I have a 2000 YZ426F Supermoto, recently bought. General service history is unknown although oil was clean, radiator fluid normal, correct level, etc. I changed the oil, rad fluid, a fork seal, water pump seals and a few other things. It has a new FMF Q4 slip on, jetting unknown. Note: lots of popping on decel. It has the Hotcams exhaust cam with the auto-decompression. When I bought the bike, I could hear the valves ticking pretty loudly so I did a check and adjustment the other night. Here is the data: Intakes before adjustment: .15mm, .13mm, .08mm Exhausts before adjustment: .45mm, .37mm It's a 2000 so the specs are looser than the 01 and 02. OEM specs .15-.20mm intake and .25-.30mm exhaust. I checked the Hotcams website and they suggest .17-.22mm on the exhaust. As you can see, intakes were a little tight so I adjusted them all to about .17mm. You can also see the exhaust valves were WAY out of spec and were probably responsible for all the clacking I was hearing before the adjustment. As far as the adjustment on the exhaust, I went with the hotcams suggestion and set the exhaust valves at .20mm Also, while I was working on it, I loosened the throttle cables just a little since there was some, but very little free play at the throttle tube. Also put in a new CR8E plug, just like what was in there, which looked pretty good actually. Anyway, I go to fire it up and just kick and kick, choke, no choke, plenty of gas in the tank, but it just wont start. It was popping and backfiring every few kicks. Finally got it started by giving it about 1/4 throttle while kicking it over. It always started right up before, no throttle needed, just some choke when cold. Anyway, thought maybe I somehow got the cams out of timing, took it apart but all seemed normal. Below is a pic of how it looked before and after the adjustment. Please note its not exactly at TDC in the pic, but very close. When at TDC, the punch marks on the (OEM) intake cam aligned perfectly with the head and the punch mark on the Hotcams exhaust cam was about a mm above the head surface. Just to test it out, I rotated the exhaust cam one tooth to see if the punch mark would line up exactly like the intake, but it was way off so I set it back to how it was when I first cracked it open. In other words, rotating it one tooth was too much to get the punch mark even close to lining up. So I went out for a test ride and aside from having to give it throttle to get it started, it seemed to run fine, and the valve clatter I heard before was gone. Got home from a short ride and it spewed some coolant and the radiators were abnormally hot. Never had it spew coolant before and it wasnt a particularly hot day and was an easy ride. So, any ideas on what has changed this bikes starting mannerisms or what might be up with the sudden unusual overheat? I'm taking it to the shop tomorrow to put it on an exhaust sniffer to see whats up with the fueling. Im thinking its running lean. Should I consider setting the exhaust valves to the looser OEM specs instead of what Hotcams recommends? Any advice appreciated!