engine piston check
-
@SpookDog i got a top end athena gasket kit but since i have to rebore to 57mm bore will it be a problem ?
-
No, I have a 58 I use (about 140cc)
You do have to check it doesn’t touch the power valve when it gets to a certain size…
-
@SpookDog yeah i know about power valve, i was just thinking would the top end gasket be smaller than the barrel but it should be fine
-
@SpookDog yo one last thing i made a video today of kicking the bike over just so you can hear the bike make that friction noise to know if the crank is good, idk maybe just my stress is making me hear it or idk here is the vid https://imgur.com/gallery/HRIy3mb
-
@SpookDog yo one last thing i made a video today of kicking the bike over just so you can hear the bike make that friction noise to know if the crank is good, idk maybe just my stress is making me hear it or idk here is the vid https://imgur.com/gallery/HRIy3mb
-
Can’t hear anything over the exhaust! You’ll have to do it turning the stator by hand…
-
@SpookDog no i mean the noise that it makes the first 3times that i kick it or maybe its just the normal sound the bike makes when turned over, as for when its runing it doesn't make any noise
-
@erion1 Have you done a compression test,if something is wrong with the piston or piston rings it should show low compression.
@MadGyver yeah it has low compression its easy to kick and had blow by when i opened it, the bike is waiting for a rebuid i just got a top end athena gasket today i will get a piston in 2-3 weeks and i will send the barrel for a rebore to 57mm im just trying to check if the crank bearings are in good condition as my bike drank coolant before and i was thinking it could of caused corrosion in the bearings and that could sent my whole engine to the moon
-
@SpookDog i will make a vid when i open it up, but all im saying is if that noise is normal i think it comes from crank rotating and the pistons it should be normal as things move there and make friction. anyways i will make a video when i open it up again and send a video and we can discuss a bit more acurately
-
@erion1 After you remove the top end,only an experienced one can tell you if it's ok the bottom end at a 90%.
To be sure 100% you have to dismantle the engine.
When rebuilding,changed conrod just in case,because 0f 56k km's of the engine.bearings still had life and the con-rod was so good that a friend with a machinery shop checked for tolerances and told me to keep it for backup with a new set of bearings.
I just couldn't gamble with a top end rebuild of an unknown internals condition.Piston condition was way better than yours,still have it.
You get me what I mean. No video/sound recording can replace that. -
@erion1 After you remove the top end,only an experienced one can tell you if it's ok the bottom end at a 90%.
To be sure 100% you have to dismantle the engine.
When rebuilding,changed conrod just in case,because 0f 56k km's of the engine.bearings still had life and the con-rod was so good that a friend with a machinery shop checked for tolerances and told me to keep it for backup with a new set of bearings.
I just couldn't gamble with a top end rebuild of an unknown internals condition.Piston condition was way better than yours,still have it.
You get me what I mean. No video/sound recording can replace that.@MadGyver yeah i get what you mean, im not woired that much about the crank i just know that it used to loose my coolant and i know that i drove it everyday and i dont think water could of stayed in the engine to cause corrosion, based on my thinking(haha) i just imagine that the water evaporated from the crank everytime i ran the bike
-
@MadGyver yeah i get what you mean, im not woired that much about the crank i just know that it used to loose my coolant and i know that i drove it everyday and i dont think water could of stayed in the engine to cause corrosion, based on my thinking(haha) i just imagine that the water evaporated from the crank everytime i ran the bike
In my experience with blown head gaskets. The coolant doesn’t rust the bearings or the crank. As long as it hasn’t been too long since it ran and it’s all well lubricated with 2T in the crankcase , it should be fine.
Just keep it lubed and buttoned up till you send off the barrel for reboring.If I’d had a piston disintegrate I’d at least want to flush out the bottom end with clean fuel and oil. Turn it upside down, ect…
I get the impression that you don’t want to remove the engine from the frame tho?…
I understand that we don’t all look at a situation in the same way. Not everyone wants to remove the lump and split the casings.
As long as you clean up the gasket mating surfaces, ect, there’s a good chance that you can just put a new top end on and be fine. It’s mostly about preparation and not re-using head gaskets!
… -
Just a quick dumb question: when you order pistons they have a size listed such as ø56.5 mm.
Is that the diameter of the piston, or the cylinder hole it is supposed to go in?
If it is the diameter of the piston as I suspect, how much larger should the cylinder diameter be?
-
Just a quick dumb question: when you order pistons they have a size listed such as ø56.5 mm.
Is that the diameter of the piston, or the cylinder hole it is supposed to go in?
If it is the diameter of the piston as I suspect, how much larger should the cylinder diameter be?
@Hark_Ptooie yeah its the diameter of the piston, the standard is 56.00mm if you get a bigger one you need to rebore the cylinder so that piston can fit
-
@Hark_Ptooie yeah its the diameter of the piston, the standard is 56.00mm if you get a bigger one you need to rebore the cylinder so that piston can fit
-
@erion1 i ordered a piston now but im concerned about my rod bearing or crank bearings so im thinking about spliting the cases, so i want to know if the mid case gasket is reusable or do i need a replacement
-
Doesn’t have one. It’s just sealant.
The clutch casing gasket? always good to get new ones.
If I’m stuck. I reuse them if they’re in really good shape.. -
Most people recommend Yamabond. It’s a silicon RTV type sealant I believe. I have used Hermatite red without any leaks or problems. I prefer it just because it doesn’t shed ‘worms’ of sealant into the gearbox. Not so important on a 2/ but can be death to a 4/ if it clogs an oilway…
