Donor Gearboxes

[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.

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[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.

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[el chupacabra]

More Progress, I have drawn the reed cage housings and started looking at where the studs will go to join the halves. Do you reckon m8 would be enough? I am also tossing up using cap heads and recoils as they will make less of an obstruction in the transfer port feeders on the case vs a flange washer. Does anyone have any objections or bad experiences with recoils vs studs?

Also look at how much room I have for carbs now with a 1370mm wheelbase, hopefully a 62mm main bearing will be enough on the lay shaft seeing as that's what a Yamaha banshee uses and they can make some big HP. A cylindrical N305 ECP has 4x the load rating and can take axial loads in each direction, are there any major downsides to this style of bearing vs the 6305 deep groove ball bearing?

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[jato]

This design has evolved very nicely imo - it looks real pretty and purposeful! - I'm also a fan of cylindrical roller bearings but i have seen wear patterns on the races showing the effects of "unrestrained" crank flex in high power/rev engines, so great for the layshaft and maybe adjacent to the crank primary if the cranks are pretty rigid.

[pete376403]

This design has evolved very nicely imo - it looks real pretty and purposeful! - I'm also a fan of cylindrical roller bearings but i have seen wear patterns on the races showing the effects of "unrestrained" crank flex in high power/rev engines, so great for the layshaft and maybe adjacent to the crank primary if the cranks are pretty rigid.
Norton had issues with commando cranks flexing and they went to barrel shaped (?) Superblend rollers to fix that

[el chupacabra]

I think I will stick to the ball bearings on the crank and use only the rollers on the Lay shaft.

[el chupacabra]

Not related to the V4 but has anyone made their own air cooled 4 stroke head gaskets before?

[jato]

40 thou copper bought from E Hayes in invercargill. prior to fitting heated to red then dropped into salt water. i understand that the salt has a hand in removing surface oxidation as it goes into the water - the gasket comes out immaculately clean like its been bead basted.

[el chupacabra]

I'll probably give that a try, I'm having trouble with the little V twin I made as there is no aftermarket head gasket so I have to conjure something up.

Here is some more V4 progress, I decided to render the model for some extra motivation. You can see I've added ribs in between the Vee to strengthen it up a bit.

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[husaberg]

I'll probably give that a try, I'm having trouble with the little V twin I made as there is no aftermarket head gasket so I have to conjure something up.

Here is some more V4 progress, I decided to render the model for some extra motivation. You can see I've added ribs in between the Vee to strengthen it up a bit.

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What bore i think i have A 54mm one here small hemisphere? pitbike

[el chupacabra]

What bore i think i have A 54mm one here small hemisphere? pitbike

It is a pit bike head, it's a 47mm bore but having widened the cam chain tunnel 14mm it proves hard to seal. I might lap the head/cylinder in the morning and use some of that copper head gasket spray on the lapped surfaces, I could add O rings to the oil galleries too. but all this requires a 2+mm base gasket to account for the lost head gasket. I have a feeling that the thick (2.5mm) gasket material I have will crush over time, maybe I should make a 1mm steel shim and run 2 thinner gaskets. The race is on sunday and I would like to test the engine out properly.

hmmmmm.

[husaberg]

i bought these years ago not sure where they are though.
http://dratv.com/nealbainth.html
http://dratv.com/cohega54bofi.html

for a race motor i would oring and steel oring it.

[el chupacabra]

I haven't made much progress lately as I've been working on the bucket. It finished every race and didn't explode, not bad for an engine cast at home.

I have however finished modifying the case to accept the GSXR water pump and designed a small adapter to mount it on. The next steps will be to model the lay-shaft and finalize bearing locations. I'll get some foam cut to cast the forward crankcase or the cassette. I'll start with some of the smaller parts.

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[el chupacabra]

It's time. . . something clicked and I've decided it's time to make some parts. So I cocked up this pattern as the piece of foam was too small, tomorrow I am picking up some more XPS foam and am hoping to have some patterns ready before the end of the year. I'll hunt around to get them cast and heat treated by someone professional or I can just cast/heat treat myself although I don't have a good supply of virgin aluminium and would likely recycle something.

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[el chupacabra]

I've cut the foam and now it is time to get to casting, hopefully sometime in the new year as life has thrown me a curve ball. Does anyone have a good supply or know where I can get some LM25 or a quality heat treatable casting alloy? I'm wanting to avoid mostly recycled material of questionable quality. Also on the off chance does anyone know someone who will cast something this small for me? It might be less hassle to get someone else to pour it if it is cheap enough, otherwise I'll get around to it sometime in February at the earliest.

Thanks in advance.

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[el chupacabra]

I've gotten a local foundry to agree to pour these castings for me and they are only 20 minutes from home. As of now I am finishing the front crankcase half, I am a third of the way there (2/6 pieces). This and the Cassette plate will be cast on the same day before moving onto the rear crankcase half. The front pattern is made of 6 pieces of 50mm thick XPS foam.

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[el chupacabra]

Ready to cast, well kind of, it could be all go next Friday. I seem to have over looked the front engine mounts when double checking everything after the full redesign from before. Now what's the best solution, bolt a laser cut plate onto some raised bosses (with a solid bush in between) or glue on some lugs (will also have bush in between)? It seems like it done many different ways, the TZ250 seems to use a bolted on plate with no problems.
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[F5 Dave]

Sometimes you have to go What the Hey, and just do it (Ferris Bueller reference).

. . . although, a small +++ on the keyboard and it could be a 500. . .

[husaberg]

Spreading the load over two mounts with the bracket seems potentially more sturdy
the weakest part of any v engine is apparently the thigh gap
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[F5 Dave]

Yeah but he doesn't have two hoady 500cc overly complex pistons waving around.

[husaberg]

Yeah but he doesn't have two hoady 500cc overly complex pistons waving around.
Granted but I would personaly rather sacrifice a few gms of weight rather than recast and re-machine a set of cases.

[Grumph]

This is the point where you pause and reflect on whatever frame design you have in mind - and how much frame loading you're prepared to put through the cases.
If the answer is "some" then cast in lugs - albeit with a spacer between - are your preferred option
If the design isolates the motor then the bolt on plates - with maybe urethane bushings - will suffice.

The trick is to finish up with a nicely integrated design which both looks good and functions well.
And of course has access for servicing.....

[el chupacabra]

It's happening. . . Only the rear half to go.

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[el chupacabra]

I am about to cut the pattern for the second half of the engine in the next week. I realised after some looking around that the gearbox from a 675 Daytona will also drop straight in, I can also make some modifications before casting to allow this to fit directly into a 675 chassis.

[el chupacabra]

I’ve been making progress on one of my other projects and in working on that, I’ve learnt more and more about how I wish I did the V4 in the first place (I’ll be using patterns on a match plate) . . . I’m about to cut my losses and do a complete redesign.

It will be designed like an RZ500 (each crank individually drives the clutch) except it will be a 90* vee angle, same triumph gearbox and Yamaha banshee cranks. I will also run banshee cylinders on the first edition. Making it a cylinder reed 700cc V4. It should make the design simpler and the overall size much smaller.

The only thing I’m wondering is if I will be able to balance it very well with the stock banshee cranks.

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[husaberg]

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=301978&d=1411468044

always been a fan of how they built the RS500 Honda

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[husaberg]

Then you have the Cagiva/yam Way. which is similar
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[husaberg]

left feild option is to make it like a doubled up aprilia with center plates
RD cranks lend themselves to sliping in halves
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