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Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
I'll drop in. For BUB Speed Trials perforations etc. are OK, but for SCTA runs absolutely no perforations or non-leather panels are allowed. I think the issue is fuel spills getting through the suit.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Two cents: Looking good, keep it period to match the bike. One inch white stripe on the outside of arms and legs. Your last name on the back, don't gain weight and it'll last a lifetime. Vanson make nice leathers as you already know.
I have a Vanson Duo-Zip"Volante" I called Vanson to get some information on it. It's still in the line up and is a $2800.00 one piece race suit. Now here's the good (lucky) part. I got it from Craig's list $75.00 fits very well. Every once in a while even a blind squirrel can find an acorn. Love your bike.
Cheers, 50gary
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Got some done tonight - top end is all on, rocker cover on with Threebond. Just need to do final head torque and time to swap engines. Still lots to do - clutch etc. off old engine first, then pull the engine. Put new engine in, install clutch etc, and then the Pamco ignition install / coil mounts etc. But it's getting there!
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Ok - small steps - made a piston stopper from a spark plug, 6mm socket cap bolt and an acorn nut. Got a degree wheel, and did the proper true TDC measurement. Good news - the factory TDC marks on the rotor and stator are DEAD on - couldn't be better.
So next up is checking camshaft operation. Have a deflector dial and magnetic mount - just need to rig it up on the valve retainer to see what happens as we turn the engine over. Got the camshaft card and will see if I can figure it all out so I can hopefully turn the page and put this engine in the frame.
Vanson makes really nice suits. You might also want to check out these guys. They make custom suits and prices are a little less...I have heard good things about their quality.http://www.syedleathers.com/
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
So here's the table. These aren't perfect to be sure. My deflector mount is less than perfect. Going to try all this again and rig up a more solid mount, but at least the indication is things are happening at about the right times. Have to digest all this to understand if rotating the cam sprocket one direction or another would allign more of these measurements or if they're just variations caused by the grind and fine tuning the sprocket wouldn't do much.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Not a bad start Tim. The first thing that jumps out is lift on both left cams is around 1mm too much. Did you deduct the .050" allowance on both sides or not? Sounds almost like left side wasn't adjusted.
Mid point timing is L 98.5,99.5 and on right it's 102.5, 98. Compared to spec the left cam is 1.5/0.5 degrees advanced and right is 2.5 retarded/2.0 advanced.
Those numbers are well within normal measuring/manufacturing differences.
On "average" it's about 1 degree advanced which is fine. If anything it will give you a poofteenth more bottom-midrange.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
I confirmed with the source of the camshaft that the lobes aren't symmetrical, so the centerline needs to be measured as the midpoint between the opening and closing measurements. This is of course what you've already concluded as well - means I'm closer than I thought on that.
The high valve lift was I'm convinced due to my dial guage not being parallel with the valve stem and in fact moving a bit. My retainers are not flat - they have a lip towards the outside. So it's near impossible to keep the gauge on a consistent surface as the valve moves up and down 0.4". Large dial and short plunger, along with long studs sticking out for the tappet covers makes getting the gauge in there hard.
Am double checking but, given my true TDC measurements lined up perfectly with the factory marks, and I installed the camshaft as per factory spec, and how close the measurements are given my sloppy gauge setup, if I was pressed, I'd run the engine no problem. The camshaft comes from Mr Riggs, who makes rephased performance cams for the XS650 all day. They're precision ground and the rephasing he does is top notch machine work - no welding.
Anyhow - just taking a mental break from the measuring and modified my breather a bit according to some know-how from the XS650 world. Little gasket adhesive, stainless bolts and anti-seize and its on now. Can't wait to fire this thing up and see what happens. If nothing else it will be a very pretty explosion
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Oh and yep - I'm working with zero valve lash (took a bit of Google to tell me valve lash is the gap between tappet and valve - never knew the term before) and took my degree measurements at 0.05" lift.
For the max lift I measured from 0 - is that correct? I'd imagine so.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
I would run it as is. Usually max lift means just that, but in this case they may have deducted that 50 thou. Timing is close enough on both sides to use.
You could try the DTI on top of the tappet adjusting screw, but a long pointer onto the retainer is usually most accurate.
I always measure cams when they come back from the grinder to see that base circles and height are identical before they get close to an engine, but it's too late for that on yours.
Next step is to confirm piston to valve clearance and valve to valve.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
How does one go about confirming those clearances? Total noob here Engine is bolted together and no clunks or pings when I turn it over. Pistons are a big bore kit specific to the XS650 and have stock compression with enlarged valve pockets. Intake valve is enlarged (+2mm I think), exhaust is stock.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
I'm just rechecking my notes/emails. I think the exhaust has been ported, but not sure about valve size. Interestingly some people run cones in the exhaust when running larger headers, to maintain back pressure I guess for mid-range. So if it's a bottleneck, it would seem intentional. Not sure.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Interestingly enough bikes don't really need back pressure. They do need ports the right size that flow the right amount though. Old Honda twins were often exhaust restricted, but I don't know about the Excess 6.5
The "right" way to check for clearance is to use that dial gauge again. With the engine approaching TDC, lever down on the valve and see how far it can move before it contacts the piston. Rotate it a few degrees at a time and repeat. you need at least 1mm on the intake and 1.5mm on the exhaust.
You also want 1.5mm between the two valves at overlap. TO do that , I set the crank to TDC with both valves open and lever down on both valves at the same time to see what the clearance is. You can do it by feel/sight.
Re: Tim's XS project - ENGINE UPGRADES COMING - AUG 2012 SALT FLATS OR BUST
Cones in the headers are probably an anti reversion device to limit exhaust reversion along the port floor - where gas often flows the wrong way. Stepped or tapered headers and a D shaped port are probably better ideas.
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- AUG 2012 SALT FLATS OR BUST
