ST2 Pistons & Barrels to 900SS

richc

richc

New member
Hi,
Has anyone put ST2 pistons & barrels on a carby 900SS, I understand it can be done.
I've had a good look about on the web and not found much info on it. Been looking into big bore 944 kits for my 900 when this suggestion appeared, what would be the difference between the two?
thanks
Rich
 
Thought I'd resurrect this post.

I now have a 944SS. My 900SS is now running ST2 barrels and pistons, among other mods that it has, and it goes great!

If anyone is interested, I'll post some pics in a few days of the conversion. I've had help from various people, converting the barrels and then the actual swap-over, so thanks to them I have 900SS that's a bit more special.

Rich
 
I'd be interested to know how you've done this and what you did about the water passages in the heads. Is it just a case of re-plumbing them to run the oil through them?
 
Basically, the water passages are blocked on the base of the barrel. Then the side of the barrel is drilled through into the oil passage, then past that into the water passage. This turns the water jacket into an oil jacket.
It will definately be a lot clearer with pictures. The guy who did the barrel mod is currently racing a scratch built TT replica with a heavily modified 900ss engine, the barrel mod being one of them.
I'll try & get some pics up tomorrow.
 
Pictures attached. You can see the two water passages that have been blocked up on the top of the barrel (My mistake earlier when I stated the base), and also on the side where its been drilled through to let oil into the water jacket, then blocked up again.
Once the barrels had been modified, it was a straight swap over. A new gasket set and the correct 'O' rings in the same places as the 900 barrels.

I'll post later with my other mods and how it goes.

Rich
 
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I guess a complete ST2 motor will be easier to find than heads and barrels alone as pesky 900ss owners always swipe the ST2 cams ;)
 
I've now been out a few times, no problems what so ever with it. It seems to run a bit hotter than before, although that could be down to the really warm weather we are having.
The other modifications I have are K & N air filter with drilled air box, Dynojet II kit, down one tooth on the front sprocket and a lightened flywheel.
With the 944 pistons in, the bike pulls a lot better, harder and accelerates faster. Certainly feels a like a different bike again. I've made each of the modifications in stages so I've been able to tell the difference each time.
I had the flywheel turned down to about half its weight, which made the most difference for acceleration, as the engine spins up a lot faster.
Just need to think up what to do next!
Rich
 
Some info that may be useful. The Injection cams are apparently 944 cams with less duration and are a bit hotter than the carb cams, the injection bike pulls all the way to the limiter where the carbed bike runs out of breath about 7000rpm. I've got some 985 cylinders sitting in the garage waiting for the day some 944 heads and cams come along - one day.
 
Is that the 1000 Supersport you are talking about there? They might be easier, and cheaper to find than ST2 cams. There are a set of ST2 cams on fleabay for £327, from the States. silly money.
Any thoughts on if the cams from the 1000DS engines will fit?
 
OK. Now this might be a stupid question, but do I care, no! not one bit :lol2:
Why not just put a 1000DS engine in your 900ss frame?

I cannot wait for the stream of reasons why not……Hee Hee!
 
schrimy said:
OK. Now this might be a stupid question, but do I care, no! not one bit :lol2:
Why not just put a 1000DS engine in your 900ss frame?

I cannot wait for the stream of reasons why not……Hee Hee!
Click to expand...
I thought the Injection motors with inlet, throttle odies and air boxes occupy a different space to the carb Monsters and SS and it needed some minor frame modifications.
 
richc said:
I've now been out a few times, no problems what so ever with it. It seems to run a bit hotter than before, although that could be down to the really warm weather we are having.
The other modifications I have are K & N air filter with drilled air box, Dynojet II kit, down one tooth on the front sprocket and a lightened flywheel.
With the 944 pistons in, the bike pulls a lot better, harder and accelerates faster. Certainly feels a like a different bike again. I've made each of the modifications in stages so I've been able to tell the difference each time.
I had the flywheel turned down to about half its weight, which made the most difference for acceleration, as the engine spins up a lot faster.
Just need to think up what to do next!
Rich
Click to expand...

tried to send pm but probably failed
thanks for the quick reply
gerry
 
Hi Rich,

I'm considering doing the ST2 > 900ss barrel mod. I don't suppose you know if the guy who did the mod on your ST2 barrels is open to doing another one? Any contact info you could forward to me? How's the bike going these days - any heat issues from the rear cylinder?

Cheers

David G
 
Dave,
PM sent with contact details.
Rich

Elefant Man said:
Hi Rich,

I'm considering doing the ST2 > 900ss barrel mod. I don't suppose you know if the guy who did the mod on your ST2 barrels is open to doing another one? Any contact info you could forward to me? How's the bike going these days - any heat issues from the rear cylinder?

Cheers

David G
Click to expand...
 
Hello everybody. I'm a newbie to this forum - but have a keen interest in this topic.

Richc, it's been some time since you did the mod - how's the bike going?

I've often thought about doing this conversion, the only thing that concerned me was the fact that by simply drilling through from one jacket to the other would only allow the oil to get into the water jacket. How would it get out? I was also a bit concerned about tapping into the only oil feed to the cam/rockers.

My bike is a 1999 900 ssie, carbon fairing, front & rear gaurds, exhaust, eti fuelcel', Pwr Cmdr, carbon wheels, lightened flywheel, Harrison 6 - pots on front. Beringer rear going on soon. Front m/cylinder is a dual line AP racing unit, all fixings replaced with titanium parts. Arty fart bits being integrated front mirrors/indicators, rear combined light/indicator. And it's now a single seater - wife prefers to pillion on the touring bike. I have a pair of dp race cams to go in some time soon - but hanging on the 944 conversion.
 
Slow Shadow, welcome to the forum!

So far, I've not any issues with the ST2 944 conversion. I ran the bike for about 4 months in 2013, then had to take it off the road due to the oil gallery plug starting to come out. It ran slightly hotter than before, but was quite happy. I put plenty of miles on it.
The guy who did the barrel modification built a TT2 replica from scratch and raced the 944 conversion along with a lot more modifications he did to it. He never had any problems either.
I've just managed to get it back on the road after a full rebuild. The engine has been completely stripped. The main bearings were worn and the gearbox was replaced as some of the teeth were found to be damaged. It was also treated to high compression pistons, and the crank, rods and pistons were balanced as well. A 600SS flywheel was installed.
I've put about 400 miles on it so far. It could do with the carbs sorting properly, but it still runs fine with no problems at all. I am thinking of putting a 749 oil cooler on it to see if it will help cool it a bit better, as it still appears to run hot. Although, that could be the oil temp gauge being inaccurate as it runs OK.

My 900 is a 1995 carb model. 944 with high comp pistons, 600SS flywheel, Dynojet stage 2, open airbox and Termi's.
Give me a shout if I you need any more info.
 
Thanks for the welcome and all the info Rich :)

Sorry to hear the the loosening screw issue, it was probably down to the screw being a rolled item (they're always slightly undersized), if it was produced with dies the thread could have been produced to slightly interfere - and lock in place.

I was toying with the idea of using ST2 heads as well as barrels, but as most of the heat is produced in the heads, I might give this a miss for various reasons. 1, by doing that, I may as well just fit the complete ST2 mill. 2, with extra heat, more and big oil radiators would be needed - and the associated weight penalty. 3, oil only has about half the heat capacity of water, so heat will deff be an issue.

I'm not sure which engine oil you use, but I've done quite a bit of investigative work into Mobil 1, and it's just about indestructible. (I don't have any vested interest with the brand).

Before fitting the 748 rad, have a look for either a 999 or 1098 oil cooler, the 999/749 is narrower than 1098/848. I've fitted one towards the bottom of the fairing, just in front of lower exhaust. And plumbed it in series with the original.

Not sure if you've fitted the lighter flywheel, but it let's the engine spin-up very quickly, it was one of the most immediately obvious improvements I've had fitted.
 
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