which a filter then screws onto

    But sensible option would be find one from a bike which has the same filter base diameter and thread - if you wanted to be able to bypass it, make a loop that takes the heat exchanger out of the flow circuit and simply takes the output straight back to the input

    I am of course assuming that flow goes from oil pump -> oil cooler -> heat exchanger -> oil filter -> oil gallery in a system which has an OEM one fitted

    First step, check your oil filter housing and see if there is an OEM oil cooler housing available - there are quite a few, then the heat exchanger can be found and plumbed to suit
     
  3. GeorgeT

    GeorgeT Member

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    Yeah, I would probably do what you are suggesting if I could find the gear available somewhere but so far that is not an option. I have been able to find a second, standard oil filter cover that I have secured at a reasonable price. But nothing else so far.
     
  4. Andych

    Andych Moderator Staff Member Premium Member Contributing Member

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    There is a very specific adapter for the SRX to run an oil cooler. They were offered as a Factory Option along with the belly pan but there were very few sold in Australia.
    Sometimes these kits come up on Yahoo Japan but they are difficult to import.
    The adapter has outlet and inlet so it is cooled oil going through the filter and into the engine.

    As far as I know @2valve has a kit he managed to secure from Sri Lanka or some other strange place but hasnt added it to his bike yet. I did look into having the adapter made but without having the original it was next to impossible.
    Below is a pic showing the factory mounting.. this engine is a 350 but the 350 TT, XT engine and the 250 are basically the same oil circuit and side covers so it gives an idea of how it all works.
    Based on the OEM design you would need to have a bypass line rather than just a tap for cooler weather running as I believe all the oil flow goes through the cooler and it is under pressure on both hoses. OIl cooler pic.jpeg

    Realistically I am not overly sure that an Oil cooler is needed for the SRX in standard trim.. I would like one on my 350 conversion but that is further down the line.
    Maybe @2valve can throw up a picture of the adapter so you can see the way the oil flow is routed internally.
     
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  5. Andych

    Andych Moderator Staff Member Premium Member Contributing Member

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    As an add-on to the above post...there are some good 3D scanning apps for iphones now that might make it easier to make a replacement adapter. It wouldnt be too hard to have one 3D printed to proove the concept and then have them made from 6160 alloy.
    During my quick search for more info I also found adapters from Japan that are themo controlled, so at low temperatures no oil goes to the cooler.... hmm food for thought.

    Edit: This is a link to a Thermo controlled OIl cooler sandwhich plate.... similar in concept to the Factory Yamaha item.
    https://www.carmodsaustralia.com.au...jNBlymIxet-ccH1Z1QRsZjJF8k2MnaUgaArVzEALw_wcB
     
    Last edited: Nov 22, 2021
  6. GeorgeT

    GeorgeT Member

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    Yes, I have seen the @2valve adapter but my idea is slightly different. I agree that both inlet and outlet hoses to the cooler would be under pressure as they both, I believe come from either the pump or engine oil areas of the oil filter which is not fully separated. I would have thought by including the non-return valve in the cooler return hose there could only be pressure in the cooler circuit while the cooler inlet hose is tapped on? In regard to your point, i.e., "I am not overly sure that an Oil cooler is needed for the SRX in standard trim". You are probably right. It is just an experiment I am interested in at the moment. The archaeologist, the biologist in me, makes me curious I guess.
     
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  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Silly [potentially] question, where does the oil filter go on the SRX250, is it like a 2KR/3LN1 FZR250 - internal to the engine beneath a cover, or more like an external, screw on one like the 3LN3/Zeal 250 oil filter.

    For example I was intending/hoping to an oil cooler for the Zeal sump, on a 3LN1 engine with the screw on oil cooler adapter from and FZR400/600 or other suitable bike which uses the same diameter filter o-ring
     
  8. Andych

    Andych Moderator Staff Member Premium Member Contributing Member

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    It is a tiny oil filter that goes underneath the cover on the RHS crankcase.
    On the picture above it is where the hoses go to the engine.


    Sent from my iPhone using Tapatalk Pro
     
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  9. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Gotcha - that makes sense, so it is more akin to a 2KR/3LN1 oil filter

    Interested to see where you go with this
     
  10. Andych

    Andych Moderator Staff Member Premium Member Contributing Member

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    Pretty sure if I can get my hands on an adapter I can 3D scan it with my phone and then have a mate 3D print it.
    If it works the STL file can be used for Cad machining so it is feasible.


    Sent from my iPhone using Tapatalk Pro
     
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  11. 2valve

    2valve Well-Known Member

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    Sorry guy's i'm a bit late to this party , i missed this post :headbang:.
    While i was looking for part's in the very early stages on the SRX rebuild , i came across a guy making a oil cooler adaptor's to suit the TT / XT / SRX , but by the time i tried to make contact with him , he'd already had past away.

    Pretty sure he made an adaptor which still used the O.E oil filter cover , i did have a picture of his creation , but that's another picture that was lost when the PC crashed.

    The P clamp's that hold the radiator onto the front down tube's are near impossible to find , one was missing when i purchased the cooler below , but since sourced one. The P clamp's are heavy gauge clamp's , no doubt to make sure that cooler stay's in place.

    Here's a picture of the adaptor and the kit.

    DSCN0934.JPG DSCN0936.JPG DSCN0933.JPG
     
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  12. thebeefsalad

    thebeefsalad Well-Known Member Premium Member

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  13. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    This is very interesting because I just checked and the oil filter - cross referencing, see what other bikes have an oil cooler available which use the same oil filter - holes for the housing bolts being on potential hangup

    https://www.aliexpress.com/item/32660177103.html

    Huge list of bikes Vehicle Applications section on this page - there has to be one amongst them that has an oil cooler housing which fits

    https://www.knfilters.com/kn-143-oil-filter

    Now I'm thinking the same may be available for the 3LN1 to fit an oil cooler
     
  14. Andych

    Andych Moderator Staff Member Premium Member Contributing Member

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    I did a bit of searching and think I have found the machinist who was doing the adapters etc for the guy that passed away. Primarilly he was doing them for the TX200 engines but there was talk of making one to suit the XT350 (same configuration as SRX).
    His cooler takes the bypass oil from the Oil Filter that would normally go back to the sump and pass it through the cooler and then back to the sump. Pic below shows a typical setup

    OIl cooler pic 2.jpeg

    I have emailed the machinist to see if they went any further with design on the XT350 version. I am not overly hopeful of getting a response as there has been nothing on the forum where I got the info from for about 12 months now.. but it is worth a try.
     
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  15. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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  16. Andych

    Andych Moderator Staff Member Premium Member Contributing Member

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    That would work here in Aus...good info to have tucked away.
     
  17. 2valve

    2valve Well-Known Member

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    That oil cooler kit from AliExpress is so cheap , thank's for finding that listing.
    Noticed that the I.D of the fitting's are very small with the AliExpress unit , the Yamaha factory one's are huge , if anyone need's a measurement i can get them.
    I had the grand idea of fitting a side mounted oil cooler radiator like this one below , which was a side mounted cooler , this will leave maximum air cooling to the barrel / head. But the price was out there though so it was quickly shelved.
    https://jagg.com/products/chrome-yamaha

    Have a look at these ones.
    https://www.off-the-road.de/en/Othe...acc/OTR-oil-cooler-Yamaha-XT-600-SRX-600.html

    https://www.omegaracer.com/parts_store/prod_3921985-ke-japan-yamaha-sr-oil-cooler/
     
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    Last edited: Nov 23, 2021 at 9:35 PM
  18. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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  19. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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  20. GeorgeT

    GeorgeT Member

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    The "zoozoom kit" looks like it would be ideal if the pitch-circle diameter of mounting holes is the same as the SRX250? It doesn't really matter how the cast-mating lines up as long as the pump/block-oil chambers are separated.
     
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