Mk2 Bandit 1200 engine in mk2 GSX750F

[Maverik]

As the title states, I'm wanting to do the old b12 engine swap. I think I know everything I need to know at this point except for one thing.... Will the 750 downpipe fit?

Long story short, I paid more than I should have for the 750 having looked for years and seeing the prices they were listed at to be out of my budget. So I got one that's been off the road for a few years at what I thought was a good price. Only to find that no one really wants to buy them and the list prices aren't what they're selling for... so now I'm committed to keeping it a good long time.

What I really wanted was a Bandit and having been on a GS500 for many years, I was disappointed by the 600 which just didn't have the grunt I expected compared to the twin, and the 1200 was also out of my budget. Hence the 750... One thing led to another and now I'm looking at engines, but without breaking the bank. I bought a £25 end can that needs some TLC and I'm using parts from the GS to make a nice naked bike. I already had to replace one carb which was when I realised mk2 b12 carbs are identical so I guess that's what got me thinking about the engine.

If I definitely need different downpipes then I might as well stop looking at engines and look for donor bikes instead. So after countless googles searches, multiple visits to this forum and others and only really finding information relevant to the GSXR, I decided it was time to ask and hope someone still uses this forum that can help me.

[Upshotknothole]

Depends on the exhaust. Some headers are taller than others, some are designed for different oil pans. If you're talking about the stock exhaust, probably not. Stock is also going to be heavy and restrictive as well.

[Maverik]

1 minute ago, Upshotknothole said:

Depends on the exhaust. Some headers are taller than others, some are designed for different oil pans. If you're talking about the stock exhaust, probably not. Stock is also going to be heavy and restrictive as well.

Yes, as far I know it's the stock exhaust. I know the b12 engine will be taller. I've heard of people putting b12 headers on the gsx1100f engine and having to shave some of the fins on the bottom of the engine as the 1100 is designed for 4 to 2 exhausts. I wondered if this might be a possibility or if the 750 headers are simply too short for the taller engine.

I've no idea about weight but I did read that the b12 headers, despite being wider, are actually double skinned so there wouldn't necessarily be much difference in flow rate. I'd even toyed with the idea of cutting the downpipes and welding in extensions then wrapping them but that's probably a silly idea...

[Maverik]

Just now, Maverik said:

Yes, as far I know it's the stock exhaust. I know the b12 engine will be taller. I've heard of people putting b12 headers on the gsx1100f engine and having to shave some of the fins on the bottom of the engine as the 1100 is designed for 4 to 2 exhausts. I wondered if this might be a possibility or if the 750 headers are simply too short for the taller engine.

I've no idea about weight but I did read that the b12 headers, despite being wider, are actually double skinned so there wouldn't necessarily be much difference in flow rate. I'd even toyed with the idea of cutting the downpipes and welding in extensions then wrapping them but that's probably a silly idea...

I say stock, it's just the downpipe. I have a different link pipe and silencer.

[wraith]

The standard gsx750f down pipes will be to short for the b12 engine. 

The gsxr1100 (1127) the gsx1100f and b12 can all swap down pipes but you may need to swap the sump, oil strainer and return pipes, as some are 4-2 and some are 4-1 

[Maverik]

1 minute ago, wraith said:

The standard gsx750f down pipes will be to short for the b12 engine. 

The gsxr1100 (1127) the gsx1100f and b12 can all swap down pipes but you may need to swap the sump, oil strainer and return pipes, as some are 4-2 and some are 4-1 

That's that then. Gonna need b12 down pipes or get creative with a welder and cut and splice what I already have lol. I want to keep as much of the 750 engine intact for selling purposes. I've seen the 750 engines for similar prices as the b12 so if I can cover most of the expense with little outlay, winner.

[Upshotknothole]

As Wraith just said, the 750 header is going to be too short, the stock headers are pretty tight to the oil pans. Some aftermarket 750 headers will fit 1100s and 1200s, but probably easiest and cheapest to just look for a used bandit system.