RoadRace / canyon carver engine - GS1000's vs GS1100E - 70's Rickman CR chassis

[Chuck78]

So I was pretty dead set on building one of my spare gs750's into the baddest pump gas n/a 750 around still, 944cc Carillo pistons and rods, resleeved, head ported and oversize valves by rapid ray, Yoshimura Isle of man race cams .365" lift that I have.

Well upon getting a brand new unused $380 MAC GS650 exhaust off Craigslist for $65, the guy offers me ALL the rest of his GS parts for a mere $30, including a GS1100G engine and 2 racks of bs34 carbs...

this and questions of gs750 kickstart (electric start delete to save weight) potential interference with the Rickman rearsets tempted me to look into the more popular road race choice for a 70's aftermarket frame kit - a GS1000 with 1100G cylinders and 100G D-port head. The crank actually weighs 7lbs less than the GS750 crank, but I have to run the starter and gears and full size battery for street use then, but with a lithium LiFePO4 battery I can make the 1000 package with bigger cylinders and pistons weigh the same as the 750 or a pound or 3 less maybe. My Yoshi cams will go right in there on this 1000, too! Same with my GS1000 early Yoshimura Series 1 4-into-1 exhaust that was going to hang 10mm too low on the 750 based engine.

My buddy has a GS1000 engine with a bad trans that he'd sell me for cheap he says. A good trans on ebay is $45-110 + some luck. Another buddy cross country has a good GS1000 bottom that he'd ship to me for a modest price.

looking into it, I'm going to need to get the crank welded for this (& probably a FORTUNE in new crank bearings while it's apart), and back cut trans gears would also be good insurance, & may as well swap straight cut primary gear onto the crank as well. Could have it balanced and even lightened and knife edged while I was in there.. where do I draw the line for bottom end insurance?!?!



Then I came across a KILLER $1,000 o.b.o. deal on the following GS1100E parts that are severely tempting me:
V&H 1260 Big Bore Piston kit new ( $475.00 )
V&H Cam new part # 12042 74-74 HT ( $380 )
K&N air filter set ( $125 )
Falicon rebuilt and welded Crank ( $680 ) see pic for receipt ( plus crank value )
Gear set , under cut from Falicon
Welded Clutch basket ( $300 )
Full gaskets set and extra head gaskets ( $200 )
V&H Stud kit ( $80 )
Clutch and sprocket cover OEM
Stator assy, and misc item

I wasn't planning on going with the superior/more powerful 16 valve GS engine, but with $680 worth of crank work (on 15+ yr old pricing even) & back cut gears and some unknown grind cams, this sounded like a KILLER bargain even if I were to sell/trade the cams to get some MegaCycle cams and 1134cc/1170cc JE Pistons that would be more suited for my build.
I'd still need cases and several smaller bottom end parts, 82+ 1100 cylinders, and since I don't think the 1100E head fits the 70's Rickman road racer look aesthetically (& I don't like the look of it), I'd need to track down an 1150 head and top cover ($375+).

Yes this would be the baddest combo possible. BUT... The 1100E weighs close to 25lbs more than the GS1000 engine. We'll say 22lbs with the 1000 w/1100G cylinders figured in.
Weight savings is THE WHOLE REASON I jumped on this Rickman chassis project to begin with. I wanted something with a great frame and more weight savings potential than a stock framed GS, but still with classic styling. Weight is pretty imperitive...

so no matter what I build, Rapid Ray will be doing the head porting magic. They're all going to be fast. The 1085cc or 1100cc GS1000/1100G build will be extremely fast and still be fairly light and better handling. The 1100E will be THE ABSOLUTE MOST LETHALLY FASTEST but a few years newer than the most appropriate look for an early 70's British racing chassis look. The 1150 head looks a little closer to a Z1 head but still newer and more power than I need AND heavier...

Please give Opinions on best engine, with 70's authenticity, and weight in mind, as well as cost given my 1000/1100 parts here but crank/trans work needed, vs buying a while 1100 bottom and jugs plus 1150 head, but having the $$$$ bottom end crank and trans work if I jump on the 1000 obo parts lot.

thanks guys!

[bsharpish]

I'll be first - A long time ago (1986 i guess) I had an 8V 1000 with 1085 kit, lumpy cams and headwork running CR29"s

the thing pulled like a freight train and survived 2 years of serious abuse .... somehow every other big capacity Suzuki hasn't felt so right, simple over engineered and durable .... the only exception was my lightly breathed on Hayabusa which was just insane.

It may be rose tinted spectacles, however, I'd build that spec 8V 1000 again in a heartbeat

[GS1150Pilot]

Stay true to your original plan.

[Chuck78]

CRAP... the last option on the poll was supposed to say "1170cc GS1100E" but autocorrect changed 1170cc to a number slightly more familiar to it...

[Chuck78]

Two other things to add... I do have a full set (obsolete/NLA from Suzuki) of GS750 crank bearings already, but am 2 short on rod bearings if I use 2 when I do the 489cc GS425 crank. Also obsolete from Suzuki but occasionally NOS on ebay. Thrust washers I have found on a foreign bearings website.
The GS1000 crank bearings and maybe even aftermarket cranks will be available indefinitely... part of Suzuki's vintage parts program secures GS1000 parts availability.

Also, I'm trying to decipher my buddy's semi-encrypted email, but it sounds like he may be offering me a free GS1000 bottom end that he straps to a pallet, if I arrange shipping Oregon to Ohio.
Maybe I can convince him to build a makeshift crate and send it through greyhound bus lines???
I haven't heard back from my local bud about a price on the complete GS1000E engine with a bad transmission.

[Chuck78]

I may build the 944cc (or a 920cc Wiseco or JE Pistons custom order version that won't require resleeving) regardless, even if I do a GS1000. I have an older MTC piston version 920cc GS750 with a serdi valve job, but the Pistons are older technology and a bit heavier, they are only 10:1, I didn't bother checking deck height and having it milled to a zero deck, & I didn't have any porting work done to it or oversize valves.
That thing with stock 750 cams (pretty big duration like race cams but shorter lift) advanced to approximately 105 lobe centers is a terror on the streets, pulls unexpected 1st gear power wheelies now and then when the 150/70-18 Avon RoadRider would heat up enough to actually get traction! Going Pirelli Sport Demon or Bridgestone Battlax BT45V from now on... only Avon race tires, a RoadRider rear will only be ran for cross country travel.

[Nessism]

I'd put the 1100G top end on your 1000E bottom end and go ride (with the good cams of course). Mill the head to raise compression some. That's all the power that bike of yours needs. Cheap, simple, more than powerful enough, and reliable. Get the crank welded and use a HD clutch back plate.

[bobgroger]

Do you want Torque, or HP? I think the 2V has a much smoother power band, at least with stock cams. Think about your intended use and RPM range. If the RPM range is higher, think 16V. If coming out of a slow corner in 4th gear and cranking the throttle open, think BIG 2V. If you want ultimate cornering think weight. Kind of like Big Block vs. Small Block with Corvettes. BTW the 1000G\1100G clutch basket is interchangeable with the 1100E one, but not the 1150.

[GregT]

I'm going to be an unpopular dissenting view....Use a small port head on the 1085 8V motor.
I've built both the D port and several small port head motors around this capacity with various cams, both for roadracing and the street.
If you want response, you need port velocity. It's very hard IMO to get good midrange with the big port head unless capacity is right up there...
The roadrace GS1000 I look after has had both heads on, both with big valves. Both ported of course. Lap times were better with the small port head.

If Ray is doing the porting, talk to him before deciding.

[Chuck78]

I'll talk to Ray about small port vs big port. I figured if a stock heavy touring bike the 1074cc GS1100G came with large port d-port heads, that they would be optimized for mid range torque.
Looks like I may be best off to get the complete engine locally with bad trans even if crank was abused or worn, as I can get the head as well. IF it's a 79 or late 78 with the extra bolt on the front of the cam tunnel area for better sealing.

I certainly think that if using stock 1100G pistons (from a 66mm stroke 1100G engine into a 64.8mm 1000E engine) with the shorter stroke of the 1000 making only 1055cc, that the small port head would be the better choice by far. I could fly cut slightly deeper valve recesses and mill the 1000 head a bit with a locally done valve job or home valve lapping job for now if I wanted .354" lift mega cycle cams or the Yoshimura .365" lift cams that I have. Deck the 1000 head slightly & mill the block close to a zero deck with just a skim mulling of material left before zero for future teardowns (could always deck another .019 past zero deck and just run the thicker 1100G base gasket).

Still, Wiseco 1085's seem the ticket but I think really I should focus on building a bulletproof bottom end first, could do 1085cc & Rapid Ray ported 1000 OR 1100G head later on.
Milling the 1100G head to make up for shorter stroke would take a lot. Half of the 1.2mm stroke difference is .6mm. 1100G base gasket is .039", so using the .020 gs1000 base gasket is of help, but to get it zero decked with typical factory GS piston in hole spec, you still need to mill about .012" off of the block deck to get a zero deck for optimized quench and higher compression
As far as making up the rest of the equation with compression ratio, I would think you may need to mill at least .040" to .055" off of the 1100G head to make up for the difference in stroke to bump the compression ratio back up to stock, figuring in a zero deck vs factory piston down in hole spec. Taking that much off and still running stock pistons means no aftermarket cams as piston to valve clearance would be at a minimum.

This is why I was more in favor of Wiseco 1085 pistons, as I could zero deck block, run 1100G head gasket which is dead on at 73mm 1085cc bore spec so no compression lost due to bigger head gasket cylinder opening, mill head .020" or so, & end up with a mild performance compression ratio and modest lift on the cams, should be pretty durable.
VM33 or CR33 carbs. Maybe CR31 if I find a good deal.


Leaning towards building a 1000 with welded crank and 1085 pistons. Not sure on back cutting Trans gears. Swapping in straight cut primary gear on crank is supposedly only critical if over 130hp. Should be under that but while crank is apart maybe best bet since welding it...

[BadBillyB]

Don't forget to figure in connecting rod length in your math. The 4V 1100 motor not only had a longer stroke than the GS1000 2V, it also had longer rods. The 1100G crank may also have different length rods....I agree with GregT, port velocity is a key factor. If I was building a 1085 road bike, I would use the small port head and stock valves. 38/32 mm valves are plenty big......Billy

[Chuck78]

The 750 944cc is still tempting. The cam chain idler pulley jockey wheel setup on the top of the head makes the engine far superior for endurance races, as without it, Yoshimura kept causing extreme wear on cam chains the first season on the GS1000's causing them to break. Until they added a custom length cam chain and modified the 1000 heads to take the 750 idler pulley in the middle of the head...

944cc Carillo pistons and rods will be a fortune though, but that would be one badass engine with big valves and extensive rapid ray head porting...

Since I have the 1100G top and I may be able to get a gs1000 bottom from a buddy for as little as $100 (mostly shipping), I may go for both... still undecided!

I'm leaning away from the heavier GS1100E 1134cc now. As well as 1100cc Wiseco GS1000. I was told by a road racer that due to piston weight, the 1085cc pistons were the most competitive in road racing because they were lighter and gave better engine response than anything 1100-1200cc, & since most of the power at that point comes more from head porting and valve work, seems a good tradeoff. Bigger pistons also run hotter, more area to cool with the incoming a/f charge.

[Chuck78]

Don't forget to figure in connecting rod length in your math. The 4V 1100 motor not only had a longer stroke than the GS1000 2V, it also had longer rods. The 1100G crank may also have different length rods....I agree with GregT, port velocity is a key factor. If I was building a 1085 road bike, I would use the small port head and stock valves. 38/32 mm valves are plenty big......Billy

Thanks again for the reinforcement of that opinion, Billy. I would have thought that the 1100G port size would be more than adequate for mid range punch and port velocity if Suzuki designed it for a 1074cc touring bike. Even with a 1085cc 10.25:1 Wiseco kit, you think the 78-79 GS1000 smsll port head ported for CR33's (or would you do CR31's???) & maximum low lift flow would be better than a mild port job on the big port head?

[Chuck78]

Also, I forgot to mention... the 1100G does in fact have longer rods. I had read of a guy having some 1100 4v crank parts swapped onto an 1100G crank to get the longer stroke in a GS1000 engine, but he broke 2 cranks of that configuration. He said if he had it to do over again, he would consider using the 1000 crank but with the slightly longer 1100G rods. I wonder what changes this would bring in deck height? Perhaps this would allow sticking with the taller .039" thick GS1100G base gasket and oil passage o-rings, and not require any additional block decking? Or would this require custom pistons in a different compression height?

From my hot rod Chevy Camaro youth, I recall a 400-406ci small block Chevy build where they tested the stock 5.565" rods vs the popular upgrade swap 5.7" 350sbc rods vs a custom piston running modified Ford rods closer to 6" long. Despite a little extra weight, the longer rods made the most torque, & longer rods result in less cylinder wear and frictional losses due to more direct thrust (less angular force) and less piston-to-cylinder side loading force.

Longer stroke, however, increases piston speed drastically per revolution, more friction more wear less efficient. Bigger pistons in an air cooled engine are harder to cool however, & heavier piston weight is also detracting from the efficiency since each piston is basically just coasting 75% of the time due to the nature of a 4 stroke engine.

any tips/knowledge on the long rod setup or long rod length differences would be much appreciated. A call to rapid ray or John Pearson racing (crankshaft shop) would likely clear this up quickly, but we'll see what answers I get here first.

Thanks everyone.

[GregT]

Thanks again for the reinforcement of that opinion, Billy. I would have thought that the 1100G port size would be more than adequate for mid range punch and port velocity if Suzuki designed it for a 1074cc touring bike. Even with a 1085cc 10.25:1 Wiseco kit, you think the 78-79 GS1000 smsll port head ported for CR33's (or would you do CR31's???) & maximum low lift flow would be better than a mild port job on the big port head?

IMO for road use the 1100G head ports are too big. Starting from the small port head you have more meat to work with to get the shapes you need.
On a 1085 for road use... 31's. Your intended end use favours response. We've used 31's and 33's (CR's), and ideally would keep a set of each - the 31's for smaller circuits. The 33's only come into their own above about 8500rpm. Response and acceleration much better with 31's.