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Pinging

zach

zach

Just got it firing!
Joined
Aug 11, 2011
Messages
24
I recently bought this 1000sp engine from a guy in FL that turned out to have bad pistons/cylenders I spent the money and opted for the high compression pistons from gilardoni. Great idea right?

After I got my bike together (t3/1000sp) I noticed it would ping at low rpm when I got on the throttle hard and when I didn't put non-oxy premium fuel. So after discussing it with my dad he told me "definatly your timing is too advanced" so I checked my timing and realised that I had previously set my timing on the tds mark... (not sure how I made that mistake) it was running great though lots of power I could beat my dads ev as long as I ran non oxy (no pinging)

Also, occasionally after I turn the engine off it makes this awful noise that sounds like it's firing backwards... so obviously running hot and making something glow. I do have the recommended temp plugs and the look like they should

I am currently running the vhb 30s from the t-3 (with sp jetting) until I have the time to set up my 36s. which I am guessing could be running lean.

When I "set the squish" I decided to run w/o the base gasket (maybe I shouldn't have done that) so it's an option to put that in

I need to know what could be causing it to get hot...
 
Put the base gasket in. Run premium fuel, set timing to 2 degrees before top dead center. If you still have the issue, let us know.
 
Do you think the base gasket will make that much of a difference? I always run premium but non-oxygenated is hard to find. I moved it to two degrees today and it was still pinging. Is there a chance I need to run larger main jet than stock sp?
 
The main won't do anything until wide open. The needle and atomizer control most of the action. You could try raising the needles. If you are getting pre-ignition it is probably because the compression is too high and the fuel is self igniting like a diesel would. When we had issues with fuel in the 80s, or when people were cheap and wanted to run regular fuel, thicker base gaskets were available from some dealers/vendors to run the lower octane fuel. Try some 100 octane aviation fuel. Bet she won't ping. The higher the octane rating, the more resistant to pre-ignition from high compression.
 
Thanks for your help! So I added the base gasket timed it right and I took it out. I didn't really notice any pining but I did not drive for very long(just a couple miles) but when I came back and shut it down it still fires after like previously described... I did cleaned out the carbon build up in the cylinder a little. I am still wondering why is it running so hot to cause the firing after shutting off?

Next options I guess are; colder plug or more fuel. Any other suggestions?
 
I'm reaching a little here. What are your valve clearances? If set too tight, the exhaust valve won't cool as much and might cause the problem. If I remember correctly, both the intake and exhaust clearance on an early SP are around 0.009 inch. Also check for vacuum leaks around the carbs and intake manifolds. That could cause a lean condition that will raise temperatures.
 
Yeah I have them set to 0.009 I was thinking could be intake leak too but it idles right. I will check.
 
Are your idle mix screws about 2.5 turns out from all the way in? If out further you have a vacuum leak and the extra fuel is compensating, or the pilot jet is too small.
 
What air filters and mufflers are you running? If they're more free-flowing than stock, you may need to jet up to compensate.
 
My mixture screws are suppose to be at1.5. I think the right one was closer to 1 which is the side that was pining more. I checked for air leaks with carb cleaner spray(coulnt find starter fluid) an didn't notice any change. I took it out and it ran good I may have heard a ping but it was windy and hard to hear. I couldn't get it too ping when I tried though and it didn't diesel when I shut it down but... it was cool out and maybe didn't get hot enough... ugh.

I will check my float level I don't think i have ever checked it...

I am running pod filters and 2 to1 exhaust that is decently restrictive. I don't think that it would make that much of a difference in temp though.

Also I am meaning to confirm that the timing marks are accurate for peace of mind but I need make up the gauge and piston stops
 
Pod filters and modified exhaust means you take any stock jetting (US or Euro) and throw it out. How do the spark plugs plugs look? What are your current jets, atomizer, and needle?
 
The spark plugs look great! Exactly how they are supposed too... I can post a pic if you want. Everything is stock carb wise for the sp, same as the t3 but larger(130) mains. I guess I am not totally sure on what atomizer the sp has but the carbs are off my t3. Atomizer info has been hard to find
 
If stock, the atomizer would be a 265 which should be good. My suggestion is to raise the needle to the lowest notch. Needle, if stock, would be a V9. If that doesn't work, you may need a different needle taper.
 
Well I raised the needles and have not noticed any problems... I am not sure if it's an adequate solution though... it feels a little more doggy than before(maybe just in my head) I might lower the needles again(to 2) and fill with nonoxy fuel just to see how it does. I am also curious if i would I be able to advance the timing now that I should be getting enough fuel. I am interested in finding the "line" and being able to have it well tuned that's all. Am I treading on ground that someone without the technology to test can't really accomplish?

Thanks again for the help
 
Hi
You have similar issues to those I had with my high compression LM engined SP.
What did you set the squish to and what is the compression ratio set at?
What ignition system are you using? If you are using the standard mechanical advance, is it working correctly? New springs may be worthwhile as they are probably >30 years old.
If you have 36mm carbs to fit it may not be worth putting much effort into setting up the 30mm carbs.

Tony
 
Hey, I can't remember the exact number but I think without the base gasket it was around 0.06. it's the stock replacement high compression Lm pistons which are 10:1? I am using a dyna with the original springs. Once I have time ill make up a degree wheel and be able to tell where my advance is.

Did you have an advance problem?

As for the 36s I wanted to get the engine all set up right before adding more variables like larger carbs. I didn't expect to have to do much tuning to them since they were never an obvious problem before. It was an easy start point and I may be satisfied with them and not use the 36s.

On top of that I need to order a bunch of parts for them after already spending a lot this summer with little return...
 
Ok so I have rode it around for a while and it was fine but got home today and it fired after I shut it down like previously described... This is getting really frustrating... I don't understand why after riding it hard it is fine for a while and then it has a problem like this. I only drove a couple miles home and I wasn't being hard on it...
 
zach said:
Hey, I can't remember the exact number but I think without the base gasket it was around 0.06. it's the stock replacement high compression Lm pistons which are 10:1? I am using a dyna with the original springs. Once I have time ill make up a degree wheel and be able to tell where my advance is.

Did you have an advance problem?

As for the 36s I wanted to get the engine all set up right before adding more variables like larger carbs. I didn't expect to have to do much tuning to them since they were never an obvious problem before. It was an easy start point and I may be satisfied with them and not use the 36s.

On top of that I need to order a bunch of parts for them after already spending a lot this summer with little return...
Click to expand...

What heads are you using ?? If they are SP they have a smaller combustion chamber than a Lemans which the new pistons are designed for…..SP heads and Lemans pistons will be very high compression. Timing for the Lemans is 8/34. Something to consider
 
guzzigray said:
What heads are you using ?? If they are SP they have a smaller combustion chamber than a Lemans which the new pistons are designed for…..SP heads and Lemans pistons will be very high compression. Timing for the Lemans is 8/34. Something to consider
Click to expand...


Really??? Yeah I'm using the stock heads... Are you sure about that? I know they have larger valves but larger chambers???

Can you concur John?
 
I believe Guzzigray is correct. If you still have the pinging issue, you might check with Harper's. They once stocked extra thick base gaskets and may still. Otherwise head or piston change may be in order.
 
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