The Hypothetical 7/11 Thread

[markfoggy]

So if you had a cut off, of 1991, what would you be looking at.

Now I'm looking at advice on substantive changes in chassis geometry over J,K,L, M. Plus any thoughts on construction benefits that Hammamatsu thought to include in this development era. This particular project would probably require 2 bikes to be built in parallel, so any pitfalls that anybody can think of would be useful.

Advice on proven chassis reinforcement would be more than welcome, I'd be more than up for a bit of fabrication and welding. Advice on any swing arm preferences would also be handy, particularly any reflections on general geometry and short circuit work.

Engines wise, I'm looking that buying a munter would give us cams and a Dot head, I think that the M model would get ruled out as it has too many bloody tappet adjusters!.

I'm also keen on getting the 6 speed boxes.

11 side, anybody give me a pointer on what engines that I can't buy up, given the finite cut off date of end '91. Am I stuck with 1054 or could I slide in 1127?

Obviously there are a myriad other questions that I could be asking, but...

Fount of all knowledge here, so best ask before somebody goes and buy's something stoopid.

No prizes for guessing what this might be about. 

 

[Rene EFE]

1 hour ago, markfoggy said:

So if you had a cut off, of 1991, what would you be looking at.

Now I'm looking at advice on substantive changes in chassis geometry over J,K,L, M. Plus any thoughts on construction benefits that Hammamatsu thought to include in this development era. This particular project would probably require 2 bikes to be built in parallel, so any pitfalls that anybody can think of would be useful.

You looking to test 2 bikes side by side? The earlier and later frames are quite different, earlier ones being the better of the 2, but that's personal.

 

Quote

Advice on proven chassis reinforcement would be more than welcome, I'd be more than up for a bit of fabrication and welding. Advice on any swing arm preferences would also be handy, particularly any reflections on general geometry and short circuit work.

 

Never seen a Slingy braced before myself; they're quite chunky

 

Quote

Engines wise, I'm looking that buying a munter would give us cams and a Dot head, I think that the M model would get ruled out as it has too many bloody tappet adjusters!.

I'm also keen on getting the 6 speed boxes.

Dotheads and gearboxes can be had off early Teapots. They're the same, just miles cheaper because people don't know the connection. For the gearbox, you'll need to decide on which way you'll be actuating the clutch.

1127 came around with the 11K, so '89. Differences between early and later engines are all in the head so of no concern if you're using a Dot-head

[gray711]

1 hour ago, markfoggy said:

 

11 side, anybody give me a pointer on what engines that I can't buy up, given the finite cut off date of end '91. Am I stuck with 1054 or could I slide in 1127?

 

 

Someone will correct me if I'm wrong but 1127's are '89 onwards I do believe .......

[markfoggy]

That's a good start, Rene and thanks. 

Concept at the moment is to build 2 identical bikes, usual strategy. 

Looks like 1127 lumps will be the way forward then, that narrows things down a little.

 

[Rene EFE]

I personally very strongly prefer the 88/89 750 frame; lighter, smaller and a more extreme headstockangle than anything that followed. Best handling bike I've ever owned (although it could've done with a steeringdamper)

[markfoggy]

Ok, 6 speed in 1127 or only 1054 is the next obvious argument. Would be a shame to fuck this up :LOL:

For those not paying attention, this might be an 'ckle project for the winter. 

 

[Duckndive]

the 6 speed gears don't last long in a 1100........"apparently"

[markfoggy]

Sounds like K's then, what I can see on my limited research is that they start getting a little lardy after that...I'll fuck off for w while and see if I can get any geometry out of the official data, but I suspect that we could fuck about with that big time :lol:

[Rene EFE]

6-speeds; Never seen one raced properly, but also never heard one used on the street that let go. You can only know if you try.

[Rene EFE]

1 minute ago, markfoggy said:

 but I suspect that we could fuck about with that big time :lol:

The bolt-on shockmount helps

[Burnout]

7 minutes ago, Rene EFE said:

I personally very strongly prefer the 88/89 750 frame; lighter, smaller and a more extreme headstockangle than anything that followed. Best handling bike I've ever owned (although it could've done with a steeringdamper)

yup

 

[markfoggy]

Pls be aware, this little game might well be something that presents a new challenge to me and my associates. Back in the day, smart money if you wanted to be competitive was, either what the team ran then, or some Handbag, with a V4 in it.

Is looking like we might wanna set the rule book straight, and yet another :lol:

Snigger.

[markfoggy]

5 minutes ago, Burnout said:

yup

 

With respect, that's not helping, too shiny.

[Rene EFE]

Better?  

[Captain Chaos]

This thread is relevant to my interests.

The 1127 came in late 1987 with the Powerscreen by the way. Same engine as the 1100K, but with different cams and clutch. And yes the 750J/K is the best frame, in stock form let down by the rear suspension. I fixed that with a shock from a 750L and had a very sweet handling bike.

The WN was produced from sept. 1991 so that fits within your end of 1991 cut off date. But I guess fitting an oilcooled engine in one of those is too much headfuck for not enough advantages.

[markfoggy]

Which is why I have a WP frame at home that will want a 12 at some point. What could possibly go right, 

7/11 seems to have been given he Go Ahead in some racing circles, so looks like a way forward for race bike building addicts. Seems like a relatively cheap way of smearing RC30's into the track. :LOL: 

See you at Spa. 

[cregnybaa]

13 hours ago, markfoggy said:

Ok, 6 speed in 1127 or only 1054 is the next obvious argument. Would be a shame to fuck this up :LOL:

For those not paying attention, this might be an 'ckle project for the winter. 

 

I use a 6 speed in mine, have done for years this particular one has done 2 classic TTs silver rep in both races and finished 4th in the pre TT classic on the southern 100 course. you really need to use the gsxr gearbox rather than the teapot as 1st gear is taller and the gears are stronger.

[dupersunc]

Mark, this is the blueprint you are looking for I believe.

http://www.cycleworld.com/2014/01/23/cycle-world-project-suzuki-gsx-r-endurance-racer?image=1

Looking at the pictures and reading the article, I reckon they've used the earlier 1052cc crank, rods, pistons and barrels on the 750k cases, gearbox, and head. The 1054cc stuff swaps in easily, where as the later 1127cc mains and primary gears are different.  Six speed box in 1127 cases is a well trodden conversion too.

I definitely don't have all the major parts in my garage to build a replica of this bike, once the slabbie 7/11 thunderbike racer is on track, oh no.

Edited May 2, 2016 by dupersunc

[dupersunc]

43 minutes ago, cregnybaa said:

I use a 6 speed in mine, have done for years this particular one has done 2 classic TTs silver rep in both races and finished 4th in the pre TT classic on the southern 100 course. you really need to use the gsxr gearbox rather than the teapot as 1st gear is taller and the gears are stronger.

Love to know more about this bike. I'm building a similar bike for Short circuit racing currently.

[Blubber]

There was also a write up done on the old site, to fit a six box in a oilcoled engine.

something info from the OSS fault

 

4. 750R 6 box in a 1127 motor
The only hard thing here is to have a hole drilled through the gear box shaft, for the pushrod.
The 750 6 boxes have a single row bearing on the output shaft, and the clutch does
not have a diaphragm spring. So the easiest 1127 engines to put a 6 box in are the ones with a
single row bearing on the output shaft, and no diaphragm clutch, ie. only the GSXF1127 engines.
In these engines the 6 box drops straight in, only the shaft has to be drilled.
Second easy would be an 1127R engine with a diaphragm clutch, but no double row bearing (88-90).
In this case the box would still drop in, but for the clutch one would have to use the inner
clutch parts from a GSXF1127 (with normal springs) and the outer clutch basket from the 1127R
(with a straight cut gear, not helical).
Most work is in a 91/92 1127R where one would have to match the clutch as above + find a
solution for the double row bearing (the solution is actually to turn the double row bearing
inside out, and make a little hole for the small pin).
Of course the shift drum and forks from the 6 box have to be used as well, but they drop in
any 1127 without problems.

 

 

 

 

[markfoggy]

Thanks Guys. 

[Captain Chaos]

7 hours ago, markfoggy said:

See you at Spa. 

sorry but it ain't happening this year, I'm coming to NL/B in August, not July. I was really looking forward to going to Bikers' Classics but real life got in the way.

[markfoggy]

Tea and Biscuits chez Phase One for anybody that that is passing through, though. 

[Leblowski]

Well see you there i will bring Stroopwafels then.

[caferacerdan]

building a retro 7/12 myself with a 88j frame too! I am using the suspension from the 91 750 so USD forks and shock with resevoir. cant tell you how it rides as theres no motor or tail yet!

Edited May 2, 2016 by caferacerdan