Shopping list for modifying my gsx1100 engine

[gorbys]

I'm putting a gsx1100 engine in my gs750, but it's a little rough and needs new valve steam seals at the very least before swapping it.  I'm new to modifying these engines(only ever dabbled with turboed cars before) so I'm not sure what/where I can go. 
Any tips on what works and especially where to get stuff is much appreciated. Preferably in the EU but worldwide works too.

What I know is; the engine is a silver/grey 1100. It's stamped 107x cc(couldn't quite make out the last number through all the dirt). I'm thinking I want to soup it up a little, perhaps overbore it, slightly hotter cam etc... But I don't wanna go so crazy it's gonna affect driveability and reliability. So what are my options?

I have access to 95ron fuel in my hometown, 98 in the next town over(30min drive). My turbo datsun needs 98 so I'm not that worried about having to make fuel runs...

So what comp rate works? is this a good plan: Suzuki GSX1100 1168 cc 10,25:1 comp

I was planning on an efi conversion but I'm not gonna afford that this season but I have the trigger kit and might get a speeduino ecu to drive the ignition until I can afford the TB's and the rest of the efi system.

Where to get camshafts and what would be a good cam to go with for street? I've heard about the G3 grind being good found these web cams on suzuki performance spares

Quote

webcam stage 1
340 lift, 240 duration @ 50 thou

webcam G3 SPEC 

0,345 254@50 G3 SPEC

 

Same with valves, bigger ones? I've read you can go up to 28.5-24 mm with stock seats. 

Exhaust is gonna be a marvin 4-1

I think that covers it....

[Reinhoud]

What sort of Marvin exhaust do you have? The Marvin I know isn't exactly high performance..

I would go for a stage 2 cam, may be higher CR and bigger displacement. Mikuni RS carburfuckingettors are a nice additive, my experience not more power, but an incredible throttle response..

Porting the head can give a nice result too. Not more power per se, but a nice flat torque curve is quite a win too.

Keep your exhaust short, stop it before the rear axle, the shorter the exhaust, the lower the amount of revs your powerband starts, not more power, but you move it through the rev range.

Edited February 25, 2021 by Reinhoud

[Reinhoud]

Ca you post a photo of your Marving? I'm getting curious..

[Joseph]

I must say i have been experiencing with RS carbs for the first time on the bike i just finished, and i agree, they are great i' use.

Didn't know about the shorter exhaust line effect, thats interesting. Is it really noticeable ?

[Reinhoud]

Regarding valves/seats.

In the past I had the bores of the seats increased, this made a bit of difference, not a lot, but the bike didn't had to work as hard to get it going.

I was told that bigger valves increase the flow around the valves when they're open. I'm not sure if this is true, hopefully somone else can give a proper answer to this.

[Reinhoud]

14 minutes ago, Joseph said:

I must say i have been experiencing with RS carbs for the first time on the bike i just finished, and i agree, they are great i' use.

Didn't know about the shorter exhaust line effect, thats interesting. Is it really noticeable ?

Yes! BUT!! it depends a little bit on the sort of engine how much you notice the difference.

You won't get more power, you just change the rev range.

When you have a 500cc 1 cylinder, 10/15cm difference is well noticable. When I took 60cm of the exhaust of my Range rover I moved the start of the powerband from 3500rpm to 2500rpm.

I'm pretty sure when you take 20cm of a 4 cyl bike engine you lower the rev range with about 1000rpm.

 

Experiment with it. Also, with stuff like this, give the engine time to break in with this, don't take it up and down the street once, take it for a longer ride.

Exhausts are weird things. I had a Merc 5 liter V8 with a DIY exhaust, not very loud, but if you stood next to it or 50 meters away, it sounded the same.

For my DR500 I made trumpet exhaust, gained quite a bit of power, pretty loud when you were standing next to it, when the bike was at the end of the block you would hardly hear it..

 

Edited February 25, 2021 by Reinhoud

[gorbys]

59 minutes ago, Reinhoud said:

Ca you post a photo of your Marving? I'm getting curious..

I haven't bought it yet. But my current Harris 4-1 is to low so I'm getting the flat type collector for ground clearance 

https://images.app.goo.gl/snHwr3VDChDqc3wX8

[Joseph]

Thanks for the examples @Reinhoud

I have that Marving exhaust on my katana because with the Srad fork it lowered it alot. Works great for clearance

Bear in mind the quality of the chrome whether white or black is really shit. I had mine dechromed and ceramic coated after just one year

[Reinhoud]

25 minutes ago, gorbys said:

I haven't bought it yet. But my current Harris 4-1 is to low so I'm getting the flat type collector for ground clearance 

https://images.app.goo.gl/snHwr3VDChDqc3wX8

That's the one I have laying arond, they sound alright, but they're NOT high performance..

[Reinhoud]

Just now, Joseph said:

Thanks for the examples @Reinhoud

I have that Marving exhaust on my katana because with the Srad fork it lowered it alot. Works great for clearance

Bear in mind the quality of the chrome whether white or black is really shit. I had mine dechromed and ceramic coated after just one year

I'm reasonably impressed with the quality, the sound alright, I think the chrome and the whole of the exhaust is alright, just don't expect any power gains from it.

No clue what the performance is in regard with a stock exhaust.

 

I was told that the flat collector is the problem, may be someone here can tell me/us if that's indeed a/the problem with this sort of exhaust..

 

[Reinhoud]

That's the Marving I have..

[Reinhoud]

If you're serious with gainig power, the exhaust is pretty important.

Look around and gather information before you buy anything.

I made a bigger diameter muffler inside my Marving, that made a bit of difference, but still nothing to brag about

[Reinhoud]

This exhaust  (Marshall) was very good! Bike ran like lightning and sounded very nice!

I was young and hadn't heard of ceramic coating yet, also wasn't to educated how to fix small holes in thins steel... If only I knew then what I know now..

[gorbys]

That's similar to the Harris 4-1 I have already which is seriously banged up and flattened underneath because it bottoms out. And that was on a stock bike. It's much lower now with the sv1000 forks so any staggered 4-1 collector is gonna bottom out and might send me flying off the road, not a risk I'm willing to take. 

[Isleoman]

 

What's your budget? Are you doing the work? Parts estimate...  pistons $550, cams $600, clutch $350, ignition $400, pipe $500, rockers $250, valve job with big valves $750, porting $500, gaskets $225, carbs $550, misc $250.

http://www.aperaceparts.com/cylinderheads.html

 

 

 

 

 

[gorbys]

14 hours ago, Isleoman said:

What's your budget? Are you doing the work? Parts estimate...  pistons $550, cams $600, clutch $350, ignition $400, pipe $500, rockers $250, valve job with big valves $750, porting $500, gaskets $225, carbs $550, misc $250.

http://www.aperaceparts.com/cylinderheads.html

Tbh i hadn't set a limit as I didn't know what all of this would cost. But the more I'm looking into it the more I realise I might not have it in this years budget all the stuff I wanna do...  So I might have to settle with just replacing the valve seals and refreshing gaskets and be content with a working stock engine for now. It's still 30hp over the standard 750 so I guess it ain't too bad. 

[baldrick]

ive got a marving exhaust on one of my efes, its black chrome with a gold can, looks ok and better for ground clearance