Frame modifications!!

needed?

Hello Bludge. Just looked over your pics. Can`t help wondering why a beefy Husaberg frame needs any bracing. It already is cro-mo tubing that doesn't fatigue, with a load dispersing design that doesn't have unwanted flex. You may find your bike has lost a bit of leaned-over tracking ability. The finish you got is superb though. Was there enough light in the welding shop? Although plenty strong, the welds look inconsistent. How do I know you ask? A career repairing and making parts for everything from 100 ton tank cars to suspension bits for RC racers, leaves one with a terrible burden of judgemental knowledge.
Even a stock Husaberg fame, with the massive WP forks, is a bit too stiff for really fast flat-track type sliding. Of course, for "normal" brutal off roading / crashing it`s about right. By the way, did you know the earlier rectangle cross section swingarm tracks better leaned over than the stronger, prettier tapered one? Yes in all the racing Husaberg did there wasn't that much flat-tracking to do. Having looked into that rear engine case breaking issue, make darn sure your swing arm pivot shaft is tight enough. Those twisting loads had better be sent into the frame, not the fragile aluminum cases. Kawasaki has some nice small axle nuts that sure work better on the pivot rod than the light flat OE nuts. Spot of lock-tite please. Good luck, L

I believe bludgeon has pretty much copied the factory race frame I have sat here.

at least he's out there meddling and fettling! long may it continue!

regards

taffy

If you look closely at this pic, the extra bracing talked about is on this frame too.

I'm assuming it's for Supermoto, where the extra grip from slicks may put extra stresses on the frame. I know Lazzarini rode a factory supported 700cc that had the steering head braced as well.

Damo


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That's the one BLUDGEONER,

What a weapon, apparently run a 19T front sprocket too!

Still the best tank decals too that of the 2003 model.....

Damo

Nice Bludge. I have a set of cases here that have a substantial welded repair at the swingarm mount, the steel insert is actually loose in the recess! This was from sidecar abuse.
The 1988 Rgv chassis I use has a plain rectangle swingarm, the later models had a very trick looking ''banana' arm which was heavier and flexed more!

BLUDGEONER said:

Yeah - I remember reading something about that. I think the swingarm needed modifying to run that 19T!

Click to expand...

Yes I'm sure your right mate. There had to, there's not much room there even with a 15T!

So, regarding the twin exhaust, you know what you have to do! :ninja:

Do you run in a Supermono class canolman? Your RGV with Husa power? That would be cool! :thumbup:

Damo

when I raced Ducati F2s back in the day, the gearing was so high that they had to change the clutch basket and primary gear to bring the teeth back to normal. this reduced the speed of the gearbox by 10 rear teeth. shame husaberg didn't do that. I find 19T difficult to believe. 16T is what i use and this is on the road. on the track you couldn't possibly have a reason for 19T except chain wear or anti-squat. even then it is illogical.

taffy

Damo W said:

Yes I'm sure your right mate. There had to, there's not much room there even with a 15T!

So, regarding the twin exhaust, you know what you have to do! :ninja:

Do you run in a Supermono class canolman? Your RGV with Husa power? That would be cool! :thumbup:

Damo

Click to expand...

The supermono class has just started again in the UK, hope to do some of the rounds. I've ridden in many classes, Open (thrashed), Mini twin (thrashed), Super twin (thrashed), etc I can also race Forgotten Era, pre '91 even though my motor is 2006 my chassis is Jap import 1988.
There's something special about being the only single on a grid of jap 4's ! Grunting off the line at half the revs of the rest of the grid!

Taffy said:

when I raced Ducati F2s back in the day, the gearing was so high that they had to change the clutch basket and primary gear to bring the teeth back to normal. this reduced the speed of the gearbox by 10 rear teeth. shame husaberg didn't do that. I find 19T difficult to believe. 16T is what i use and this is on the road. on the track you couldn't possibly have a reason for 19T except chain wear or anti-squat. even then it is illogical.

taffy

Click to expand...

Yes I agree, I've never had the thought of running a 19T front. But if you look at that pic and count the links, it seems it's about right.... It was over 700cc I believe but still....

There must've been a good reason though, it was a factory prepared bike. Maybe it was a 4 speed gearbox with special ratios or something?

Damo

canolman said:

The supermono class has just started again in the UK, hope to do some of the rounds. I've ridden in many classes, Open (thrashed), Mini twin (thrashed), Super twin (thrashed), etc I can also race Forgotten Era, pre '91 even though my motor is 2006 my chassis is Jap import 1988.
There's something special about being the only single on a grid of jap 4's ! Grunting off the line at half the revs of the rest of the grid!

Click to expand...

Sounds great! It's the same reason why I like to compete on my Husa dinasour I'm not interested in new, I like quirky and unique.

Plus I'm not sure how well a 450 would carry my ever enlarging girth around a track at speed. Jokes.... Well, about the 450 that is. I like a beer or few afterwards....

Looking forward to seeing your bike built BLUDGE !

Damo

got it, now.

Hello All. Now I see what you are doing. Brace your frames all you want. Love Damo`s pic of the Berg ripping sideways! There isn`t really a part number for those Kawasaki axle nuts. Just bring the pivot rod to the Kawa shop, all cleaned up of course, and they will find you some. They gave me flange type nuts with a nice light gold anodized and polished finish! Can`t believe the quality they use for most items. Must be the cost-no-object superbike influence, plus a polished surface tries not to crack. The senior mechanic at our local Kawa shop has for years had a small collection of old Porsches, which he works on all the time. His know-how is very handy! One wonders how many Japanese parts wind up in his cars. Just to raise more eyebrows, while there grab a couple of gallons of full synthetic Kawa oil. It is really Motul, or used to be, with Kawasaki`s additive package to stop cam wear and eliminate clutch plate glazing. Engine wear just stops with this stuff. Usual change intervals please. Onwards always, L

Hi to all,
i know this post is old but it's the only one open that speaks about a main fraim modification.
Lazzarini's bike of 2003-2004 it's built (also today) with a modified frame that include a sandwich aluminium plates that increse the stiffness, a lot of reinforcing cro-mo-5 parts welded, a custom titanium subrafe..ecc.
The engine is 644cc stock with lighter crankshaft, lighter alu-ti rod, lighter counterbalancer, modified head, pistons...ecc
i'm adding also the pics of an italian review of the lazzarini's bike
i want also add a pdf of an other 650 racing bike of 2008.
http://www.moto-explorer.com/wp-content/uploads/2015/03/1928.pdf

redr, thanks for sharing! best way of copying is to lay under the scanner screen and press each page flat. good days, and everything done from Sweden!

Taffy

Ciao Redroom, a high resolution scan/pic would be great - to see details and to read all.