Sunday, March 23, 2008

Quick Progress

Things always seem to go in fits and starts. In the span of 3 days, I've gone from "tacking it and getting someone else to tig weld it", to what the heck -- I'll see if I can do it myself.

By jove, I think I got it. #2 tip and lots of pre-heating and deft flame work (if I do say myself), has got me a SS swing arm for my SS.

Right hand side view -- welding forged steel is a bit tough -- the welds (with oxy, anyway) end up looking mig-ish. A good tig welder would've come up with some nice fillets.

The entire assembly is boxed, with 100 wall sheet trimmed to fit.

This view looks a bit cockeyed -- I'm standing to the right of the bike when I took it; trust me, its straight. I also built in some left/right adjust ability into the frame mount for fine tuning. I then hauled the entire swingarm to Cycleboyz and to the Welding teacher at the local college. Both said the welds looked excellent, and were as good as being professionally tig'd. Three cheers for me!
The next step is sorting an exhaust system -- the Hindle unfortunately will not work. I need something that will leave the single-sided swing arm exposed, so either another high mount system, or an under engine (eg Quat D) exhaust would be the best. I think any system is going to require some tweaking, as the idiosyncrasies of the MH swing arm might foul on most rear exhaust downpipes.

Saturday, March 22, 2008

Helmets, dirt bike parts, and swingarms

I have a Vemar head. The last time we went out to the slough for ice riding, as it was considerably colder, I decided to take my full face helmet, rather than my MX lid. It was the first time wearing it. A Vemar DeAngelis replica (the cheaper version) that I fell in love with a few years ago after seeing it in a UK magazine. Over the years, I realized that they likely would never officially be imported (although Motonation in CA now carries them). I actually ordered the high-buck one from the UK online, and was then told it was out of stock -- while they were processing my refund, I found the slightly cheaper (but still DOT/Snell equivalent approved) lid on ebay, and I got it for under $100, brand new and half price! I have no idea why the seller was selling, or how he got it in the first place (it was in the US). Whatever, its mine now, and it fits the best out of the many helmets I have owned over the years. Coming from Manitoba, the mosquito motif is perfect.

The TTR rebuild has turned into an unofficial Woodshops 25 project. Class numbers being what they are, I approached the teacher to offer the activity up, as there are 22 kids present on a good day, so me taking 3-4 per class out of general circulation helps with management and safety. To date, we have disassembled the entire engine and determined the following:
  • only the transmission and cylinder head parts, as well as a few inceindentals are salvagable

  • the case halves both have internal damage beyond repair or re-use

  • the carb looks good -- we spent last class cleaning it, and removing some nearly-varnished fuel

I, of course, have decided to go whole hog -- 150cc kit, performance cam, and FMF exhaust will be installed, along with the new crank, case halves (matching) bearings, cam chain, etc. etc. Some things were surprising in terms of pricing. Case halves were $200/pr, but a complete gasket and oil ring set was $100! New bearings for the bottom end also cost $100. I tried to go a bit cheaper with non-Yamaha bearings, but I noticed that the NTN bearings had one less ball to carry the load. I checked with Pop who said this was NOT kosher -- so I returned the NTN and got the right ones from Yamaha -- from $40 to $100 in one easy step...

Since the big trip will take up most of my summer, I have decided to hold off licenceing the Ducati this summer, and endeavor to make the "Ultimate SS". I think I was pretty close as is, but what would set it apart is a single-sided swingarm. I think I found one of the last OEM MH900E swingarms on the market from a guy in England. We settled on a reasonable price, and unreasonable shipping (although it got here pretty quick), and I've started to fit the thing to the bike. It will mean stripping the frame right down again, as some maching, grinding, and welding will need to take place. However, seeing that there is some considerable value in the OEM ducati pieces I previously had on the bike, I will be able to recoup most of the costs.

It has been done before... Reed Herman from MN mounted one of the swingarms he had onto a customer's 900SS frame... as with most things Ducati (at least with aircooled engines), the swingarm is a direct bolt-on. That being said, I have to modify the frame, cutting off the lower half of the frame downtubes, as they foul on the outboard edges of the swingarm. So that means I will have to re-position the rearsets, so the 916 rearsets I got will no longer work -- considering I have custom-made probably 5 different sets of rearset plates, this is easy, and made simpler even with the fact that the brake and shift levers do not pivot on the plate. I used the 916 rearsets as a guide, grinded off an old rearset tab from another frame, and welded it "up" from one of the tabs which could stay on the frame. Then I cut off the bottom part of the frame to suit. It actually looks a bit like how the hypermotard and sport classic frames are designed. I have a pair of wooden templates made which locate the pegs from their new origin, to where they end up with the OEM 916 rearsets. Not very well explained... but if you've ever done this before, you know exactly what I'm talking about.

An email to Reed confirmed an important point -- the swingarm mount he used to graft onto his machine was chopped off of a steel SS swingarm, with hours of grinding and filing to get it to adapt to the compound curves of the MH swingarm. As chance would have it, years ago I snagged a steel SS swingarm for another project, which willfully donated parts of itself to the cause. An attempt at making a welding jig proved fruitless (as it did for Reed), as while the cantilever swingarm and MH swingarm are close on triangulated reference points, there is enough of a difference to cause a problem -- Reed ended up having a bike with an extra 2.5" of rear ride height, compensated by adjusting the eccentric in the hub. Being forwarned (and using my own eyeball engineering), I know now that the shock mount will sit much lower on the upper part of the swingarm stay. My plan is to fit it in situ, tack weld it in place (the shock mount is forged steel), and get it properly tig-welded by someone else.

You can also see from this pic the relocated rearset mounts, and the end of the orange paint...

Wooden rearset template -- needs to be finished (shops sanders at school) -- and then replicated in aluminum. I have some 3/4: 7074 plate for this...

Still lots of grinding to do!

Reed had said in his email that it took him "about 5 hours to fit" -- truth be told, it took me about the same amount of time on Easter Friday to do likewise. I ended up with a pretty good fit, one that I can tack in place, and then take to a shop for tig-welding. As my mount does not sit as "high" as Reed's less boxing is going to be needed for reinforcement, but I can put some in place with some sheet steel.

Right hand side -- need to get rid of some paint prior to welding.

LHS -- not bad!