Husaberg/KTM hybrid engine

bushmechanic · Jan 30, 2014

some KTM RFS barrels some are different heights .. whats the height of yours?

if you were to ask on the KTMtalk RFS section for the different dimensions you would get an answer really quickly

thorgan · Jan 31, 2014

I found what looks to be a nearly brand new crank sprocket on Ebay. I could hardly detect any wear by looking at the pictures and I figured that, for the $15 purchase price and free shipping offered by the seller, it's worth a try. Should be in my hands by the middle of next week. Maybe that'll help to solve my loose chain issue.

It's actually quite nice having the Husaberg habit because so many people can't get what they want for their old girls so they're parting out virtually brand new bikes almost constantly.

I would also like to know where I might purchase the Regina timing chain that's so notorious for being short. This, in conjunction with the ebay sprocket and a steel sprocket from a newer 'Berg, might be my holy grail. And, since I've got another '96 vintage 600 engine that will need a rebuild, I don't mind purchasing parts that I may not use on my current engine project.

bushmechanic · Jan 31, 2014

the Regina was listed as an 01 part i believe see page 28

http://husaberg.org/download/01-02Berg_part_manual.pdf

some threads ... maybe Pm Sparks

viewtopic.php?f=5&t=1089

Regina http://www.regina.it/
The Regina chain number given in the forum is C121CHS/001. I have found a C121CH in the online information. This is a chrome treated chain. There are other types as well but the Chroma should be best regarding the wear issue. Is the C121CHS/001 a timing chain or is it similar to the C121CH?

viewtopic.php?t=6574&p=56281

viewtopic.php?t=8659&p=74891

could be useful, Popup or Weed as he is known always comes up with good solutions

popup said:
hey denke ,i had the same problem with mine.i put a new cam chain in it thinking it would fix it,but no.
well i thought the alloy cam wheel must be a bit worn,so i replaced it with the hardened steel one,but no again.
replaced the old white style guide( on the tensioner side) with the newer longer black one,bringing adjustment back slightly.
i rang up the previous owner thinking he must have either shaved the head or taken a skim off the deck....but no!
there is no more it could be,either the deck height is wrong from factory,or the cam bearing boss height is wrong from factory.doesn't have to be wrong by much to lose adjustment.
quick fix .. heat the black guide up and put more bow in it (like in my gallery).
while i had mine apart just recently ,i thought i would do the job properly by getting the cam boss built up,then i ground it down bit by bit until it brought the adjustment right the way back.of course then the rocker cover won't bolt down flush because the bearing is sitting higher.a skim will have to be taken out of the rocker cover where the top half of
the cam bearing sits.works good if you trust yourself to do it.
told ya froggy that its a laboratory experiment!!
ya gotta love/hate these bergs ..don't ya...
..weed..

thorgan · Feb 2, 2014

Getting back to the issue of cylinder height, I measured the 600 cylinder at 3.740" which is 95mm. Incidentally, the KTM RFS cylinder also on my bench measures at 3.307" or 84mm which matches one of the ones Bushie has.

bushmechanic · Feb 8, 2014

thorgan said:
The KTM pin on the left and the 'Berg pin on the right. I had to shorten the KTM pin some .150" or so to match the Berg pin. Also, the Berg pin had no oil holes in it. That was expected. The KTM pin does have oil holes in it, which was also expected. One oil hole must match up with an oil hole in one of the crank webs of the KTM and the other aligns with the big end bearing.

Plus, the KTM pin was plugged and not open to the crank case so the oil pressure would feed the big end bearing. I opened the pin so the hole goes all the way through and I will orient the center oil hole so that any oil the might build up inside the center of the pin will sling out into the rod bearing.

Hi thorgan

this reminded me of an idea I had for ktm 85 2 stroke big ends .. if there is room make a scoop to cover the hole in the pin bore perhaps even just flush with the end of the pin and grind a little relief on the end of the pin

as it rotates the scoop picks up oil and forces it into the big end bearing

tack welded in place it shouldn't do anything odd.

we never followed through on the idea as it wasn't needed we just opened up the axial play of the rod, rich jetting and ran 20:1 oil/fuel.

thorgan · Jun 12, 2014

I know it's been a while. A lot of drama has gone down since February. I received my "pink slip" from work on the same day that 29 others were layed off from my company. Since then we have decided to sell our house and, after completing all of the honey-do's related to that and sending out countless resumes with a few interviews here and there, I finally decided to put this bike back together since it would be easier to place in storage as a whole bike and not a crate full of parts. Along the way, I had the crank tig welded since the press fit was lighter than I was really comfortable with. I received a new timing chain (thanks Taffy) and crank timing gear that looked virtually brand new from Ebay. All in an effort to avoid using a base gasket and hopefully overcome some of the .5mm difference in piston height due to the KTM rod and piston.

No such luck. I had to assemble with a base gasket.

Well...it runs! It seems to idle with more vibration since I made no attempt to balance the assembly (this is really turning into more of an academic exercise anyway). However, I'm now consumed with how to fix all of the fuel leaks that have developed in the year or so since I last had fuel in the tank. Going to replace the o-rings under all of the various fittings and petcocks the single-sided tanks had and then see if a new diaphragm in the fuel pump might be in order.

It's also leaking coolant and I'm hoping that a little sealant on the pump cover gasket will solve that. Otherwise it'll probably need a new pump shaft seal and seal housing o-rings.

Luckily it's not leaking oil anywhere. Taffy, this is good info for you in that the little seal around the clutch arm shaft that I sourced seems to be working, at least for the time being.

Progress will be slow in the coming months because I'm living and working about a 5 hour drive from my family and my motorcycles. This means that when I'm home on the weekends, visiting with my wife and my 3 year old will take priority. But, since this bike is the only legitimate green sticker bike I've got, and the riding in the area where I reside during the week is epic, maybe I'll make it a bit more of a priority so I can actually provide a ride report of sorts.

I'd post a link to a video I took of it running...but that proves nothing since it just shows an old Husaberg sitting there idling (and leaking).

Oh, what the hell, here's the link. It's the only video in my gallery.

Husaberg project - yellowbronco

bushmechanic · Jun 12, 2014

awesome stuff Thorgan!

those terramaximus tyres are pretty out there hey?

Taffy · Jun 13, 2014

should have just simply had a hard ring put inside the original rod. but good luck anyway.

regards

Taffy

thorgan · Jun 13, 2014

bushmechanic said:
awesome stuff Thorgan!

those terramaximus tyres are pretty out there hey?

I've been running the big 150/90-18 Teraflex on my KTM 950 Adventure and see a lot of fear in the eyes of my riding buddies when they contemplate the thought of following behind me. Comparing it to the Dunlop 908 RR that I've run previously, again on the big 950, I actually find cornering performance is much more confidence inspiring off road, especially when fully loaded with camping gear. No idea how the Teraflex performs on a regular dirtbike. This is another reason why I'm excited to get the 600 in a rideable state. I can't wait to do significant damage to terra firma with that tire.

Taffy,
you make a very good point about the old rod and pressing in a hard ring. I have another 600 engine with a bad rod and let's say that I want to purchase one of your pin and bearing sets. Would that come with a diameter and tolerance to machine the inside diameter of the hardened ring to? I still have the original rod from this hybrid engine and the bearing surface actually looks to be in great shape.

Don't get me wrong, I'm seriously considering purchasing one of the last few complete rod kits you have but, seeing as how those parts will be unobtainable after yours are gone, I'm really doing all of this in the interest of forging ahead with a solution for everyone who might have one of these engines with a bad rod.

Plus I've been unemployed for the last few months and if I spent money from savings to buy engine parts instead of pay the mortgage, I'd find myself suddenly without a wife and daughter or without testacles.

Taffy · Jun 13, 2014

everyone makes all the parts to pre-scribed size. so they machine the rod out, press the ring in, bore grind to the exact size.

also, I have no rods left now......

regards

Taffy

bushmechanic · Jun 13, 2014

thorgan said:
I've been running the big 150/90-18 Teraflex on my KTM 950 Adventure and see a lot of fear in the eyes of my riding buddies when they contemplate the thought of following behind me. Comparing it to the Dunlop 908 RR that I've run previously, again on the big 950, I actually find cornering performance is much more confidence inspiring off road, especially when fully loaded with camping gear. No idea how the Teraflex performs on a regular dirtbike. This is another reason why I'm excited to get the 600 in a rideable state. I can't wait to do significant damage to terra firma with that tire.

Plus I've been unemployed for the last few months and if I spent money from savings to buy engine parts instead of pay the mortgage, I'd find myself suddenly without a wife and daughter or without testacles.

i ran the big flex tyres for a year or so.. very good grip but I found the IRC M5B to offer similar grip with much better handling, the tyranosaurflex is great just a bit heavy and they were costing me about $150 each landed here. the M5B i can get for $90 from rocky mtn.

hope the job works out, I can't imagine life without wifes daughters or testicles :cold:

thorgan · Nov 4, 2014

Continuing with my history of slow progress, I've got the fuel leaks fixed and apparently the water pump gasket just needed to absorb some coolant and swell a bit because the coolant leak has fixed its self! Yay!

I purchased a Keihin FCR41MX from ebay and filled it with the closest jetting I could find which was a jetting recommendation for a 650 found here somewhere. I can't remember the needle but the main was a 160 and the pilot was a 45 if I remember correctly. The carb was from a '08 KTM 450SXF so I made an adapter ring, filed the lip off of the inlet bell of the carb and pressed the ring in place on the carb so it'll now fit in intake boot of the old 'Berg. I'm going to keep an eye on this ring because the press fit was a touch light and, if it loosens, I'll use a little green loctite to stick it for good.

Results - it fired on the third kick and, after fiddling with the idle a bit, settled into a nice purr. I installed a stock '99 FE 600 muffler with stock FE600 head pipes. I'm on a quiet kick lately and this exhaust is just what the doctor ordered (compared to the racket of the Big Gun I had on when it last ran).

I rode it around in my yard a bit but, seeing as how I live in the city and my property is just under 1/4 acre, it was hardly worth the effort. However, I was at least able to ride enough to get a big smile stretched across my face. The acceleration in the bottom end of 1st gear is quite shocking and reminds me of how to make a 500cc two stroke seem lazy. Just ride a big bore Husaberg.

I'll reply again with a better ride report if I can ever get some time on the thing. Maybe I'll include some pictures as well to illustrate the adapter ring for the carb, etc. Might be a while though because it needs fork seals, brake pads, and wheel bearings.

In the meantime, I've already started planning for the next engine. As I mentioned previously, I have another early 600cc engine sitting on my workbench with a bad rod. My plan for this one involves opening the bore up to 100mm (stock for a 600 is 95mm) and having a custom rod made. With the 84mm stroke this'll get me 660cc

thorgan · Jan 7, 2015

Well, I've got my fork seals, wheel bearings and brake pads done and finally got some time to ride the bike yesterday. I took it slow to start but quickly turned up the intensity. I put together a big desert race-type loop with fast sweeping turns alternating with a slow tight sand wash section with some big whoops and rode that loop for about 30 minutes. Then I spent another 30 minutes on a short motocross track with some nicely banked turns and lots of braking and acceleration chop and a few jumps thrown in here and there.

This engine really seemed to be happy everywhere I rode. On the desert race loop it pulled nice and strong throughout the bottom end and mid range but fell a little short in the top end. Compared to the 2008 FE550 that I used to own it was up on low end and mid range but down on top end. Compared to this same FC600 engine prior to the original rod bearing failure, it feels just a smidgen down on power everywhere. Probably the .5mm shorter piston/rod assembly and resultant low compression that's responsible here. I've said it before and I'll say it again. I really like the close ratio 6 speed in the FC engine. For some of the faster sweeping turns, I was initially using 4th gear and revving the engine fairly high. Then I tried 5th gear in the same corners and it felt like the engine could really grab ahold of the corner and rocket through on sheer torque. Were I to be using the FE transmission, 5th gear would have been too tall necessitating a sprocket change and the elimination of 4th gear as an option.

So, with the short shifting lesson learned, I headed to the motocross track. There, the engine did not feel down on power at all. Really, what mere mortal can use the full power of an FC600 on a motocross track anyway? I can see why the 501 was generally considered the king there. Wasn't the Smets bike something like a 540 or 550? My biggest discovery here was the need for suspension work. The forks are working great (I asked my fork tuner to emphasize "plush" during his rebuild and he's hit the nail on the head). The shock is a pogo stick typical of big MX bikes from the 90's. Needs additional compression and rebound damping as well as the obvious sag adjustment.

Anyway, after a full hour of riding, I felt that my lunch time was stretching a little too long and, before my co-workers started to miss me, I headed back to work. The truth is that I haven't ridden since September and I'm totally out of shape. Plus, since I made no attempt to balance the rotating assembly, the engine has a little more vibration than a stock FC600 (which had quite a bit) and my arms were pumping up badly.

Going to head out for another long lunch today and wring this bike's neck a little more. Fun fun fun!

thorgan · Jan 8, 2015

I've now got a full tank through the bike. I'm a little concerned because it burned through that tank waaaay quicker than I thought it would. Got a bit of a partial-throttle stumble in the mid range that might be needle related so I've got to confirm what the needle is and it's clip location. Maybe the fuel consumption and the stumble are related.

tourist · Jan 9, 2015

I'll do my usual muppet meep - thank you for these posts, they make for fascinating reading ...

tdetlor · Jan 26, 2015

Really enjoyed reading this thread this morning over coffee! Giving me all sorts of ideas. Most out of my league :/ ... for now.

thorgan · Jan 28, 2015

If anyone is having thoughts about restoring one of these old beasts...DO IT! I'm having so much fun with this bike! Plus, they were really rare before the KTM buyout when they just became a little rare.

I had this bike sitting in the back of my truck all last week in case I could steal away from work and go for a quick ride. Then a co-worker came in and mentioned a black pickup truck that drove by with the driver and passenger staring so intently at my 600 (possibly trying to figure out what it was) that they almost ran into several cars parked along the street. Then they turned around and drove by staring at it again. Then they drove down the next street over and stared at the bike one last time. We were worried that they were figuring out how to steal the bike so I unloaded it and rode it behind the locked gate here at work. I also had another co-worker compliment me on the bike which I found quite amusing. Although it looks a fair sight better than the original price tag would indicate (I bought it for $400), it still doesn't hold a candle to most of the bikes riding around in pickup trucks around here. Part of the reason is because the previous owner had it fall off of his trailer out on the highway and the plastic is quite a bit worse for the wear.

As for an update, I've got about 3 tanks of gas through it now. Still chasing jetting issues but it continues to run really well past about 1/3 throttle.

I've got my "Frankenberg" with me in the back of the truck this week and took it for a ride yesterday for comparison to the FC600. They're very different bikes. Frankenberg is a 2003 frame with the suspension from a 2000 and a 501cc FE engine from a '95 (wide ratio gears). The forks have been modified by Dick's Racing and the shock is basically stock. This bike also sports a Rekluse Z start and a 40mm Keihin pumper carb from a Honda TRX450R.

I'm happy to report that the 600 engine with the KTM rod and piston is definitely stronger than the 501, especially throughout the mid range and off idle. The suspension on the 600 needs some serious help even though I just had the forks rebuilt. The front end is harsh on little chop and then bottoms too easily. Typical for the old 40mm forks. The shock has yet to be rebuilt and is clearly in need of it. Future plans involve mounting a newer set of KTM or Husaberg forks because they're just soooo much better (I also have a 2008 KTM 250 SXF and the forks are worlds better than either the '96 40mm units or the Dick's Racing set from the 2000).

Fun fun fun!!!

thorgan · Apr 14, 2015

More updates

This beast is still running. I continue to chase the jetting but that's not keeping me from enjoying my time on it. I've swapped the forks to a set of 2013 KTM closed chamber forks from a 250 SX. The triple clamps are from an '08 KTM and are black anodized which is going to somewhat dictate the color theme going forward with this machine. I'm really liking the black and yellow (with a touch of blue here and there). The front brake setup is one I found on ebay for really cheap from an '08 Husaberg. I'm using a front wheel that I had from one of my old race bikes. It's horribly bent so I'm planning a swap to an Excel A60 rim.

I pull no punches with this bike and ride it hard. The engine has yet to miss a beat (outside of the jetting issues) and has given me no reason to believe that the hybrid parts inside are stressed beyond their limits. I've been venturing farther and farther from the truck on my rides as I gain more trust with the engine although I still am a little nervous. The only thing really holding back my speed is the rear suspension. I'm struggling with what to do here - find someone to rebuild/revalve the stock Ohlins or go to something aftermarket. I'm eyeing trying to find an Ohlins TTX 44 or a Fox Podium that will adapt easily. I like the adjustability of those units over the simple compression and rebound adjustment of the stocker.

In the meantime, my efforts are finally retuning to the spare 600cc engine on my workbench. I suppose it's time for a new thread there.

So, for now, here's a parting shot taken last week.

tourist · Apr 14, 2015

this is just such a f'in awesome project

I'd be thrilled to see some video if that's at all convenient

thorgan · Apr 14, 2015

Tourist,

I'm back to working in Northern California and don't have nearly the opportunities for riding during the week. Plus, I'm spending all of my income on Husaberg parts with nothing left over for a GoPro. That being said, I'll see what I can do...

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