RD350 into a KTM chassis??

[apexdc]

As I am a huge fan of KTM's and looking for a new project, has anyone put an RD350 into a KTM dirt bike or supermoto frame? I know an Indian builder put one into a KTM 200 Duke, so perhaps that is the way to go. The problem there is I don't think the bike is sold in the US. Although, they might sell that frame in another configuration.

I want the final bike to have the styling of a KTM/Husky motocross or supermoto with the seat extending up onto the tank.

The bike is, for sure, going to be a long project, but when finished, I want to ride it.

Look at it as an RD350 supermoto. I have attached a photo of an 625SXC that I made into a supermoto about fifteen years ago.

I would appreciate any input on this path.

[redeem ouzzer]

Waste of a good RD350.
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Be a REAL MAN!

[apexdc]

You know, in researching this more, I tend to agree with you, if you mean pulling an RD engine out of a running bike. I would have actually just started with an engine.

I am back to thinking that I would be better off modifying an RD aesthetically to get where I want to go.

I did look into putting an RD engine into a KTM 390 frame, but am now not so sure it would be worth the effort.

I will be starting with an RD that needs everything, so is currently dead, but I don't want to do a restoration as stock. I have done those on other bikes. I just want to build up something around that engine.

I just finished an XS650 project and it started in a similar way. I knew I liked the engine.

Thanks for the input!

[Easy-X]

May I suggest re-examining your targets? As in "I like this bike and the way it handles but it's lacking power." I admit I'm quite amused by ppl throwing 300cc engines in a MSX125 though
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[apexdc]

When I checked into it further, the KtM weighed more than I thought it would and the RD is beautifully simple.

Also, the KTM 390 is already a pretty nice motor. In any event, I'm getting back to my concept of taking an RD350 that need everything and bringing it back to life a sort of supermoto. I just love that motor!
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1992 Ferracci built 900SS Ducati, 2006 KTM 950 SuperMoto, '71 Yamaha XS650(750) flat track racer

[Teflon-Mike]

Me thinks of re-inventing the wheel somewhat:-
https://www.advpulse.com/wp-content/uploads/2014/02/Yamaha-TDR250-88.jpg
That is a Yamaha TDR250, a parts bin special 'Factory' super-retard, from about 1986, utilising a TZR250 two-stroke twin engine in a trail bike frame.... like mi old granddad used to say, there's been little new in mechanics since Archimedes had his screw.. then a Yank comes along and re-invents it!
I take it you are a Yank?
Oh-Kay.. a moment's history lesson.
The Yamaha RD350YPVS was about the pinnacle of evolution of the two-stroke road bike. The two stroke engine had the potential to produce, for the era, audacious amounts of power from a very small and light weight package. Somewhat prone to accelerated wear and rather 'peaky' power delivery if tuned to get that power though, the Yamaha RD's went liquid cooled to get a modicum of reliability and avoid nipping up, and packed an exhaust resonance valve to try and take the edge off the peakiness and beef up the low and mid-range power delivery.
B-U-T, on the borders of chucking the baby out with the bath water; by the time the suppoisedly 'simple' two stroke had got a couplke of cylinders and water cooling and exhaust power valves, as well as crank-case valving to make them somewhat more rideable and get that suggested benefit in power to weight... they were't 'so' simple anymore. 1984 Kawasaki GPZ600R road bike came along, a four stroke with four cylinders, and the writing was on the wall for the hi-po two stroke, the four-strokes were starting to make similar power to weight, without the peakiness or convolions of harmonic exhaust valves, or the reliability issues or the, significantly, need to burn oil with the petrol ruining 'emissions'.
It was actually that, the need to burn oil with the petrol that effectively 'killed' the hi-po two stroke in the USA, whilst advances, particularly in tyres, meant that they had few if any advantages over more conventional four-stroke motorcycles. They continued in larger scale manufacture, for some years, probably until the early 2ooo's in off-road motorcycles, and for precedent the Montesa 315R competition trial (not trIal, not trAil) bike, where the light weigh was more important than the high power, but, to all extents and purposes the two-stroke had been regulated into obsolescence.
Here in Europe the Hi-Po two-stroke in general, and the Yamaha RD350YPVS, in particular, have something of a 'cult' status, by dint of that legendary peaky power delivery and reletively low weight.... but that 'legend' does not alone make them a particularly great bikecompared to say a contemprary Yamaha R6...
Does mean that prices tend to be pretty strong though... which is rather irrelevant if you are going to chop one up to make a 'special', that is normally a dang site more money and work to make a bike a dang site less practical, and valuable.....
Over here, the common 'thing' was to take something like a Cagiva Mito 125, that probably ate its own engine by dint of the motor being near race tuned to start with, and owners who never did the prescribed maintenance, like change half the engine at oil change mileages, and had notions to tune them even more, and slap in an RD350 motor from a bike that had probably been smashed up half a dozen times due rather dated chassis and more owner ideas of going fast. Made for a pretty good package, b-u-t..a lot of work to get a bike less valuable, even as a regular road bike, let alone a 'classic', that STILL wasn't any better in any significant way than an off the shelf R6 or similar!
On to Super-Retards... more perversity.. take a bike evolved for moto-cross racing, with soft long ravel table-top landing suspension, and rather questionable knobkly tyres... and de-evolve it back into a road-bike... with soft squidgy suspension, and better road bike tyres... err yeah.. like I said, 'perverse'!

Sooooooo Where do we get to?
What are you trying to achieve?

If you want a fast road-bike, then an old RD350YPVS, and anything powered by its engine, isn't really. One is beaten by an out the crate, or even pretty knackered 600 sports 4, and was quarter of a century ago!
If you want a light tight Super-retard. Well again, the factories have been making them, no spanners required, for oooh... over thirty years, and not making too bad a job of it... why not just buy one?
If its the allure of the two-stroke 'experience'; peaky power delivery, nipped up pistons and a bottle of strimmmer oil stuffed up your jumper... why build a 'special'? Why not just get an old 2-smoke, like an RD350YPVS and enjoy as intended? Heck, a late KTM, even the 125 would offer full measure of the two-stroke experience, and not beg trying to get 'expansion chamber exhausts' that even moderately work blown to suit....

Actually, that, sourcing custom made spannies for any 2T special, even here in the UK where there's still a couple of specialists that still do it, would be the sticking point I had to ANY 2T 'project' let alone some weired sports-bike/super-retard mongrel.

SO.. what are the actual objectives here?

Be clear on what you are about. Just making something a bit different has been done to death, and back to that pic at the top... even the chuffing factory has stiffed a two-stroke twin engine into a dirt bike frame.. its hardly avante guarde never been done experimental engineering.... is it?
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[redeem ouzzer]

Teffers, your ignorance is astounding. Please pipe down. You have no experience of 2t tuning, pipe design or dyno work. Whatever OP decides to do, sorting pipes to give desired performance characteristics isn’t an issue. Using modern pipe design techniques and ignitions it’s possible to make an AIRCOOLED 350 that will do a standing quarter faster than a GPZ600 and be docile enough to ride in town. The YPVS has even more potential.
____________________
Be a REAL MAN!

[apexdc]

That is a fair question.

I have several fast and agile road bikes, including a KTM 950 SuperMoto with carbon fibre wheels, which is about as good as it gets on a real world windy road.

But, what I REALLY want is a project! I have a modest but workable shop, as well as fabricating and design skills, so reinventing the wheel is fine for me as long as the journey is a fun and challenging one.

Oh, as cool as the 250TDR seems, the bike was a surprise to me, as we Yanks didn't get 'em. I love the concept, but that is not an option.

I just finished a restoration of a Yamaha XS650 (750) seventies flat track bike. The final step is getting it legal for the street. That all started because I wanted to do something with that engine.

It is the same with the RD350.

I have been looking at salvage KTM 390 in various stages of damage. It is a really beautiful frame and I thought would make a really cool custom bike, except the engine is not so pretty and is watercooled. For a custom, that is not so good.

So, that is really why I am on this crazy path. At the end of the day, some would say that motorcycles themselves don't even make any sense. Or, one could say it is very hard to live without them.

Thanks for all the input!
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1992 Ferracci built 900SS Ducati, 2006 KTM 950 SuperMoto, '71 Yamaha XS650(750) flat track racer

[apexdc]

Pk, ok. After doing a bit more research, the swap is sounding less and less like the way to go.

The last bit of info I got is that an RD400 engine is about 90 pounds and the KTM 390 is about 79 pounds. Even after dumping the radiator and assorted parts, there is no way I'm going to do a swap of a watercooled four stroke to an aircooled two stroke and not lose some weight.

So, it looks like I'm lookin' for a dirtbag RD to bring back to life.

Too bad, but that's sure not the first great inspiration that I have had that turned out to be not so great.

I sure did like the concept though of that ring ding engine wrapped up in that great KTM chassis and suspension. Have they EVER built anything that didn't handle great?

Attached is current project, almost finished. It has a temporary licence plate at the moment pending final inspection. Since the photo, I have fitted temporary turn signals on a separate wiring harness. It raced flat track in Texas and New Mexico in the seventies and ran at Pikes Peak with a front brake on July 4, 1976. Paint is original.

Thanks, all.
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1992 Ferracci built 900SS Ducati, 2006 KTM 950 SuperMoto, '71 Yamaha XS650(750) flat track racer

[Easy-X]

Mmmm....

The politest thing I can say is "each to his own" not really my cup of tea but excellent workmanship
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[apexdc]

No worries. I fully understand. I didn't design or build it originally. That was almost fifty years ago.

I bought it from a friend back in New Mexico. He had had it in a barn for over forty years. I just restored it to what it was back then. It is sort of a snapshot of what the racebikes were like then.

Since I started working on it, I have learned the entire history of the bike. I have talked with several owners and riders and heard some great stories.

So, that one was a different kind of journey.
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1992 Ferracci built 900SS Ducati, 2006 KTM 950 SuperMoto, '71 Yamaha XS650(750) flat track racer

[apexdc]

Perhaps this one is a bit more palatable?

I've had it for twenty years now. Did a total restoration a few years ago. 365 pounds with no fuel and about 105 hp at the rear wheel. Very old school.


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1992 Ferracci built 900SS Ducati, 2006 KTM 950 SuperMoto, '71 Yamaha XS650(750) flat track racer

[Easy-X]

[apexdc]

I bought it about twenty years ago from the original owner. He was a mad physician who was a fast rider and did a lot of track time. He spent as much with Ferracci on modifictions as he did to buy the bike. It is a bit over the top, but fun nevertheless.

I rode it many times from Southern Calilfornia up to Monterey for World Superbike and MotoGP. When I ride it now, it astounds me that I did so.

I am 73 and fairly fit, but perhaps I'm just getting a bit soft!

When I did the restoration, I thought about doing it yellow like the Superlights, but i loved the old race bikes with white frames and white wheels. Mine is actually a mix of bits aesthetically. For example, the number graphic on the monoposto tale is a late design and was never used with the early white frame bikes. For that matter, there were never any white frame monopostos. Since mine was white frame from the factory, I worked around that.

It is remarkably easy to work on, as well. I do my own belt changes and have done the valve adjustment, also. But, I have to drive 100 miles to a dealer to get the correct shims, so I don't do my own valve adjustments any longer. I have also opened up the clearances a bit on the valves to allow longer intervals between adjustments. It takes a little of the "crispness" out of the bike, but it is still absurdly quick for its age, so that doesn't matter much.

I hope this current world wide craziness is sparing you and your family!

All the best,
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1992 Ferracci built 900SS Ducati, 2006 KTM 950 SuperMoto, '71 Yamaha XS650(750) flat track racer

[G]

Waste of a good KTM.

Get a KTM250SX, stick on some SM wheels and you've got a whole load less weight with similar listed power.

[A100man]

[A100man]

[apexdc]

[apexdc]

[apexdc]