Well my bike is back together now, and I've been out on a 30min test ride on a variety of roads. And it's all working great.
Starting state:
Massive pod filter, Wild Bore exhaust and open header pipe, Power Commander 5 with my own custom map. Problem is 'pinging under medium to heavy loads at medium rpm. In that area of the map I was running roughly +16% fuel and -4deg ignition. Piston and chamber full of thick flaky carbon after 8,000 miles. Squish band at about 2.2-2.4mm. Multi-layer steel head gasket roughly 1mm thick, composite base gasket roughly 0.8mm thick.
Modifications:
A small area of powder coat was files off the lower end of the top frame member under the ECU, and a small peice of the top fin on the outside intake edge on the spar plug side, close to the plug (I hope that makes sense!). This allowed the intake rocker cover to be remove with the engine in the frame. It was only about 1mm away anyway, so other bikes might be ok. Chamber and piston decoked. The was head material making shrouded areas on wall-side of each valve, presumably from when the bore was for a 500. This material was removed as much as possible. There was a step in the intake passage in the head coming from the inlet spacer. This step was chamfered and rounded to try to smooth the flow a bit. The base gasket was replaced with porous (non glossy) paper from an envelope (the kind bribes usually come it!
), which was roughly 0.2mm thick. This was then coated with engine oil to stop it bonding to the alloy. I HATE scraping off old paper OEM gaskets! I took GHG's advice and drilled out the rivets from the stock head gasket, and used the middle layer as my new head gasket, this being the cleanest layer and only about 0.1-0.2mm thick. I applied a very thin line of red hylomar around the sealing faces, only about as thick as a small paperclip wire. This was flattened out with the applicator to be about 2mm wide. Care was take to avoid getting too close to the oil way. Everything cleaned up ready for reassembly. When refitting the rocker boxes, the hydraulic followers will have taken up all the 'slack' from the missing pushrods. So when you tighten down the rocker boxes the 'high' followers will actually open the valves a bit. Tip: take a picture of the valve without the boxes, from a view point level with the rocker cover mating face. This will give you a reference of the closed position. Once you've tightened them down the followers will take atleast 15 mins to relax and close the valves. Before replacing the covers, compare the valves to your photo to check they've closed. I didn't have a camera, so I turned the engine over by hand, watching the rockers, and made sure I gots compression with no escaping hiss of air. Another method I've seen is to check you can just about twist the push rods by hand, this only worked on my exhaust rod. The intake rod refused to turn, even though I confirmed that the valve was indeed shut. Before refitting the covers I also remove any loose silicone sealant from where the factory had bonded the gaskets in place. Generally I also make sure all external thread were greased, and all internal thread were oiled with engine oil (I don't want any grease contaminating my clutch, call me paranoid!). Most were dry out the factor, and some were a nightmate to undo, even the rocker boxes, which are inside the engine! Their threads were bone dry, as the oil must have been added later. I'd strongly advise people to regularly undo, grease, and re-torque (25Nm) the two head nuts that are external (next to spark plug, and another opposite). Thee can get plastered with crap form the great outdoors, and seize up. My spark plug side one was REALLY bad, and needed well over double the force to undo compared to when I re-torqued it afterwards. It nearly cancelled my whole project, yet it's very easy to avoid this problem. Lastly I made a new custom map (this is my 17th iteration) using dynojets own map for the 500 UCE engine (which was much richer and more advance than mine in the midrange) for my low and midrange, and for my top end I used my existing map, because I know my pod filter requires far more fuel up top than stock airbox + K&N filter (when testing this change last autumn I had to go from +16% fuel to about +24% fuel because it actually began to nip up on me was doing high speed runs!).
Results:
The bike started first time (yay!), and ran fine. Low and midrange power is immense. Full throttle over 4,000rpm feels a little fluffy, and not an 'clean' and the midrange grunt. I suspect it's a bit too rich (I'm curently running +26% fuel up there!), but at least it's safe for now. After a good run, I did the pinging challenge. I took her up a long steep hill at in 5th gear and below 2000rpm, then opened the throttle wide to almost lug the engine. She grunted a bit, but pulled hard up towards 50mph without a hinting of pinging. Last week I wouldn't have dared this, as she would have instantly begun to ping.
Final test:
Tomorrow (or should I say today, as it's 1am my time!) I'll be going on a long ride out with several other GTs. Cue acceleration tests!
Topic: What did you do to your RE Continental GT today? (Read 391208 times)