Has anyone actually tried welding or otherwise permanently "fixing" the alternator damper? I am in the process of attempting an EFI conversion and most likely supercharging my 88 Hurricane 1000 and the alternator shaft would make a pretty ideal/easy spot to modify and add a SC drive pulley, but of course I worry about putting several hp more load through the apparently already failure-prone damper and ending up with it slipping. What are the realistic consequences of welding it? Does it actually provide individual power-pulse torsional cushioning, or is it simply an engineered fail point to prevent breaking the chain if something locks up? Frankly, I'm prepared to deal with whatever the consequences may be but am looking for input/experience from those who have actually modified one, either to be stiffer, or completely rigid. Thanks.

 

Also, does anyone know what the drive ratio between the crankshaft and the alternator shaft is? Is it just 1:1?

 

I like the way you are thinking and am tempted to weld my damper too. SC sounds great!. I would be concerned about the strength of the alternator chain and tensioner- as long as these are good enough to spin the SC it should work, and obviously you need to put a charging system on somewhere.

 

Or do you mean spin from shaft outside of alternator?

 

I was thinking extend the existing alternator shaft enough to add a 4-rib pulley, space the alternator out accordingly. That is definitely one of my concerns though, I have no idea how strong the chain is, or what the drive ratio is. I can't imagine that the torque to spin the SC is going to be more than what the starter transmits through that chain anyway. I mean I haven't measured the amp draw of the starter, but it has crazy amounts of gearing, it's got to be putting substantial torque into the chain.

My alternate idea, that has really been growing on me, is to attach a SC drive pulley to the front sprocket. This could give me boost that would increase with each gear. I plotted roughly what that would look like on the compressor map with 7.5psi in first ramping up to around 20psi in 6th. It's right in great efficiency islands through all the main places I'd actually likely be accelerating. I've got no interest in doing 170mph on a bike as old as me, lol...or really any bike for that matter. The supercharger I am planning to use is an Eaton TVS R900. So if I did my math right, I would have to drive it off the front sprocket at about 4:1 ratio to get this desired boost level, which most likely will require a 2-belt system to step the speed back up, because I don't think I'm gonna squeeze an 8" lower pulley on there, lol. Frankly, I am not very familiar with the bike and don't get to see it that often so I'm working off ****ty service manual and other online pictures for most of this planning, it is stored at a friend's place because he also has a bike project and talked me into getting one and keeping it there to hang out/fix them up at the same time. I did grab the carbs for a size reference for thinking about an intake. There should be plenty of space for the supercharger, it's hardly bigger than the carbs. The other challenge, which is kind of a pre-requisite to this, is getting the bike converted to a proper EFI system. I'm thinking mid 2000s GM 4 cylinder, as I'm familiar with tuning them and think I can make it work. The only real trick there is going to be adding a 60-2 crank reluctor. I really want to do all this within the confines of the factory fairings so that may mean some...clearancing.

 

I do have a wrecked donor car for the computer/harness/sensors, and have plenty of random fuel injectors, etc laying around that should be appropriate. Already got the necessary reluctor, just have to figure out how I'm going to attach it to the end of the crankshaft...which shouldn't be physically too hard to do, it's just going to be doing so in the available space, without creating any leaks or balance issues, etc that's a trick.