EFE Crank

[clivegto]

How mutch power will a standard gsx1100efe half welded crank hold before it spins. Or perhaps a better question is what power are your efe engines making reliably. 

[Arttu]

I think it depends on usage. On street use (=no hard launches on prepped track) I think it should be fine for way over 200hp. That's assuming it's in good condition, runout within the spec and no pitting on bearings.

The biggest problem is that you have no way to know condition of the bearings without disassembling the whole thing. So if you really want to ensure the reliability the only option is to get it checked and rebuilt. Alternatively you can check what's possible without disassembling, throw it in and see how it goes.

[clivegto]

Thanks @Arttu200hp sounds a lot. 

[Blower1]

On 4/13/2022 at 8:32 PM, Arttu said:

I think it depends on usage. On street use (=no hard launches on prepped track) I think it should be fine for way over 200hp. That's assuming it's in good condition, runout within the spec and no pitting on bearings.

The biggest problem is that you have no way to know condition of the bearings without disassembling the whole thing. So if you really want to ensure the reliability the only option is to get it checked and rebuilt. Alternatively you can check what's possible without disassembling, throw it in and see how it goes.

One problem with long (or wrong) stored cranks is moisture in the crank bearings. I have so far dismantled two otherwise nearly perfect crankshafts but found them scrap because rust has destroyed the crank pin bearing surfaces. 

[Reinhoud]

On 4/14/2022 at 6:45 AM, clivegto said:

Thanks @Arttu200hp sounds a lot. 

492 rods? How/where is it welded?

[clivegto]

1 hour ago, Reinhoud said:

492 rods? How/where is it welded?

Standard rods I think.  later efe cranks are half welded.  

[Joseph]

I have no idea 

However, quoting top HP figure resistance is one thing, but, how often does an engine get pushed and kept at its peak HP ? 

On a road used bike these days, i'd say, not often ?

So if it's in decent shape as is, you should be OK for quite some ?

[Gixer1460]

IMO - its not necessarily HP that does cranks / rods in.

Its instantaneous acceleration's / deceleration's like missing a gear at peak rpm's that tend to twist cranks. A good working engine will sustain a lot of revs and HP - but drop a cylinder due to a misfire and that won't help crank longevity.

[Arttu]

6 hours ago, Reinhoud said:

492 rods? How/where is it welded?

492 are standard rods on 1074cc engines, 18mm small ends. First turbo engine that I built had those rods and stock factory welded crank. Welded just like the EFE crank in picture above. It had slightly below 200 whp and run fine for few years and about 20000 km.

And like said above the hp figure isn't the only thing that defines stress for the crank. High rpms with big heavy pistons can be really hard even at low power. And hard acceleration and deceleration. And high instaneous torque like dropping clutch from high rpm with sticky rear tire.

[Reinhoud]

On 4/21/2022 at 3:22 AM, Arttu said:

492 are standard rods on 1074cc engines, 18mm small ends. First turbo engine that I built had those rods and stock factory welded crank. Welded just like the EFE crank in picture above. It had slightly below 200 whp and run fine for few years and about 20000 km.

And like said above the hp figure isn't the only thing that defines stress for the crank. High rpms with big heavy pistons can be really hard even at low power. And hard acceleration and deceleration. And high instaneous torque like dropping clutch from high rpm with sticky rear tire.

492 should be strong enough! 

I'm aware about the other stuff you mention, that's why I don't have the guts to go above 9000rpm. I hardly go over 7000rpm

[Reinhoud]

On 4/20/2022 at 10:17 PM, clivegto said:

Standard rods I think.  later efe cranks are half welded.  

Weld wise I wouldn't be too worried!

 

But your rods, are that 492's? My 493's have very clear 493 on it, my stock GS1000 haven't got a real number on them..

 

I was told my stock rods should be able to handle 200hp, but one snapped, or they can't handle 200hp, or I accidently did something right..

Edited April 23, 2022 by Reinhoud

[Reinhoud]

On 4/21/2022 at 2:51 AM, Gixer1460 said:

IMO - its not necessarily HP that does cranks / rods in.

Its instantaneous acceleration's / deceleration's like missing a gear at peak rpm's that tend to twist cranks. A good working engine will sustain a lot of revs and HP - but drop a cylinder due to a misfire and that won't help crank longevity.

That's when a con rod of my bike snapped

[Gixer1460]

2 hours ago, Reinhoud said:

I was told my stock rods should be able to handle 200hp, but one snapped, or they can't handle 200hp, or I accidently did something right..

Just compare the cross section of the 'std' 492 rod with the 493 Katana rod - its no wonder they are sought after for anything upto and including Funnybike engines!

Not sure who thought those wimpy rods would cope with 200hp bearing in mind they were designed for 110hp? plus a bit of headroom - maybe 150 ish tops?

[Reinhoud]

7 hours ago, Gixer1460 said:

Just compare the cross section of the 'std' 492 rod with the 493 Katana rod - its no wonder they are sought after for anything upto and including Funnybike engines!

Not sure who thought those wimpy rods would cope with 200hp bearing in mind they were designed for 110hp? plus a bit of headroom - maybe 150 ish tops?

The con rod on the crank is from a GS1000

[Gixer1460]

Yeah - realised that!

[clivegto]

Compared my efe little ends with the B12 and busa ones I have and the efe one are meatier than the B12 but the busa little end look way stronger. I know B12 rods to be alright to 250hp and even beyond that.