94 RM250 Piston hitting cylinder head.

Ryan_Glatz
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Ryan_Glatz 12/16/2018 12:08pm
12/16/2018 12:08pm

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Ryan_Glatz
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Ryan_Glatz 12/16/2018 12:11pm
12/16/2018 12:11pm
Ryan_Glatz wrote:
[img]https://p.vitalmx.com/photos/forums/2018/12/16/310600/s1200_15449908721896059449300807965046.jpg[/img]

May I suggest using a dremel or rotor cutting tool like for drywall but with a metal bit if anyone try this themselves because it sucked @$$ using a jigsaw. But it's done and will serve its purpose
Nial_Darragh 12/16/2018 2:30pm
12/16/2018 2:30pm
Hi .... have you the original piston ? If you do check the wrist pin position to your new piston I’m assuming you have a long rod the only way it would work without a spacer , is a special piston a lower wrist pin position
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FahQ
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FahQ 12/16/2018 7:56pm
12/16/2018 7:56pm
Ryan_Glatz wrote:
[img]https://p.vitalmx.com/photos/forums/2018/12/16/310600/s1200_15449908721896059449300807965046.jpg[/img]

Looks like you did it! Not bad for a jigsaw
i'm guessing the previous owner was an offroad guy, thats alot to take off the base

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Ryan_Glatz
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Ryan_Glatz 12/17/2018 3:41am
12/17/2018 3:41am
Nial_Darragh wrote:
Hi .... have you the original piston ? If you do check the wrist pin position to your new piston I’m assuming you have a long...
Hi .... have you the original piston ? If you do check the wrist pin position to your new piston I’m assuming you have a long rod the only way it would work without a spacer , is a special piston a lower wrist pin position
No that was suggested and ruled out long ago. it's actually because the cylinder base has been milled/shaved/serviced. The rod and piston are correct. I just didn't realize the squish band was considerably thinner than a stock cylinder but someone pointed out what most of us missed. Got it running last night. Now I need to jet the carb correctly and I'm good to go.
Ryan_Glatz
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Ryan_Glatz 12/17/2018 3:45am
12/17/2018 3:45am
Ryan_Glatz wrote:
[img]https://p.vitalmx.com/photos/forums/2018/12/16/310600/s1200_15449908721896059449300807965046.jpg[/img]

FahQ wrote:
Looks like you did it! Not bad for a jigsaw
i'm guessing the previous owner was an offroad guy, thats alot to take off the base
Yes your right they were off road I believe. They have an RMX250 carb mounted on it as well.
40acres
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40acres 12/17/2018 10:16am
12/17/2018 10:16am
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike (shorter). Purchased an 03 rod, rebuilt crank and still have a brand new crank for an 04 in the tool box. Check your specs on year models and stroke to be sure, but it looks like you're already too far down the jerry-rig path...
Ryan_Glatz
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Ryan_Glatz 12/17/2018 2:23pm
12/17/2018 2:23pm
40acres wrote:
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike...
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike (shorter). Purchased an 03 rod, rebuilt crank and still have a brand new crank for an 04 in the tool box. Check your specs on year models and stroke to be sure, but it looks like you're already too far down the jerry-rig path...
Actually if you think about it all I'm doing is replacing the aluminum that was shaved off the bottom of my cylinder by PO. So if anything I am correcting a "Jerry rig" back to a stock setup...
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plowboy
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plowboy 12/17/2018 4:25pm
12/17/2018 4:25pm
40acres wrote:
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike...
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike (shorter). Purchased an 03 rod, rebuilt crank and still have a brand new crank for an 04 in the tool box. Check your specs on year models and stroke to be sure, but it looks like you're already too far down the jerry-rig path...
Ryan_Glatz wrote:
Actually if you think about it all I'm doing is replacing the aluminum that was shaved off the bottom of my cylinder by PO. So if...
Actually if you think about it all I'm doing is replacing the aluminum that was shaved off the bottom of my cylinder by PO. So if anything I am correcting a "Jerry rig" back to a stock setup...
Well, technically not "stock" since your new spacer requires an extra gasket which is a potential leak point...BUT...you are obviously a handy fella that digs making things work. Nothing but kudos for ya bro. Rip it.
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Tracktor
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Tracktor 12/18/2018 11:51am
12/18/2018 11:51am
40acres wrote:
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike...
Ran into this issue with an 04 rm125. Full engine rebuild only to find out one of the PO's had a 03 cylinder on the bike (shorter). Purchased an 03 rod, rebuilt crank and still have a brand new crank for an 04 in the tool box. Check your specs on year models and stroke to be sure, but it looks like you're already too far down the jerry-rig path...
Ryan_Glatz wrote:
Actually if you think about it all I'm doing is replacing the aluminum that was shaved off the bottom of my cylinder by PO. So if...
Actually if you think about it all I'm doing is replacing the aluminum that was shaved off the bottom of my cylinder by PO. So if anything I am correcting a "Jerry rig" back to a stock setup...
plowboy wrote:
Well, technically not "stock" since your new spacer requires an extra gasket which is a potential leak point...BUT...you are obviously a handy fella that digs making...
Well, technically not "stock" since your new spacer requires an extra gasket which is a potential leak point...BUT...you are obviously a handy fella that digs making things work. Nothing but kudos for ya bro. Rip it.
Running spacer plates is not uncommon on 2-strokes. Plate needs to be quality material however. BITD I had a 250r motor built by LRD that ran a spacer plate. That bike/engine absolutely ripped. Also had a Cobra 65 that we ran a spacer plate on due to crank being discontinued. That engine was one of the best running 65's we ever had. rest of the bike kinda janky but that motor was smooth and pulled hard. And then I bought a KTM 65 thathad a 80cc stroker setup. You had to run 5 stacked base gaskets to get squish right. The only on that had issues with base gaskets leaking was the 250r. LRD ended up cutting grooves on the sides of plate to hold gasket in place. That or some Yamabond worked a treat...........

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