XR11/73

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garry55
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Joined: Fri Dec 27, 2013 2:49 pm
Location: White Rose County

XR11/73

Post by garry55 »

allow me to introduce the reason I am frequenting your rather excellent forum - project XR11/73. This is being built in response to a challenge on another 2-stroke forum, the rules of which are fairly simple - build a project bike using an engine and frame combo that aren't made for each other. My entry into this challenge is a GT750-powered, GSXR400 (GK73A)-framed track day bike which will have visual connections to the early TR750 racers - namely the blue/white paint scheme, gold wheels, TR seat unit, forward-facing calipers etc.
With the acquisition of a GK73A frame today, I now have a near-complete rolling chassis to complement the GT750J motor I bought from DK a while back.Shame they aren't compatible..........
So first job is to get the behemoth of a motor to snuggle into the lovely alloy beam frame. The rear mounts on the Kettle motor measure 16.5mm across (with the rubbers in place) - the cast-in frame lugs are 14mm apart. So thats the first (of many) obstacles I will have to overcome.
Pictures to follow.....................
Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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yeadon_m
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Joined: Sat Jan 02, 2010 7:10 am
Location: Canterbury Kent

Re: XR11/73

Post by yeadon_m »

Welcome Garry!
I am 'a standard man' myself so I don't know anything about converting bikes...however, on another forum there clearly is expertise:
http://www.suzuki2strokes.com/forum/vie ... 4&start=15
Looking forward to progress on anything with a GT motor in it :-))
Cheers,
Mike
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garry55
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Location: White Rose County

Re: XR11/73

Post by garry55 »

some pictures - saves a thousand words.............

first trial fit of GT750 motor in GSXR400 frame - the front mounts

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and the upper rear mounts

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my solution - make new mounts and attach in-line with existing mounts, but spaced much wider

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the front mounts had to go..............

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that allows the motor to sit a lot higher in the frame

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I was about to take the frame for welding of the new rear upper brackets when I realised I could move the motor further back to give more clearance for the headers, so......................
Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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garry55
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Location: White Rose County

Re: XR11/73

Post by garry55 »

............so, time to fire up the grinder again and remove some more metal - this time, all the rear motor mounts

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the frame, de-mounted

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fitting the swingarm allowed me to shift the motor as far back in the frame as the swingarm pivot would allow - I shimmed it at 2mm from the pivot and 2mm below the cross-piece and it starts to look promising...........

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next step is to fabricate some new rear upper motor mounts and clean the frame where the original mounts once were

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Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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Rhencullen
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Location: Lincolnshire

Re: XR11/73

Post by Rhencullen »

Will the engine 'stiffen' and form part of the frame, like my 900R then Garry ?
1977 Suzuki GT750B - 2003 Honda CB1300 - 1979 Honda CBX1000
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garry55
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Location: White Rose County

Re: XR11/73

Post by garry55 »

Indeed it will. Current thinking is to "hang" the motor via the cylinder head, like the Drysdale kit for RG500's.
I really don't want a cradle as it will spoil the illusion of the engine hanging unsuspended from the frame.
Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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garry55
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Location: White Rose County

Re: XR11/73

Post by garry55 »

when space is at a premium, every little helps. This casting on the back of the Kettle gearbox is what I used to shim the motor away from the swingarm pivot - it's approx 3mm wide -

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but not anymore.............

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:D
Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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garry55
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Location: White Rose County

Re: XR11/73

Post by garry55 »

A few pics of the new rear upper engine mounts..............

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time to visit my welders..................
Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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garry55
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Location: White Rose County

Re: XR11/73

Post by garry55 »

To pass time, and move the project forwards, I have spent part of my last 2 night shifts at work grinding-off the remains of the front engine mounting castings and weld to tidy the frame. A bit of filing and rubbing with emery cloth and it will be a lot neater. And lighter ! :D

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Look away now if you are of a nervous disposition - to clear the new rear motor mounts, I had to relieve some more surplus metal from the Kettle motor. Who needs an oil pump cover anyway? :wink:

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Garry.

Inside every standard Kettle is a bloody good engine crying for help............... :D
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Rhencullen
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Re: XR11/73

Post by Rhencullen »

You're certainly making good use of that grinder / cutting wheel Garry :-)
1977 Suzuki GT750B - 2003 Honda CB1300 - 1979 Honda CBX1000
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