Can KTM build a significantly lighter 700-800cc twin? Is there a market for it?

[crofrog]

Originally Posted by LukasM

Have you actually tried a single disc setup or is this all theoretical?

I rode around the house like that by just swapping banjo bolts and pulling one caliper off.

I can (and do) live with the additional risk that a 0.4" lower rotor brings, not an issue in real life IME.

On your hard core adventure tourer your not worried about getting it through rock gardens in once piece?

With a 21" wheel and a TKC type tire even repeated stops are not going to overheat a single disc.

Long downhills, 2 up with luggage can put allot of heat into the system.

And again, if you want to use it primarily on tarmac - presumable with a stickier tire - then the Motomaster caliper is very simple upgrade. Those hold up even on the race track in the heavier and more powerful 990 as some other inmates have tested.

Calipers have very little to do with heat management. With the exception of the increased fluid capacity. With good brake fluid though you're allot more likely to get pad fade instead of fluid fade.

[LukasM]

No, I am not really worried about the additional risk from the disc going .4" lower, I don't think it really makes a difference as I haven't bent one yet. Switching to a 300mm disc is easy if you are.

You seem to imply that I think this bike will be able to do everything better than a 990, which I do not. Obviously the focus of this lighter and smaller twin would not be to be a good 2-up with lots of luggage tourer. If that's what you want, then you already have the 990 available.

In practical application, speaking from my own experience and that of most owners of a F650GS twin, the single disc will work fine even with a 300mm disc, on a heavier bike.

[crofrog]

Originally Posted by LukasM

You seem to imply that I think this bike will be able to do everything better than a 990, which I do not. Obviously the focus of this lighter and smaller twin would not be to be a good 2-up with lots of luggage tourer. If that's what you want, then you already have the 990 available.

Saying it is what I want is not exactly right. I'm saying what it would take to compete with other 800cc ADV tourers from a feature standpoint.

I think your concept is neat. My guess is it would be hard to get it much less than 400lb unless you make it really minimal more like a ktm 690E instead of a adventure.

The 640adv was around 350 dry...

[wilmar13]

Originally Posted by Tee2

I think you missed one.

Easy to lower for a short person or a chick bike. How many guys would buy this for their wife? A REAL off road/adventure bike.

Oh bugger off! Seriously, there are already a million lame bikes... A REAL off road bike needs to have real suspension. Buy a f650gs if you are short and need to flat foot it.

[gunnerbuck]

Originally Posted by LukasM

Lot's of discussion about this topic in the 1190 thread already, so in order not to derail it any more I'm starting a new thread.

Many of the "old school" 950/990 owners are claiming that this would be a useless exercise as you would just give up a lot of horsepower for only a couple of lbs of weight loss.

Well, I don't agree.

The weight difference between a 690 and a 990 (non ABS!) is around 140 lbs, with the engines accounting for around 40 lbs of that. Considering the smaller displacement and that manufacturing technologies have improved, a die cast 700-800cc twin engine should be at least 10 lbs lighter than the 990, probably more.

So you've got around 110 lbs difference after the engine, you don't think you can beef up a 690 chassis enough to deal with 80-90 horses and add a fairing and be left over with a significant portion of that? The 450RR rear tank that bolts to the 690 chassis is available already and weighs maybe 1 lb more, and with it's 18 liters of fuel will give you better range than a 990 has.

And don't forget that the 690 already has 48mm forks, 21"/18" wheels with Dirt Star rims, the same brakes as the 950SE and that the 690 rally replicas and even the factory LC4 rally bikes (some sporting a >80HP 730cc engine) run through the desert at up to 200 km/h for two weeks during the Dakar using that same trellis frame and I have never heard of anybody having problems, have you?

I think with some modern and creative engineering a 80-90 HP 700-800cc twin with 360-380lbs (wet no fuel) is a realistic goal, and I'd buy one tomorrow.


What do you guys think?

For sure a lightweight V Twin Adventure bike is needed at this time... All the manufacturers seem to have caught the fat pig syndrome, where they are pushing displacement and weights upwards in the so called Adventure category... Most of these bikes end up being a street bike you can ride on gravel..

Aprillia brought out a very lightweight V-twin in the RX a few years back that was a bit of leading edge... The problem is the engine proved unreliable as they were sucking too much power out of it... Drop the power by 20% and it is likely the reliability of that platform would go up while still providing plenty of punch...

KTM or somebody should get there act together and create a 700-750 cc light Adventure... In Canada our insurance rates double when you step up to the next displacement class, I wonder if that is the same elsewhere?

I do like the single 320mm disk idea as I have ran one on my 640 for years with no issues in fact I have nearly 100,000 miles on the original and it is still going strong... I worried about the bigger disk being more prone to getting bent up for the first little while but it never happened and I have ridden some pretty gnarly stuff...Also when riding 2 up loaded I never experienced any problematic brake fade up front even at times when the rear did fade and more emphasis was put on the front to get the job done ... The later 640s went to double disk and according to specs it added 8 lbs to the overall weight... Shedding 8 lbs is a good start for a new platform...

[NKL]

A lighter 700-750 twin adventure is what I'm waiting for, certainly not interested in the lard ass 1190

[crofrog]

Originally Posted by gunnerbuck

For sure a lightweight V Twin Adventure bike is needed at this time... All the manufacturers seem to have caught the fat pig syndrome, where they are pushing displacement and weights upwards in the so called Adventure category... Most of these bikes end up being a street bike you can ride on gravel..

Aprillia brought out a very lightweight V-twin in the RX a few years back that was a bit of leading edge... The problem is the engine proved unreliable as they were sucking too much power out of it... Drop the power by 20% and it is likely the reliability of that platform would go up while still providing plenty of punch...

The 5.5 put out 61hp. 61 * .8 = 48.8, hardly impressive power output and the bike was ~310lbs.

[cyborg]

Originally Posted by crofrog

If you want a really small light motor with great ground clearance where is the sump going to be? And how much oil is it going to hold? I'd rather not have a 1qt motor like an RFS for a adv bike... Nor would I want to worry about if the motor is running low on oil loosing oil pressure.

I think or would hope a design team looking to create this Adventure bike configuration know that this will be a long-range bike and will design-in enough oil capacity -- 2 to 3 liters at least.

Oil cooler would add price, complexity and weight, but always a great option to add longevity to an engine.

[crofrog]

Originally Posted by cyborg

I think or would hope a design team looking to create this Adventure bike configuration know that this will be a long-range bike and will design-in enough oil capacity -- 2 to 3 liters at least.

If you didn't do a dry sump the sump you would have to design the sump to be big enough to hold that oil capacity in the most vulnerable part of the bike the bottom.

Oil cooler would add price, complexity and weight, but always a great option to add longevity to an engine.

Yeah, that's actually I consider a design oversight on the part of the LC8 production bike.

[LukasM]

The 690 has an internal oil sump and tons of ground clearance, since the V-configuration of the cylinders and the shorter stroke would make a twin less tall you could make the sump bigger without losing any clearance.

And while many people were complaining about the lack of frame tubing below the engine at first, I have not heard of a single broken case. Install a good skid plate that is supported by two beams off the main frame up front and by the frame in the rear and it will be fine.

[Grinderman]

Ok flanny, you and Gregor threw out some teasers in the 1190 thread. I really Am interested to hear what your ideas are . I know you two have thought through some different directions. If Cj gets involved with awd i can't even imagine what a bitchin bike that could be created with all you guys collaborating. Looking forward to you showing your cards a little more because I am sure it's a bullseye 🎯

[yellowbronco]

Highland didn't seem too worried about the sump. Of course, their bike had somewhere around a 41" seat height (the OK highland, at least).

[wilmar13]

Originally Posted by crofrog

The 5.5 put out 61hp. 61 * .8 = 48.8, hardly impressive power output and the bike was ~310lbs.

Huh? Maybe in restricted form... My SXV makes 71whp and weighs 290 lbs with full tank of gas...The RXV is same engine with less aggressive cams.

[Navin]

Why bother making it a 700-800? The LC-8 engine as a 950 could be reduced by 20 lbs thru a SOHC conversion and better casting tech that KTM now uses. Add a 2-1 stock exhaust, a plastic subframe/fuel tank and keep it SKINNY!!!

No reason they couldn't build a 90 HP version that gets far better MPG, need to carry less fuel for the same range and has proper ergos. I got pretty sick of the Ob/gyn groin splay forced on my by my SE!

If they had built a lighter, thinner Adv or SE I'd have bought one.

[Flanny]

Originally Posted by Grinderman

Ok flanny, you and Gregor threw out some teasers in the 1190 thread. I really Am interested to hear what your ideas are . I know you two have thought through some different directions. If Cj gets involved with awd i can't even imagine what a bitchin bike that could be created with all you guys collaborating. Looking forward to you showing your cards a little more because I am sure it's a bullseye ��

We're gonna lay-low. This thread is about everyone else's ideas...so let's hear 'em.

I'm curious to see what others think.