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| Rotax pistons melting http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=17874 |
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| Author: | Specter [ Mon Feb 05, 2018 11:01 am ] |
| Post subject: | Re: Rotax pistons melting |
i will place some calls today. I will keep this thread updated. |
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| Author: | FloridaEdd [ Mon Feb 05, 2018 12:12 pm ] |
| Post subject: | Re: Rotax pistons melting |
OK. I see where timing came in. I hadn't looked at it that way. |
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| Author: | Specter [ Mon Feb 05, 2018 3:07 pm ] |
| Post subject: | Re: Rotax pistons melting |
Someone recommended an EGT gauge. It updates every 250 milliseconds. I ordered one. Anyone have experience with these? Seems like an excellent idea for monitoring sudden spikes in temperature. It even has a relay tied to the temperature alarm. guess you could have an automatic kill switch or just light an LED. Attachment: 2018-02-05_13-04-36.jpg [ 55.37 KiB | Viewed 1124 times ] |
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| Author: | go oddy [ Mon Feb 05, 2018 3:23 pm ] |
| Post subject: | Re: Rotax pistons melting |
Give this a read... http://www.contactmagazine.com/Issue54/ ... asics.html |
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| Author: | canadian oddy [ Mon Feb 05, 2018 3:32 pm ] |
| Post subject: | Re: Rotax pistons melting |
This should stir a hornets nest ------------------ complete waste of FN money. Why do I say that you ask -- because when I was having our Engine problems I bought two of these units (similar) to install on our oddy's. When my brother blew his engines I told him to keep a very close eye on the gauge. He did just that and told me that the gauge never went over 1100'F and yet we blew another Engine. That was one of the engines that only went about 100 yrds before it blew up -- no FKN lie. Also (as I found out later) you can not use this gauge to jet your Engine. Your Engine must be good to go and then if the temp spikes a bit you shut her down. Well buddy if you are looking at gauges you're gona have a huge crash. Keep your head on a swivel and eyes on the road. I am not a fan of gauges. All they will tell you is the Engine is now FKD. Most of the time you are not looking at them because there is no time. If you are looking at it and you see something then it's probably to late. The reason I have this mentality about gauges is that I used to race cars. Formula sports cars. We had oil pressure, water temp, rpm range all set on relays to cut the ignition if something went wrong. I told my dad at the time that I got no FN time to look at the gauge so make it automatic shut down. He did. I literally had no time to look unless I was on a straight away and even then I only had seconds to look. At 170 mph your gona die fast. Same holds true for an oddy. Don't waste the money. |
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| Author: | Specter [ Mon Feb 05, 2018 3:35 pm ] |
| Post subject: | Re: Rotax pistons melting |
go oddy wrote: Thanks. read it last night. Very good article. another good one. http://mcbperformance.com/p-25418-pisto ... auses.html |
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| Author: | canadian oddy [ Mon Feb 05, 2018 4:20 pm ] |
| Post subject: | Re: Rotax pistons melting |
In a detonation scenario that gauge won't help you. My brother was looking at the gauge the whole time before the Engine blew a hole in the piston and he said it didn't go over 1100'F |
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| Author: | go oddy [ Mon Feb 05, 2018 5:22 pm ] | ||
| Post subject: | Re: Rotax pistons melting | ||
canadian oddy wrote: In a detonation scenario that gauge won't help you.
My brother was looking at the gauge the whole time before the Engine blew a hole in the piston and he said it didn't go over 1100'F
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| Author: | Specter [ Mon Feb 05, 2018 5:37 pm ] |
| Post subject: | Re: Rotax pistons melting |
go oddy wrote: canadian oddy wrote: In a detonation scenario that gauge won't help you. My brother was looking at the gauge the whole time before the Engine blew a hole in the piston and he said it didn't go over 1100'F well damn. Glad you posted that. I guess i can still use the EGT to adjust the air/fuel mixture... at least to some degree. Maybe see if the Engine starts to run hotter at certain throttle positions. |
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| Author: | Specter [ Mon Feb 05, 2018 7:02 pm ] |
| Post subject: | Re: Rotax pistons melting |
Just got off the phone with Farr-offroad. It was running lean. The marine carbs have been a problem for them and they don't use them anymore. They had to use them on the FL400 because you couldn't fit regular carbs in the space between the Engine and transmission. Now they have a new intake so they can use regular carbs. He is going to send out replacement cylinders, pistons, rings and even a new intake and carbs. =) I couldn't be any happier. Anyone want a set of marine carbs? You pay for shipping and you can have them. But i highly recommend you don't use them for anything but a boat anchor. |
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| Author: | canadian oddy [ Mon Feb 05, 2018 7:07 pm ] |
| Post subject: | Re: Rotax pistons melting |
Well we all knew Manny was a stand up guy and this proves it. You can't get a better deal than that. |
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| Author: | go oddy [ Mon Feb 05, 2018 7:09 pm ] |
| Post subject: | Re: Rotax pistons melting |
I'm using flat side carbs on my Rotax twin. Pulls like a freight train. Starts easy, Idles smooth etc. |
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| Author: | FloridaEdd [ Mon Feb 05, 2018 10:45 pm ] |
| Post subject: | Re: Rotax pistons melting |
That is just awesome. Congrats |
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| Author: | adnoh [ Tue Feb 06, 2018 11:34 am ] |
| Post subject: | Re: Rotax pistons melting |
Cool, it always pays to talk with your Engine builder. Now, no more 7 range plugs. Do as he list on his site 9 Inspect the rods since it went lean with blow by Good luck Check your cranking compression and make sure it's in line with Farr's specs While your at it measure each exhaust port roof to top of cylinder must be close. Cc your heads make sure there close Check you head gasket thicknesses before install. Have some fun while your at it. Even though he is sending parts check your ring caps in each cylinder Check your pistons of, done at ring land, 10 mm up from bottom of skirt. If all in check proceed with build any thing seam off call your builder. |
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| Author: | Kuma [ Tue Feb 06, 2018 9:35 pm ] |
| Post subject: | Re: Rotax pistons melting |
as was mentioned earlier on, clean out your pipe before putting it back on. the EGT from what I have heard should be mounted about 8" from the piston, do some research on that as I have a bad case of CRS. The EGT should not be used so much for tuning as a monitor, once you have the tuning where you want it now you can use the EGT to fine tune for elevation and temperature changes, personally I have my Engine tuned so it runs great at my ride spot, glamis in cool conditions, about 60-65 degrees, when it's warm, 85-90 it still runs alright, not really worth the hassle of changing jets, if I were racing, different story. |
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| Author: | Specter [ Wed Feb 07, 2018 12:50 am ] |
| Post subject: | Re: Rotax pistons melting |
adnoh wrote: Cool, it always pays to talk with your Engine builder. Now, no more 7 range plugs. Do as he list on his site 9 Inspect the rods since it went lean with blow by Good luck Check your cranking compression and make sure it's in line with Farr's specs While your at it measure each exhaust port roof to top of cylinder must be close. Cc your heads make sure there close Check you head gasket thicknesses before install. Have some fun while your at it. Even though he is sending parts check your ring caps in each cylinder Check your pistons of, done at ring land, 10 mm up from bottom of skirt. If all in check proceed with build any thing seam off call your builder. Already running BR9ES plugs as recommended on the site. Cranking pressure? you mean cylinder pressure? will do that. might just get a new head gasket. Also going to get a new head (well used head). As for the other stuff, will definitely do those tests. What about testing for a crank seal leak? That could cause it to run lean, from what i have been reading. Also going to check the ignition timing. will definitely clean out the exhaust. Thanks KUMA, I will do some research to find the best location for the temp sensor. Then I can ride it without worry. =) can't wait. |
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| Author: | canadian oddy [ Wed Feb 07, 2018 2:07 am ] | ||
| Post subject: | Re: Rotax pistons melting | ||
canadian oddy wrote: Specter wrote: canadian oddy wrote: Your going to have to do a complete check list I think. 1) timing 2) fuel pump flow 3) jetting 4) float levels 5) air leaks 6) rusty gas tank and pickup lines ?? Avgas well it only had about 4 hours on it before the meltdown the first time. Then only about 2 hours again before the second piston melted. maybe riding style? I really don't know. 1. I will definitely check the timing first. 2. will then fuel pump. 3. jetting is good, i can set it to run rich (which i did). 4. no floats (it has marine carbs on it). 5. checked for air leaks with carb cleaner. 6. gas tank look really good inside. but i will replace all the fuel lines. I was checking around and at 150 is should be able to run on pump gas. it has to be either number 1 or 2, or both. Not so fast. You said you checked for leaks with carb cleaner ---- give it up. I got no faith in that. You need a test rig. You need a test rig. Below is a pdf of one for a single cylinder. Not sure how the guys with rotax do it.
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| Author: | Specter [ Wed Feb 07, 2018 8:17 pm ] |
| Post subject: | Re: Rotax pistons melting |
canadian oddy wrote: canadian oddy wrote: Specter wrote: canadian oddy wrote: Your going to have to do a complete check list I think. 1) timing 2) fuel pump flow 3) jetting 4) float levels 5) air leaks 6) rusty gas tank and pickup lines ?? Avgas well it only had about 4 hours on it before the meltdown the first time. Then only about 2 hours again before the second piston melted. maybe riding style? I really don't know. 1. I will definitely check the timing first. 2. will then fuel pump. 3. jetting is good, i can set it to run rich (which i did). 4. no floats (it has marine carbs on it). 5. checked for air leaks with carb cleaner. 6. gas tank look really good inside. but i will replace all the fuel lines. I was checking around and at 150 is should be able to run on pump gas. it has to be either number 1 or 2, or both. Not so fast. You said you checked for leaks with carb cleaner ---- give it up. I got no faith in that. You need a test rig. You need a test rig. Below is a pdf of one for a single cylinder. Not sure how the guys with rotax do it. cool thanks. that looks easy enough. seal it all off and pressurize it. |
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| Author: | ZeroClient [ Thu Feb 15, 2018 11:20 am ] |
| Post subject: | Re: Rotax pistons melting |
Measure your squish band and post here please. http://forums.everything2stroke.com/thr ... ing-Squish |
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| Author: | Specter [ Fri Mar 16, 2018 1:37 pm ] |
| Post subject: | Re: Rotax pistons melting |
ZeroClient wrote: Measure your squish band and post here please. http://forums.everything2stroke.com/thr ... ing-Squish actually think that is part of the problem. Apparently the 583 head has less volume than the 617 head. So I have been using the wrong head, which was causing that high compression. FarrOffroad sent 2 brand new cylinders, pistons and rings. =) I will keep you guy posted as things progress. |
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| Author: | Specter [ Mon Apr 30, 2018 12:07 pm ] | |||
| Post subject: | Re: Rotax pistons melting | |||
Farr-Offroad sent me all the parts i needed to get the pilot back to health. New cylinders, pistons, carbs and custom made intake manifold. I put on an ebay head from a 617, that helped fix the 170psi compression issue. It now has 145 both cylinders. Put it all back together and it runs great. It has about 4 hours on it now and runs great. The spark plugs look good too. I couldn't be happier. Runs like new again. =)
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| Author: | go oddy [ Mon Apr 30, 2018 4:20 pm ] |
| Post subject: | Re: Rotax pistons melting |
Sexy intakes. That solves the carb clearance issue. |
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| Author: | ZeroClient [ Mon May 11, 2020 12:00 am ] |
| Post subject: | Re: Rotax pistons melting |
I know this is an old thread but I was doing a search for Rotax 617 engines and this came up. I picked up a Rotax conversion kit designed for FL350r, which was never installed / unused from a local seller. The Engine in the kit is a 617, but it had a 583 head on it! The squish clearance was about 35thou - which is way too tight with a 583 head / 617 cylinder. The 617 head gives clearance of about 65 thou which is on-par with pump gas. Honestly I don't even think race gas would have helped a 617 with a 583 head. Stroke distance is about 4mm difference between 583 & 617. Different crank, cylinders, and head between the two engines. 583 (bore 76 mm x stroke 64 mm) vs 617 (bore 76 mm x stroke 68 mm) The 583 head BOLTS to a 617, but it will cause burn-downs. If I had not picked this out I would have been in the same boat as the OP. Good thing I took the head off, measured bore/stroke, and that's when the situation revealed itself. On the good side, a good used 617 head only cost me $50. Thing is, 583 engines are more plentiful, whereas 617 only sold for about 2 years. All good engines, just the parts are not interchangeable. 617 parts are marginally harder to locate. |
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| Author: | Kuma [ Mon May 11, 2020 3:48 pm ] |
| Post subject: | Re: Rotax pistons melting |
always check the squish clearance, I bought a modified HO head for my 670 from a known sled performance guy, it was modified to run with domed pistons, I ended up needing to stack 3 gaskets, I don't like doing that, I will see if I can have a custom copper gasket made, the 3 is what it took to get the squish to .06" so far I have not had an issue with the gaskets, I used copper gasket spray to glue that all together. |
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