EC200 Cylinder Measurements
- Thread starter WTEC
- Start date
WTEC
New member
I could really use some help with this, I've got a bike here with 4mm of squish and I'm trying to figure out where the problem lies, cylinder, piston, head or rod dimensions. I suspect it's the cylinder as the piston sits about 1-2mm below the exhaust port at BDC, but could be the rod's too short or the piston pin hole is too high as well. It only has one 0.020" base gasket installed.
Wes.
Wes.
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Jakobi
Super Moderator
The piston sits below the exhuast port at BDC. Thats the first time I have read that. My 250 + 300 cylinders required 1.3mm of gasket to get them flush.
Whats the history of the bike Wes? Is this the new one you bought? Sounds like a Friday arv special. 4mm is outrageous. So so so. Lets start. Get the part numbers off the piston, and rod. Check that they are correct. If that checks out, then I'd say its probably the cyl. Warranty?
Whats the history of the bike Wes? Is this the new one you bought? Sounds like a Friday arv special. 4mm is outrageous. So so so. Lets start. Get the part numbers off the piston, and rod. Check that they are correct. If that checks out, then I'd say its probably the cyl. Warranty?
WTEC
New member
This is the new bike I just bought. I have been struggling to get it running decent on the bottom end, numerous jetting combos including 2 different slides and 4 different needles, tried a DEP 200 pipe, then decided to do a compression test which revealed 90psi compression. From there I pulled it apart expecting to see broken/missing rings or cylinder/piston damage but there was no obvious reasons for the low compression (ring end gap is 0.48mm). Last ditched attempt, I checked the squish and found out it was 4mm! I'm thinking the cylinder base wasn't machined enough because of the piston being below the exhaust port, but as I said, it could be a few other things. Here are pictures of the numbers on the piston and rod. Working on warranty, but I didn't buy it through a local dealer this time which is making things a bit more difficult.
Wes.
Wes.
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Jakobi
Super Moderator
Ok. So the rod is a genuine Vesrah (same as the 250 and 300 also). I'd say its unlikely to be that, but if you wanted to measure, I have a used one on the bench beside me. The Piston is also a genuine Vertex stamped so I assume its height would be in spec, and if out it should only be minimal. Which leaves the crank offset, but I'm guessing more likely the cylinder height. The problem being that if you have to machine the cylinder, what effect will that have on the nikasil?
WTEC
New member
It may come down to that, but if anyone has the cylinder height measurement I could prove that this is the problem and hopefully work this out through warranty. Biggest problem right now is that I'm less than a week from a long weekend camping/riding trip and I need this sorted before that.
Wes.
Wes.
WTEC
New member
Glen, I totally agree. My concern is that the factory 200 pipe has been on backorder for 3 months, how long is it going to take to get a new motor?? Our riding season up here is short enough, I'm actually contemplating pulling my 07 250 motor and installing it in this frame, or just ride the 07... I guess.
Wes.
Wes.
GMP
Active member
Wonder if GoFasters has a cylinder in stock they could measure? Maybe even motocrosscenter or greenlandmx, especially if your a customer.
You could rule out the crank by measuring the stroke, and someone else couple do the same with an intact 200 through the spark plug hole. That would mean cases or cylinder. It also may be possible to get a measurement externally that's close enough to prove the point. One would need a large caliper.
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You could rule out the crank by measuring the stroke, and someone else couple do the same with an intact 200 through the spark plug hole. That would mean cases or cylinder. It also may be possible to get a measurement externally that's close enough to prove the point. One would need a large caliper.
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roverhybrids
Member
I don't know if this will help or not but; measuring on the bike I'm seeing about 4" for the cylinder height. obviously may not be accurate enough.
are you sure about the piston?
i've measured (from my 2001) piston that's been replaced, 23mm from top of piston pin to top of piston.
if your piston is not the correct one, meaning, if it doesn't have the correct height, it might allso give these results that you have now...
ciao, Hannes.
i've measured (from my 2001) piston that's been replaced, 23mm from top of piston pin to top of piston.
if your piston is not the correct one, meaning, if it doesn't have the correct height, it might allso give these results that you have now...
ciao, Hannes.
noobi
New member
Done very inaccurately whist the cylinder was on the bike. I measured from the base gasket to the head/cylinder join, 100-101mm.
Don't know whether thats accurate enough, might be enough to indicate whether yours is much taller than that though.
WTEC
New member
Thanks Noobi, now I'm even more worried because mine is 100.5mm. If the cylinder is good then that pretty much leaves the machining on the cases as the issue. If anyone has a cylinder off they could measure with a caliper just to make sure, I'd appreciate it. If anyone has the top end off their 200 I could also use a reference measurement from the case base gasket surface to the piston pin at either tdc or bdc? Or maybe referenced to the crank? I know this is a bit to ask and I am still hoping to hear from the factory on this, but hopefully someone has their 200 apart who can check this out.
Wes.
Wes.
