GS400/500 Gr650 Hybrid engine

[Rensdw]

Here is a little sneak peak of what I am doing to the frame:



The rear wheel is just for measurements, it will be a spoked wheel.






Frame will be stiffened and braced by a professional frame builder, and I have a special idea for the swingarm

[Rensdw]

Anybody still following this?

I got most of my stuff back in the Netherlands now, the cilinder head will be here the 30th with the second shipment.
Dropped the frame at the frame builder together with the crankcases, apperantly the GS400 block DOES NOT fit in the GS450 frame at all.
Only the mount at the back of the engine will fit, the lower mount that is, all the others will need welding to the frame or some kind of brackets.
Not a big deal at all but I did not suspect it to be this bad :P

After plenty of research I bought a Kipplewhite/APE valvetrain and guides, all the stuff came in, and I had to pay a ****load of import duties
I made some measurements today and it is (most likely) going to fit!

Valve Springs




Buckets



The shimholders and retainers WILL work with the stock OEM GR650 valves as you can see in this picture:





And here you can see the difference between the buckets, the KPMI buckets are slightly thinner walled I have the feeling the buckets are slightly lighter.



The APE valve guides will definitely work too, only real difference is they will stick out less on the exhaust side, but thats a good thing I Guess



Here a table with all the general dimensions:



So looking at all the dimensions And by just looking and examining them they are going to work in the GR650 cilinder head.
Now I have to decide what to do with the camshafts, to make this GR650 head a revvy beast!
The camshaft have plenty of lift already, just don't know about the rest of the parameters yet.

Hope this information will help someone doing a head swap.

[Bizzel]

Thanks

The idea is that this is the first bike I ever had, I did about 15K miles in 5 months on it in the UK during an internship, countless hours of fun.
Riding the bike for EVERY SINGLE DAY never got old, I had some serious near-death moments and moments of laughter.

I remember this one time I had to go out of bed early, (the morning is not my best moment of the day, (amnesia)), and I came up to the very first corner and did just plain forgot to steer.
So there I am; 6AM in the morning, somewhere on the side of an idyllic English country road, trying to get myself out of the bushes, woken up by an OD dose of adrenaline.
I got on my bike again and drove off thinking; **** **** **** that was stupid! g*d*mn*t! but that quickly turned into having to stop because I laughed so hard thinking about myself laying there in the bushes all by myself.


I will try to never sell this bike, and I will put some serious money in this bike to make it like I want it.
It will also act as an showcase, I would like to build some bikes for customers when i'm done.

Pffhaha lekker bezig Rensie. Interessant topic maar ik snap niet alles, ik zal eens op mijn gemakt wat lezen.

[Rensdw]

Pffhaha lekker bezig Rensie. Interessant topic maar ik snap niet alles, ik zal eens op mijn gemakt wat lezen.

Hi Bizzel, do I know you? :P

[Chuck78]

Rens, this is looking fantastic!

What forks and rear shocks do you plan on using? I've got nothing but great things gs to say about YSS shocks in the $500-870 USD range, best bargains...

For GS wire spoke hubs, Honda 296mm late model rotors in the 6 bolt pattern 78mm PCD (bolt circle diameter) with 17mm to 23mm offset work awesome, and work with many cbr's, cb400sfsuper four's (great forks & rotors), cbr900rr's, VFR750 94-97 (slightly taller than the others, can run clipons above the upper triples with them no problem, & run 2 piston sliding calipers, do much easier clearance to wire spoke wheels, full on cartridge forks).
I'm running vtr1000f superhawk/Firestorm forks on my next build, taller like big 4cyl gs lengths, calipers almost touch spokes, had to run 01-02 gsxr1000 6 piston calipers to get a little more clearance to the spokes...

Great build, I gotta check this thing out if you ever bring it to the USA!

I'm still planning on the 475cc+ GS425 racer build at some point in the next year, got the bike, DID alloy rim 18"GS wheels, spare engine, etc already. Rickman frame build detoured me a bit, & trying to sell my old house to finance the fancy engine builds...

[Bizzel]

Hi Bizzel, do I know you? :P

Well I was drooling all over your Duc last sunday so I would imagine so

[Chuck78]

Maybe I should have planned on using a GS450 bottom end & 500 cylinders & GR650 head! Those pistons are AWESOME! How much did they run for a pair of 2???

[Big Rich]

This is shaping up to be a great project Ren. Very surprised to hear about the bottom ends between the 400 & 450 being different though.

[Rensdw]

Well I was drooling all over your Duc last sunday so I would imagine so

Aaaah, that guy! haha

Maybe I should have planned on using a GS450 bottom end & 500 cylinders & GR650 head! Those pistons are AWESOME! How much did they run for a pair of 2???

Chuck78, I don't recall exactly, I would say somewhere between 6-800 bucks, maybe cheaper now since the design is already there.
Thanks for your compliment BTW

I already have the front forks, they are 50mm GSXR750 forks and triple clamp, so much lighter! and I like to stay within the Suzuki realm.
Rear shocks are going to be a pair of baddas piggytail Ohlins I think, haven't made up my mind about them yet.

In the end, only the frame identification plate will be original, lol!


Workshop is taking form too, this is what it looks like atm

[Chuck78]

Maybe you could post your order number from CP/Carillo for others to place orders for duplicate pistons???

[Rensdw]

Maybe you could post your order number from CP/Carillo for others to place orders for duplicate pistons???

I will make a scan of the spec sheet asap

[Chuck78]

Now I have to decide what to do with the camshafts, to make this GR650 head a revvy beast!
The camshaft have plenty of lift already, just don't know about the rest of the parameters yet.

Don't go too revvy, it will be absolutely no fun on the street with too much valve opening duration. With shim under bucket setup, you lose easy 30 minute valve adjustments (have to pull cams every time) but you gain the ability to run over .400" lift cams. Megacycle makes one particular high lift street cam that would be exactly what you want unless you plan on this being a high rpm only track bike.
The gs400/425/450/early gs500 mechanical tachometer cams all interchange with the gr650 which has the biggest lift of all of them, so look up those in the megacycle catalog.
Remember, the higher the cam lift, the less durable & reliable your engine will be. High duration only affects low & mid rpm streetability, no effect on duration. High lift will be more street power, too high & it won't be durable.

[Chuck78]

One of these two will be best, the .417" lift doesn't say that you are required to run shim under buckets, but .400" is where that starts to become a good idea if revving high... over .420" lift is mandatory. .417" is close enough to .420" for sure


From the Megacycle Cams catalog:

Grind # 384-70
.380" lift
261° duration @ .040"
107.5° intake lobe center
108.5° exhaust lobe center
23 btc/58 abc.004" INTAKE OPEN/CLOSE
59 bbc/22 atc.004" EXHAUST OPEN/CLOSE
.004" running valve clearance

Use modified pistons and springs. Best all around street and road performance. Increased mid-range and top-end. Wide, smooth power band.

----------------------------------------------------

Grind # 384-20
.417" lift
268° duration @ .040"
107° lobe centers
27 btc/61 abc INTAKE OPEN/CLOSE
61 bbc/27 atc EXHAUST OPEN/CLOSE
.004" running valve clearance

Must use modified pistons and springs. Road race performance. Maximum top-end power. Power from 3500 to 8500 with high compression.

[GregT]

Got a couple of 450's racing here with cams very similar to the Megacycle .417 lift profile. Very close specs indeed which gives to think as our profile is a Lotus Ford twincam one from back when they were current race engines. However, the point I'd make is that they're using the std shim over bucket setup with no probs whatsoever. That profile on 107/108 lobe centers comes alive at about 5500rpm but isn't too bad below that.

[Rensdw]

One of these two will be best, the .417" lift doesn't say that you are required to run shim under buckets, but .400" is where that starts to become a good idea if revving high... over .420" lift is mandatory. .417" is close enough to .420" for sure


From the Megacycle Cams catalog:

Grind # 384-70
.380" lift
261° duration @ .040"
107.5° intake lobe center
108.5° exhaust lobe center
23 btc/58 abc.004" INTAKE OPEN/CLOSE
59 bbc/22 atc.004" EXHAUST OPEN/CLOSE
.004" running valve clearance

Use modified pistons and springs. Best all around street and road performance. Increased mid-range and top-end. Wide, smooth power band.

----------------------------------------------------

Grind # 384-20
.417" lift
268° duration @ .040"
107° lobe centers
27 btc/61 abc INTAKE OPEN/CLOSE
61 bbc/27 atc EXHAUST OPEN/CLOSE
.004" running valve clearance

Must use modified pistons and springs. Road race performance. Maximum top-end power. Power from 3500 to 8500 with high compression.

Chuck, thanks, I've seen those camshafts in the catalog, so you are 100% sure they will fit in the GR650?
I can compare my 650 camshafts with my 450 and 500 camshafts myself so that should be easy enough!

I don't know where the GR650 redlines, But I would think the longer stroke and heavy piston weight is the limit there.
In my case I think the crankshaft strength and piston weight is the RPM limit, not the head (with shim under bucket), those CP pistons are not that light.
I should measure my piston and rod weight, compare that to stock and the guesstimate my redline and go from there.
Both intake and exhaust will be tuned for bottom end power to make this thing fun to ride and reliable.
So I would say the second camshaft would be the best one to get, I could also regrind my 650 camshafts, I have to measure the lift and duration.

Also I have my doubts about the crankshaft, the GS500 cranks are supposed to be pretty bad when raced seriously.
This engine is (according to my calculations) going to make 60+ HP and is it going to hold up?
Now the crank is going to be seriously lightened to accommodate the removal of the balancer, and maybe I can have it welded?
I have no experience on this area at all so any help would be greatly appreciated
The piston rods are made by CP Carrillo so that should be no issue.

Anyway, lots of stuff to think about!