having some head work done to better HP?

[bear265]

i would like to here some feedback on this topic

[The CyberPoet]

While in theory you could increase the compression ratio by milling down the heads minorly, it's a very unusual mod to do because unlike water cooled engines, our heads don't normally ever warp (and thus there is no premade excuse to have the head milled, unlike the case with overheating a water-cooled system). Instead, what some riders choose to do is the much more common WiseCo brand bore-over kits (for the 750 and 1100 engines), which both increase compression and displacement, or a flat-out engine swap (replacing the stock 600 with a 750/1100/1200 engine).

Cheers
=-= The CyberPoet

[SweetLou]

How much extra HP are we talking about with the bore kit for a 1100?

[J. Kidd]

How about a mild port and polish job? Then possibly a shaving a bit for compression?

[The CyberPoet]

How much extra HP are we talking about with the bore kit for a 1100?

Not sure off the top of my head. Go visit www.wiseco.com for more info... Post the change in compression rates and the CC displacement and I should be able to rough-estimate a new number.

Cheers
=-= The CyberPoet

[Mojoe]

While in theory you could increase the compression ratio by milling down the heads minorly, it's a very unusual mod to do because unlike water cooled engines, our heads don't normally ever warp (and thus there is no premade excuse to have the head milled, unlike the case with overheating a water-cooled system). Instead, what some riders choose to do is the much more common WiseCo brand bore-over kits (for the 750 and 1100 engines), which both increase compression and displacement, or a flat-out engine swap (replacing the stock 600 with a 750/1100/1200 engine).

Cheers
=-= The CyberPoet

If you have enough clearance, you could try installing a different head gasket. The stock ones are usually thicker than some that are available. That will give you a little bit. If you go with a big bore kit, on a 600....I will guesstimate you will get a 20-25% increase in hp. If you have a 100hp, you will get maybe 120-125. But I am being generous. You might only get 15hp. The 1250 big bore kit for the 1100, with the head ported and polished, was told to me that I would get around 165hp. Stock was 136. Almost 30hp more. This is for the CND model...US is around 10% less hp stock. One thing you can always do is port/polish the head. I posted a link with an easy to follow "how to" a while back. I don't have it anymore cuz I don't need it, but I think md86 said he had it bookmarked. If you are handy with the tools and can follow instructions, you can give your bike a big boost by doing that.

I will tell you this....it can be expensive. I happened to luck onto a good deal, but I did plenty of research on the cost. Unless you can do the work yourself, expect at least $3-4k just to do the minimum you should do to take advantage of planing the head. The prices I was quoted were between $12-1500 just to have a big bore kit installed and the head ported and polished. Add in carbs (you will need bigger carbs), valve job (makes sense to at least touch them up), exhaust (stock won't cut it), upgrade the ignition.....it all adds up.

If the cost seems too much to do all that, the next best thing (or maybe even better) is to do like Cyber said and do a swap. Lou went from 600 I think, up to an 1100 engine. He will push more hp by doing that than you will get from adding a bigbore kit to a 600. But my real suggestion would be port and polish the head and forget about milling it. It is the easiest and most efficient way to gain a real power boost. Add a jet kit and a good exhaust to that and you will see some very noticeable hp.

Lou....the 1250 kit with the head ported and polished with 38mm carbs will give you roughly 165hp....so I was told. He also could have just been giving me a sales pitch. It might only be 155....I really can't say. If he was being straight...it's around 165.

[Mojoe]

How much extra HP are we talking about with the bore kit for a 1100?

Not sure off the top of my head. Go visit www.wiseco.com for more info... Post the change in compression rates and the CC displacement and I should be able to rough-estimate a new number.

Cheers
=-= The CyberPoet

you can do that? i am having a hard time imagining how accurate it can be. if you can add 10-15hp just by jetting, exhaust, ignition, and air-filers....without changing the compression/cc's, how can you get an accurate estimate? You would need at least a 10-15hp margin of error, which can translate into a big difference on a bike. I am not trying to nit-pick or anything, but I would think there would be too many variables to do that.

[The CyberPoet]

Post the change in compression rates and the CC displacement and I should be able to rough-estimate a new number.

you can do that? i am having a hard time imagining how accurate it can be. if you can add 10-15hp just by jetting, exhaust, ignition, and air-filers....without changing the compression/cc's, how can you get an accurate estimate? You would need at least a 10-15hp margin of error, which can translate into a big difference on a bike. I am not trying to nit-pick or anything, but I would think there would be too many variables to do that.

I said a rough-estimate (say within 10%). The heat efficiency is fairly well known, and there are enough sources of pre-printed before/after dyno runs to give me a reasonable ball-park check on what I think it will have based solely on the change.

PS - there is no bore kit for the 600's that I'm aware of.

Cheers
=-= The CyberPoet

[Mojoe]

Post the change in compression rates and the CC displacement and I should be able to rough-estimate a new number.

you can do that? i am having a hard time imagining how accurate it can be. if you can add 10-15hp just by jetting, exhaust, ignition, and air-filers....without changing the compression/cc's, how can you get an accurate estimate? You would need at least a 10-15hp margin of error, which can translate into a big difference on a bike. I am not trying to nit-pick or anything, but I would think there would be too many variables to do that.

I said a rough-estimate (say within 10%). The heat efficiency is fairly well known, and there are enough sources of pre-printed before/after dyno runs to give me a reasonable ball-park check on what I think it will have based solely on the change.

PS - there is no bore kit for the 600's that I'm aware of.

Cheers
=-= The CyberPoet

Like I said...not trying to nit-pick. In fact, I know nothing about calculating the estimated hp with all that. You could do a calculation and my only response would be, "if you say so".

[lucky6man]

well or you could always drop the gsxr engine in it. right lou?

[SweetLou]

well or you could always drop the gsxr engine in it. right lou?

As long as you got time and tools. I went from a 750 to the 1100, and man what a freaking difference, and I haven't even really got to play yet because it is still being broke in.

[Yellow]

What break-in theory did you go with, finally? A bit curious...

[SweetLou]

What break-in theory did you go with, finally? A bit curious...

We went with the Corey and Sweet Lou break-in method.

It involves riding it like you plan on riding it, not babying it. By no means did we beat on it either. For the first 20 miles, rode it it gently, kept it under 4.5 grand on the tach. At 20 miles brought it back to the hanger. Did a oil change and filter change. Refilled and went. Kept it under 6k on the tach. So far I have about 90 miles on the new engine. As soon as the new carbs come in, I plan on getting it fully broke in (600 miles) in one weekend. Then we will drop the engine, do a valve adjustment, go over everything, make sure everything is remaining tight, and put the body back on.

[Wild1_Robertson]

Lou....the 1250 kit with the head ported and polished with 38mm carbs will give you roughly 165hp....so I was told. He also could have just been giving me a sales pitch. It might only be 155....I really can't say. If he was being straight...it's around 165.

So there are 38 MM carbs that fit the 1100 in a kat?

my 2c i have bored/stroked quite a few car motors and if you do not also port/upgrade the head, add more cam and intake/exhaust flow all you will add is low end torque.
The bottom line is all most be in balance you can perhaps cover-up lack of port flow with more cam timing but then the ramp rates change for the opening closing events and this will limit rev limits unless upgrades are done to springs.... This is just general info as I do not know the volumetric efficiency of the heads.

Also I do not see aftermarket cams for the 91-92 1100? When I asked in other forum was told the valve train on the 91-92 1100 would not take more of a ramp rate, with out failure, they suggested using a 'busa 1300 head. Can anyone shed light on this?

[The CyberPoet]

...I plan on getting it fully broke in (600 miles) in one weekend. Then we will drop the engine, do a valve adjustment, go over everything, make sure everything is remaining tight, and put the body back on.

Are you saying that to do a valve adjustment on the 1100 engine when it's mounted in the Kat 600 frame, you have to drop the engine each time?

Curious
=-= The CyberPoet