Does anyone know for sure the differences between the Bonnie/T-100 engine, and a Thruxton engine of the same year? Different pistons for more compression? Cams? A different tune? Or just marketing? [emoji16]
If there are actual mechanical differences, would I need a Thruxton ECU, or maybe just a Thruxton map in my T-100 ecu?
Two of the most likely candidates for a replacement engine for my T-100 on Ebay are both from Thruxtons, thus the question.
You are probably OK but it’s not necessarily straight forward.
I’ve done a check on several part numbers for crank shaft, camshaft, pistons and they are the same in EFI T100 and Thruxton. BUT, they did make some changes to the crank and pistons from Thruxton and T100 E/N 438195 >. The cams were the same throughout, including carb models. I doubt you’d encounter any problems with Bonneville or Thruxton engines regardless of Engine Number.
The ECU could be a problem though; certainly something you need to check. While they are the same across Bonneville and Thruxton models, it is important that you find out what vintage the Thruxtons are you’re considering. I’m sure many will remember that In late 2014 and early 2015 all the new 865s at that time were recalled to get replacement ECUs due to the “old” ones dumping fuel and causing lots of smoke and a couple bursting into flames. As yours is a 2010 it almost certainly has the original version ECU and this may not work/be safe on a later model engine. The VIN range for the Thruxtons needing the new ECU starts at 451500 and for Bonnevilles it’s 438195. If an engine you’re looking at is from a model with VINs lower than those you should have no problems. However, if you’re looking at a newer engine you perhaps should try to buy the ECU with it.
I made an assumption about the timing of the update and we all know what assumptions do......
Based on your info I did some more digging and the ECU update was in fact connected to the intro of electronic gauges and probably some other charges and is not due to the recall. Based on that I’d still say that @maydaymike will be fine with the engines he’s looking at and any others that came from bikes with electronic gauges. It actually not as complicated as I thought. In my defence, it was very late at night.....
The engines are the same and are dumb, so any 360° engine will work with your ECM. But you do need an engine with a position for the speedo sensor, otherwise you'll end up with a whole load of grief.
The ECM's were matched to the loom coms and speedo type, not the engines.
Sorry to hear of your engine problem and good luck in sorting a new one for your Bonnie.
Yup. I've already been offered another 2010 T-100 engine (3500 miles, and a great price [emoji853]) that had the mechanical speedo. Mine must later in the model year, because it has the electronic.
I believe the compression ratio was raised somewhere along the line for the Thruxton, but then later models of the Bonnie were using the same pistons, so who knows.
Maybe the Thruxton has "marketing" power.
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