At the moment I am rebuilding my engine to get it ready for the Dutch Scott Run. Is has been rebored and fitted with Silk pistons. So it now is a fully gasflowed 600 shortstroke.
I now have the choice what gearratio’s to fit. Previously I used the vintage wide but as you know this has a very large gap between 2 and top gear. Not very pleasant to ride I think
I also have a vintage/ultra close box in my parts. This has much better spacing between the gears but as a result has a very high first gear. In fact, the first gear of the close box is the same as the second gear in de wide box! So, that means quite a lot of clutch slip while getting away but better ratio’s while on the move.
So what would be the better choice in your opinion?
If you are taking a pillion passenger with you, choose the wide set.
If not, especially on the flat roads in your area, the close would be better. If your clutch is OK, then with your weighted flywheel, the increased flywheel inertia will help to overcome the high first gear to some extent. The later medium close set is a good compromise that Scotts were obliged to change to, as the bikes got heavier than the Vintage type bikes. We are expecting to have more medium close sets in about 2 months time and our new Yowl Editor, Eddie Shermer will be able to do a conversion service when they are available.
We are interested to know to what extent the gas flowing together with the weighted flywheel will co exist with the Ultra Close Vintage box. I think it will be a big improvement. Do let us know!
Personally i think Wide is great if you are planning to tow a very heavy trailer up a very steep hill. Considering your location, I’d be doubtful thats going to happen. You could on the other hand take on the Dutch 0 to 10kph drag record.
I want to build up an ultra close for racing as i have a hybrid box which is not even in its ratios. Roger used to run it very successfully but i think the gap between 2nd and third is too wide. The sprinters used to use this design i read in techicalities somewhere..
The best for the road on a tuned bike is surely as Roger said the modern or medium close which is a good compromise, but out of the two you’ve got, I’d definitely go for the close.
Then you can liberate the wide set to fulfil their true purpose: to hold open the workshop door.
I’d definitely prefer the close ratio set: you get a decent range of speed in first gear and the top gear is (i think) the same as most other Scott 3-speed ratios. Personally I don’t think there’s a decent set of 3speed Scott ratios which are suitable for both heavy traffic conditions and touring on open roads (maybe that’s why my Yamaha RD has six speeds to give the best for all types of modern road conditions). so, given your options i’d go for the close ratio (and it sounds more sporty too).
My experience is that the Vintage Close works best with the 596cc engine as the extra torque over a 498cc helps to pull the high 1st gear. I can manage the hills on the Levis Cup Trial with my TT Rep and some of these are 1 in 4 (25%) Once rolling the ratios are a delight.
All the arguments are very convincing! So I will try the ultra close box. I am now trying to make one up from my spares so I can swap the box as a whole.
Will keep you posted on the results!