B12 engine build recommendations.

[BoostedRooster712]

Afternoon all,

I have a late model B12 motor which I want to have ready in case I need to do an engine swap in one of my bikes at some stage.

I'd like to know if these plans will work.

It's a V720 so a 2006 model. 1156cc from what the SACs engine code sites tell me.

I have the yoshi stage one cams out of my 1216 that were in the RR to go it in. I have a set of APE adjustable cam sprockets.

I'm entertaining a dot head for this build so I'd like to know if the dot head would help with getting a bit more out of the motor.

I have a set of 81mm Yoshi Busa (99 model) pistons (12:1 in their intended application) which I would potentially like to put in but I understand this will lower the compession a bit, a "man in the know" suggested this might give me a CR of about 10:1. I'm not totally set of doing the piston swap and could be content leaving the pistons stock. I'm not chasing bulk horsepower, just something reliable but lively.

I plan on injecting it with single injector GSXR600 throttle bodies but that's another step I'll tackle later, I just would like to know if anyone has done something similar mechanically and if there are any tips, tricks or recommendations with this setup.

Any input would be greatly appreciated.

Cheers.

[DAZ]

Not 100% on this but I thought that they changed the crankcase engine mounts ,along with the frame ,in 2006 to halfway house set up before going w/c in 2007 with the 1250 , hence why the change from v719 to v720  PLEASE check this out before you do anything with a 2006 motor ,I may be wrong hopefully I am . Maybe @fatblokeonbandit may know .Your build stage one cams dot head is good dot heads have smaller chamber so will raise std compression, watch out for carb to tank clearance as dot head is slightly downdraughted compared with std. Honestly no idea about the 12:1 busa pistons you would have to work out the numbers ,there are online calculators for this hth

Edited January 7, 2023 by DAZ
Addition

[Ted M]

Be very careful with the 81mm pistons and a dot head set up as the CR might be that high you can run diesel. I was going to do something similar but using Wiseco pistons but I checked the CR and found it to be in the region of 15:1. Also the piston crown was running very close to the cylinder head. 

[colinworth79]

V720 is as you say a late oilcooled bandit 12 motor it differs from the earlier engine in that it had the pairs system fitted and the exhaust cam has slightly less lift and duration due to emissions but the rest is identical. 

Main way to gain power with these is cams and compression. I would either go dot head and stock pistons or the correct big bore kit , stock head and some cams . 

 

[fatblokeonbandit]

I did my first dot head and cams onto a standard B12 about 2004, it was epic bolt on HP. 
It did 133 rwhp with decent can and pod filters and went like fek, I dint degree the cams as I don’t know I supposed to!!

I was told it wouldn’t work unless the cams were degreed??

this was after I had done a track day at snetterton, it didn’t blow up…

Ive done 2 more since using aftermarket camS, they have all been lively to say the least…..

2006 was the last year of the oil cooled bandit motor, like Colin said, very similar, the frame was different and the wheel are from Gsxr, but motor the same…

 

[coombehouse]

I've just finished building a very similar motor to yours. I went with standard pistons as they were all good, standard head but skimmed to bring the comp ratio up to 11.5:1, gsx11k cams, slotted sprockets, mild head porting, gsxr600 throttle bodies. I did have to increase the valve pockets, substantially on the exhaust side. Hopefully it will be running in the spring 

[BoostedRooster712]

15 hours ago, DAZ said:

Not 100% on this but I thought that they changed the crankcase engine mounts ,along with the frame ,in 2006 to halfway house set up before going w/c in 2007 with the 1250 , hence why the change from v719 to v720  PLEASE check this out before you do anything with a 2006 motor ,I may be wrong hopefully I am . Maybe @fatblokeonbandit may know .Your build stage one cams dot head is good dot heads have smaller chamber so will raise std compression, watch out for carb to tank clearance as dot head is slightly downdraughted compared with std. Honestly no idea about the 12:1 busa pistons you would have to work out the numbers ,there are online calculators for this hth

Cheers for the reply.  I've compared the cases with my 1127 cases and they seem to be almost identical so all good on that front. I have been advised by a mate about the downdraft situation with the dot head. It shouldn't be an issue as the throttle bodies won't give me clearance issues with a frame like a set of carbs would, whatever frame that might end up being I think I'll be safe there.

4 hours ago, Ted M said:

Be very careful with the 81mm pistons and a dot head set up as the CR might be that high you can run diesel. I was going to do something similar but using Wiseco pistons but I checked the CR and found it to be in the region of 15:1. Also the piston crown was running very close to the cylinder head. 

The Busa pistons have a completely different crown to the standard and aftermarket pistons for the 1127 and B12 motors. These pistons are usually used by people in turbo builds to the lower compression. From the other responses here I think I'll give them a miss this time and just use stock pistons and save the busa pistons for something else. They're a bit nice to be stuffing them in a spare engine that I may not use for quite a while. I had a mate do some calulations and he said this would come out at about 10:1. I'd be triple chech that first though if I did go mad and put them in this. 

Wiseco pistons in my 1216 are this shape crown wise.

Busa piston crown is recessed, this shape.

3 hours ago, colinworth79 said:

V720 is as you say a late oilcooled bandit 12 motor it differs from the earlier engine in that it had the pairs system fitted and the exhaust cam has slightly less lift and duration due to emissions but the rest is identical. 

Main way to gain power with these is cams and compression. I would either go dot head and stock pistons or the correct big bore kit , stock head and some cams . 

 

Thanks for your input, looks like I am heading in the right direction! I have some pairs block off plates I bought a few years ago sitting around somewhere.

2 hours ago, fatblokeonbandit said:

I did my first dot head and cams onto a standard B12 about 2004, it was epic bolt on HP. 
It did 133 rwhp with decent can and pod filters and went like fek, I dint degree the cams as I don’t know I supposed to!!

I was told it wouldn’t work unless the cams were degreed??

this was after I had done a track day at snetterton, it didn’t blow up…

Ive done 2 more since using aftermarket camS, they have all been lively to say the least…..

2006 was the last year of the oil cooled bandit motor, like Colin said, very similar, the frame was different and the wheel are from Gsxr, but motor the same…

 

Awesome ot hear that worked for you, that's exactly what I was hoping to hear and helps me plan this out. You guys have been exceptionally helpful. This forum and the inmates are frigging top notch. Cheers. 

[BoostedRooster712]

13 minutes ago, coombehouse said:

I've just finished building a very similar motor to yours. I went with standard pistons as they were all good, standard head but skimmed to bring the comp ratio up to 11.5:1, gsx11k cams, slotted sprockets, mild head porting, gsxr600 throttle bodies. I did have to increase the valve pockets, substantially on the exhaust side. Hopefully it will be running in the spring 

I'm on the right track, thanks for letting me know. What injection system did you use for yours?

[coombehouse]

7 minutes ago, BoostedRooster712 said:

I'm on the right track, thanks for letting me know. What injection system did you use for yours?

Gsxr600k1 throttle bodies with secondaries removed & blanked, IAT thermistor in one of the blanks, 24-2 trigger wheel (36-1 I used in the past wasn't great), external map sensor, cylinder temperature sensor clamped to fin on block, ford car eds type coil, Bosch 2 channel igniter, microsquirt semi sequential alpha-n. 

[BoostedRooster712]

9 minutes ago, coombehouse said:

Gsxr600k1 throttle bodies with secondaries removed & blanked, IAT thermistor in one of the blanks, 24-2 trigger wheel (36-1 I used in the past wasn't great), external map sensor, cylinder temperature sensor clamped to fin on block, ford car eds type coil, Bosch 2 channel igniter, microsquirt semi sequential alpha-n. 

Perfect. I've just sent an email to microsquirt NZ to order one for the Martek. That has a Dyna 2000 and a KMS ECU but I'm not content with that and I'm going to rip it off and replace it with the microsquirt. By the time I have that bike up and running I'll be familar enough with the system to make this easier once I move onto this engine build. 

[coombehouse]

6 minutes ago, BoostedRooster712 said:

Perfect. I've just sent an email to microsquirt NZ to order one for the Martek. That has a Dyna 2000 and a KMS ECU but I'm not content with that and I'm going to rip it off and replace it with the microsquirt. By the time I have that bike up and running I'll be familar enough with the system to make this easier once I move onto this engine build. 

If you get any problems please message me & I'll try to help. Arttu is the real expert though.

[BoostedRooster712]

52 minutes ago, coombehouse said:

If you get any problems please message me & I'll try to help. Arttu is the real expert though.

Thank you for the offer. It's greatly appreciated.  Arttu has been a great help with the other bike. I better grab two trigger wheels off him, one for this as well.

[DAZ]

11 hours ago, colinworth79 said:

V720 is as you say a late oilcooled bandit 12 motor it differs from the earlier engine in that it had the pairs system fitted and the exhaust cam has slightly less lift and duration due to emissions but the rest is identical. 

10 hours ago, fatblokeonbandit said:

2006 was the last year of the oil cooled bandit motor, like Colin said, very similar, the frame was different and the wheel are from Gsxr, but motor the same…

 

 

Gents thank you for the clarification about that ,it was something that I'd been told, and like I said in my post wasn't 100% sure of so as I've said before,every day is an old skool day