ronoc88 Posted November 28, 2007 Report Share Posted November 28, 2007 Hello I have owned a 04 290 for about a year now and its hasn't given any real trouble until last week. heres the story: Started bike, ran for approx 2-3 mins stoped and loaded onto trailer, 5-10 min trip, bike off trailer wont start. Checked all the obvious, petrol, plug etc. nothing unusual. Bike back on trailer. Upon further inspection it looked like the spark was quite weak, replaced plug no difference. Suspected timing was out checked woodruf key ok. Pulled off the head and cylinder, checked the rings. Rings were very worn piston and bore looked ok. replaced rings, put back together and it fired. Now heres the question. Why did the bike start then just not start, its not like the rings just wore out in 2-3 mins. I bought the bike second hand so never knew that the compression was low, its always just been like that. Takes a good oul kick now to start it, and the extra power is noticable. Decided that I would replace the Pistion and top end bearing while I had it all apart. Problem 2 - My original piston has a semi circular cut out in the skirt at the rear, I bought a new piston from the dealer and it doesn't have the same cut out. When I returned it as I presumed it was the wrong one I was told its ok thats just the way they come now. This seems strange the cut out leaves the inlet port open where as the new pison almost completly covers same port. The bike just couldn't run properly. It would be the same as putting the piston in back to front. Has anybody replaced a piston lately? Is this the correct piston? The dealer has no other and is certain its the correct piston, im considering altering the new piston to match the old one, or reusing the old piston, but that would be a waste of E90. Any thoughts? Thanks Conor Quote Link to comment Share on other sites More sharing options...
copemech Posted November 29, 2007 Report Share Posted November 29, 2007 Thoughts, well I'm not quite sure what you have done to fix it! Would require a signifigant loss of compression for it to not run, however if you noticed a major difference in kickover? I seem to recall the later model pistons not having the cutaway, as the later bikes are tuned a bit smoother, I think RLracer just installed one in a bike, maybe he can confirm. But if it runs fine I would not be overly concerned about it. Hope that helps. Quote Link to comment Share on other sites More sharing options...
gasgasssser Posted November 29, 2007 Report Share Posted November 29, 2007 Believe it or not the 290 will run with the piston in the wrong way round,i once bought a bike in this condition,i didnt notice it when i did a test ride,it was weeks later when i began to notice things were not just right.During my attemps to sus things out,i too noticed that the spark was weak,but i have since discovered through my postings on this site that its not un common. On the subject of your piston,if your dealer is certain its the correct one, i would put it in.Afterall, he is the MAIN dealer an he is CERTAIN its the right one. I had a similaar problem to yours regarding the starting,when i turned up at a trial,sometimes i realy struggled to get the bike started,things came to a head at one particular trial when it just wouldnt go.I ended up stripping carb off etc.eventually got it going.I came to the conclusion that the engine was getting flooded while being bounced around on the tailer.Now i turn fuel off and let engine run out of fuel befor loading onto trailer,and now the starting problems have dissapeared. i have also changed the plug to a BP5EVX. Quote Link to comment Share on other sites More sharing options...
ham2 Posted November 29, 2007 Report Share Posted November 29, 2007 On the subject of your piston,if your dealer is certain its the correct one, i would put it in.Afterall, he is the MAIN dealer an he is CERTAIN its the right one. I know nowt about your your piston...but..Not all dealers are equal...my ex-local Sherco dealer told me I would need a brand new rear wheel assy' when I asked him if he could repair my leaking spokes!!!! You may well have been supplied with the correct piston but it might need the skirt milling?? or filing?? if it won't run properly un-modified. Quote Link to comment Share on other sites More sharing options...
ronoc88 Posted November 29, 2007 Author Report Share Posted November 29, 2007 Thanks for the replys, It certainly would be interesting to find out did RLracer's bike run Ok. In the end I gave in and modified the piston couple of mins with a file, it turned out quite well. Im still not sure why it wouldn't start, spark is still quite weak, my ignition is leonelli but i think some newer/older bikes came with a different ignition. has anybody else found that the spark is very weak? Gasgaser what were the symptons when the piston was back to front? I will try turning off the fuel also. Sound almost too simple. Thanks Conor Quote Link to comment Share on other sites More sharing options...
gasgasssser Posted November 30, 2007 Report Share Posted November 30, 2007 Thanks for the replys, It certainly would be interesting to find out did RLracer's bike run Ok. In the end I gave in and modified the piston couple of mins with a file, it turned out quite well. Im still not sure why it wouldn't start, spark is still quite weak, my ignition is leonelli but i think some newer/older bikes came with a different ignition. has anybody else found that the spark is very weak? Gasgaser what were the symptons when the piston was back to front? I will try turning off the fuel also. Sound almost too simple. Thanks the bike had a splutter at lowish revs,you could hardly when the engine was under load.It wasnt that obvious at first,if i was a total beginner,i probably wouldnt have noticed at all. Another sympton was that the idle screw had to be turned in a lot further to make it idle. Quote Link to comment Share on other sites More sharing options...
copemech Posted November 30, 2007 Report Share Posted November 30, 2007 Apparently RLracer has been busy and has not picked up on this topis as I had hoped, but too late now as you have already modified it. Non the loss as it should be fine I would think. Do not expect any excess sparks from these things at kickover speeds, difficult to see, but basically it seems they either make spark or not on a simple ck. You may have to be in a dark spot to see it well! Quote Link to comment Share on other sites More sharing options...
ronoc88 Posted November 30, 2007 Author Report Share Posted November 30, 2007 Apparently RLracer has been busy and has not picked up on this topis as I had hoped, but too late now as you have already modified it.Non the loss as it should be fine I would think. Do not expect any excess sparks from these things at kickover speeds, difficult to see, but basically it seems they either make spark or not on a simple ck. You may have to be in a dark spot to see it well! They say a picture tells a thousand words, so here you are. Conor Quote Link to comment Share on other sites More sharing options...
copemech Posted December 2, 2007 Report Share Posted December 2, 2007 Conor, in Spain they call that a "new engine thermodynamic" or something like that i believe! It should probably work untill the 2012 models arrive! Quote Link to comment Share on other sites More sharing options...
kjax Posted December 4, 2007 Report Share Posted December 4, 2007 I also have an 04' 290 that had spark problems. The spark issues seemed to have come from poor grounding in some or all of the electrical components under the tank. I had no compression issues, and the bike did exactly what yours did. Ran fine one minute and not another. Upon close inspection, I would not always loose the entire spark, it would be diminshed one time, fine the next, and entirely gone the next time. I determned it was not the coil and had no way to check the stator, so I disassembled everything in the entire electrical system. It ran fine when I put it together. The problem started again a week or so later. This time, I just pulled the electrics under tank off, and after cleaning and brightening all contacts reassembled with dielectric lube. Problem solved- still fine over a year later. Keith Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.