Tuesday, October 21, 2008

If it ain't one thing, it's another...

Well, the GTS is down again for another week. When I checked out the exhaust leak, I discovered that one of the exhaust studs had completely fallen out of the cylinder head! Of course, this stud is not just a run of the mill part either, it's a 7mm stud that apparently no one carries, besides Vespa. Luckily Vespa does have them in stock, so hopefully it should be here this week. However, it still remains to be seen whether the threads are still ok inside the head, or if they're stripped. If they are damaged or stripped, my best bet will probably be to epoxy the stud in there with some JB Weld, although I'm concerned that the heat might be too much for it to hold in the long run, since it's about 1/4 inch away from the exhaust port. Failing that, I'll need to either install an insert, if I can even find a 7mm one, or tap it out and install a larger stud. Hopefully it won't come to that, but we'll see. Wish me luck!

Wednesday, October 15, 2008

Running again!

I totally forgot to post that I got my GTS back on the road Monday night! I installed the new variator, belt and the freshly cleaned clutch, leaving out two weights from the variator, for better gearing in the hills with the oversize rear tire. I have to say that it does rev a lot higher with fewer weights, reminiscent of the Polini, and it's a little slow when first taking off. However, acceleration is quite good when I punch it, and I'm sure that the extra torque will be very useful on the trip over to Santa Cruz.

I also got a new set of Heidenau tires at Moto Amore, a K66 130/70-12 in the front and a K58 140/70-12 in the rear. They're still breaking in, but I really like the K66 on the front, it's much quieter than the K58 was, and it seems to grab fairly well. The K58 on the rear does seem to handle differently, it feels a little less sticky, but that may be due to the fact that it's not completely broken in yet. I'll give it some time and see how it goes.

One thing I noticed tonight is that it sounds like there's a small exhaust leak. John mentioned that one of the exhaust manifold nuts was loose. I'll check it to see if maybe it came loose again. Stupid scooters... it's always something! ;)

Monday, October 13, 2008

On the road to recovery

Well, I didn't get the GTS fixed this weekend, but I did get the transmission apart and found that the variator is worn out. This was a bit unexpected, as was the mess I found when I opened it up. First, the belt wasn't just shredded, it had completely disintegrated! Whereas before there were lots of rubber bits strewn about, this time I found little more than pieces of string wound around the variator and clutch, with bits of dust and fluff everywhere... wow! Once I removed the clutch and cleaned up most of the mess, I pulled the variator off to find that the weights had somehow become wedged between the pulley and the bell housing, and a few of them had even melted against the bell housing from the friction, when the belt let go! It took quite a bit of work to clean everything up and scrape the melted kevlar off the bell housing, but I managed to sort it out. However, I noticed that there was a lot of play in the brass bushing on the inside of the J Costa variator pulley - not a good sign. It looked to have close to 0.5mm of play, so I was concerned that this was too much for it to run reliably... if there's too much play, the pulley will wobble, producing excessive vibration and pressure on the sides of the belt, and before long the belt will fail. I suspect this was a contributing factor in why this belt failed, and possibly why the previous belt failed on the last day of the Cannonball.

The brass bushing in the inside of the J Costa variator is a rather special piece, which appears to have graphite inserts on the inside, in order to provide lubrication as the pulley spins on the shaft. I'm not sure whether J Costa makes a replacement bushing, but I hope so, because the rest of the variator appears to be in good shape. It would be a shame if they don't, because the rest of the variator still is in pretty good shape. Now if this variator just had a regular brass bushing in the center of the pulley, I could just have one machined and pressed in, which would be no big deal, but that's not going to cut it without some way to lubricate the surface between the pulley and the shaft. So for now, I'm just going to get a whole new variator, and see what I can do to get a new bushing and set of weights for the old one, so that I have a spare on hand in case I need it at some point.

Thankfully, Rich has a brand new J Costa variator that he's willing to give me tonight, which I'll replace with another new one as soon as I'm able to pick one up. So, hopefully I'll have the GTS back on the road and running great tonight! Then maybe tomorrow afternoon I'll be able to run down to Santa Cruz to pick up another one, a belt, and whatever other parts have arrived that I ordered. Wish me luck!

Tuesday, October 7, 2008

Post-Cannonball Blues

As if it weren't enough of a downer to have to spend 8 hours a day sitting at a desk staring at a computer screen, instead of sitting on my Vespa enjoying beautiful scenery, it seems that the rigors of the Cannonball have caught up to my GTS. I just shredded my other belt, the used one I installed on the last day of the ride. Even better, it gave out while I was heading back to work on my lunch break, while I was riding on Highway 85! Thankfully it didn't lock the rear wheel and I was able to safely coast over to the very meager shoulder on the right. I knew it would only last so long, but I didn't think it would go quite so soon. Ugh! I already ordered parts, hopefully they'll be here soon. If I can get it all sorted out by this weekend, I'll be happy... keeping my fingers crossed!