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Post by StewRoss on Sept 13, 2006 6:51:53 GMT -5
Hi, You were able to get octance booster from speed shops etc...perhaps see if you can get some of this and try it and see what difference it makes...might be a viable alternative? SR  |
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Post by wotavidone on Sept 13, 2006 19:34:53 GMT -5
SR,
I have indeed tried the octane boosters, including the one recommended by my Hyabusa draggin mate. The claimed 0.7 octane boost has not proved to be enough.
Also tried ethanol blends of 5% and 10%. Best not to ask where the ethanol came from.
Interesting side bar. BP 98 octane is rather cloudy looking, but clears up instantly when ethanol is added to it.
Here's the best one though.
One day a little red devil sat on my shoulder and whispered in my ear.
Michael, he said, are you not an assayer by trade? Did you not spend 19 years slaving over the hotplates in the laboratories of the worlds biggest lead smelter.
Are you not still gainfully employed at said lead smelter, with access to aforesaid laboratory.
Michael, asked the evil little demon, why are you not applying your undisputed skills, gleaned from many hard years amongst the burettes and pipettes, to making your very own tetra ethyl lead? Is not adding 4 ethyl groups to a lead atom fully within your capabilities, whispered the little fiend? If you look back through your notes from lab. practice at the institute of technology, would you not find you have already studied the methodology, he prodded.
Temptation beckoned, like the sirens to ulysses, but stuffing my ears and tying myself to the mast was not an option.
Research beckoned.
Yep, an afternoon with a popular brand of paint stripper, some filings of a certain lead alloy, some judicously applied heat, and a modicum of skill would indeed see me with enough tetra ethyl lead to see out my days.
Unfortunately, it so poisonous that allegedly DuPont, who get blamed for everything in the world whether they did it or not, allegedly I say, had about 5 workers die before they realised that tetraethyl lead can kill you just by landing on your skin. So the rest of my days might not be very long.
So, sanity prevailed and I am seeking other means.
Gotta go look at piles of dirt. Look forward to continuing this conversation.
Mick
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Post by theswede on Sept 15, 2006 9:51:40 GMT -5
Mick, I am surprised that you still have these knocking problems after all actions made...
One thing that affect the dynamic compression ratio is cam timing. Early intake valve closing raise the compression ratio. I don't know what cam you run, but standard IVC for SR's are 68-71 deg ABDC depending on year model. You could also try to retard the cam a few degrees with an offset sprocket.
Did I understand you correct that your ignition is a few degrees retarded from standard value? Do you have round or oblong holes in the stator plate? Can you extend the holes to increase trimming allowance?
Also, carbon buildup in the combustion chamber rises compression slightly, but more important increase the heating of fresh mixture during intake cycle, which reduce knock resistance.
Anyway, the tetraethyl lead project sounds interesting! ;D
/Jonas
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Post by wotavidone on Sept 17, 2006 19:04:32 GMT -5
Jonas,
That's where my efforts fall down. The cam is one of two big unknowns. Its kinda hard to tell what cam you've got without pulling bits off the engine. The other big unknown I have is how much did the guy who put the 10:1 piston in shave off the head?
Carbon doesn't look too bad from what I can see with a strong light through the plug hole.
The stator is around as far as it will go. Could not go any further as the little pulser coil is pretty much up against the case.
I will try an offset key on the ignition as it is the easiest step. After that, who knows, a little bit of bucket chemistry in the back shed is looking good.
Though an offset key or sprocket on the cam doesn't sound all that difficult.
On the other hand I put a new front tyre on last night - now that was easy. Looks the part and only cost $80.
One thing about SR's. They hardly require $300 sports bike semi slicks to get the best from them.
I'll keep you posted on developments.
Mick
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Post by wotavidone on Sept 17, 2006 20:18:58 GMT -5
Tell ya what though - offset keys are proving hard to locate.
I can see myself getting an ordinary one from the local engineering shop and attacking it with a file.
Mick
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Post by StewRoss on Sept 18, 2006 3:01:00 GMT -5
Hi, Fuel additives can certainly be nasty...ask some of the earlier F1 drivers...bad news...but the engine goes better.. Not sure where you'd even source an offset key...you may have to get one made. I recall years ago poeple having a selection of these for other bikes, but I think they were made for them as well. Bit like half links in chains I think.... SR |
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Post by theswede on Sept 18, 2006 3:48:45 GMT -5
Mick, the easiest way to determine the cam specs is actually to keep it in the engine. The only parts you have to remove is the flywheel cover and the (2) valve covers. You put a graduated disc? (not sure its the right word) on the flywheel and measure the valve motion with a dial test indicator. On the SR engine the cam sprocket is fixed with a pin at the end of the cam, not a key. You could drill a new hole in the sprocket to get the cam timing you want. Another thing you easily could do that reduce compression a little bit is to lessen valve clearance. Just beware to go too far, it can lead to a destroyed exhaust valve! If you suspect that the head have been shaved off, I'd rather put an extra gasket at the bottom of the cylinder, or a thicker head gasket than retarding the ignition that much. You will get it running, but much hotter than necessary. Have your engine been built to run on methanol?  /Jonas |
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Post by wotavidone on Sept 18, 2006 17:53:04 GMT -5
Jonas,
Have considered the thicker base gasket or thicker head gasket route. Calculate only need an extra 1.5 mm or so to get the compression ratio back to something sensible.
However, an engine out and on the bench job will definitely be my last option.
All other avenues will be explored first.
Went out to the club last night on a mixture of BP 98 octane + 10% ethanol + octane booster.
Went extremely well, no pinging.
Things can't be too far off the mark.
Take it from a man who lives in a country where 45 degrees centigrade is an relatively common summer's day - a couple of degrees retarded from standard makes an engine run a touch coolerm - so if it stops the pinging, that's the way I'll be going.
Take a look at the advance curves that Sjef posted, you can see that some of these programmable ignitions actually give huge reductions in advance for hi-comp engines.
In any case, it is a relatively simple mod that, if successful, costs very little, so I'll be trying that first.
Spoke to a guy who's a fitter by trade. Stepped key will be along soon, I hope.
I'll let you all know how it goes.
Mick
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Post by wotavidone on Sept 24, 2006 23:21:29 GMT -5
Found a fellow member of my motorcycle club who once ran a motorcycle shop. Traipsed out to his place on the weekend, had an interesting discussion about keys and tapered shafts - i.e. the key is only for locating the flywheel in the correct position, and the work of holding the flywheel in position is done by tighteneing the flywheel onto the tapered shaft.
He said years ago the old blokes working on British bikes would actually spit on their finger and wipe the inside of the flywheel so that a layer of rust would grow to hold the flywheel on tight.
Then he produced a range of flywheel pullers. Which one for the SR?. Perhaps if you'll lend me an Allen key, I said, I'll pull the cover off and see which one fits. No need he said, as he produced a whole SR flywheel and stator assembly off a shelf!
Looks like this one'll do, he said. Don't break it he said.
So off home I went, to pull off the flywheel and have a look at the key.
It was all too easy. I pulled out the key, measured the diameter of the shaft and got out the trusty calculator, this intimated that approximately 1 mm of offset was required to move the flywheel by five degrees. The stator had no more to go on the slots, by the way.
An hour with a piece of steel, a set of vernier calipers and a file produced an offset key which was a snug fit in both the crankshaft and the flywheel, so back on it all went.
The ride out to return the puller was accomplished at 110 - 120 km/hr, about 68 - 74 mph, up a hill with almost no pinging at all.
I reckon I will try with about 1.5 - 2.0 mm of offset next, this being so simple and quick and seems to be effective as well, that I might as well experiment with a range of adjustments.
STD key is 5 mm thick so there is a fair bit room for offset.
Mick
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Post by StewRoss on Sept 25, 2006 4:12:37 GMT -5
Well done...don't let that flywheel come loose though or it will really score the nice crank end. Then you'll have problems. My old 360 RT1 was like that. I ended up replacing the crank in the end; couldn't keep keys up to it. Tried lapping it in but the grooves were too deep. Keep us informed as to how it all goes... SR  |
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Post by wotavidone on Sept 25, 2006 22:16:41 GMT -5
She'll be right Stew.
First job I did was create a flywheel holding tool based on the pictures of the genuine article.
Then I was able to get a decent grip and tighten the flywheel to 59 ft lbs as per the manual.
Quite proud of my flywheel spanner actually. Took about ten minutes with an angle grinder and an electric drill and works like a bought one.
Perhaps the only question mark I'd have is whether the key can flog around in the keyways, which is why I put some effort into ensuring a slight interference fit. I made d**n sure the shoulder on the key was seated below the surface of the crank so that there was no question that the flywheel was seating on the taper, then pulled it off again after torquing the nut the first time to check everything had seated correctly. I will probably pull it off again this weekend to check it hasn't been flogging around.
Was truly a pleasure cruising home last night and just rolling the throttle on at 100 kmh and feeling the bike just step out without hesitation.
Only problem is, I'm now finding myself riding a bit quicker, and accelerating a bit harder than I used to. (Same reason the dog sits in the road licking his you-know-whats - because he can!)
Fortunately my new front tyre seems to have transformed cornering ability. Right side footpeg must be a bit low, I keep scraping my toes on the corners.
I put a 3.50 - 19 tyre on, because that's what the manual said. It looks huge! Bloke who loaned me the crank puller observed that it was bigger than the tyres he ran on his SR's. Bike a little bit wandery at 110 km, but feels heaps better when its laid over. Also, while it wanders a little, it no longer tracks in grooves in the road like it used to. Is this normal do you think?
Mick
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Post by StewRoss on Sept 26, 2006 5:42:01 GMT -5
Hi,
I run a 100/90 on the front and a 120/90 on the rear. I have no problems with that setup at all. It doesn't follow tracks and it is steady on the road.
Sounds to me like you're reaching the rear-sets stage.
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Post by StewRoss on Sept 26, 2006 5:48:28 GMT -5
...darn fingers...too many buttons... Now where was I...oh yes, with decent tyres and corner speed, the pegs virtually ground continually. The easy fix is to fit rear-sets...home made or otherwise. Try changing up a gear when the road is in the way... Probably worth stiffening up the suspension as well...that's if you haven't done so yet...helps with stability in the corners. The trade-off is that too stiff and you increase the tank-slapability of the SR...compromises...steering dampers help there. SR |
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