Dot Head Swap On The G Bike

[XXXSpro]

1 hour ago, Duckndive said:

on that calculator dome volume should be a positive no for busa pistons 

What rods are you using ? 

I believe it is a positive number on there, but I’ll double check

 

I’ll be using the stock 1127 rods, 117mm I believe 

[XXXSpro]

1 hour ago, coombehouse said:

Are you sure about the compressed head gasket figure? Doesn't seem right to me.

I believe the head gasket is 0.7mm, the base 0.2mm

I didn’t catch that! It’s supposed to be 0.03” not mm

[coombehouse]

2 minutes ago, XXXSpro said:

I didn’t catch that! It’s supposed to be 0.03” not mm

In that case it needs to be 0.036" to include the base gasket 

[XXXSpro]

39 minutes ago, coombehouse said:

In that case it needs to be 0.036" to include the base gasket 

Got it, thanks 

I know I’m still going to need to measure come pick up,  just trying to have a good grasp on where to go next.

 

[Duckndive]

You say you have had the blocked decked by 1.5mm ? 

So given a busa piston on a stock gsxr rod is flush with the top "deck" on a stock block .then surely the crown of the piston will be out of the bore or have I missed something ? 

[Gixer1460]

44 minutes ago, Duckndive said:

You say you have had the blocked decked by 1.5mm ? 

So given a busa piston on a stock gsxr rod is flush with the top "deck" on a stock block .then surely the crown of the piston will be out of the bore or have I missed something ? 

Think so! I thought the whole reason for using Bus pistons on stock 1100 rods was that they dropped down the hole to drop comp for forced induction use ! ! !

They got nothing going for them otherwise, apart from being an OEM forging LOL!

[clivegto]

36 minutes ago, Gixer1460 said:

Think so! I thought the whole reason for using Bus pistons on stock 1100 rods was that they dropped down the hole to drop comp for forced induction use ! ! !

They got nothing going for them otherwise, apart from being an OEM forging LOL!

Yes there about 2mm down the bore on a 1127 and the 1157 standard block. 

[Duckndive]

1 hour ago, Gixer1460 said:

Think so! I thought the whole reason for using Bus pistons on stock 1100 rods was that they dropped down the hole to drop comp for forced induction use ! ! !

They got nothing going for them otherwise, apart from being an OEM forging LOL!

 

42 minutes ago, clivegto said:

Yes there about 2mm down the bore on a 1127 and the 1157 standard block. 

I,ll just leave these here then....

Stock Crank , Stock GSXR Rods, Stock 1157 Block, Gen 1 Busa Pistons..  ..

[XXXSpro]

4 hours ago, Duckndive said:

You say you have had the blocked decked by 1.5mm ? 

So given a busa piston on a stock gsxr rod is flush with the top "deck" on a stock block .then surely the crown of the piston will be out of the bore or have I missed something ? 

I decked it by 1.2mm, I had read of a guy on the bandit forum who did it by 1.5mm to up compression.

didn’t you do a build with busa pistons too?

[XXXSpro]

2 hours ago, Duckndive said:

 

I,ll just leave these here then....

Stock Crank , Stock GSXR Rods, Stock 1157 Block, Gen 1 Busa Pistons..  ..

This is with no decking at all? What was compression on this build?

Edited November 23, 2023 by XXXSpro

[Duckndive]

3 hours ago, XXXSpro said:

This is with no decking at all? What was compression on this build?

Yes As the text says "Stock Crank , Stock GSXR Rods, Stock 1157 Block, Gen 1 Busa Pistons."    Draw Thru Turbo...

 

[XXXSpro]

5 hours ago, Duckndive said:

Yes As the text says "Stock Crank , Stock GSXR Rods, Stock 1157 Block, Gen 1 Busa Pistons."    Draw Thru Turbo...

 

That’s quite a beast you got there!

Any head work or Swap? 
 

This is my current project 

 

[Upshotknothole]

Just out of curiosity, has anyone ever figured out how much power those shaft drives can take before they pop?

[spiderpig]

You're never getting 12:1 on busa pistons, dot head or not. 

I've a heavily skimmed dot head I was gona use with busa slugs and the comp wouldn't be near that. 

[Gixer1460]

And to be honest, whilst the output numbers are ballpark, you ain't gonna get them at those rpms! Maybe add 2k to each to be nearer the mark?

[XXXSpro]

18 hours ago, spiderpig said:

You're never getting 12:1 on busa pistons, dot head or not. 

I've a heavily skimmed dot head I was gona use with busa slugs and the comp wouldn't be near that. 

What kinda comp did you get with it on paper?

I read busa slugs drop comp to 8:1/8.5:1, dot head is 1.5 comp increase and 1.2mm deck was around 1.5-2 points up 

based on that I was estimating 11.5-12 : 1

Edited November 25, 2023 by XXXSpro

[XXXSpro]

16 hours ago, Gixer1460 said:

And to be honest, whilst the output numbers are ballpark, you ain't gonna get them at those rpms! Maybe add 2k to each to be nearer the mark?

Damn, I didn’t think it’d get moved up the revs that much!

Stock this thing hit peak torque at 5k and peak power at 7.5k

[DAZ]

6 hours ago, XXXSpro said:

Damn, I didn’t think it’d get moved up the revs that much!

Stock this thing hit peak torque at 5k and peak power at 7.5k

It's basic maths really , if you limit displacement then the only way (apart from forced induction or nitrous) is to increase the rpm , BHP = (torque x RPM)/5252 ,a dyno doesn't measure bhp it measures torque and without increasing torque which is limited by capacity and cylinder filling the only variable left is rpm ,hence why in the mid 2000s F1 cars were 3.5 litres turning 19000rpm to make 900+ bhp... 

[Duckndive]

7 hours ago, XXXSpro said:

I read busa slugs drop comp to 8:1/8.5:1, dot head is 1.5 comp increase and 1.2mm deck was around 1.5-2 points up 

based on that I was estimating 11.5-12 : 1

As measured in a real build not a guess or hearsay   Busa Slugs in a Stock Block on a Stock Crank and Rod are 8.41 : 1   

A Dot Head will give a 1.1 increase in Comp at Best "real build fact not a guess" 

A 1.2mm deck of a stock 1127 or 1157 block will leave the crown of the busa piston 1.2mm out the block "Interesting to see how you deal with that" 

Please feel free to post pics and dyno sheets of the magic build you read about on the Blandit Forum ....

Edited November 25, 2023 by Duckndive

[Dezza]

7 hours ago, XXXSpro said:

Damn, I didn’t think it’d get moved up the revs that much!

Stock this thing hit peak torque at 5k and peak power at 7.5k

Really? Even a big aircooled lump like an EFE revs a little higher than that, although not by much. (Which is a definite plus .)

[XXXSpro]

6 hours ago, Dezza said:

Really? Even a big aircooled lump like an EFE revs a little higher than that, although not by much. (Which is a definite plus .)

Ya this bike is such an odd ball for how it made power compared to the other 1100s 

I think it’s most similar to the b12 but I think even those made power a bit higher in the revs

[XXXSpro]

6 hours ago, Duckndive said:

As measured in a real build not a guess or hearsay   Busa Slugs in a Stock Block on a Stock Crank and Rod are 8.41 : 1   

A Dot Head will give a 1.1 increase in Comp at Best "real build fact not a guess" 

A 1.2mm deck of a stock 1127 or 1157 block will leave the crown of the busa piston 1.2mm out the block "Interesting to see how you deal with that" 

Please feel free to post pics and dyno sheets of the magic build you read about on the Blandit Forum ....

Here ya go, idk if I can post links on here but you can take a read https://www.banditforum.co.uk/forum/index.php?topic=73284.0

 

ps. problem is there’s some people who post everything they did in detail and some people throw a couple pics up and loosely describe things. Some people just say that works or that doesn’t but don’t say why, then shyt  people who just want info to make better decisions.

So the amount of conflicting info is unbelievable 

At the end of the day a build is supposed to be fun and a forum is supposed to be about community.

That’s why I ask around, DM, talk to my machinist ( he’s a busa builder ) and try to piece info together

Whatever hurdles pop up I’m sure someone out there will help

Edited November 25, 2023 by XXXSpro

[XXXSpro]

7 hours ago, DAZ said:

It's basic maths really , if you limit displacement then the only way (apart from forced induction or nitrous) is to increase the rpm , BHP = (torque x RPM)/5252 ,a dyno doesn't measure bhp it measures torque and without increasing torque which is limited by capacity and cylinder filling the only variable left is rpm ,hence why in the mid 2000s F1 cars were 3.5 litres turning 19000rpm to make 900+ bhp... 

That makes a lot of sense, specially when you use the F1 example.

I didn’t that of how that would come in to play with the bigger slugs or change in compression

[DAZ]

40 minutes ago, XXXSpro said:

That makes a lot of sense, specially when you use the F1 example.

I didn’t that of how that would come in to play with the bigger slugs or change in compression

Basic improvements will increase power but that's only because what you start with is less than optimum or less capacity in the case of a big bore kit ,so if you take the basic 1100 g rated at approx 100 hp increase the compression to 12:1 you will see an increase in power ( because it was less than optimum, assuming the fuel used and ignition timing can cope ) add a 1216 kit and again you will see an increase because you have more capacity, fit 1100f cams and yes you're right you will see more power because the valves are lifted higher for longer but that will be at higher rpm ,not just because of the cams but because the timing of the opening and closing events of the cams push the power peak higher and so gsxr cams or ones from kent cams or web cams push the rpm higher as they get more radical in the search of ultimate power     note I say power because as always it is torque that is measured, and converted mathematically to bhp 

Edited November 25, 2023 by DAZ
Addition

[XXXSpro]

29 minutes ago, DAZ said:

Basic improvements will increase power but that's only because what you start with is less than optimum or less capacity in the case of a big bore kit ,so if you take the basic 1100 g rated at approx 100 hp increase the compression to 12:1 you will see an increase in power ( because it was less than optimum, assuming the fuel used and ignition timing can cope ) add a 1216 kit and again you will see an increase because you have more capacity, fit 1100f cams and yes you're right you will see more power because the valves are lifted higher for longer but that will be at higher rpm ,not just because of the cams but because the timing of the opening and closing events of the cams push the power peak higher and so gsxr cams or ones from kent cams or web cams push the rpm higher as they get more radical in the search of ultimate power     note I say power because as always it is torque that is measured, and converted mathematically to bhp 

This is the info I was looking for, appreciate it a ton!

I feel like understanding the process of what each change makes to an engine changes how you go about things.

Previously I had only thought about more displacement + compression = mopowa

i kept reading about gsxr cams being pesky and 1100F being all arounders 

Knowing this, I understand why people keep the stock ( intake? ) cam from the b12 for retaining low end.

Do you have a build new or old?

I know you put this knowledge to use haha