Donor Gearboxes

[jato]

...actually it would be interesting to see what balance factor the crank has - hopefully near to 50% for you setup

[el chupacabra]

I’ll measure the weight on Friday. I’ll also check the balance factor, hopefully it’s nothing I can’t fix with a couple of holes.

I’m thinking that the crank bearings will be replaced often enough that having them oiled by premix shouldn’t be a massive issue. At least it’s something that can be changed further down the track if need be by swapping the order of the components.

The GSXR1000 pump also showed up today, it’s bigger that I thought haha. Tonight’s job is to accurately model the pump and see where I can fit it on the engine.

[el chupacabra]

The fit is looking promising, I will make some room in the bottom of the case for the drive sprocket.

[el chupacabra]

The crankcase shape is modified and I have added a drive shaft for the water pump. It will use 2 x 61901 ball bearings and run the standard ANSI 25 chain (at least that's what I think it is without looking too hard), if it's slack I can add a nylon guide of some description.

[el chupacabra]

Progress has been slow as I've been busy with my V Twin race bike prepping that for the coming season. Tonight I measured and roughly modeled the shift fork guide and selector drum bores.
Also another happy coincidence is that the local library has a 1200x1200 CNC router which I can use to cut my XPS foam for the casting so I will only need to flip the patterns once and machine the entire engine
from 1 large piece of foam in 2 set ups. Then I will glue all of the sections together.

[el chupacabra]

Getting back at it, the lack of wine I've been drinking lately may have been the culprit. This is starting to look a bit silly with some no name 32mm carbs I found a model for online. I've also cleaned up the selector guides and the outside of the case. It's simulated to weigh 28kg minus Gearbox, cylinders, heads, flywheel and cranks. I'll need to do some strategic lightening prior to the first pattern, I'll have a think of anything I have missed and then it will be time to cut some foam.

[el chupacabra]

Tonight I added the outlet for the oil to get from the pump to the inside of the input shaft. You can see where the 6x16x5mm lip seals which will be used to hold the 6mmOD 4mmID tube will be seated.
You can also see the cover for the oil gallery, I'll likely modify this as it is fairly ugly.

Moving on, I am thinking about how to actuate the clutch. I am thinking of using a hydraulic setup from a KTM Mx bike pushing a rod through the input shaft. Are there any obvious drawbacks to using this kind of set up vs a cable pulling on the clutch side as it seems easier to implement the hydraulic solution in my mind.

[husaberg]

Tonight I added the outlet for the oil to get from the pump to the inside of the input shaft. You can see where the 6x16x5mm lip seals which will be used to hold the 6mmOD 4mmID tube will be seated.
You can also see the cover for the oil gallery, I'll likely modify this as it is fairly ugly.

Moving on, I am thinking about how to actuate the clutch. I am thinking of using a hydraulic setup from a KTM Mx bike pushing a rod through the input shaft. Are there any obvious drawbacks to using this kind of set up vs a cable pulling on the clutch side as it seems easier to implement the hydraulic solution in my mind.

hydraulic or manual pusher is tidier anf less likely to be damaged in a crash.
Honda VT250 ran both set ups likely a far bit cheaper than KTM or Husaberg set ups.


Honda CR's 250 and 500 at least used a cable push from the countershaft side.


there is also conversions for the cavble pusher CR set ups


https://www.aliexpress.com/item/1005...ct.mainProduct

can't complain about the price
52 nzd landed

[el chupacabra]

I'll keep my eye out for one from a VT250.

Tonight I thought it was best to see if the engine would even fit in a chassis without being 100m long before continuing. . . As you can see the minimum wheelbase will need to be 1440mm(ish) based on Bridgestone tyre diameters and an RSV1000R swingarm length. It seems bikes are only getting longer and longer, although now they also have over 220hp. I'm sure the V4R/RC213VS etc don't feel too bad although I've never ridden them obviously. Does anyone have experience with longer wheelbases and they make the bike feel or if it's less important than I think as I don't want to make something that is hard to turn or handles like a boat.
For reference:
RS125 1215mm
RS250 1340mm
RGV250 1370mm
R6 2014 1380mm (Best handling stock bike I've ever owned)
RSV1000R 1415mm (Very stable, preferred riding a 600/750)
S1000rr 1425mm
M1000rr 1457mm
RC213 VS 1465mm
Ducat V4R 1471mm

[jato]

what year rsv1000r is the swingarm off? i have a 2010 one here and i recall it is around 540 or so, and horrendously heavy...
the yamaha tracer got a 60mm longer swingarm for 2019 and testers appear to all report no noticeable change in performance on tight winding roads ( for what that is worth) its wheelbase went from 1440 to 1500. scaling side on pics of fast gp bikes show the swingarm makes up around 45% of the wheelbase. re the clutch actuation i would go for whatever is lightest.

[el chupacabra]

You are correct it is about 530-540mm, I was just going off google last night as I couldn't be bothered walking to the shed (mine is a gen2 2004). I also checked the RGV250 one and it is 560mm long.
I wouldn't use the RSV1000R swingarm, it was just for rough length. I would be inclined to use one from a GSXR600/750 as I kept the set of wet rim when I sold the bike.

[el chupacabra]

It's a bit disheartening, but I've decided to do a major redesign. I've known for the last week the engine will be too long with the carbs installed. I am going to have the crank coupling gears drive the clutch, doing away with the lay shaft. This makes the engine around 100mm shorter and will allow me to easily fit the carbs inside the V. This does mean the primary ratio will change to 2:1 and it will necessitate a slightly larger rear sprocket. It also comes in at 20mm narrower overall.

Seeing as the weather is trash and I am trapped inside I thought I may as well get stuck in. This is the start of the redesign.

[pete376403]

Have you had a look at how this guy does a V twin? https://www.facebook.com/rimarmotors

[el chupacabra]

I’ve been following him from the start on Facebook. I love the project, and have the same philosophy about using off the shelf parts. That’s what’s got me in a rut, I could make a custom crank and a fairly standard layout but then it wouldn’t be quick and easy to service and it has to be a v4 to make the most project worth while.

[el chupacabra]

Ok so I'm back to the lay shaft but re modeled it this morning so it is 10mm narrower, 75mm shorter but 50mm taller. It looks like there will be a lot more room for carbs.
Same centre coupling but the layshaft is on the same split plane as the crankshafts. at this stage it is also 3kg lighter.