1100g d port head on 1000

[thebrandonbeezy]

Is it worth doing? The top is coming off anyways so i wanna ad a little bit of power.

[dorkburger]

Search up Chuck78. Very knowledgeable on this sort of thing.

[storm 64]

Also get a hold of "drey6" he was recently selling so "D Port heads.
You might give Chuck a couple of days to get back to you. Last I heard he was riding in Virginia/West Virginia. Out of all cellphone contact! 👍

[thebrandonbeezy]

I messaged him, didn't know he was out riding! Lucky him haha

[trippivot]

I did that - many times .. What you have to understand is port velocity . to make it pay off in noticeable horsepower gains you need more compression, larger pistons and mill head for starters. then bigger carbs , weld crank fix your clutch blah blah blah by that time you will wish someone would have told you the truth what you are really getting into.

Without going all the way to 1240 14-1 comp you are going to be slower. period.

a small port head with bigger intake valves is cheaper and really runs great. .425 cams shim under buckets --meow 1085 or 1105cc never felt so fast under a grand in parts and labor. - - fyi its going to still be slower than a 16 valve stocker.

[thebrandonbeezy]

The d port has a smaller combustion chamber than the 1000 head does so theres more compression.

[Big T]

Trippivot knows his stuff

The D port head will make your stock motor slower.

It will make your big bore, high compression, big cam and carb motor faster. Just spend the $3k and be really fast

[thebrandonbeezy]

I dont doubt him. But i have to ask, why. The 11g the head came off of made more power and had a much better midrange grunt. (I found more info after posting) when you say slower do you mean in bottom end and midrange and the power will come on way up top that its basically impractical for a 1000?

[John Kat]

I did this modification and I don't know if the power increased due to the extra capacity alone or not but you need to know that if you also go with the 1100 G cylinder block you will have to mill it quite a bit to get the pistons to be flush with the deck!
This is due to the fact that stroke on the 1100 is greater than on the 1000.
My main reason for doing it was to keep a maximum of metal following the rebore to 1085 cubic centimeters.
Here's the whole story:

https://www.thegsresources.com/_forum/showthread.php?228737-GS-1000-upgrade-to-GS-1100-G-cylinder-block-head&highlight=

[thebrandonbeezy]

From what im gathering, for the 1000 to effectively use the better ports it needs to rev?
Anyways, i wasnt meaning to sound like an ass in my previous posts. I just dont agree with it needing 14 to 1 and 1200+ cc to take advantage of the head.

[trippivot]

I started with why. Port velocity is why horsepower is lower. Little lung pulling a specific volume thru a larger port results in slower filling.

Torque and horsepower are 2 different building strategies.

64.8 stroke verses 66mm. Higher compression is a must but filling the cylinder quickly is how you get both.
My best engine broke cranks easily. Heck i sawed a set of cases in half at 115 mph and that was a mess.
I went 16 valve after i reached the dimential limits of the little hemi

[Chuck78]

If I don't tear down my 1100G engine in the next two days ( trying to clear out the garage to make way for more bikes and more work space!), my buddy is dropping off another one that I bought from him a while back after he disassembles the engine (he's moving, clearing out space as well!) by the weekend. I was not aware that the D Port heads had smaller combustion chambers, as they have both bigger bore and a longer stroke, both of which would require larger chambers -OR- smaller piston domes to keep the compression ratio in check. I'm curious about this, and will check when I get time. I am very busy though!

What was said is true, per our conversation, I gather that you are trying to put this on a stock bore 1000. The small port head is definitely better on a stock 1000 if running direct linkage carbs. The only place the big port head will do substantially better is a big bore engine with the right camshafts.
The D-port exhaust port heads are made to give more torque, but still, you'll need to compare your stock head (is this a 1000G you are talking about?) to the D-Port to compare intake port sizes. Try checking partsoutlaw.com parts riches for all models of 1000G and 1100G and 1100GK heads to see the superceededd part numbers. The early non-D-Port 82 1100G vs later 82 1100G & 83 D Port heads are likely very similar port and carb sizes, but is the 1000G that large??? Researching some very basic info about the factory engineers' decisions will help you a bit with this.

The bottom line is, I would not put a d-port head on anything less than a 1074cc stock engine (GS1100G), and its best for a Wiseco K1085 kit in 1000 cylinders or Wiseco K1100 kit in GS1100G cylinders with trimmed 1000 base gasket and somewhere between .025" & .038" milled off the 1100G cylinder block deck surface (1.2mm longer stroke, half of the stroke is going deeper at BDC, the other half of the strip difference is going higher at TDC, & the 1000 base gasket is only .020" vs the 1100G base gasket is at .040" thick). Then use a thin head gasket (.043" or thinner, to get a good squish band/quench height of around .039" - .049") to optimize the quench effect and promote better combustion and better detonation resistance while building a more powerful, efficient, and reliable engine.

The D Port head is really worth it with the above when you have bigger cams, much bigger than a 1000 or 750 8v cam profile.

Basically, for you, I'd keep the top end together as is until you have the opportunity to buy a 1085 kit for it. If you do big cams then, that would definitely warrant the extra expense of a D Port head. BUT the big issue is that you then really need to send your crank out to Stan Gardiner or Pearson Racing to have it welded, or else aggressive riding habits, racing, etc especially with sticky tires...will end up twisting your crankshaft in time!!!!

The welded 1100E/1150 crank engines are WITHOUT A DOUBT the best place to start if you are trying to go real fast...




I am personally hung up on the 77-79 GS's, looks-wise, and the fact that the 1000 8v chain drive engine weighs in at under 200lbs (193???) vs an 1100 TSCC 16V which is about 225lbs. This is the biggest reason I opted not to pursue an 1150 head on an 82+ 1100E/1150 bottom end, I'm a bit of a weight weenie as I get severe thrills from riding ultra twisty Appalachian hills & mountains roads, where a very well built GS550/650 with 740cc pistons will likely be faster in the long run than an 1100E/1150...
Ray is going to be re-sleeving a GS425 cylinder and porting it's head for me in my experiment to build a 335lb 489cc GS425 canyon carver/track day bike and possible future WERA Formula 500 racer... All in my quest for a fast bike for the twisty roads... (sorry for the off-topic rant)

[Nessism]

I thought the D port head has a larger combustion chamber, not smaller.

[Chuck78]

Brandon, it's a shame you aren't closer, as I'm trying to get rid of an 1100G bottom end minus stator/ignition covers and clutch parts... and my buddy has a complete D Port engine to get rid of as well. Too much to ship to Florida though... and for mine, I'd give it to you for free but you'd still need head and cylinders!!!!!


Figure out why you were bike has no power, it's probably an issue of compression, ignition advancer, carbs, something is wrong there....
Rebuild all of that first, and if it doesn't have compression and you have to tear off the top end, might as well bore it out!
Dave and I have some stock 1100G Pistons that will put a 1000 at something around 1055cc, if you are needing to bore your cylinders out. You could have a set of these for next to nothing, plus $200 @ machine shop and a new gasket set. You might get lucky and find that these piston rings are well within spec even.

I recommend this because I wouldn't be too afraid to cautiously ride a 1055cc with stock crank.... you just can't do any really hard lunches on one unless you don't care if you have to tear down your engine and put a new crank and head in it from street abuse...

Also, I can't recall exactly, but the 1000 8 valve definitely does not have any heavy duty backing plates available anymore for the clutch basket. The 1100 G does. But the 1000G may also use the 1100G/1100E clutch basket which is a better design and does have heavy duty backing plates available for it. This is going to be another source of trouble when building a very stout 8 valve Hemi.

1000/1100 8v performance build reliability downfalls:
***non-welded crank stock, good tires and hard launches will twist it!!!! (80-81/82[?] 1100E cranks, too, are not welded from factory!!!)
***1000 chain drive clutch baskets have no HD backing plate kits available, they will flex a lot under hard use
***1000 chain drives have weaker transmissions - the 3rd and 4th driven gear shift dogs in particular - they are ALWAYS very worn on every one I've torn apart or even looked at on ebay.
***a welded crank TSCC 1100 is going to be near bulletproof on thr street with a good clutch basket, and will make far more power if this is what you're after


Sorry to shoot down your dreams! Just trying to give you a good dose of reality before you find out the hard way and blow up an engine that you've dumped hard earned $$$$ into!

Figure out why yours is not as fast as it should have been stock, fix that, maybe take me or David up on the offer up some 1100G Pistons if you need to over bore your cylinders to 1055cc or so, or go for $460 in Wiseco 1085's.... but know that without a welded crank, you're a real serious gamblin' man! And you'll have to resist the hard launches!

Just trying to make sure you know the limitations of your build without a welded crank...
If you really ask nicely, if you could find out if and 1100 G crank fits in a 1000g crank case, I might be able to make a side trip when visiting family and drive another 35 minutes and drop off a free (+ gas money) 1100 G crank to Pearson Racing if you want to pay John to weld it. This won't be cheap, and neither will be the shipping it to send it to Florida!
Heck, you could even have these cases here for shipping plus a few bucks for my time packing it if you really liked this idea...

But still, you'll need 1100G cylinders at minimum!


As far as the crank twisting goes oh, I got a junkyard 1978 GS1000 engine that was basically totally stock, and wondered why it had a 1979 head on it... Until I tore it down and found that it had a welded crank... It also had a broken tooth on second gear in the transmission... a sign of very hard use!
I then came to the conclusion that the original owner wrote it very hard, and twisted the crank on a stock engine, and destroyed the cylinder head, which is why this 78 engine had a 79 cylinder head and a welded crank! Then the owner proceeded to blow up the transmission as well after putting the bulletproof welded crank in... from hard shifts 1st to 2nd...
These sorts of things really are making me think that if I ever clear out some of my hemi head GS 2v/cyl collection and build a Harris F1 frame or XR69 (Team Yoshimura GS1000R) Replica frame for the ULTIMATE GS-based vintage road racer, I will seek out a GS1150 engine or 1150 head for an 82-83 big end welded crank GS1100E engine....
Or I could spend 1/3 as much and build an 01-04 GSF1200 Bandit (an overbored but de-tuned air/oil cooled engine based on the early GSXR1100engines) with GS1200SS bodywork (same engine and similar bike but a retro throwback tribute styled after the XR69-GS1000R & the 1st GSXR1100 race bike). 100hp stock in severely de-tuned street form (but insane flat broad torque curve!) & VERY easy to squeeze 140hp out of, and the engine is still tough enough for A LOT more!
With my vintage desires and drive, the Harris F1 frame for a GS1100E engine will likely remain the long term goal for building the ULTIMATE big four cylinder vintage road racer that will have no major issues competing performance head to head with more modern sport bikes. I've already learned that a decent novice twisty road rider can definitely out-ride people on modern ninjas and ZRX's on twisty roads on a well prepared modified vintage GS...


Just food for thought...

Best of luck,

Chuck

[Buffalo Bill]

All very interesting. You talked me out of porting my 1100G engine.
I was already afraid the final drive splines would strip out if the engine made just 110HP.
I would like to get more top end power, right now I'm shifting at 7000. HP seems to plateau at 6000 RPM.
All stock intake and exhaust.