Bigger Radiator - Any Experiences?

Trierer · Mar 4, 2026 at 4:48 AM

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!

Pegscraper · Mar 4, 2026 at 12:54 PM

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.

Eldon · Mar 4, 2026 at 11:40 PM

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

joe mc donald · Mar 5, 2026 at 7:34 PM

Trierer said: ↑

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