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Big Block Engine On The Street?

  • Thread starter Thread starter Fate
  • Start date Start date
F

Fate

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Just wondering if anyone on here has a big block GS and rides it on the street. I'm talking 1400+ccs. I'm looking to rebuild the engine this winter and upgrade to somewhere around 1500ccs, 40 or 42mm carbs, full dyna programmable ignition(already have dyna coils), new clutch, air shifter, etc etc.

I'm figuring since this is more of a street bike then an all out drag bike I'd keep compression in the 10.5:1-11.5:1 range.

What do you guys think?
 
Fate said:
Just wondering if anyone on here has a big block GS and rides it on the street. I'm talking 1400+ccs. I'm looking to rebuild the engine this winter and upgrade to somewhere around 1500ccs, 40 or 42mm carbs, full dyna programmable ignition(already have dyna coils), new clutch, air shifter, etc etc.

I'm figuring since this is more of a street bike then an all out drag bike I'd keep compression in the 10.5:1-11.5:1 range.

What do you guys think?
Click to expand...

I understand that there are a couple of guys on this site who do it and I know one guy here in Beaumont who rides a GS1150 with an GS1100 motor and APE 1500cc block. If you do a lot of in city riding, I would be very cautious because there are no cooling passages between the liners on the big blocks. All that said, it appears to be something that can be done, just be cautious of overheating.

Hap
 
Yea I knew about the cooling issues. I do some city driving but its usually at night for the cruize nights. If I'm not cruising its sitting at the parkin lot @ my work.

Would there be anyway to help cool the engine at all besides an oil cooler?
 
Polishing the combustion chamber and the exhaust ports will help keep the heat down.

It's not much, but every little bit helps.
 
Fate said:
Yea I knew about the cooling issues. I do some city driving but its usually at night for the cruize nights. If I'm not cruising its sitting at the parkin lot @ my work.

Would there be anyway to help cool the engine at all besides an oil cooler?
Click to expand...


I had a problem with cruise night on my 1100 and all it has is a 1166 kit. The stop-and-go-and-sit situation caused problems with the valve seals thus I started to burn oil (just ask some of the Texas Hill Country Crew:oops:) but the rings seemed to be fine.

An oil cooler is a must in this situation and Tim's suggestion is good also.

Hap
 
Thermal coatings!!! They're not as expensive as you may think. I would put them on the combustion chambers, exhaust ports, and exhaust valves... and leave it off of the pistons... but use an antifriction coating on the skirts. In this case you probably want the pistons to absorb some ehat so as to keep it away from the block... if you can install piston oil squirters it would help even more. Oh, and shorter duration cams and less compression help too... at the expense of horse power.
 
I wouldn't go with anything this big for a GS street bike. There are so many reasons not to and I can't come up with even one good reason why you would.

So, maybe start with why you want to consider doing this?

Why not just buy a used Busa or GSXR? They would out drive, out power and be more reliable than the old GS. Unless someone is offering free parts, I bet the cost to build a new motor for the GS is about what you could pick up a used Busa for.
 
When I lived in Hawaii I had an 82 GS1100 with an APE block & 1400 cc 10.5 to 1 Wiseco pistons. I rode the bike on the street every day in stop & go traffic & never had trouble at all. The only issue was it cranking slow when it was hot during a re-start. I cured that by wiring the starter button hot so I could crank the motor & get it spinning with the ignition off. I would spin the motor for a second or 2 & then turn the key on & it would fire right up. This motor had stock 82 cams, 1150 carbs, & ran 10.0s at 130 all the time. If I were you I would at least put a GSXR oil cooler on it. I think for the situation you say you are going to use it for I wouldn't hesitate to build it. Ray.,
 
We do a surprising lot of those big block street setups. We advise people about overheating if they are struck in traffic, etc. With the real big motors, you don't need compression to make them move. keep it down to 10 - 10.5:1. There is no sub for cubic inches.

Jay
 
See thats the thing, I love my older bikes. I just want the guys with the newer bikes to be like WTF when I pass them.

I know I'm not going to be able to hang with turbo bikes and the like but I'd like to be able to run 9.5s-10.0s all day.

Also, would a little shot of the giggle gas be bad?
 
Well from everything I've collected this is the plan for this winter.


Rebuild with APE 1500 big block kit, put some street/strip cams, have everything coated, install oil cooler w/ fan(my preference), air shifter w/ new clutch, some gauges, head work, and hang on.
 
Fate said:
...... I love my older bikes. I just want the guys with the newer bikes to be like WTF when I pass them.

I know I'm not going to be able to hang with turbo bikes and the like but I'd like to be able to run 9.5s-10.0s all day.
Click to expand...

There was a guy on here that said he was running in the 9's with a stock GS. I have never seen a GS run this quick, nor did I ever see anything that backed up his claims. I have had my GS into the 11's once from what I remember, but I am pretty big.

Ryan really is running mid 9's with his bike. You may benifit from looking at his site just to see all the mods it took to put this together.

You don't metion the clutch, crank or transmission. Make sure you know what your getting into before you open your wallet. Hate to see you end up like that last poor sole who after he sent his crank to APE to be welded, then realized it was not such a good thing to do afterall. Do a search on this site. Your not doing/asking anything new.

Or, get a Busa and cover it with your GS body parts... Instant low 10's GS. Your friends wouldn't be able to tell the difference when you blow by them...
 
I would go 1400 cc instead of 1500 as you will have thicker sleeves & more aluminum left in the block for cooling. I also wouldn't bore 1100 cases that large as it doesn't leave much metal around the cylinder studs. Also, nitrous will help BUT you need to be set up for it: ability to retard timing on a whim for use is DEADLY important to keep from melting pistons! I read in your first post that you want to build this over a 2 or 3 year period & that kind of a schedule will be a good guide to use so you have a realistic completion time frame. Remember, to do this CORRECTLY using QUALITY parts will end up running you $6000.00 to $8000.00! You will need to have a crank prepped correctly with a straight cut gear set, billet clutch hub with matching crank gear, trans prep with heavy duty bearings, cylinder studs, case studs, oil pump, oil pump gears, cam chain, cam sprockets, cams, valves, valve springs, valve seals, valve retainers, valve job, porting, pistons & rings, nitrous wrist pins, block, carbs, ignition, wheels, brakes, & suspension to handle this engine... do you see what this involves to do it correctly? If you can afford it I say "GO for it!!" Ray.
 
Contrary to the above post, a motor that big should have the crank welded.

Jay
 
Big Jay said:
Contrary to the above post, a motor that big should have the crank welded.

Jay
Click to expand...


Jay, you're very correct that the crank needs to be welded if you build a large displacement motor, and I'm fairly sure that lecroy agrees with you but I believe he was was talking about the guy who did not expect the price tag from Falicon when he sent the crank in for rehab - sticker shock caught him in the nads. The guy was starting to question if it was worth all the money to build a mega motor for a GS if my memory serves me right.

Hap
 
I never stated that the crank should not be welded. What I was referring too was the poor fellow who had sent his crank to your company, APE, to have welded and when he received it, it was not true. He would have been much further ahead had he spent the money and sent it to a crank builder.

I think Ray is in the ballpark with his numbers. Figure..
Head: $1500 - $3000 (port, valves, springs, rockers? )
Crank: $1000 - $1400 (all new bearings, maybe rods, full weld...)
Transmission: $500 - $1100
Block & pistons: $1200 (nothing special, no gas port etc)
Prep cases: $100
Clutch: $1200 (lockup, billet basket, SC gear....)
Cams: $300
Oil pickup and new pump: $150
Case and head stud kits: $300

You can buy bigger pistons and slap them onto a 20+ year old stock motor, but don't expect things to live. You can also send your crank to APE to be welded, just don't expect them to do anything but weld it for $100.

Once you start talking this much cash, may as well get a new bike...
 
Last edited:
Contrary to the above post, a motor that big should have the crank welded.

Jay
 
If you want to know, ask a pro. Jay is the ultimate pro. His company has built more of these motors than most any of us has ever seen
 
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