So now that most of you have heard of what happens when you mis-time some cams and disaster strikes. A new-to-me engine and a month later, I have a Bandit again.
I was originally looking for a new head but once again, ebay saved the day with an 11k motor and a shot set of carbs. The shipping was more expensive than the engine itself and arrived yesterday so with some help from the little lady, I got to work (no we didn't do the swap in the kitchen but she did help me hoist it into the frame).
This time around I was unbelievably anally retentive in the cam installation. I should have just left the stock cams in the motor just to make sure the damn thing worked but I decided to just turn it over by hand as many times necessary to make sure everything cleared sufficiently. Plus I needed to beat the thing that originally beat me. Some anal-retentive hints on cam installs:
-Disregard the markings at the end of the cams and match up the cam wheels/pin count. E/1 flush with the head and 20 pins to the "2" on the intake. Doing this will make the marks on the ends of the cams not match but those only matter when you're setting lash. That's it. Also, don't be alarmed by the excessive amount of slack in the chain inbetween the cams. The adjuster will take it up (manual or otherwise). The other good part: you now only need one feeler guage to set lash: .005".
-The cam sprockets are the same for both intake and exhaust, just positioned differently. Same part number and all, make sure you have some loctite on hand when you spin the bolts off.
I originally had set everything up using the end marks on the cam and that was my demise. The exhaust cam had enough clearance but the intake cam following behind didn't and met Mr Pistons.
-Make sure you turn the motor over by hand until you are sure that Mr Piston is not about to smack Mr Valve. I must have dry-spun the motor 50 times honestly, I was that nervous. When I had placed the cams in using the end marks, it was obvious that there was some resistance which made me rethink and go back to the manual again.
-Things are going to sound a bit different. The cam will make the motor sound different, a bit deeper and more sharp. It didn't sound like the same bike. I had also modified the collector in the headers with the thought that it was opening things up by removing the silencer. There is now a straight shot from the header tubes into the 2-1 splitter into the midpipe. Call it the poor man's header.
-Midrange is where the swap shines. That dead spot at 6-7k before you hit the mains? Gone. Mid-throttle roll-on just has acceleration now till you get to 3/4-full throttle. It's nice and fat and you can roll onto it as early as 4-5k if you wanted to.
For reference sake:
-3.5 turns out
-105 MJ (Mikuni) Dynojet needles
-middle needle position with one shim
-modified airbox using a different snorkel
I think I may be fat on the mains, but we'll see. I'll get some miles on it and check the plugs (new) for some color.
Now, the downsides or, "not everything is a bed of roses".
-Jury is still out on valve to piston contact in the upper ranges. Maybe its me but when I brought it up above 10k, it had the same sound as when it broke on me a month ago. Maybe I'm paranoid, but time will tell. Jay did you rev out beyond that when you did this with no ill effects?
The tone that the motor makes is even different. Very vtec like once above 10k. You can hear it from the headers right on out the back of the bike.
-Idle is really low for some reason. The cam overlap at low revs is probably so much that there is a huge wave blowing back through the carbs reeking havok on the CV slide. I had it set at 1200 and anything more than that would cause the rev to hang up around 2k and then come very slowly back down. Backing the screws out another 1/2 turn helped but not by much. It did die out on me a couple of times but whatcha gunna do?
-It's LOUD. The bike isn't nearly as quiet as it used to be. It really is like a different bike the way the power delivery has changed. This is regardless of the collector mod or not, the cams have changed the breathing of the motor.
-If you F it all up, a motor weighs in the range of 150 lbs or so. Start lifiting weights, saying your prayers and taking your vitamins Hulkamaniac because it's cumbersome as hell to work with.
-Re-jetting. Yes it sucks and I'm not looking forward to it either. That and having to relearn the damn bike. Yet another thing.
So there you have it. Just in case you want to take this on yourself, there's something to refer back to. I can't stress it enough to be anal about the cam timing, it cost me nearly $300 once it was said and done. Don't make the same boneheaded mistakes I did. I'll report back with some ride impressions as I get some miles on the new setup.
-Randy
