Sister of Muffin is a 2002 X1 that I bought on impulse about two years ago.
It was in a sorry state (and to a certain extent it still is) with the previous owner, obviously after discussions with Maz, tried to turn it into a 2001 model. He did this by taking a paint brush to the engine
Anyway, it has had lots of bits replaced that were worn out after its 20000 mile hard life, these include a new fork leg (previous owner had fixed the loss of chrome by applying silicon sealant), an EBC Pro-Lite disc (the original 9 bobbin disc was very loose), new headrace bearings (the original ones had 10 degree indexing which meant you had to fine tune cornering by huge shifts in body weight) and a replacement shock (thanks Cooter).
I took it for an MOT just after getting it (and changing the headrace bearings) and it passed. I quite enjoyed the 100 miles I rode it that day and I quite enjoyed the 100 miles I rode to Berkshire and back a few days later, however I knew deep down it needed a Buell Pro Race exhaust. I found one in the states that cost me an arm and a leg and this is where the problems started...
I broke both header studs on the front trying to remove the exhaust, which led to me removing the head and drilling out the studs on the milling machine. Whilst I was at it, I decided to look at the combustion chamber, squish band and piston crown...
viewtopic.php?p=210294#p210294I ended up skimming 0.9mm off the heads, they then went in one of my green grocer baskets and the heads stayed off the engine. Whilst they relaxed, I had a quick look in the barrels and to my astonishment, I found a strange mark in the rear cylinder:
On closer inspection it looked like corrosion, perhaps with the bike standing a long time at some point in its life... I tried to hone it out, but it wasn't playing and the ring gaps were getting closer to spec limit, so in the end I went for a rebore to first oversize.
Whilst that was being done, I changed the oil pump gear (which was showing lots of wear), cut down the cam cover and polished it up. Valves were lapped in and valve guide seals replaced.
I put the heads on and checked the squish. All a bit disappointing cos it came out at 1.1mm min (would prefer 0.75mm but far better than the 2mm it had as standard), however it was always going to be crap cos the piston has a 10 deg squish angle and the head has a 15 deg squish angle:
viewtopic.php?f=8&t=16100As I was building it up yesterday (and this is the real reason for the post), I was a little concerned about the head skimming and the effect it would have on the pushrod length.
HD do a set of Screaming Eagle pushrods, 50 thou shorter than stock, but at £120 they are getting close to the value of the bike... I have a few sets of adjustable pushrods, but would prefer to use fixed ones due to (valve train weight) weight and simplicity, hence did a bit of study...
I built the engine up with stock pushrods but no pushrod tubes:
I left the engine overnight to let the tappets bleed down completely. In the morning, I went to see if I could turn the pushrods by hand, and I could... So, in theory, they could be used, however the amount of margin was unknown...
So, out came the adjustable pushrods. So I built the engine up with said pushrods and then adjusted them so the valve train was loaded and a bit more. Then I went to town and hung out with Ms Pash. On my return, I reduced the length of the pushrods until I could spin them by hand, then took the rocker box off and measured the pushrods using my verynear calipers.
Next, I rebuilt the engine and loosened the pushrods until they were loose, then tightened them to take up the slack, pulled the rocker box and measured.
Then I measured the stock pushrods and calculated the margin against full movement (or accommodation) of the tappet:
So, for a total tappet movement of 4.8mm or so, the stock setup used up 3mm, now it uses up 3.9mm.
This means I can get away with using stock pushrods and I don't need to pur-chase Screaming Eagle or similiar, or use adjustable pushrods.
Engine built up again. Quick pic of the tool to torque the rear 1/2" AF rocker box bolt:
Interestingly, looking here:
http://www.hammerperf.com/ttpushrodlength.shtmlHammer Performance say that the stock lifters work well between 50 and 150 thou (maybe to sell more adjustable and shorter pushrods), however, a few tests showed that the lifters bled up ok with the stock pushrods. It will be evident if it doesn't work properly cos the valve train will be noisy, in which case I will be looking for shorter pushrods
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did she pass the MOT Nick 
) to check for a spark, yes there was one, then motored the engine and there was no spark. Out with the battery and I found that the breather pipe I had pushed through under the battery tray had dislodged the CPS plug. Reconnected and the missing wedge in the female receptacle replaced. Starts great now. Need to take it for a ride up and down to ensure that I have really fixed the problem.