cheesemethod
2nd September 2011, 11:29
About six months ago, I decided to do the CCTs on my 36000km 2005 Firestorm. I've built a couple of cage engines before, and have done plenty of my own maintainence on bikes, but the firestorm engine is still new to me. Acting on some terrible advice, I was told that changing the CCTs would not upset the timing, just swap them out and you'll be fine. So, after an hour's work, I have my new CCTs in, and I go to start it up. CLACK. Doesn't start, just jams. Fuck.
So, off with the fairing, radiators and the cam covers. Sure enough, the rear cylinder timing is miles out. Front cylinder is still fine. Time it back in according to the manual, start it up. Runs rough, slight clacking noise from the rear cylinder, generally sounds not good. Check the valve clearances on the rear cylinder, have excessive clearance on the intake. Carbs off, exhaust off, head off, two bent intake valves.
Order new valves and head gasket. No marks on the piston or the head, valve seats still fine. Put new valves in and lap them in. No excessive play from valve stem seals. Head back on, timed in. Valve clearances are spot on. Checked timing 3 times after turning over by hand dozens of times. Start it up. Sounds a little flat, a little bit off. Needs choke and throttle to run when cold.
Took it for a ride to work. Idles at about 500rpm when hot, occasionally stalls. Still plenty of power, but after riding a 400 for the last 6 months I can't really trust the butt dyno.
So, what have I missed? I'm putting ignition out of the question as there is ample spark and no existing problem in that area.
Timing wise... how obvious would it be if I had one of the cams out by a tooth? Would it run at all? Would it spit flames or bang and pop a lot? It's doing none of that, but the exhaust note just still sounds a little 'off'
Fuel wise... I touched nothing on the carbs in the way of idle or mixture. Fuel is fresh. As far as I can see the rubber bits are attached properly between the heads and the carbs. No loose or MIA vaccum hoses. Unfortunately I don't have any gear to sync the carbs or check the exhaust gases, so anything like that I would have to get a shop to look at.
Has anybody experienced anything like this before? I'm tempted just to bump the idle up a bit and take it for a good ride and see if it all sorts itself out, but my concern is burning a valve if I have the timing wrong.
So, might just get the motorcycle doctor to pay me a visit and get his advice. Was thinking of getting him to:
Check cam timing
Check compression
Look for any vacuum leaks
Check mixture and carb balance.
Can anybody observe any issues with my method, or suggest anything else to try before I drop my dollars on a potentially expensive checkup?
So, off with the fairing, radiators and the cam covers. Sure enough, the rear cylinder timing is miles out. Front cylinder is still fine. Time it back in according to the manual, start it up. Runs rough, slight clacking noise from the rear cylinder, generally sounds not good. Check the valve clearances on the rear cylinder, have excessive clearance on the intake. Carbs off, exhaust off, head off, two bent intake valves.
Order new valves and head gasket. No marks on the piston or the head, valve seats still fine. Put new valves in and lap them in. No excessive play from valve stem seals. Head back on, timed in. Valve clearances are spot on. Checked timing 3 times after turning over by hand dozens of times. Start it up. Sounds a little flat, a little bit off. Needs choke and throttle to run when cold.
Took it for a ride to work. Idles at about 500rpm when hot, occasionally stalls. Still plenty of power, but after riding a 400 for the last 6 months I can't really trust the butt dyno.
So, what have I missed? I'm putting ignition out of the question as there is ample spark and no existing problem in that area.
Timing wise... how obvious would it be if I had one of the cams out by a tooth? Would it run at all? Would it spit flames or bang and pop a lot? It's doing none of that, but the exhaust note just still sounds a little 'off'
Fuel wise... I touched nothing on the carbs in the way of idle or mixture. Fuel is fresh. As far as I can see the rubber bits are attached properly between the heads and the carbs. No loose or MIA vaccum hoses. Unfortunately I don't have any gear to sync the carbs or check the exhaust gases, so anything like that I would have to get a shop to look at.
Has anybody experienced anything like this before? I'm tempted just to bump the idle up a bit and take it for a good ride and see if it all sorts itself out, but my concern is burning a valve if I have the timing wrong.
So, might just get the motorcycle doctor to pay me a visit and get his advice. Was thinking of getting him to:
Check cam timing
Check compression
Look for any vacuum leaks
Check mixture and carb balance.
Can anybody observe any issues with my method, or suggest anything else to try before I drop my dollars on a potentially expensive checkup?