Joper wrote:Hehe! I have no idea. Ive owned this bike in about a month and only driven it round the block! The strange thing is that the only lobe that is worn is the one on the picture, left side exhaust. The right side exhaust have some marks and the intake lobes look perfect.. Very strange to me!
It may have begun with some rust. Look for pitting in the bores or other rust damage.
The exhaust valve is a hot spot and the oil flowing down the exhaust pushrod tube to the lifter is the hottest---the exhaust lifters run the hottest. If the oil was poor/low/too thin you might see problems on those before the others.
You might also have a defect, either in cam hardening or perhaps in the lifter. One surface failed early and chewed up the other.
You could also have a lubrication problem---perhaps a bit of swarf or other defect in the oil way dripping oil on that lobe. Check this.
If the heads were rebuilt the valve spring pressures may have been set up incorrectly. Look for a bunch of shims under the springs. Someone may have set it up for high RPM racing---this has a price.
You want to wonder where all that metal went. Some got around the filter on startup. So you look over the big end bearings. (new bolts there always)if no embedded metal and good spec. no worries on the rest. If you have metal in the bearing and perhaps scoring on the journals, pull the crank and check all bearings. (ug!)
Major lubrication failure will result in discoloration on the crank. You probably would have noticed by now.
You can theorize further after looking at things like the wear on the oil pump---this can also indicate mileage on the motor although looking over the frame and controls can say more, quicker.
The later lifters (spiral hole) are lighter. I would keep all of the same type rather than some light and some heavy ones. That said, I consider the camshaft to be in 'deep'. lotta work to change it (and the new on better have a strait nose---beware of that!). But the lifters are not in 'deep'. You can swap them out in a couple hours for the price of new head and base gaskets. And you are in there every 8 years or so anyway for fresh pushrod tube seals. So you might push it there without worries of big effort and expense to replace them later. I have a nice cam sitting here, and probably some lifters, but I suspect the shipping to Sweden from the USA could be steep. Look into it maybe. Bet Duane has some too and he might even pay you to haul them off.
If you don't have magnetic plugs, now is the time.
Those Hondas are getting valuable and even ratty ones are wanted for cafe projects.
