Bigger Radiator - Any Experiences?

Discussion in 'Technical Help' started by Trierer, Mar 4, 2026.

  1. Trierer

    Trierer Well-Known Member

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    After two years with my Speed Twin 900 I did not encounter any severe weaknesses, although the rear suspension is a bit weak. Apart from that everything is good, I enjoy riding it a lot.

    However, as I live in the Philippines, where it is rather hot and use my bike as a commuter, sometimes in stop-and-go traffic the engine tends to heat up pretty quick. Mind, not overheat, but the radiator fan is running a lot, especially in urban traffic.

    My idea is to replace the radiator with a bigger, more capable one. Does anyone have experiences with that in this forum or maybe has some ideas which one to get?

    Cheers!
     
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  2. Pegscraper

    Pegscraper Elite Member

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    Never heard of an issue requiring a bigger rad. If its not actually overheating then there isn't a problem. The fan may be cutting in frequently but that's what it's there for.
    If you're intent on a bigger rad, logic would suggest one from a 1200 but they seem to have the same part number, as do the thermostat and fan so maybe not.
     
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  3. Eldon

    Eldon Crème de la Crème

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    As @Pegscraper said, the fan coming on and off is simply doing it's job.
    If you feel the temperature is getting excessive, then there are a number of ways to up the coolant quantity, however I would first prove your thoughts running a calibrated thermocouple (cjc) to ensure there is actually a problem. A cheap type J should be adequate.

    If there is an issue, then you may want to consider the viscosity of the engine oil used. A 10w50 oil performs better than a 10w40 over 100⁰C
     
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  4. joe mc donald

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    @Trierer Don't know about over there but here you can get oil additives that help cooling a lot.
     
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  5. RickM46

    RickM46 Active Member

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    Been running Castrol Power 10W50 per rec of Triumph Dealer in my Bonne; fan rarely comes on; no issues.
     
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  6. Pegscraper

    Pegscraper Elite Member

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    In reality, choice of oil brand or grade will make minimal difference to running temperature on a liquid cooled engine IMO. If an engine is prone to overheating it certainly won’t prevent it.
    I’ve used numerous additives over the years, many with claims of increased power, engine smoothness and longevity but now just stick with the MO of using a quality oil, of the manufacturers specified grade and change it regularly, adjusting change intervals to suit type of use and riding style if required.
     
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  7. Eldon

    Eldon Crème de la Crème

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    I wasn't suggesting magical cooling powers of the oil @Pegscraper but providing better lubricating properties at elevated temperatures if they are inevitable to minimise wear.

    On a separate note @Trierer I fitted YSS gas rear shocks and it made the rear suspension far superior to OE. Mine is mainly used two up and the originals were far too weak for spirited riding.
     
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