GS Big Block

[blowerbike]

Want to bet?!! Ive DONE it! I had a 1400 daily driver in HAWAII, in traffic EVERY day, 182 @ the rear wheel at 9200 rpm & not 1 problem in 2 years. Ray.

what YOU do and how YOU operate the bike is 2 different things.
you know what happens when you do work for people.
they have you do the work because they have no idea of the workings of a high performance engine.
they will sit and idle in traffic or drink 3 cups of coffee with the choke on while the engine melts in the driveway.
been there......done that with customers.
this is why i hate silly questions...plus the cost of what your speaking will more than pay for a nice used hayabusa.
i get it but most people don't.

 

[blowerbike]

and mr. wu...
a 1200cc turbo engine will more then get the job done.
turbo's don't need to be bigcc's...just big enough.

 

[Guest]

and mr. wu...
a 1200cc turbo engine will more then get the job done.
turbo's don't need to be bigcc's...just big enough.

I figured as much....Gluttony on my end...ugh

Also really not interested in a Busa....I strive to be different

 

[Guest]

Once you get over 1260 / 1327cc you would need a cylinder head that cost more than the rest of the motorcycle, just to feed it.

The bigger motors require heads that have relocated and/or canted intake valves to try and get 33 mm valves in it. That is very high maintaince stuff.

I was glad when the busa came out so we didn't have to build that kind of stuff anymore.

Now it is just 1260/1327 with 29.5/24 heads for street bikes.

 

[yoshisakan]

If I wanted a hayabusa, i'd go buy a damn hayabusa. I have owned 3 GS's. I like these bikes. I want to build one to be as fast as would be safely streetable and not cost a fortune. Thanks for all the advice here. Ray, i'll give you a call tomorrow. My name is John.

 

[ozman]

If I wanted a hayabusa, i'd go buy a damn hayabusa. I have owned 3 GS's. I like these bikes. I want to build one to be as fast as would be safely streetable and not cost a fortune. Thanks for all the advice here. Ray, i'll give you a call tomorrow. My name is John.

somewhat of a contradiction is wanting to go big block, bulk horsepower and not wanting to spend a fortune
why not sleeve it out to near 1300cc and not have as many drama's with overheating
it will still be not be cheap to build a complete package properly so its reliable
sleeved or big block means cases bored crank welded straight cut gears on primary hd clutch bigger carbs bigger cams etc etc

ozman

 

[blowerbike]

a fortune it will be...
to be continued

oh,
and the hayabusa part of my comment is pointed towards the cost of a decent GS build.

 

[rapidray]

Once you get over 1260 / 1327cc you would need a cylinder head that cost more than the rest of the motorcycle, just to feed it.

The bigger motors require heads that have relocated and/or canted intake valves to try and get 33 mm valves in it. That is very high maintaince stuff.

I was glad when the busa came out so we didn't have to build that kind of stuff anymore.

Now it is just 1260/1327 with 29.5/24 heads for street bikes.

A 31/27 head will support over 250 HP on a 1500 cc motor so I disagree with the "unobtanium" headwork for big motors. Yes, Busa heads are a better platform for headwork but the GS heads are what we have been dealt & I do the best I can with the hand I have been dealt. Big GS street motors are a BLAST due to their torque advantage more than just about anything else. Hell, you want some REAL fun, a 1400cc GS, with STOCK head & cams, with correctly jetted 1150 carbs will smoke the back tire in 2nd gear roll ons!!! The torque from a motor like that WILL yank your arms straight! Until you have ridden a bike with a motor like that you just have NO idea! Ray.

 

[Nessism]

Just my opinion, but it strikes me as risky to dump big money into a high HP air cooled engine. Get stuck in traffic, pick up some crud in your jets, get an air leak in the carbs, etc, and the engine will cook from all the heat. There's a reason modern high performance bikes are water cooled.

 

[Guest]

I have to agree with Ray on this one I have had a 1327cc big block on the street here in Florida heat with no problems. It all depends on how you set it up. And I agree with Jay on the fact that a Nicely ported head is needed to bring out the full potential of the big block. I don't believe you n?ed to go with a big block to get the 180hp your looking for a Nicely ported 29.5/25 GS1150 head on a 1260cc motor will get you the HP your looking for. A 1425cc GS motor with a GS1150 Nicely ported head 29.5/24 valves will get over 200 HP on a street motor and over 220hp with higher compression. But anyway you do it it won't be cheep. Your looking at 2 grand just in the head if not more. Just the parts are going to be in the 4 grand range not counting any labor so be ready for the big bill but you will have something not many have and will surprise the crap out of most Busa's. on more thing if you don't do any chassis work all that HP will be wasted on wheel spin. Most of your power is made in the head so without some good head work you will be wasting a lot of piston displacement. You will get more power from a small cc motor with a Nicely ported head than a big motor with a stock head.

 

[Guest]

Just my opinion, but it strikes me as risky to dump big money into a high HP air cooled engine. Get stuck in traffic, pick up some crud in your jets, get an air leak in the carbs, etc, and the engine will cook from all the heat. There's a reason modern high performance bikes are water cooled.

A modern engine will need modifying also to get 180hp at the rear wheel also.
I am building or collecting parts for a 225hp N/A 1340cc Bandit and I could buy a brand new Busa for what I am spending on this bike but it will be a brand new bike also just an older style that will fool a lot of people. My build budget on this project will be in the 12 to 13 grand range with over half of that building the motor. Oh and did I mention that I do all my own work so there is no labor figured in on this build. I am using all new parts on the motor build except for the cases and head casting

 

[yoshisakan]

Would it be a better idea to turbo a smaller displacement motor? I have a t22 sitting on my desk at home collecting dust. No shaft play.

Maybe I could just slap some low compression pistons in my current block, change out the valve seals, weld a custom turbo mani and use some 1150 carbs? Thoughts? I think heat wise, it would probably generate a lot less at idle than a higher compression engine.

 

[kawfeedave]

A lot of good thoughts in this thread, but all this talk about 2013 type HP out of a motor with 1982 type tires and brakes seems a little short sighted. Maybe a lot short sighted.

For the price of building the motor/clutch/trans, you could buy any number of used bikes that will be close in power/performance. Anything with 150hp, that weighs 100lbs less with modern, wide rubber will eat a GS for lunch.

Add in the cost of upgrading the wheels/tires/brakes/suspension, and you have even more bikes to choose from with even more power to be had.

If you love the GS, then build it. Just be ready to eat 75% of the build cost for lunch if you choose to sell the bike, as we have seen many, many times in the past. If you do build it, post video of the beast, I would love to see it.

 

[rapidray]

Would it be a better idea to turbo a smaller displacement motor? I have a t22 sitting on my desk at home collecting dust. No shaft play.

Maybe I could just slap some low compression pistons in my current block, change out the valve seals, weld a custom turbo mani and use some 1150 carbs? Thoughts? I think heat wise, it would probably generate a lot less at idle than a higher compression engine.

A turbo IS the easiest way to make a lot of power if you don't know how to build cylinder heads. It will only build REAL heat when it's on boost so that is an advantage. You still have to do everything else you need to do to build either motor correctly. Studs top & bottom, crank work, trans work, cams, valve springs, cam chain, pump gears, pistons, big oil cooler, etc.... THEN the cost of the turbo setup is MORE than a good cylinder head for the big motor build. A 1200cc turbo will do 200-220 RWHP easy. Heat is an issue once you spool it up & plumbing the thing is an issue too. 6 to 1, half a dozen to another. EITHER motor is a BLAST!!! Ray.

 

[Guest]

I rode my 1327 for 3 years on the street... They do get warm. But like Ray said,Torque is a blast...If you want to see what it cost in 1990 dollars and see the dyno numbers, type in historical documents into the search button. It dynoed at 180 back then... And its still running in my drag bike. I had a off brand turbo that was a blast on the street. XS1100 with 20 lbs of boost with a shaft drive. At the track it ran 9.20's with bars and 125 octane fuel... Those were the days.
Curt

 

[Guest]

A lot of good thoughts in this thread, but all this talk about 2013 type HP out of a motor with 1982 type tires and brakes seems a little short sighted. Maybe a lot short sighted.

For the price of building the motor/clutch/trans, you could buy any number of used bikes that will be close in power/performance. Anything with 150hp, that weighs 100lbs less with modern, wide rubber will eat a GS for lunch.

Add in the cost of upgrading the wheels/tires/brakes/suspension, and you have even more bikes to choose from with even more power to be had.

If you love the GS, then build it. Just be ready to eat 75% of the build cost for lunch if you choose to sell the bike, as we have seen many, many times in the past. If you do build it, post video of the beast, I would love to see it.

For what it is worth I don't sell my bikes so resale value is of no concern to me. My 85 GS1150 I have owned it since 1990 with no plans on ever selling it. As far as far as power it has more than enough to eat any newer stock bike for lunch. With the cost of the bike I would say I have a little over 6 grand into it so not a ton of cash to be wasted . I wonder what a high 8. Second GS1150 street bike would sell for? I know not what I have into it.

 

[Guest]

I rode my 1327 for 3 years on the street... They do get warm. But like Ray said,Torque is a blast...If you want to see what it cost in 1990 dollars and see the dyno numbers, type in historical documents into the search button. It dynoed at 180 back then... And its still running in my drag bike. I had a off brand turbo that was a blast on the street. XS1100 with 20 lbs of boost with a shaft drive. At the track it ran 9.20's with bars and 125 octane fuel... Those were the days.
Curt

9.20's with sissy bars. Try high 8,s with no bar street tire bike now your talkin power. Sissy bars aren't all bad they have their place. Even I have a bar bike for bracket racing

 

[yoshisakan]

During the course of this conversation, I have researched many different bikes, suzuki m109r, vrod, vmax, triumph 3 etc. I'm sorry to say but all of these bikes leave a lot to be desired in the appearance department. I'd much rather invest in my GS and have a great looking bike. As a side note, i have a 1973 datsun 240z in my garage, it's another lifer. When you put money into these kinds of vehicles, its a given that you're going to lose your ass if you try to sell them.

The turbo is probably a bad idea from a tuning perspective. The last thing I want to do is mistakenly run it lean through the powerband and melt my pistons.

That being said, It seems like a naturally aspirated 1327cc's is where I want to be from a heat/reliability/practical standpoint. Ape makes a kit for $1850, includes pistons, gorilla block, cams, valve springs and arp studs. If I go a step further and do porting and oversized valves, that should put me at a reliable +50-60hp.

Biggest concerns are transmission and clutch. What are the requirements here? Carb wise, will 1150 carbs do the trick with the right combination of jets?

 

[rapidray]

Stock carbs will work but will limit the REAL power that will be available. For a 1327-1400 I would use RS40s or FCR41s. Stock carbs would choke the potential real HP. Ray.

 

[Guest]

That 9.20 was 25 years ago and it was a street bike. I put bars and good gas in for the track. I tried it without the bars and 3rd gear was a little scary!
Curt