SP4 Rebuild

Mr.R

I don't want to piss on your corn flakes or upset you chap but...
That's a good final run figure for a standard 33/29 valve SP2, 3, and SP4, but for a fresh motor with reshaped combustion chambers, 37/31 valves and a spaghetti system it seems a bit low IMO.
To be honest I'd be disappointed if it were my bike.
I know that Chris knows his stuff so I think the standard SP cams are being overwhelmed by the bigger valves slowing the gas speed down.
The 888 SPS and SP5's are kicking out 120+ rwbhp using 34/30 valves, my 916cc 851 made 128 @ 9,300 rpm and 76.8 ft/lbs of torque using retimed T1 9*6 SPS cams 35/30 valves, on the same dyno piloted by the same genius.

Steve R

tubbylad

Mr.R wroteI don't want to piss on your corn flakes or upset you chap but... That's a good final run figure for a standard 33/29 valve SP2, 3, and SP4, but for a fresh motor with reshaped combustion chambers, 37/31 valves and a spaghetti system it seems a bit low IMO. To be honest I'd be disappointed if it were my bike. I know that Chris knows his stuff so I think the standard SP cams are being overwhelmed by the bigger valves slowing the gas speed down. The 888 SPS and SP5's are kicking out 120+ rwbhp using 34/30 valves, my 916cc 851 made 128 @ 9,300 rpm and 76.8 ft/lbs of torque using retimed T1 9*6 SPS cams 35/30 valves, on the same dyno piloted by the same genius. Steve R

Thanks for the feedback. Was aiming for 120 so close enough. Chris did mention 748R cams would probably release nearer 130 but push it further towards the top end.

If you reference Brad the BikeBoy SP3 and SP4 runs https://www.bikeboy.org/888sp4.html you'll see best figure of 104BHP and 62'ish ft/lbs torque all dropping off around 9000 RPM so I guess a more freely flowing exhaust and heads are making the difference, as you would expect, higher up the rev range holding on from 9-11000 RPM with no significant losses lower down.

Brads best optimised 916 with aftermarket exhaust got 110BHP - again all dropping off around 9000 RPM.

So overall, considering what it cost me, I'm more than happy. In hindsight fitting 996SPS cams would probably have made a difference but I got fed up waiting for a full set to become available. Options there in future ...... 😉

It'll be faster than me as it is though 😄

jakepeewee

Nice curve.
Looks a lot like my SP3 dyno graph. My SP3 also hit the 100 RWHP @ 8200 rpm and did rise to 105 and kept this number until over 10500. Out of breath with the OEM valves (33/29). Don't think the spaghetti system does make much difference (the OEM 50mm cross pipes do perform pretty ok), your additional 10 hp at 10k+ is mainly because of the bigger valves / free flowing heads.

With 748R cams you will probably lose some torque at lower rpm, that's why they often advance these cams with a couple of degrees. Will also move top power to about where you right now are making top end power (10.5k rpm).

I did modify my SP3 and she is since last weekend a runner (well, the engine). 36/30 valves, optimized 748R heads and cams, spaghetti exhaust, compression approx 12.2:1, 4 x IW031 injectors P8 ECU.

Now looking for a good dyno tuner, prefereably where I can help a hand my self with the ECU. I did buy an eprom emulator which is a very handy tool for this stuff!

Regards,
Jacco

econti

Remember as well that every dyno reads different, and there are many factors that affect the final number too. As long as it's not concerningly low, and the AFRs are still safe, the important bit is the area under the curve. If all that mattered was a number then the operator could just run correction factors to make it read 200hp.

Matt888

jakepeewee wroteNice curve. Looks a lot like my SP3 dyno graph. My SP3 also hit the 100 RWHP @ 8200 rpm and did rise to 105 and kept this number until over 10500. Out of breath with the OEM valves (33/29). Don't think the spaghetti system does make much difference (the OEM 50mm cross pipes do perform pretty ok), your additional 10 hp at 10k+ is mainly because of the bigger valves / free flowing heads. With 748R cams you will probably lose some torque at lower rpm, that's why they often advance these cams with a couple of degrees. Will also move top power to about where you right now are making top end power (10.5k rpm). I did modify my SP3 and she is since last weekend a runner (well, the engine). 36/30 valves, optimized 748R heads and cams, spaghetti exhaust, compression approx 12.2:1, 4 x IW031 injectors P8 ECU. Now looking for a good dyno tuner, prefereably where I can help a hand my self with the ECU. I did buy an eprom emulator which is a very handy tool for this stuff! Regards, Jacco

Hi Jacco,
Are you familiar with Ruud Fredriks Dynojet Tovami in Goes, Netherlands?
I realise it's far from your hometown but definitely worth recommending.
Matt

jakepeewee

Hi Matt,
Yes, I've heard of Ruud Frederiks.

But I found a nice dynometer nearby, I am thinking of No Limits in Roden, up in the northern part of the Netherlands.

Currently trying to get her to run decently to have somewhat of a baseline. Then next stop No Limits.
She is also leaking a little oil, need to sort that as well.

Jacco

tubbylad

Baby Turbo Mirrors - how cool is that name!

Call out to the collective regarding whether or not the SP4 had the Vitaloni decals on the mirrors?
These along with the Michelin on the swing arm are the last two on the list to do.
Not sure about whether I like the Michelin for the swingarm though.

tubbylad

Original Engine Dyno vs Rebuild

tubbylad wroteDay spent with CJS Racing http://cjsracing.co.uk/ got the bike set up and running smoothly. Chris truly knows his stuff and I recommend him - highly! The mix of 031 green injectors, non airbleed throttle bodies, P8 ECU from a 916 and a base Ultimap EPROM that was from a 916SPS saw 104 BHP first run. I think Chris was being polite when he described the map as "rough". Quite a few loops of adjustment, flash the eprom, log, adjust, flash again - especially low down between 0 and 10% throttle actuation to get the pick up smooth and ensure a reliable idle. Unlike the Ultimap Chip that turns off 2 of the 4 injectors, Chris kept both injectors active and adjusted injector timing map accordingly. Each cylinder was mapped independantly (as the P8 tables can be adapted to do that where P7 cant) then harmonised to get the best overall tune. Alot of low and mid throttle opening logging and adjustment to ensure optimised cruise. I think its fair to say she's run in now. In the end we achieved 115BHP at the wheel and 65ft/lb torque with smooth clean drive all the way through the rev range running standard airfilter and Tesco Super Unleaded. Chris reckoned with an aftermarket filter and some Shell V Power we'd have squeezed a little bit more out on the day.

Discovered the original P7 ECU dyno run to compare and contrast with the rebuilt motor.
I always understood for a dyno graph to be considered unmolested the torque and power curves shoudl intersect at ~5250RPM so the original is a bit suspect.

Putting that to one side, the improvements are very healthy across the board. Bottom end is so much stronger with torque arriving a lot sooner than original and top end holds on higher for longer.

May have lost a bit of character now the "coming on cam" at 6k of old appears to have been smoothed out.

tubbylad

AJV wroteVery nice job you've done - you must be well pleased My SP2 TB's could do with the same attention. Did you outsource the plating or do it yourself?

I used a kit from t'internet and a 12 volt power supply.

tubbylad

May not be to everyone's taste but I always preferred the look of the wheels on the race bikes.
I found a pair of wheels on ebay from a Ducati race bike (supposedly 750 TTF1) and the fun began.

No cush drive for the rear and the speedo drive seal bore in the front was much larger than original Ducati part.
Front wasn't too bad and everything lined up only requiring a 0.5mm shim between the speedo drive and bearing to put the wheel in the same place as original.
Disc mounting faces are same distance apart as original.

Eventually tracked down a cush drive with the right PCD for the drive pins from a Bimota SB6.
Had to remake drive bushes from Nylon66 sleeved to fit the 16mm Bimota drive pin diameter. Original rubber bushes are tired but sleeved for 11mm drive pins.
Sprocket carrier face had to be adjusted to put the rear inline with the gearbox sprocket.
Drive pins needed shortening to miss the swing arm.
Carrier bore had to be resleeved to fit correct bearings and adapter for the 17mm spindle.
New spacer required for the caliper side overcame the completely different shape of the wheel on that side of the bike.

Interestingly, the wheels are aluminium the rear brake disc carrier is magnesium.

Sprocket is from Laverda Ghost having the right bore and drive pin PCD mentioned fit for Marchesini wheels so they've been badged accordingly.

Found a seal from a French supplier with the correct OD and bore to fit the speedo drive.

A lot of messing about for cosmetics and bit of weight saving - 1kg rear, 0.5KG front - but got there in the end.

Will be interesting to see how Nylon66 stand up as cush drive material.

tubbylad

So after an unfruitful search I decided to have a go at making what appears to be the unobtanium carbon exhaust straps.

The buck was machined out of aluminium so two straps can be moulded at once.

I tried just vac bagging 4 layers of carbon fibre cloth wet laid over the buck but it creased too much as a result of the bag moving as it collapsed under vacuum and was a failure.

Decided to make an offset split mould (https://www.easycomposites.co.uk/epo...ng-starter-kit) with a sheet of mould wax over the buck to eliminate movement of the cloth as the vacuum is drawn and the bag wraps around the part..

Once the mould was finished and polished it was a case of wet lay up of 4 layers of cloth in one half of the mould, drop the buck in then wet lay over the other side of the buck before closing the mould. The cloth was long enough to wrap around the buck so there are no joins just a small crease at the base where the mould halves meet.

Quick vac bag and pop in the oven for a couple hours and the end result is OK.

Jut got to cut them in half, bit of clean up and shaping to finish them off then fit and finish on the biike.
.

Now understand why they are so hard to come by......

.

tubbylad

The carbon conversion for hangers and straps is pretty much done.

Hangers from RedFox Grinta (https://www.redfox-grinta.com/) required making some 14mm spacers to the frame to put them central to the can. Triumph front disc bolts are the convenient length and shoulder style to perfectly fit the hanger spacer arrangement.

Replicated the OE bolt and carrier arrangement joining strap to hanger replacing the rubber bushes with a couple machined up nylon parts.

1mm rubber sheet on the inside of the strap keeps everything tight and will hopefully avoid scuffing of the can.

Requires just a little further optimisation to shorten the through bolt mount so I can remove the gold coloured washer you can see.

MarkT

This is the first time I have seen the use of spacers to space out the carbon hangers. Are you using a Sil Moto system that fits the mufflers far outboard so you have to fit spacers--you cannot move your mufflers closer inboard?

I only have experience with Corse's and Termi systems which always fit close to the subframe so the hangers have the correct offset.

tubbylad

It is a Sil Moto system that originally mirrors the offset mount arrangement so I've blanking bolts in the can where the original mounting holes are right now.

I did fit it up without the spacers but both cans required some tension to pull them in closer to the frame and they tapered in towards the number plate..

t was do able however did'nt want to tension the carbon straps.

With the spacers the cans measure the same distance apart at the outlets per the original offset mounting arrangement.

Though about making offset hangers of the correct length but that's maybe a job for another day.

MarkT

OK, I believe I see now. Your carbon hanger's offset is duplicating the offset of the aluminum street hangers. That means that your carbon hangers are offset to fit the early street termi cans with the bolt-on brackets (matched to aluminum hangers) that are positioned on the inner side of the cans. When you switch to the Corse style bands you need the spacers to move the street offset the early termi hangers to the middle of the cans. Would it be easer to buy Corse replica carbon hangers?

tubbylad

Thanks for sharing your experience.
Out of interest what is the dimension you have between the tailpipes if you use inner edges of outlets as the two points to measure between?

jakepeewee

Hope this works as I seem to have difficulties with the new web site format. Just wanted to respond to tubbylad's remark about the power and torque graphs and that they should interect at 5250 rpm. That's true, if we're talking torque in pound feet. If it's about torque measured in Nm than they will intersect at about 7022 rpm

tubbylad

Still running in......

Picture courtesy of https://rutlandphotographic.smugmug....2023/i-RWXXcr3

tubbylad

So after a 1000 miles or so have ended up with floppy gearshift. Made it home in 4th and started the investigation. As suspected one of the shifter springs snapped (didn't replace during rebuild) however seems the 6mn bolt and washer that holds the shifter mech is absent!

Sump plug is out as is the gause filter but I can't find them with my endoscope.

Anyone have experience of where these end up? Not sure how feasible it is that they found their way through the drain hole in the case next to where you see the remnant of broken spring.

Also having made it home 10 miles without seizing gears in the alternator cover leads me to suspect it wasnt present when the motor was built.

Will be a pain to split cases and not find it!

mike

Seems wrong to click on "Like" on that post - that's nasty. Can't directly help, but perhaps popping the barrels off might provide additional visibility into the cases for you and your endoscope to investigate before committing to a case split?

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