EFE Frame Dimensions

[inazumarob]

Hi Guys and Gals, I am thinking of buying a set of custom yokes to fit  my EFE. I was wondering if I could tighten up the rake, the EFE seems to have a bit of a stretch on it compared to other models in the GS/GSX range, and was thinking that a slightly reduced rake would help the handling. I do not know the standard values for the EFE against the ET and bandit, does anyone know how the head angle compares to the other models in the Suzuki Oldskool range. I was thinking that a 2 degree steeper angle would probably help it handle better.

Many Thanks Rob

[arnout]

Well.. Despite the 16" front wheel the stock EFE was never a nimble bike due to the weight and  given the length and trail (117mm). Lots of room to improve the handling like you suggest. But rather than limiting the focus on rake alone I'd say you'd better look at the whole picture, as donor part front ends come with their own dimensions that make up a large piece of the overall steering geometry.

So instead of looking at just replacing the yokes (with raked triple trees??) take stock of the whole package first. One given factor is the headstock angle of the frame. This is a lazy 28 deg., which is also the reason why just swapping the complete frontend form one of a more modern sportsbike will actually result in a worse handling bike (as the rake on the donor bike was much steeper). So the easiest way to counter this is of course also steepening the rake on the EFE. But unless you want to start cutting and welding on the frame, the only way to do this is by tilting the whole bike forward by dropping the front and/or raising the rear. An alternative to this (apart from trying to find a set of raked triple trees?) is just concentrating on the trail number you're aiming at via an alteration of the offset in the yokes alone. Adjustable yokes have been available in the past from Spondon, nowadays because of improved CNC tools bespoke yokes have become more accessible/affordable for regular folk (but still expensive of course compared to donor parts).

So.. What is the current chassis/suspension/geometry setup of your EFE? Measure and compile that data into the geometry tool below, and play around with the various variables to arrive at the desired trail. (It's a bicycle website, but geometry theory is the same for motorcycles)

http://www.kreuzotter.de/english/elenk.htm

Stock EFE chassis spec:  Rake/Caster = 28/62 deg. |  Trail = 117 mm  |  Wheelbase ≈ 1550 mm

Typical 1000cc sportsbike: Rake/Caster ≈ 24/66 deg. |  Trail ≈ 100 mm  |  Wheelbase ≈ 1420 mm

Of course lots of other factors determine the handling of the bike too, like weight (overall, balance, position), inertia of rotational (engine) parts, rider postion, suspension, tyres, etc

 

[Rene EFE]

I know you have to take geometry in consideration when building or riding a bike, but for me personally, for the most part i will always be down to the person on the bars. 

I have 2 stock-framed EFE's and I can scratch the pegs wherever I go and I know I could even get it going fast round a track; no need for huge modifications.

[dupersunc]

You wont change the rake with custom yokes, only the trail.  

[vizman]

you could change the rake with custom yokes.....but it'd be a fook load of design

[yantosh]

i've made raked yokes for v rods and triumphs in the past,  but they were designed to have them,  run the risk of messing up the trail...like Viz says, need much working out 

[dupersunc]

1 hour ago, vizman said:

you could change the rake with custom yokes.....but it'd be a fook load of design

The rake is the axis which the forks pivot about.  You don't change that with yokes, unless they go with some very trick offset bearing cup inserts in the frame.

[vizman]

…..duh

whad'ya think i was suggesting?

[no class]

Yoshimura nake them...... had a set on my slingy ..... which basically means they will fit an efe 

[arnout]

14 hours ago, Rene EFE said:

I know you have to take geometry in consideration when building or riding a bike, but for me personally, for the most part i will always be down to the person on the bars. 

I have 2 stock-framed EFE's and I can scratch the pegs wherever I go and I know I could even get it going fast round a track; no need for huge modifications.

Wow.. The only parts I was ever able to scratch were the engine side covers. In most cases those situations ended rather poorly for myself though..

[inazumarob]

Many thanks for the input Guys, I have decided to go down the tried and trusted route of fitting 1100 Slingshot front end with slightly longer legs. I am not trying to turn it into a sports bike, just improve the suspension slightly. I realise that it can be a long and rocky road to make it as you want. Have booked ticket for EFEST at Santa Pod in September to give me a timetable. Thanks again

Rob