Lack of acceleration possible engine swap
 

I have noticed that my class B monster is lacking acceleration along the straights. At Cadwell "Stafford" was making approx 30 meters on both straights on a 600ss.
On a track day this at Snetterton the same thing happened with another 600ss who was running standard road sprockets and I had a 15 toothed front sprocket and 48 toothed rear sprocket, so should have had the extra get up and go.

I am going to carry out a compression test and then if the results are near 10.7:1
I will chuck it on a dyno to see the power output.

Hopefully this will this will tell me if the lack of acceleration is down to the engine or my fat arse?
So my question is:-
1) Can anyone help with the lack of power?
2) Ithought about buying an engine and overhauling it for the future, can anyone tell me if a 600ss engine will fit in my monster frame.
3) Has anyone an engine for sale

Thanks in advance for any help.
Lee

Basic stuff like a valve regrind, valve clearances and belt tension will have a positive effect. Carb set up and a dyno run are a must really but you also need to get the gearing right and get out of the corners right. Yes the SS engine will fit.

:)

So today I carried out a compression test, engine warm, throttle fully open and assuming the valve clearance is correct; the results are as follows:-
Front Cyl - 100-105 psi bouncing dry and 122 psi wet
Rear Cyl - 115 psi dry and 125 psi wet

As the book compression ratio is 10.7:1, assuming atmospheric pressure is 14.7 psi I take it is just a case of multiplying 10.7 by 14.7 equalling 157 psi or there abouts.

If this is correct the front cylinder is losing 57 psi overall made up from:-
157 – 122 = 35 psi from the valves and 122 – 100 = 22 psi from the rings and the rear cylinder is losing 42 psi overall , 157 – 125 = 32 psi from the valves and 125 – 115 = 10 psi from the rings

Or looking at it another way the front cylinder is working at 63% and the rear at 73% giving me an overall engine performance of 68%.

Bad news for the engine but at least I can keep eating pies and drinking ale.

What to do now?

Lost compression could just be poorly adjusted valve clearances (closers could be too tight). I would allow for some piston/bore wear but removing the heads and re seating the valves and adjusting the clearances correctly will pay dividends and not cost very much.

:)

Yep, I suppose that would be the way forward to bring both cylinders up by over 30 psi each. My concern is the piston losses; 10 psi on the rear is on the edge of acceptable but 22 psi from the front is a little large.
I suppose if I take the cylinder heads off I can sort them out and look at the pistons at the same time.
Can the cylinder heads be removed with the engine in the frame?

Leak down test needed

Can you please explain a "leak down test"?

You pressurise the cylinder on The compressions stroke with both valves closed using compressed air through a leak down tester that contains a pressure regulator and a couple of gauges, the difference in the gauges then tells you your losses.
Any leaks can often be heard either by listening to the end of the exhaust or the airbox inlet or the crankcase breather

Rings a bell, I will look in to it.
Thanks

one of these
http://www.ffx.co.uk/tools/product/S...oJwwo dsF4A8w

maybe a local garage has one

Nice maths Lee, but flawed. Your calculations do not take into account that the compression ratio is theoretical and that it doesn't take into account valve timing. i.e. The inlet valve doesn't close until well after the piston's on the way back up the bore from BDC. A leak down test will reliably indicate any problems, but doing the valves and rings will always help an old clunker 😛

Speak to the Ghostmeister, sounds exactly like the problem I had (fat arse too). He did lots of lapping and magicery with my engine and it improved many fold.

Other than that you can buy my engine at the end of this season.

Umm, the old dynamic Vs static, I have ordered a leak tester as recommend by Kev, so I will be able to find out more when it arrives.

I have stripped the bike down in preperation (removed - fairing, battery and tray, air box, carbs etc). I also removed the rocker covers and cannot get my smallest feeler gauge 0.05mm under the inlet shim on either cylinder and only just get it under the closing shim though all four shims can be rotated. So perhaps that's part of the problem.

Shame I didn't know about your engine earlier as I brought a winter project engine today, was advertised as a 1999/2000 engine with approx 8000 miles. With my limited knowledge spotted it was a 600SS engine, I now think it's also 1994/1995, but Kev is helping me identify the bad boy.

I will post the leak test results when known.

0.05mm opener clearance :eek: :eek: :eek:

Always set the closers first then the openers.

:)

i believe the "correct" clearances are open to debate, I've been told that 0 is "correct" for a race engine and without the belts on you can feel when its touching but not rubbing.

however, my new philosophy is if it starts its good, learned that from the pie man.

0 on closers Matt. 0.10 - 0.12 on openers

:)

Disappointment springs to mind:-
I ordered an engine drop leak tester and awaited it's arrival. On Tuesday I travelled down to Epsom to pick up a 1999/2000 monster 600 engine. With the help of Kev, we think the engine is a 1995-7 as it is supposed to be from a 'T' reg monster with approx 8000 miles.

This morning (due to the lack of work) I thought I would compression test the newly acquired engine with a set of jump leads, (the engine was cold). Rear piston 100 psi and front piston 25 psi? Uhmm disappointment, but a winter project.

The engine drop tester appeared this afternoon so this evening I gave it a go (engine cold as it's stripped down). On unpacking the new toy and saw that the percentage loss gauge was broken, uhmm disappointment, not letting that stop me I plumbed it in and cranked it up to 100 psi, on both cylinders the valves held and both sets of rings leaked......but I don't know by how much %.

Phoned up ducatimondo (www.ducatimondo.co.uk or Chris Brody 01422 345823) and new rings are £95.43 per cylinder, uhmm disapointment.

Has anyone any ideas, like would hone/deglazing work. I am investigating an alternative source for rings.

Just make up up what you lose on the straights in the corners and you'll be fine

Hope they replace it for you, they are a useful tool to have aound

Phone a Ducati dealer with the engine number, if you ask nice they might find what it came out of. (Ducati Manchester did this with my frame number so I could get Badger's reg and V5)

If it's not what was advertised take it back and get your money back.

Buy mine with the recouped cash.
Easy!

I am tempted to buy your engine; but on one level buying your winnng engine would create a sense of expectation and keeping this engine is easier than taking it back to Epsom.
I did try my friendly Ducati dealer (Seastar superbikes)they only work of frame numbers and not engine numbers.

Can people let me know their valve clearance on openers and closers please and state if its in inch or mm........ thanks in advance.

From the manual

Thanks Kev,
what is the significance of the left and right column? Is it hot and cold engine?

go with left column cold- forget the right- easiest way to adjust them is with head off then you can lap them in with grinding paste before you set them- also you can spin cam with opening rockers pushed out of way and check cam turns free without dragging on closers- california cycleworks vid "valve adjusting on ducati 2valve" on youtube makes all very clear

Thanks for the heads up. I have now dismantled the engine and I am currently lapping the valves in before taking the heads to a ducati man on Friday who will sort the shims out for me.
I have spotted that the engine barrels are from different engines and the lower one has been re bored. I can still even see the honing marks. Its strange that this lower piston had the low pressure. The piston, rings and valves seem ok; but the vertical piston with all the pressure hasn't been rebored and both valves seats were ropey; has this all been in vain?
Maybe it wss the pies and guiness al along?

on the Left we have what Ducati recommend you set them to and on the right the tolerance

the tolerance/ service limit given always seemed so wildly out to me seems better to keep them closer than that- 0.05 and 0.2 seem a world apart??

I took my pistons, rings, barrels and heads to a local "ish" Ducati Ninja to cast his eye over and shim my valves that I had previously lapped in.
He said that everything was good now the shims hasd been done as there was no gap on the inlet valves and the rest of the engine was in fine shape.
He patiently listened to my perceived lack of acceleration problem, looked me up and down and said "lose some weight fat lad", the other option is to throw more money at it and adjust the compression and valve timing.
I think the money will be better spent on guiness, pies and rolling in last as someone needs to take one for the team.
Just got to put it back together now.

Lee is this the 1999 to 2001 Monster engine or the Earlier engine

94 engine with 2.28:1 primary, rear sprockets 37, 38, 39, 40
95 - 98 engine with 2:1 primary. rear sprockets 41, 42, 43, 44
99 - 01 engine with 1.85:1 primary , rear sprockets 44, 45, 46, 47

Hi Kev, I am unsure. I have looked at the embossed date stamp which looks like 93, the cylinder head has 8S, the belt adjusters are on the barrels and it has the rounded belt teeth.
perhaps I should try a 44 rear sprocket?

8S Heads makes it the 1999 to 2001 model, so standard gearing on the road would have been 15/46 on the Monster, they didn't do a faired SS version with that engine but if they had the gearing would have been 15/44 as standard

Thats interesting as I am running a 15 front 48 rear set and its still slow. Just have to accept that "not being shy at a buffet" has finally caught up with me. This is where I need to say "its not all about the winning; but the taking part that counts". It won't stop me from enjoying myself and gives me a plausible excuse when I lose to Stafford. Thanks for everones help, see you at Snetterton.

48T rear is going to be way to big for Snetterton

Go for a smaller rear and get more out of each gear

I am not racing at Snetterton due to my family holiday a week later. But from the track day I day there about 2 weeks ago I didn't manage to grab 5th gear on the straights unless I short shifted and Mark No 81was making at least 30 meters on both straights on standard gearing on a 1995 600SS.

Jeez Lee. Have you actually got around to setting up/dyno-ing the engine yet? A simple dyno run would/will reveal if all is well. Count the teeth on the primary gears to check what ratio you have. You can't re-bore Ducatis in the conventional sense! If the original honing marks have disappeared, then the bore is probably shagged (technical term).

Hindsight is a wonderful thing. I original said to myself that I would run the bike on a dyno and that would prove if the acceleration problem was the engine or me. But the logistics of the dyno test against having a compression tester at hand in my garage didn't equal out.
I suppose this is where it all started to go wrong. Patients is a virtue and I went "bull headed" into stripping down the engine on the back of the compression test instead of running a dyno.
Lesson learnt.

Here's another lesson.
Don't let a mint, proven, Ghostie fettled engine slip your grasp at the end of this season!

I wouldn't beat yourself up over that- if you did the comp test right and there was nearly no compression you know what the dyno would say without having to run it!

So to recap I have stripped the top end, lapped in and reshimmed the valves. Checked the piston rings and bores, reassembled again carrying out a soft solder squash and setting the base gasket..... well today I took it for a dyno test, changed a faulty ignition coil which was causing a misfire
The read out was just got over 47bhp but was set to 46.7bhp to get a better torque curve.
Uhm.....what 4 bhp between friends when your a fat lad.

Mark No81 who has a standard 600 ss produced 46.8bhp.

Roll on Mallory!

What's the cam timing set to Lee