Blow by

[chchnick]

Pulled the pipe off my 300 at 20 hours from new, this is how the piston looks. It was jetted for me and I run 50-1 belray h1r. What do you guys think?

 

[stabak]

I think its ok, I have exactly the same hours piston and looks the same

 

[Zman]

IMO it looks like you need to replace the piston and rings, because you are getting combustion past both rings.

 

[memphis2857]

Looks to me like that is some nasty oil you are running! How is your jetting? There is an awful lot of carbon and oil gunk build up, especially for 20 hours. I bet your powervalve is a mess


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[elemetal2]

Could all that burned oil below the rings be from scavenged exhaust? The bottom of the piston should be much cleaner but I'm having a hard time believing that much blow by with so little run time......

Better go check mine soon.....

 

[Dunc]

The rings can get gummed up with build up of deposits causing blow by, looks like allot of carbon for only 20 hrs! What does the plug look like?

 

[chchnick]

Further down the the piston is clean as a whistle, top of piston looks pretty good as well. Running belray h1r at 50-1 and plug looks a tad rich.

 

[Dunc]

I would look at running leaner for a while and recheck, your dealer should be best person to advise jetting etc... May be try a different oil 1st and then look at mixture, motor should be sweet for 100hrs before needing to do anything to it. How does it run?

 

[memphis2857]

Here are a few shots of mine. Bike is a 2011 with 31.7 original hours. I run Motul 800 at 50:1. Jetting is 178m 42 pilot and NEDW clip 2. Notice you can still see the coating on the piston and there is very little blow by between the two rings. Also the exhaust port is nice and clean and dry.

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[chchnick]

Does look like it's running rich compared to your pics, she runs really well, doesn't bog and response is crisp. The exhaust port on mine does look quite wet in comparison, but I have little to no spooge out the silencer

 

[chchnick]

I've just had a thought, I've just picked it up from the dealer and the choke was left on, it was had to start and wanted to stall. Once I got it started it spewd oil out the silencer. Could turning the engine over with the estart and choke on multiple times cause this kind of build up?

 

[(F5)]

Maybe your fuel tap is leaking a little or your float height a bit off. But if it now runs right I'd stop worrying, read some jetting threads and consider if you bother. And then ride the thing, enjoy this golden era before the sunset is upon us.

 

[chchnick]

It went in for starter issue under warranty, when I picked it up fuel and choke was on. Turned it off and thought nothing of it. Tried starting her later that day and it was a mission. Kept stalling, idled very low and spooge everywhere and I mean everywhere, trailer gaurds seat etc. One I got it warmed up and went for a blast it cleared. Seems fine now. Just wondered with the choke on and multiple starts without actually cranking into life may have guard her up,

 

[pscook]

It went in for starter issue under warranty, when I picked it up fuel and choke was on. Turned it off and thought nothing of it. Tried starting her later that day and it was a mission. Kept stalling, idled very low and spooge everywhere and I mean everywhere, trailer gaurds seat etc. One I got it warmed up and went for a blast it cleared. Seems fine now. Just wondered with the choke on and multiple starts without actually cranking into life may have guard her up,

I have had pipes flood with premix after many failed start attempts, then the gas evaporates leaving a lot of oil in the pipe. Hard to start, hard to keep running until it burns or pumps the oil out of the pipe. So a definite possibility.

 

[Niall-griffiths]

My supermoto 250 is the same as Memphis after 35 hours no blowby and most of the coating is left jetting is 42 pilot, needle halfway and 180 main jet, have just gone to a 185 main, I would be pretty upset if my piston was in that condition espeshily at those hours I run 50 or 40-1, castrol

 

[barossi73]

Is the photo true to colour?the exhaust side always gets a little "stained",the inlet side will be way cleaner,looks ok to me.what octane fuel?
If you dont want to mess with your jetting but think you might be rich you could try mixing a tank at 40:1 and see if you notice any difference(better or worse).sounds wrong i know but when you add more oil you reduce the amount of fuel per litre,actually leaning the petrol mix a little,whats recommended on the h1r pack?you can check plug after a ride and see if its better,but you may/maynot also notice a small change in the way it runs.h1r has a very high flashpoint meaning it works best at full noise,max temp,if youre riding slower technical type stuff it just doesnt get hot enough to burn well leaving a film of unburnt oil(everything lightly oiled-how can that be a bad thing?),it keeps things in very good cond internally,your powervalve @20hrs will be a little oily(wet) thats all.a pic of your plug will give the jetting gurus something to work with if you want suggestions.(try and show down inside plug with light)you can get some idea of main jet,idle jet,heat range,ignition timing.otherwise post your jets,slide no.,needle,fuel mix,typical riding elevation and temp range,or trawl the jetting database for others to compare with keeping in mind youre looking for similar octane fuels and similar elevations to what you ride.some of the jetting sounds nuts until you realise theyre at 5000ft or running ethanol,etc.
if you have the choke lever on the bars,make sure its not coming on a little when you turn fully to either side
also if it had no fuel when it went to dealer,or they removed and emptied tank they may have mixed up a small amount or tipped in ?mix
how was the choke left on?ive had both the handlebar lever and carb button versions on mine and both require holding "on",maybe the cable is pinched under tank?

 

[chchnick]

All is well, I cleaned up the exhaust side of the the piston and put four hours on it with various throttle, 1/4 to pinned flat. It's crisp and clear, very little spooge. Basically it came back from the dealer flooded with oil after the gas had evaporated and left a brownish oil stain on exhaust side only, crown of piston was clean as a whistle. Plug is just into a brown, not black but not quite chocolate either. H1r was recommended by the dealer to be run at 50-1 as per the jetting work that was done by gas gas nz. When I get it back, hopefully with functioning email start I'll pull the pipe and check again.