1168 vs 1198 big bore?

[imago]

I need to have a cracked liner replaced on the ET, so it seems a logical point to go for a big bore. The options are 1168 Wiseco with one replacement liner and bore the lot, or 1198 MTC pistons with all four liners replaced. It's only going to be a road bike, so head work won't be more than improving the flow. Not sure about cams and carbs, but lets just assume standard for now.

Aside from the obvious, is there anything to tell between the two overbores for road use? Is the larger kit going to throw up overheating issues for example?

I've ridden an ET with an 1170 big bore on it which wasn't massively different from a stock ET, just had more grunt and a bit more wind on from lower rpm. That's fine as an improvement for what I want but I'm wondering if there's much benefit in changing three additional liners?

[Duckndive]

If you get hold of an EFE block you could go 1230cc 

you would need to do some minor grinding to the top crankcase for the thicker liners ..

[imago]

I'd like to keep it looking standard from the outside really. It's more a case of if I have to spend the money I might as well get a little extra, rather than wanting a big increase in power. 

[buff]

Depends how much money you want to throw at it doesn't it,  whats the price of liners nowadays. 1170 with one replacement liner and you'd have money to sort out any clutch issues or maybe a cam re grind.

[imago]

2 hours ago, buff said:

Depends how much money you want to throw at it doesn't it,  whats the price of liners nowadays. 1170 with one replacement liner and you'd have money to sort out any clutch issues or maybe a cam re grind.

It's not so much a question of money (I don't mean blank cheque territory!) I have no idea what an additional three liners would cost. It's more a case of  while it's in bits and going to cost a fair bit to sort is it worth spending the extra?

At the moment I'm leaning towards the Wiseco 1170 kit as it's tried and tested, and also easy to get a complete kit off the shelf.

[buff]

I went from 1170, to 1260 and wished I'd never bothered to be honest. Just my experience.

[imago]

15 minutes ago, buff said:

I went from 1170, to 1260 and wished I'd never bothered to be honest. Just my experience.

That's the sort of thing I'm after.  

Just asking around generally, most people seem to be of the opinion that going bigger than the 1170 is only worth it if you're going to forced induction.

[R1guy]

41 minutes ago, buff said:

I went from 1170, to 1260 and wished I'd never bothered to be honest. Just my experience.

Interested to hear the reasons behind this...?

[wraith]

Not the same but is  gs1000 run better with the 1085 kit than the 1100 kit unless you have work done to the head.

[buff]

43 minutes ago, R1guy said:

Interested to hear the reasons behind this...?

Cooler running, power cutting in was smoother. The extra expense didn't give me a better engine. Throw that into a harris frame and no room to fit a lock up clutch, no fun.

[imago]

24 minutes ago, wraith said:

Not the same but is  gs1000 run better with the 1085 kit than the 1100 kit unless you have work done to the head.

Yeah, most people I've spoken to say the same. Above 1170 is pointless without all the other stuff, head work, bigger valves, cams to suit etc. I'm not going that far with this, so it'll be an 1168 kit with the ports tidied and valves lapped.  

[Reinhoud]

15 hours ago, imago said:

I'd like to keep it looking standard from the outside really. It's more a case of if I have to spend the money I might as well get a little extra, rather than wanting a big increase in power. 

I've got a 1245cc on my GS1000, you don't see anything different from the outside.

The big bore makes it an incredible smooth engine with lots of torque from low revs, I can ride mine at around 2000 rpm without any problems.

[Reinhoud]

12 hours ago, imago said:

It's not so much a question of money (I don't mean blank cheque territory!) I have no idea what an additional three liners would cost. It's more a case of  while it's in bits and going to cost a fair bit to sort is it worth spending the extra?

At the moment I'm leaning towards the Wiseco 1170 kit as it's tried and tested, and also easy to get a complete kit off the shelf.

http://dynoman.net/bikepages/gs1100/index.html

[Reinhoud]

12 hours ago, buff said:

I went from 1170, to 1260 and wished I'd never bothered to be honest. Just my experience.

Did you get a higher CR? Hard to imagine you don't like it.. Or did you had different expectations?

[imago]

28 minutes ago, Reinhoud said:

http://dynoman.net/bikepages/gs1100/index.html

That's a useful link, thanks. 

It'd be very easy to get carried away ordering stuff from there though. 

[buff]

1 hour ago, Reinhoud said:

Did you get a higher CR? Hard to imagine you don't like it.. Or did you had different expectations?

No I just preferred on hindsight the lower tune. Going to 1260 with billet basket and straight cuts/branch crank / efe head etc was a big outlay and didn't give me anything back really other than stretched chains, great if you wanted to add nitrous and go racing. But over kill to me for a road bike. I blame being an impressionable 18 year old and superbike magazine

[kat1127]

interesting info here, as im about to build an engine for my kat

[Ibbo]

Curious this. I did a fair bit of work on my efe in the late 80s. 1260, flowed, megacycle cams, flatslides, v&h exhaust. When i decided to sell it I put the std carbs back on, and pulled the cams out, and it was way nicer to ride, so I kept it another year. 

loads more midrange. still had some top end, but not as much. Never needed to go there though.

Dont think i would put cams in again. Certainly i cant put flatslides on. Too hard to keep open.

[Reinhoud]

On 6/21/2020 at 8:14 PM, buff said:

No I just preferred on hindsight the lower tune. Going to 1260 with billet basket and straight cuts/branch crank / efe head etc was a big outlay and didn't give me anything back really other than stretched chains, great if you wanted to add nitrous and go racing. But over kill to me for a road bike. I blame being an impressionable 18 year old and superbike magazine

With a big bore you don't need a billet clutch basket and all that stuff.

Personally I prefer an engine with a strong mid range, big bores are good for doing that..

[Bubba1135]

Run a 1230 kit with dialed in stock cams & 36mm gsxr carbs in my efe, definitely gives more torque.

[Blower1]

I´ve 1296cc in my EFE with original carbs, SPS JR3 cams and Delkevic Bandit downpipes & free flow muffler. Nice torque from idle to redline, 144rwHP / 136rwNm.

[imago]

I think people often misunderstand what performance/race cams are for to be honest. A standard cam is set up by the manufacturers to be the best compromise across the rev/rotation range. A performance cam increases what's available within a particular band because that's where it will be spending most of its time. If you add something at one point, you will lose it at another. So the 'best' cams for road use are the standard ones that the manufacturer used their considerable resources developing.

Increasing the engine's capacity (up to a point) with the standard cams fitted will increase the available torque and power across the range.

I have no intention of riding the bike anywhere other than on the road, so standard cams make the most sense for me.

[buff]

19 hours ago, Reinhoud said:

With a big bore you don't need a billet clutch basket and all that stuff.

Personally I prefer an engine with a strong mid range, big bores are good for doing that..

I was originally going to turbo the engine before it went into the harris frame, hence the straight cuts and billet basket

[Gixer1460]

Nothing wrong with a strong bottom end - ooooh er matron!

If you can afford to do the work - it's likely to never need to be touched again whatever tune / setup is thrown at it.