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Absolute amazing how you approach this project! You're truly creating a parts-bin motorbike, which will be awesome in the end :cool:


I see you've done some proper investigation of the cam timing in these 955 and 1050 motors. It is very interresing to see that Triumph has changed the cam timing significantly over the years. Comparing all the S3 models reveils a steady increase in lobe seperation angle, with less overlap. Cam duration went down a bit eventhough power was raised from 110hp (955) to 148hp (1050RS). Do you think it would be benificial to run a S3 99-01 with the S3 RS lobe seperation angles?
 
Discussion starter · #22 · (Edited)
Thanks, it's gonna take me a while but I can't wait to see how it turns out.

I think the general trend of reducing overlap is to meet emissions targets as it can increase unburned fuel in the exhaust.

To answer your question, the first gen 955 Speed Triple stock cams set to RS lobe centers (105/108) would give a lobe seperation angle of 106.5°, overlap of 27° and 1.5° of advance. Apart from slightly more overlap this matches the RS exactly. I'm no cam expert but I think this would generally create more torque lower in the rev range and reduce the top end a bit.
 
Discussion starter · #23 · (Edited)
Update time! My RS parts arrived so I have done some measuring and installing. The new liners are definitely aluminium and are a bit different to the cast iron liners they will be replacing. Firstly, they have to be fitted a particular way round and have casting marks to show. The hone looks good too.



Also, instead of a flat face on the side they have a shoulder at the top and bottom of the side face, I assume this is to allow coolant flow between the liners for more even cooling. I’ve tried to get a picture but the shoulder is pretty small so it’s hard to see. According to the RS service manual, once installed you should be able to pass a 0.1mm feeler gauge between the liners. I assume this is to allow thermal expansion without distorting the liners.



I was wrong about the pistons being forged, they are cast. There are clear casting marks on the underside, and even the label says so! They must be a stronger design to withstand the extra 1000rpm, maybe different alloy or manufacturing process. Reading up on piston manufacturing processes, forged pistons are denser which gives them their extra strength vs a cast piston, but it means they expand more when heated. This necessitates a looser piston/bore clearance so they don’t seize at normal operating temperatures, meaning poorer cylinder sealing when cold.



The RS pistons are noticeably more ‘castellated’ on the crown than the stock pistons, and the exhaust side is marked by two dimples cast into the crown and an arrow on the underside. Triumph didn’t care to mention that in the RS service manual so I had to work it out from looking at the valve reliefs, I ended up drawing an arrow on each piston crown with a pencil so I didn’t get it wrong when fitting them.



I checked all the piston ring end gaps and ring-groove clearances and paired up my pistons with liners, then got to work removing the old liners using the tool Rob Blackburn lent me. This was so easy it was comical and I had all three out in half an hour. I started with cylinder 3 using the tool and got it out with no fuss.



I was turning the crankshaft to get the next piston at the bottom of the bore to make room for the tool, and the liner for cylinder 1 came up with the piston! I used the tool to finish pulling the liner then started on #2. When I was doing up the bung I noticed the liner was turning in the bore with the bung, so I gave it a pull and it came out without having to use the draw bolt at all.



It’s a good job Rob cautioned me about resealing the liners after turning the engine over with no head on. Admittedly it’s sat with no head for around 6 months which won’t have helped. Having removed the liners I can see they are held in place in an assembled engine by the cylinder head. Without the head fitted, they're only held in place by a smear of sealant. Let me reiterate, don’t rotate the crank with the cylinder head off unless you have clamped the liners in place!

I removed the pistons next, the process is pretty simple. Rotate the crank so a piston is at TDC, then pull the circlip and gudgeon pin and the piston lifts off. However, it seems getting the circlip out is bloody fiddly whether you’re doing it via the top or bottom end of the engine. The gudgeon pin for piston #1 was a pig to get out, I think there was a lip on the circlip groove which stopped it coming out smoothly like the others. I had to get a get a large allen key into the pin bore and beat it out with a hammer, good riddance.

 
Discussion starter · #24 · (Edited)
Before installing liners you need to clear off all the sealant left by the old ones. This is pretty easy with some brake cleaner, a rag and fingernails.

Installing the RS pistons is a reverse of removal, but you need to make sure the piston rings are all properly aligned to get proper sealing. The top and second ring are easy enough but the oil rings and expander all have to be in different places and are a pain to adjust without moving the others. Speaking of pain, if you think getting the circlips out is fiddly, I can tell you it’s worse getting them in. I gashed my index finger pretty badly on the first cylinder when the screwdriver I was using slipped, so along with homemade assembly lube (50/50 engine oil/moly grease mix) there’s blood on them thar pistons. I’m hoping blood magic will help the engine run better. I also repeatedly dropped circlips down the bores and had to fish them out with a magnet wand. By the third piston I’d worked out a method for getting the circlip in a bit more easily but you still need 3 hands really, I got one end of the circlip in and worked the screwdriver round the circumference pushing it into the groove.



I’d say I found the liner installation pretty simple but I made a mistake so I don’t think I can claim that lol. I started on cylinder 3 and wiped the bore of the liner with assembly lube, then ran a bead of Threebond 1215 round the mating face. You need to be really careful when getting the liner over the piston rings, and I managed to dislodge the bottom oil scraper ring and didn’t notice. I tapped the liner down into the bore and started on the other two. They all went in fairly easily, but the last one (cylinder 1) was rotated a bit so I tried to rotate it in place using a pin punch on the shoulder I mentioned earlier. That didn’t work so I used the crankshaft to lift it up a bit and used a G clamp as a huge spanner to get it in the right orientation, then seated it again. With all three in, I checked with a feeler gauge and it fits between all the liners as specified in the RS manual so that’s good.

I then noticed #3 piston was sitting weirdly and I realised I’d caught a ring, so I took the liner back out and found a mangled oil ring in the bottom of the liner :eek:😭 Luckily the liner and piston were undamaged.



My next thought was that the piston rings come as a set for £60, but the bags they all came in have the individual part numbers on them! I checked with Fowlers and you can buy them individually so I’ve got a new oil control ring in the post for £6, which makes me feel a bit less of a dick haha. For now I’ve got two liners clamped in place (clamps also courtesy of Rob Blackburn) and some sealant to clear out while I wait for the ring to arrive.



I had no idea you could buy the rings separately as they’re always listed as a set on the parts fiches. They’re the same ring set used on earlier 1050 engines so here are the part numbers for posterity:

Piston ring set – T1120728

Top piston ring – T1120710

2nd piston ring – T1120720

Oil control ring – T1120727

Oil ring expander – T1120726

Oil control ring – T1120727


Edit: Turns out Triumph won't sell the individual rings, see post #37

The RS pistons come right up level with the top of the liner at TDC, I’m hoping I’m not going to run into spark plug or valve clearance issues…

I weighed all the liners and pistons for interest, and I’ve stripped 1404g out of the engine which is nice to know. The RS pistons are slightly heavier and no doubt their mass distribution is different so the engine won’t be properly balanced. I couldn’t even start to analyse how Triumph have split the balance mass between the crankshaft counterweights and the balance shaft so the only way to definitely remedy this would be to use the RS crank and balance shaft. That is veeerrrry pricey, so I’ll stick with my engine being slightly out of balance and hope it doesn't catastrophically shorten the engine life.

Original Liners - 829/832/834g
RS Liners - 353/357/357g

Original Pistons - 252/253/250g
RS Pistons - 260/259/260g


Lastly, I thought I’d got myself a Gen 1 955 intake cam for the princely sum of £25, but on measuring it up the lift is around 8.5mm instead of 9.35mm. I’m going to contact Triumph to try and identify it, and I might pull the intake cam out of the engine in my bike to compare as in theory they should be identical.

I was curious so I measured the other three camshafts I have and found the lobe lift is 0.1 - 0.2mm less than spec on all of them, which I think is to account for the valve clearance. I’m struggling to visualise it but I think that if you set the valve clearances to be on the loose end of the tolerance you would get slightly more valve lift? Food for thought.
 
Discussion starter · #25 · (Edited)
I got a bit panicked about the possible spark plug/piston crown interference so I bought some plugs (CR9EIA-9 to match the RS) and put one in the head to see how much room there is between the end of the plug and the head gasket surface. There's a good few mm of clearance so that won't be an issue, I'd just made it up. Fictional crisis averted lol, and now at least I have the plugs.
 
Damn this is is interesting project to follow, if I happend to find a reasonably priced 1050 engine during winter I just might follow your footprints with my 98 cafe daytona, it has 03 955 engine now but I'm on the market for serious midrange punch that it lacks and high compression 1050 could really be what the doctor orders 🤔
 
Discussion starter · #29 · (Edited)
Love it!

You should have a look at Rob Blackburn's Daytona 1075R thread, you could go for the RS pistons and liners with the Daytona cams in a 1050, should be fun [emoji6]
 
You've been quite lucky with that 6pound ring 😅 Good that you've found it in time, before it chewed up your nice shinly liner.

Great to see all these detailed pictures! Pictures of internals are hard to come by, as most of this type of work is done at dealers / tuning shops that don't tend to document what's done to a bike.

Thanks for the feedback related to the cam btw ;-)
 
Discussion starter · #31 ·
Yeah, I noticed the other 2 liners were much easier to tap down into the bores and it got me worrying. No prizes for anyone who noticed I'm an anxious person lol. I know I checked the pistons rings were all properly seated on the other 2 cylinders before getting the liners any further on, you can check using the cutout at the bottom of the liner.

I realised I made a typo in the overlap figure I gave you, it should've been 27° not 23° (that's the RS figure). I've updated the original post as well.
 
Great photos of the new pistons and liners. I'm hoping you'll get the bottom oil ring back on to number three without pulling the other liners back out. Best of luck - you are a brave man.

Regards

Rob
 
Discussion starter · #34 ·
Yeah me too, I'd hate to pull the liners back out and risk screwing up more rings getting them seated again. I think the oil ring shouldn't be too hard to get back on, they have to expand to bigger than the piston to get there in the first place so I just need to be gentle.
 
Update time! My RS parts arrived so I have done some measuring and installing. The new liners are definitely aluminium and are a bit different to the cast iron liners they will be replacing. Firstly, they have to be fitted a particular way round and have casting marks to show. The hone looks good too.

View attachment 731063 View attachment 731061

Also, instead of a flat face on the side they have a shoulder at the top and bottom of the side face, I assume this is to allow coolant flow between the liners for more even cooling. I’ve tried to get a picture but the shoulder is pretty small so it’s hard to see. According to the RS service manual, once installed you should be able to pass a 0.1mm feeler gauge between the liners. I assume this is to allow thermal expansion without distorting the liners.

View attachment 731062

I was wrong about the pistons being forged, they are cast. There are clear casting marks on the underside, and even the label says so! They must be a stronger design to withstand the extra 1000rpm, maybe different alloy or manufacturing process. Reading up on piston manufacturing processes, forged pistons are denser which gives them their extra strength vs a cast piston, but it means they expand more when heated. This necessitates a looser piston/bore clearance so they don’t seize at normal operating temperatures, meaning poorer cylinder sealing when cold.

View attachment 731067 View attachment 731069

The RS pistons are noticeably more ‘castellated’ on the crown than the stock pistons, and the exhaust side is marked by two dimples cast into the crown and an arrow on the underside. Triumph didn’t care to mention that in the RS service manual so I had to work it out from looking at the valve reliefs, I ended up drawing an arrow on each piston crown with a pencil so I didn’t get it wrong when fitting them.

View attachment 731068

I checked all the piston ring end gaps and ring-groove clearances and paired up my pistons with liners, then got to work removing the old liners using the tool Rob Blackburn lent me. This was so easy it was comical and I had all three out in half an hour. I started with cylinder 3 using the tool and got it out with no fuss.

View attachment 731060

I was turning the crankshaft to get the next piston at the bottom of the bore to make room for the tool, and the liner for cylinder 1 came up with the piston! I used the tool to finish pulling the liner then started on #2. When I was doing up the bung I noticed the liner was turning in the bore with the bung, so I gave it a pull and it came out without having to use the draw bolt at all.

View attachment 731059

It’s a good job Rob cautioned me about resealing the liners after turning the engine over with no head on. Admittedly it’s sat with no head for around 6 months which won’t have helped. Having removed the liners I can see they are held in place in an assembled engine by the cylinder head. Without the head fitted, they're only held in place by a smear of sealant. Let me reiterate, don’t rotate the crank with the cylinder head off unless you have clamped the liners in place!

I removed the pistons next, the process is pretty simple. Rotate the crank so a piston is at TDC, then pull the circlip and gudgeon pin and the piston lifts off. However, it seems getting the circlip out is bloody fiddly whether you’re doing it via the top or bottom end of the engine. The gudgeon pin for piston #1 was a pig to get out, I think there was a lip on the circlip groove which stopped it coming out smoothly like the others. I had to get a get a large allen key into the pin bore and beat it out with a hammer, good riddance.

View attachment 731064
What a fascinating thread - well done, I'll follow it and am looking forward to the next episode.
Alan
 
Discussion starter · #36 · (Edited)
It turns out the camshaft I bought is the correct one. I spoke to Triumph and they couldn't identify it so this morning I took the intake camshaft out of my bike and measured it up, the base circle and nose-heel figures match. I'm confused as the lobe lift is still around 8.5mm which is nowhere near the 9.35mm valve lift quoted in the service manuals. Once I've got a DTI I'm going to have to verify the actual valve lift achieved by that camshaft in the 1050 head.

I chased up Fowlers today as I still haven't received the oil control ring and they'd cancelled the order without telling me. Apparently that part is discontinued, I call shenanigans since it's used on the current production Speed Triple RS. I have emailed Triumph to see if it's correct, I really really don't want to have to buy a whole piston ring set for one damn ring.

Finally, once I put my bike back together after measuring the camshaft it won't start. FFS :mad::poop: It cranks but won't fire, I suspect at least one ignition coil has finally given up as it was pretty badly split at the top and the bike has been hesitating at high revs occasionally for a while.
 
Discussion starter · #37 ·
Triumph have confirmed that they don't sell the piston rings separately, looks like I'll have to buy a set :(
 
Discussion starter · #39 · (Edited)
Thanks but I'd rather not go the second hand route since it's a new piston and liner, otherwise I could just pinch one off the pistons I took out. I'm hoping to sell them so I don't want to move the problem onto someone else lol
 
Discussion starter · #40 ·
I picked up a set of rings from Fowlers today. I replaced both oil control rings and the expander to be on the safe side, and very carefully seated the last liner. I think I'll take the sump off and check there's no rings lurking under the other pistons just in case.
 
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