gasgas Posted February 2, 2006 Report Share Posted February 2, 2006 Rode this bike for one year, new rings/piston, cilinder freshly hooned. lubrication 1% synthetic. Rings were sticking due to carbonised and were not sealing properly. Engine did run oke nevertheless, which is funny. In my area i never use more than half throttle max. Is this picture a normall clinderbowl look due to low throttle for one year. Quote Link to comment Share on other sites More sharing options...
rapid roy Posted February 2, 2006 Report Share Posted February 2, 2006 hi Carbon/sludge my kids 315r started to rattle (not very loud) due to it being 4 years old i order a piston kit striped barrel piston ring seized with sludge cleaned with petrol problem solved looked at the 2 stroke oil from the dealer (rock semi syn) dealer says i have seen this before using cheap 2 stroke oil his advise was only run fully syn oil hope this helps Quote Link to comment Share on other sites More sharing options...
ham2 Posted February 2, 2006 Report Share Posted February 2, 2006 Speaking from indirect experience-- it looks like you may be burning a little gearbox oil there Quote Link to comment Share on other sites More sharing options...
gasgas Posted February 2, 2006 Author Report Share Posted February 2, 2006 Ham2, yes cld be, but i have that covered see my topic:gasgas splitting cases. But, yesterday when i took the exhaust pipe off, and looked tru the port i saw this carbon appearing after only approx 15/20 hours of riding(not in the quantitiy shown here on this pic, but there was already some), so i like to know how many of you did actually have a look into the barrel/head and give some back up. Quote Link to comment Share on other sites More sharing options...
coxy Posted February 2, 2006 Report Share Posted February 2, 2006 when riding your bike every so often rev it to its max for maybe 2-3 seconds this will clean the bike out and should get rid of any sludge or carbon in your bikes barrel and on the piston/ cylinder head, i do this at least once everytime i go out on my bike Quote Link to comment Share on other sites More sharing options...
barrybaines Posted February 2, 2006 Report Share Posted February 2, 2006 there is always one option for cleaning the expansion chamber bung one end fill with a mix of caustic soda leave a while overnight maybe aggitate a little empty and that should clear the best part of it out Quote Link to comment Share on other sites More sharing options...
manz Posted February 2, 2006 Report Share Posted February 2, 2006 Adding to this, youre probably also running it a bit rich. This can be caused from anything from too much oil in the filter or bad jetting. And the fact that 2strokes needs rpm. It'll clog up otherwise. Clean the filter, repack the rear silencer, put a new plug (ngk's iridium resistorplugs works the best imho) Go for a 6, or a 5 (if it's cold). Either buy a new midsilencer, or blow it out with a heat gun (it will probably start to burn, this is ok. Do it until you see the grid in the muffler glow. Let it cool down. Get a used clutch/throttle cable, pass it through the muffler, attach it to a electric drill, and pull the strings apart on the end, on the other side of the muffler, start the drill, and pull it back and forth a couple of times. Then blow the carbon out with pressured air. Get good new gas, mix it 80:1 with a good full syntetic oil. Run the engine warm, and go and bash it on the road. Its hot enough when it starts to emit blue smoke. Dont overrev it, just run it with power&resistance at top gear. Reving it up on the spot helps in the section, to burn the oil in the chamber, but it doesnt "clear it out". If it doesnt start running good (ie, revving nicely, doesnt "bog") then its time to lean the mixture. Start with the mixture screw/air screw. If this doesnt help, try leaning the pilot abit. Then lower the needle etc (good topics on jetting here at the forum). Almost all 2-stroke trials does pink abit when running good (running on 98 octane "premium" fuel) , when doing a climb and letting of the gas. (esp. Montesas) Spark plug color doesnt really tell if its running lean or rich in theese machines, because they are ridden mostly with wery little throttle) so they get black anyway. It's normal for the machine when hot to pink one/twice when revving it up on the spot and quickly turn off the throttle. If its pinking all the time, richen the mixture. As a sidenote, when the machine is running good, dont push it on the road. It will detonate and there is a chance that it will seize. Remember to once a while clear it out on the road, and repack the rear silencer. It's also good to get the gas from a busy station (as the gas there prolly hasnt sat in the tank too long). Dont mix/buy more than you can use in a week. Preferably, use a metal cannister. They're better than the plastic ones. Just my 0.02 Quote Link to comment Share on other sites More sharing options...
marlintec Posted February 3, 2006 Report Share Posted February 3, 2006 I had the same problem running with modern full synthetic (Elf XT2, Castrol R2, Motorex CrossPower) from 1 to 1.25 % (100:1 to 80:1). Also I rarely use more than 2/3 throttle. Even in few hour the carbon builds up in head, rings and exhaust. I'm very sure my bike is right jetted. The problem was resolved using semi-synthetic oil at 1.25 %. No ring sticking, no muffler-clogging. Not always the hi-tech synthetic is better. Cheers, JM. Quote Link to comment Share on other sites More sharing options...
gasgas Posted February 3, 2006 Author Report Share Posted February 3, 2006 guys, very nice replies here. You all more or less express my feelings about why it builds up carbon. Since my bike really runs smooth when warm, without smoking, i feel my air/fuel mix is ok. I ran it 1:100 one whole year with that picture as result, so i feel that it is caused by not running it hot enough so not revving it enough. At this moment it is around 0 degrees celsius overhere, and i am running a 40 pilotjet, so it cld be a little rich although i don't think so. What i will do, is the down the road running, get it really hot and see how that turns out, by again looking tru the exhaust port. Will reply later, how that went. O btw, when did you guys have a peek tru the exhaust to see how yr cilinderheads/cilinders look? And are there more with good results going to a half synthetic 2stroke oil? Maybe there is a gain there also. Quote Link to comment Share on other sites More sharing options...
gasgas Posted February 3, 2006 Author Report Share Posted February 3, 2006 Just an hour ago i ran the bike full throttle a couple of times up the hill, and evently it started smoking out of the exhaust pipe when closing the throttle. I have never seen this with this bike only with my crossbike. Tomorrow i will check the cilinderhead and see what happened there. Quote Link to comment Share on other sites More sharing options...
t-shock 250 Posted February 3, 2006 Report Share Posted February 3, 2006 Modern synthetic oil is such high quality that it can be overkill if used in a (fairly) low stressed trials engine at no more than half throttle. Simply put,the engine will never be worked hard enough to generate the heat required to burn synthetic oil properly. Even David Knights factory (2 stroke) KTM's run on semi-synthetic oil as the mechanic reckons they never have any problems with engine wear due to oil. Quote Link to comment Share on other sites More sharing options...
donmurray Posted February 3, 2006 Report Share Posted February 3, 2006 Has anyone tried running some of the fuel system cleaner like SeaFoam or Chevron Techron additive? I see some of the outboard marine guys do this. I'm thinking of trying the recommended ratio (or lower) in the next tank of my 315. There's a concentrated procedure they use on marine outboards. In this procedure they spray a continous dose in the intake until it's loaded up, pour a little in the plug, let it sit for awhile, then do a blow out run. Quote Link to comment Share on other sites More sharing options...
donmurray Posted February 3, 2006 Report Share Posted February 3, 2006 I thought the full synthetic was supposed to burn cleaner. Quote Link to comment Share on other sites More sharing options...
sam Posted February 3, 2006 Report Share Posted February 3, 2006 Which oil brands are semi-synthetic? I have a constant battle with my Montesa 315 loading up! I run silkolene/102octane racing fuel 80:1. If run to hard down the road they can seize? Quote Link to comment Share on other sites More sharing options...
magicmat Posted February 4, 2006 Report Share Posted February 4, 2006 all this semi and synthetic oil, are you all talking about pre-mix oil, or the gearbox oil as mentioned earlier, im guessing premix? Mat Quote Link to comment Share on other sites More sharing options...
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