[richard211]

I had an idea of building a bullet 350 engine with a long(er) stroke crankshaft and decided to give it a try with leftover parts that I have had from previous engine builds. I wanted the main engine components to be off the shelf easily accessible RE parts rather than have all custom-built components. To begin, I used crankshaft flywheels off a 350 AVL engine and the holes where the connecting rod big end pin fits onto the flywheel was completely welded shut. I decided to use a 103mm stroke, the machining process was pretty straight forward on a milling machine. The reason I chose the 103mm stroke was because when I had compared the IB piston and AVL / UCE piston side by side, the compression height on the IB piston was 6.5 mm more than the AVL / UCE piston.  So, in theory it meant that I could use the IB big end connecting rod pin, connecting rod and the AVL / UCE piston without having to use spacer plates and then I don’t have to worry about a stock header pipe not being a bolt on or use longer push rods and having to extend the rocker oil feed lines. There were a couple of mods being done as well and that’s to increase the mass of the crankshaft from 8kg to 10 kg and also used taper roller bearings (perhaps not the most straight forward thing to do) instead of the roller and ball bearings. Basically, all the ingredients to have a workhorse tractor engine. I had re-sleeved an old cylinder barrel I had laying around, its just a dry sleeve pressed into an existing bored out sleeve / barrel. While doing a mock fit, I noticed since the 350 bore was smaller compared to the 500cc bore, the connecting rod would strike the sides of the cylinder sleeve, so I had to notch the bottom of the cylinder sleeve to create sufficient clearance, nothing an angle grinder could not sort out. To get the AVL / UCE piston pin to fit the IB connecting rod, the small end hole on the IB connecting rod needed to be roughly enlarged by around 1mm. The five speed gearbox and the stroker engine is a surprisingly good combination, makes life so much easier when crawling through damaged roads and heavy traffic. 

[Paul W]

That should be a slogger, alright! By my calculations it will be +/- 409cc.

[richard211]

 I am currently using a standard size UCE piston, the engine displacement should be somewhere around 396 cc. The compression is much higher compared to the stock IB 350. Also the 3 phase charging, TCI ignition and the electric start is retained.
 For the AVL and UCE 350 stroker crankshaft builds there is a couple of piston options too, 72 mm piston from the RE 350 J series and the 78 mm piston from the himalayan 411 engine. That's going to provide more options when building hybrid stroker engines.

[AzCal Retred]

Nice! That UCE piston looks right at home. What are the cranking compression values now? 150-180 PSI (10.3-12.4 bar) range? Still using a composite head gasket?

[richard211]

 I have not measured the cranking compression just yet, but because the stock decompressor is retained, the start up is just like a regular bullet. I am also using an aftermarket copper type head gasket. The reason being it does not require much surface preparation once the cylinder head is taken off (during oil changes i have a habit of pulling apart the engine to see what's happening inside the engine) .