Honda CR125R piston slap?

[Stusmoke]

when I did the top end on my 2002 Honda CR125 this past November I ordered the "A" piston for mine to go with the "A" cylinder when the parts arrived I had a "B" piston and a note from the factory stating that you can NOW use the "B" piston in the A cylinder Honda discovered that the tolerances were much closer and could use the B piston with A cylinder without any problems as far as any other years useing those two together I couldn't tell you. Honda pistons are for break in purposes only OOOMMMGGG thats a good one super trucker who told you that BS your pro racing buddies and there mechanics and team managers??

  That,s the word right from DGY, on some cr125 another year cr piston works better, other manufacters pistons also, especially for expert level mod engines. Yeah honda just figured it out, that you can use the wrong size piston, whatever man. Let,s just try to help Stu out, or you can throw more insults my way, I don,t care.

Agreed. If either of you feel the need to trade barbs please take it off my thread. Not upping either of you just saying please don't bother here. I want to get this sorted and back on the rev limiter.

Ok. My current status is: Con rod says B, piston is a vertex and has 1001 on it. Piston was also damned hard to get back into the cylinder. Theres a notch in the slot for the ring. My question is, is that notch where the ring gap is meant to be? Cos I've found my problem if the answer is yes. Numb skull didn't have it anywhere near there. My current shopping list at Rockymountain stands at:
All the seals, gaskets, separators and oil seals that were listed for the water pump (They didn't have a kit for it), base and head gaskets and a manual. I really don't think the piston is to blame anymore, it has absolutely no budge whatsoever when inside the cylinder and moves through its strokes well without a hitch. I think the rattling noise could be coming from the side to side play in the conrod maybe. Or maybe as Jeram pointed out, the powervalve.

Will I need any specific tools for inspecting the powervalve? Also whats the best way of going about it? Cheers

[2T Institute]

Ok. My current status is: Con rod says B, piston is a vertex and has 1001 on it. Piston was also damned hard to get back into the cylinder. Theres a notch in the slot for the ring. My question is, is that notch where the ring gap is meant to be? Cos I've found my problem if the answer is yes. Numb skull didn't have it anywhere near there. My current shopping list at Rockymountain stands at:
All the seals, gaskets, separators and oil seals that were listed for the water pump (They didn't have a kit for it), base and head gaskets and a manual. I really don't think the piston is to blame anymore, it has absolutely no budge whatsoever when inside the cylinder and moves through its strokes well without a hitch. I think the rattling noise could be coming from the side to side play in the conrod maybe.

Looking at your youtube video I don't think your in any position to judge anyones engine building. The video sowed completely normal side clearence on big and little ends. Ever consider the ring moved in the groove while you were banging it around? Piston sows no sign of hitting the head, so unless the crank mains ave movement, would be easy to think this 'noise' is the sound of a CR125 " title="Roll Eyes" class="smiley"> 

[Stusmoke]

Ok. My current status is: Con rod says B, piston is a vertex and has 1001 on it. Piston was also damned hard to get back into the cylinder. Theres a notch in the slot for the ring. My question is, is that notch where the ring gap is meant to be? Cos I've found my problem if the answer is yes. Numb skull didn't have it anywhere near there. My current shopping list at Rockymountain stands at:
All the seals, gaskets, separators and oil seals that were listed for the water pump (They didn't have a kit for it), base and head gaskets and a manual. I really don't think the piston is to blame anymore, it has absolutely no budge whatsoever when inside the cylinder and moves through its strokes well without a hitch. I think the rattling noise could be coming from the side to side play in the conrod maybe.

Looking at your youtube video I don't think your in any position to judge anyones engine building. The video sowed completely normal side clearence on big and little ends. Ever consider the ring moved in the groove while you were banging it around? Piston sows no sign of hitting the head, so unless the crank mains ave movement, would be easy to think this 'noise' is the sound of a CR125 " title="Roll Eyes" class="smiley"> 

No I definitely checked everything BEFORE I moved anything around. The ring was definitely out of place and it is most definitely NOT the sound of a 125 engine. The wristpin was out of place, the big end of the rod was moving around both up down and side to side, its hard to see in that vid though. Everything is hard to see I had auto focus off on my phone. Also, to clarify the wristpin bearing is mean to slot inside the small end of the conrod right? Cos I can't see one there. I could be wrong though it was just something I noticed. Oh and theres also scoring on the crankshaft.
I know there is meant to be a tiny bit of side to side play in the big end, theres a little bit too much for my tastes. And also, the small end moves freely from side to side on the wristpin. I'm over it though, if it hasn't grenaded by now its unlikely that it will. Definitely need to do those waterpump seals though.

[Jeram]

powervalve is a simple test,

just lockwire it open or shut the next time your ride the bike and see if the noise still exists. if this is the cause of the noise just make sure the cables are adjusted properly and then if the noise is still there just put up with it  as its not doing any harm


side to side movement in the small end is purely based on the movement in the big end. ie: it is free to move as much as it likes but is limited by the big end crank washers

[Stusmoke]

powervalve is a simple test,

just lockwire it open or shut the next time your ride the bike and see if the noise still exists. if this is the cause of the noise just make sure the cables are adjusted properly and then if the noise is still there just put up with it  as its not doing any harm


side to side movement in the small end is purely based on the movement in the big end. ie: it is free to move as much as it likes but is limited by the big end crank washers

Alright if you're sure. I kinda wish I had thought of that test for the powervalve though When I tore it down  I first noticed those scratches on the crank and the up/down play of the conrod. aswell as the side to side play. I knew immediately that the piston can hardly move side to side while its in the cylinder though I'm not quite that retarded even though nothing seemed to be wrong, besides that ring being out of place I'm still happy that I tore it down, never know what numb skulls like the previous owner do to their bikes. Oh and when I tore the engine down there was practically no coolant in it, so I texted him asking if he had coolant and he said no... Yes... No. Thats right. No wonder it was running so goddamn hot its a miracle it didn't seize.

Thanks for the help guys. Ordering in my stuff now and I take a pic of the finished product too.

[Jeram]

oh and when you lockwire it open, be sure to disconnect what ever it is that drives the powervalve, (gear, cable, shaft ect)

[Stusmoke]

oh and when you lockwire it open, be sure to disconnect what ever it is that drives the powervalve, (gear, cable, shaft ect)

I'm sure you're unsuprised when I say this but I probably wouldn't have done that

Cheers mate

[2T Institute]

No I definitely checked everything BEFORE I moved anything around. The ring was definitely out of place and it is most definitely NOT the sound of a 125 engine. The wristpin was out of place, the big end of the rod was moving around both up down and side to side, its hard to see in that vid though. Everything is hard to see I had auto focus off on my phone. Also, to clarify the wristpin bearing is mean to slot inside the small end of the conrod right? Cos I can't see one there. I could be wrong though it was just something I noticed. Oh and theres also scoring on the crankshaft.
I know there is meant to be a tiny bit of side to side play in the big end, theres a little bit too much for my tastes. And also, the small end moves freely from side to side on the wristpin. I'm over it though, if it hasn't grenaded by now its unlikely that it will. Definitely need to do those waterpump seals though.

If the ring was not in the groove the engine would not run or even turn over. How on earth was the gudgeon pin 'out of place' ?
The small end SHOULD move side to side. Again , your looking at things that are entirely normal.

[Jeram]

if the small end bearing was missing, the motor would have lasted less than a few seconds before the rod lets go.

the only way the gudgeon could be out of place would be if a c-clip was missing? even then aslong as it wasnt destroying your cylinder it shouldnt be making any sound.


If your worried about the crank, just split the cases and have it rebuilt, its not expensive.

[Stusmoke]

if the small end bearing was missing, the motor would have lasted less than a few seconds before the rod lets go.

the only way the gudgeon could be out of place would be if a c-clip was missing? even then aslong as it wasnt destroying your cylinder it shouldnt be making any sound.


If your worried about the crank, just split the cases and have it rebuilt, its not expensive.

This whole engine just looks dodgey but if you guys are sure, I drop my case.

No I definitely checked everything BEFORE I moved anything around. The ring was definitely out of place and it is most definitely NOT the sound of a 125 engine. The wristpin was out of place, the big end of the rod was moving around both up down and side to side, its hard to see in that vid though. Everything is hard to see I had auto focus off on my phone. Also, to clarify the wristpin bearing is mean to slot inside the small end of the conrod right? Cos I can't see one there. I could be wrong though it was just something I noticed. Oh and theres also scoring on the crankshaft.
I know there is meant to be a tiny bit of side to side play in the big end, theres a little bit too much for my tastes. And also, the small end moves freely from side to side on the wristpin. I'm over it though, if it hasn't grenaded by now its unlikely that it will. Definitely need to do those waterpump seals though.

If the ring was not in the groove the engine would not run or even turn over. How on earth was the gudgeon pin 'out of place' ?
The small end SHOULD move side to side. Again , your looking at things that are entirely normal.

Okay, I've got the good graces to accept when I'm wrong. I'm wrong. If you're sure its normal I'm sweet with it. The whole ting looks dodgey to me, but to be fair this is the first time I've ever taken the jug off a bike. Well besides that fooper that I used to familiarize myself with how a four joke went together. Oh and just to clarify I meant to gap in the ring on that little upwards grove on the piston. not that the whole ring was out of the grove lol. Not quite that stupid.