Sprocket choice help needed.

[rbgaz]

mmmm-just-looked-at-them-charts
and-theres-noway-my-rb22-with-a-nk-race-will-pull-in-4th-with-a-4.7-4.9

[jonashford]

I'm going to the Doncaster hunters do tomorra, it's only 50 odd miles there so I've gone for 5.2 ratio on my rb for sum fun, and to stretch a nice new Iwis chain so it fits my 19 sprocket.

[jonashford]

at 4.6 my rb wud only pull me in third!!! :fb:

[camel]

yes this thread is labouring on a bit.......but entertaining
ok 5.2.......at 6000 revs =58mph
4.8......at 6000 revs=62mph
theres friken 4mph in it.......
one WILL pull
one MAY pull
with that combined weight

[soullad]

[quote="soosh"]Lots of "opinion" and "theory" going on,wheres all the people who run Taff pipes on a TS to give "actual" account? Be interested in their account of running 5.2.

As previously stated I have a TS 230 (60mm crank) with a Taffy MK4, it runs 18 x 47 on an LI 125 box which is approx 4.8, gives the clutch an easier life and has a nice easy 1st gear for me and my luggage .... not saying it'll suit everyones set-up but it works for me.

[Darrell Taylor]

heres a ts1 dyno graph,well set up with 30mm and jl4 ill add a new twist to gearing choices tomorrow thats not been covered yet

[rbgaz]

I'm going to the Doncaster hunters do tomorra, it's only 50 odd miles there so I've gone for 5.2 ratio on my rb for sum fun, and to stretch a nice new Iwis chain so it fits my 19 sprocket.

hi-jon--i-hav-4.8-with-a-franspeed-road-and-it-still-strugle-in-4th-up-hills-into-wind-etc
when-it-was-5.2-with-a-nk-race-it-fecking-fast-it-would-hit-the-powerband-for-fun-going-up-hills-in-4th

[jonashford]

I'm going to the Doncaster hunters do tomorra, it's only 50 odd miles there so I've gone for 5.2 ratio on my rb for sum fun, and to stretch a nice new Iwis chain so it fits my 19 sprocket.

hi-jon--i-hav-4.8-with-a-franspeed-road-and-it-still-strugle-in-4th-up-hills-into-wind-etc
when-it-was-5.2-with-a-nk-race-it-fecking-fast-it-would-hit-the-powerband-for-fun-going-up-hills-in-4th

Yes matey. I usually run 19 47 its a bit revvy at that, but fun. As I use a af cassette clutch I havent tried 19 46, 20 47 was too high, gud on the flat and o wind, it got the revs down too, but when I went to whitby, it didnt like it and it got dangerously hot as well, Experience has taught me that my engine luvs to rev, it great fun to ride, will pold along at a genuine 70 does just over 80 when I have the bottle to do it! It isnt great on fuel and I never ride 2 up, that wud kill it completely lol!!!

[nelson pk]

The AF gear chart is very optomistic in my opinion. Again, depends on your style of riding and how well you like it to pull up hills, against winds.

[Terrible Taff]

Hi, I'm building a new TS1 225 engine and I'm looking at using a Li 150 gearbox, but not sure on what sprocket combination to use. I have had a look at the gearing calculator but aint got a clue on whats what and all the jargon.
I will be using a Taffspeed touring pipe and it will be used for riding 2 up occasionally. I'm about 15 stone and the other half is about 9 stone, so it will be like wanting to pull an elephant
Any help much appreciated
Bizz

ps.....if you dont think that gearbox will work, I could always use something different.

Hi Bizzly,
I ride a TS 230 with a taffy mk4 touring pipe. My dyno graph clearly shows that the pipe will brickwall at approx 7250 revs. There is hardly any rev-on at all. Peak power is approx 5250 rpm, enabling you to pull tallish gearing. I initially spoke to Ian at Taffspeed about suitable gearing. He said that providing the exhaust port hadn't been raised that his preferred choice was to aim for around 4.8. He also mentioned that there was no proven real benefit of transfer timing of over 125 degrees.
He also did say that he produced shorter header pipes for those scooterists who liked to raise the revs a little ( and therefore pull shorter gearing) thou this was moving away from what his pipe was originally intended for - a touring pipe.
He further added that other barrel mods could be done allowing even taller, 4.4 gearing to be pulled, thou he stressed that an engine was the sum of its parts and needed to be designed with an end goal in mind.

Just as an added consideration, what reedblock you thinking of using?

Having just read through all the postings I have to agree with soullad's findings.

When ever I have followed scooterist to or back from rallies they all seem to travel at 45-50mph on A / B roads, motorways 50-60mph.
So you ask yourself do I want ecconomy or driveability? 4.8 or 5.2? In the end it's your choice!

If you use the stock cylinder on a Indian casing transfers are 130' exhaust 180' giving that motor shut down feeling due to the exhaust gasses not being able to get out, & if run hard at higher revs all the time leads to the cylinder over heating & carbon deposits within the transfer outlets!
Usually giving around 16-18bhp mark due to lower compression heads used. 60% to 80% over stock!

The TS1 cylinder has too much transfer feed area in relation to the exhaust port area for touring, hence we built engine units with 110mm long yam or Kawasaki conrods so as to run lower transfer timings 126 with the exhaust raised & widened to give 190' port width 47mm inlet lowered in a radius to ease the piston over the inlet.
This results in the piston coming 0.5mm btdc & no head gasket but the Indian 200 head recessed 1.2mm centralised & dowelled to the bore with our Mk4 Taffy pipe, 30mm Dellorto, gave 22bhp+ with a wide tourque spread that suited touring or thrashing. 120% over stock!

With our ported TS1 motors they had 25bhp with the Taffy race box (JL4) but unlike Darrel Taylor's graph held the power after peak for another 2000rpm giving 25bhp from about 45mph to 90mph 2nd to 4th.
That was in the early 90's when we were hell bent on top speed!

Todays riding conditions dictate 70-75mph max with the best ecconomy possible but still with the ability to pull Solo/Pasenger/Rally Loaded in the end it is a compromise as to what suits your riding.

Use the 5.2 set up & when the chain stretches fit a 16t & try that, better still get it ported & have the best of both worlds ~ But that takes loads of wonga!

Ian Frankland
Taffspeed
07794 003276

PS; The best power output we ever got from our Group 6 TS1-230 was 38bhp @ rear wheel back in 1995 with a very wide power spread which gave Stuart Day 6 years of dominance in that class & loads of Championship trophies. Also 113.5mph on the Scooter Crazy Shoot Out Video @ Bruntingthorpe.