750 Spine Frame

chrisk

chrisk

Hero member
Location
Brisbane, Australia
I've been thinking about the spine frame (or SF frame) for a SF750 motor I have tucked away, for a track bike.

I was in the "hallowed mancave" on the weekend, and while I was there moved a 1000 frame I have. It then hit me, why not use the 1000 frame??

Would it not be feasible to remove the front and bottom cradle, add some supports from the bottom of the headstock, back to the forward head mounting points and up to the spine. Weld on the rear head mounting brackets to the spine.

The rear downtubes removed and new ones made up to suit the swingarm pivot, while using aluminium rear engine mounts as per the Czech kit Gert has mentioned in previous posts.

Any thoughts?
 
Weight.
Especially for track use, the lighter the better.
The triple frame is very heavy for that purpose even though you?d cut off much of it, as well as not having being designed for racing as re steering geometry etc.
It depends on your budget and how serious you are.
Also, are triple frames growing on trees?
 
A Spine Frame is 850? new here. No-brainer if you want something really great and are able to weld some parts to the frame yourself (footrest-mountings, brackets for this and that).

;)
 
novel idea, which I have though of in the past, except it was atriple in a twin frame, but if you were contemplating it, then a 120 frame (semi spine already) might work better, but without the rubber mounts.
CLEM
 
yep.

as said, if you want something very nice for your 750 engine, stiff and with excellent handling that comes at reasonable price, I can help. See:

http://www.forum.laverda-register.de/viewtopic.php?topic_view=threads&p=12419&t=1556

Text is in german, sorry, but pictures will tell enough I would say... That frame comes at below 1.000?. Alloy tank can be made to suite, too, and comes at roughly 700?. But to be clear, the guy is not the expert in tanks. they do work well and if you want to paint them anyway, they are OK. The frame comes with VERY tight tolerances, which might need some work to make it fit to your special engine (castings are not always 100% accurate...). Frame comes bare without coating and as said, you need to weld your own brackets here and there, as each person has different ergonomic sizes (footrest position etc.) or wants different technical solutions, so that needs to be considered. But then, it's really a very cost effective thing and handles like a dream...  ;)
 
Laverdalothar said:
yep.

as said, if you want something very nice for your 750 engine, stiff and with excellent handling that comes at reasonable price, I can help. See:

http://www.forum.laverda-register.de/viewtopic.php?topic_view=threads&p=12419&t=1556

Text is in german, sorry, but pictures will tell enough I would say... That frame comes at below 1.000?. Alloy tank can be made to suite, too, and comes at roughly 700?. But to be clear, the guy is not the expert in tanks. they do work well and if you want to paint them anyway, they are OK. The frame comes with VERY tight tolerances, which might need some work to make it fit to your special engine (castings are not always 100% accurate...). Frame comes bare without coating and as said, you need to weld your own brackets here and there, as each person has different ergonomic sizes (footrest position etc.) or wants different technical solutions, so that needs to be considered. But then, it's really a very cost effective thing and handles like a dream...  ;)
Click to expand...

Lothar, can you find out price and availability please.  I've tried to contact the Bruehl frame people, but no replies to my emails?

Thanks

Chris
 
Hi Chris,

I'll send you a mail with the mail-address. please state to him that you got it from me. Not sure Burkhardt is good in english, but normally he replies to mails within 2 days. If you don't hear back, let me know, please.

cheers

Lothar
 
There is, slightly higher in price and to be honest - I wouldn't use a spine frame for a triple. It has massive downsides which you would not want:

1.) for every valve check, the engine hast to be completely removed
2.) center carb is conflicting with the spine tube
3.) the mounting points of the triple engine are mainly very low, which leads to loooooong tubes needed to connect them with the spine tube, which will make the whole thing not as much stiff as with the 750's
4.) the triple spine frame does not offer much weight saving over the standard one, it weights roughly 16 Kilos

I haven't tried it yet, but due to the concept, I would assume that even getting the center spark-plug out could be an issue... Not sure about that, though...

I would use a space-frame concept like Motoplast or similar, it offers all the advantages: easy access to valves, carbs, etc.
 
Thansk for the answer.
There where two german guys att Aragon motorpark 1 1/2 year ago with each a spineframe tripple.
My duc 888 blowed the gearbox so I rode my spare/rain bike. An almost standard 900 ss -00 with about 75 hp at the wheel.
I could not keep up with the Laverdas. They probably had an extra 30 hp or so but I thought the handling on the ss would compensate for the lack of power.
Anyway, I still got a lot of work to do with my 500 and my 3c before I?ll start any treipple projects.

 
one of the two for sure was Uwe & Frank's bike. This bike has a modified RAU Frame. They did overcome the issue with the carb by making the top tube shorter and weld two bars in that go down to the rear-frame/seat-support both aside of carb 2 (one left side, one right side). This way, they did overcome that problem, but still have to dismount the engine any time they have to work on the cams or even just want to check clearance...
 
Burkhardt Bruehl can also supply a modified rear swingarm like the one the picture in my profile shows. I hope i find the time to post some more pictures these days

H.-C.
 
Here is a picture of my Bruehl spine frame with all the mountings ready to get chrome plated and the modified swingarm that will be chrome plated too.
This swingarm was the first prototype, the verical tubes will be parallel to the tube coming down from the frame in the final version.

H.-C.
 

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