Time for a quick build update on 924 conversion. The heads are now built and are back from Baines racing after re-shimming. I've replaced the main bearing as a precaution and ground the spacers the achieve .17mm of preload. The next objective is the determin if I need the crank rebalancing or not. I'm hoping to have it assembled before xmas. Then I can start stripping the bike as its due a fresh coat of powder coat. And after 7 years of Trackday abuse it's ready for a freshen up.
if you got the crank out id definatly get it and the rods balanced, proberly the best mod you can do to an engine.
Some more progress photos. Just need to finish off behind the side covers and fit the belts and set the valve timing.
I use the chisel as a gasket scraper. It's razor sharp and if used carefully won't mark the casings. Unfortunately it's not my workshop. I've been building the motor at work.
More. But steady progress on the Motor build Cam timing is now dialled in and the top end is buttoned up. Next up is to finish off behind the side covers. Then strip the bike.
The crackle took a few attempts. Too much paint and they looked like a sunburnt scrotums. Not enough and they looked like red eggshell. But pretty pleased with the results. However I imagine they'll be a bitch to keep clean.
Piston were direct from Pistal €600 749s heads. Seats recut and throats opened. Ports cleaned up. And the mods to the water passages and head gaskets.
The 999 barrels came off flea bay and were in excellent condition all I did was a very light hone/de glaze. To help bed the new rings in. The mod to the head gasket is to increase the width of the water passage where I've had to knife edge the head passage. I compared the the 749 & 999 gaskets and that's the main difference. Bare in mind I'm not referring to lapping the valves in. I've had the profile of the seat and valve re-ground. I don't have a seat cutter. But I do have contacts at Northampton engine services. Who help me out once in a while Next time I'm in the garage I'll take a few photos and diamension of the engine stand. But it was a quick cobbled up affair so it's not my finest work. Exhaust is 57mm
The mod to the combustion chamber is to open the obstruction and allow for free flow where the 749 cylinder would be. There is no issue of interference with the Pistals.
Yes I did remove the valve "Shrouding" after consulting a work mate who has been involved with designing and developing the Ilmor MotoGP engine. And various F1 engines. (If he says it's a good idea. Just do it! After all he is a Doctor) I built most of the motor at work In the Subassembly dept where I spend most of my time. But I do have the use of all our facility's. Which make these build project possible for me. And is one of the few perks of working for a smaller team.
So you sourced the 999 barrels or did they come with the piston? One thing I'm interested in is that the water galleries aren't opened up on the 999 gasket and barrels and also why the 749 head gallery divides, because your head mod essentially removes the split to all low the 999 gallery to flow. Did you cut the valves into the seats yerself? Also any chance of those take off point dimensions on your mounting stand 50mm hole centre's 150mm z height 85mm hole centre's Rear z height 150mm front 145mm. I drilled everything .1 over to give some clearence. Please excuse the crap welding. I was short of time and didn't clean prior welding.
Nice. I was reading on Bike Boy about this conversion, I'll look forward to seeing the finished engine running What will you do about mapping?
