2 strokes 4 life
New member
Wait CR250 pistons will fit in the Gasgas EC/DE250?
A peek inside my '05 DE250
- Thread starter AZRickD
- Start date
widebear
Banned
MonkeybuttParts is only a few miles from my house.
As for CR vs EC, the only cross reference I saw was with the TM250.
I can assure you they work, two of my bikes are running them @ $113 each yet! Same goes for the rod kit.
2 strokes 4 life
New member
Widebear thats amazing. Now I know what I am going to run next. THANKS!!!
The work begins tonite.
Any advice on measuring squish (I'm going to use squishy-core solder and then see what modeling clay will do as well)?
Any primo deck height I should attempt to achieve with my vast supply (not) of gaskets? I'd like to try just one gasket if I can get away with it.
Rick
Any advice on measuring squish (I'm going to use squishy-core solder and then see what modeling clay will do as well)?
Any primo deck height I should attempt to achieve with my vast supply (not) of gaskets? I'd like to try just one gasket if I can get away with it.
Rick
cvl05
Gold Level Site Supporter
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Rick, just make sure you get the solder across the middle of piston all the way to the cyl wall with no gap. Also loop in the middle out around spark plug hole, there is a detailed pic at rbdesigns web site. Very easy. Make several impressions, 3 would be enough. Then send your head off to RB. Doos not matter id orings are in place or not for this measure.
Rick, just make sure you get the solder across the middle of piston all the way to the cyl wall with no gap. Also loop in the middle out around spark plug hole, there is a detailed pic at rbdesigns web site. Very easy. Make several impressions, 3 would be enough. Then send your head off to RB. Doos not matter id orings are in place or not for this measure.
I took a look at the innards tonite. Everything looks normal. The BDC piston is almost but not quite flush with the bottom of the port. The power valve is really sloppy. I hear that's normal for Gassers.
Let's see if I can get some 2 megapixal cell phone pics to show...
If not, click on the link.
Bore:
Head:
Let's see if I can get some 2 megapixal cell phone pics to show...
If not, click on the link.
Bore:
Head:
The new Vertex piston and rings are now in the bore. The old piston (looks like a forged Wiseco) had at least one of the rings locked up, both out of spec. PV is now nicely cleaned up. We used one .5mm base gasket if only because that was the sole base gasket in the kit, which also didn't include that little water inlet gasket on top of the head next to the sparky plug hole.
My mechanic-buddy measured the piston at 66.25 mm which, according to this table, http://www.oemcycle.com/Item/product/1268 is a couple tenths of a mm below spec.
We did the squish band measurement. It's averaging around 1.93mm which is at least a one mm above spec IIRC. I look forward toward a new experience in throttle response when I get the head back from the machine shop to cut out the slop. Also, I tried using modeling clay to measure the squish and got a reading of 2.25mm.
On a very related note, yesterday I got a PM from our own "whodat." Unbeknownst to me, his office is just a few miles from my house and he regularly does silly hike-a-bike rides with some of my club members (he used to be a member as well way back when).
He said that when he got his squish mod done, he bought an extra head (from a part-out) so he wouldn't miss a weekend of riding. And he's loaned it to me (and gave me some .125-inch acid-core solder as well).
Yes, I won't miss a weekend of riding, but the other thing I'll be able to do is a seat-of-the-pants A/B comparison between my bike's performance pre and post top end, and then again pre and post squish mod. Coolness.
My mechanic-buddy measured the piston at 66.25 mm which, according to this table, http://www.oemcycle.com/Item/product/1268 is a couple tenths of a mm below spec.
We did the squish band measurement. It's averaging around 1.93mm which is at least a one mm above spec IIRC. I look forward toward a new experience in throttle response when I get the head back from the machine shop to cut out the slop. Also, I tried using modeling clay to measure the squish and got a reading of 2.25mm.
On a very related note, yesterday I got a PM from our own "whodat." Unbeknownst to me, his office is just a few miles from my house and he regularly does silly hike-a-bike rides with some of my club members (he used to be a member as well way back when).
He said that when he got his squish mod done, he bought an extra head (from a part-out) so he wouldn't miss a weekend of riding. And he's loaned it to me (and gave me some .125-inch acid-core solder as well).
Yes, I won't miss a weekend of riding, but the other thing I'll be able to do is a seat-of-the-pants A/B comparison between my bike's performance pre and post top end, and then again pre and post squish mod. Coolness.
SideshowBob
New member
That is cool!
Looking forward with trepidation to tearing down the 250 completely this fall.
Looking forward with trepidation to tearing down the 250 completely this fall.
I got the GG back today with the borrowed head installed. First thing I noticed was the increased resistance in kick-starting it as I performed a few heat cycles. It got up to 103F, so I re-jetted to a fairly rich 175/42. It's tough to discern increased power on the street, but it was ample.
Now I have to wait for RB to get my squish-modded head sent back in Phoenix. What kind of beast am I going to have when that is paired with my new top-end? I may have to go back down to 50T to tame it.
Edit: Looks like a one-day turn-around. Just got the shipping notice.
Now I have to wait for RB to get my squish-modded head sent back in Phoenix. What kind of beast am I going to have when that is paired with my new top-end? I may have to go back down to 50T to tame it.
Edit: Looks like a one-day turn-around. Just got the shipping notice.
Last edited:
That's why I live on the edge, SkiDad.
I only got one gasket (.5mm) from the Go-Fasters kit, so if compression is an issue (we'll do a compression test comparison), I'll have to order more.
A limiting factor is that "pump gas" "Premium" in Phoenix = 91 octane.
On the plus side for me, I ride like a slug and am a short-shifting weenie. I also jet a tad rich and run 40:1 Maxima pre-mix.
One last note, my mechanic said my lower bearing was wobble-free.
I only got one gasket (.5mm) from the Go-Fasters kit, so if compression is an issue (we'll do a compression test comparison), I'll have to order more.
A limiting factor is that "pump gas" "Premium" in Phoenix = 91 octane.
On the plus side for me, I ride like a slug and am a short-shifting weenie. I also jet a tad rich and run 40:1 Maxima pre-mix.
One last note, my mechanic said my lower bearing was wobble-free.
Rick (from a WiFi node at a NW Ohio Captain D's Seafood Restaurant).
I'll be done with my worcation and back in Phoenix and ready to swap heads by Wednesday or so. We'll warm it up, test compression with your head, test compression with my new and improved head.
Only then will you see your precious GG head, Mister WhoDat.
I'll be done with my worcation and back in Phoenix and ready to swap heads by Wednesday or so. We'll warm it up, test compression with your head, test compression with my new and improved head.
Only then will you see your precious GG head, Mister WhoDat.
Back from vacation.
I did two measurements using my analog dial calipers not the digital one I used before at the shop.
These are the numbers from both sides of the squish (I don't know if they were left or right).
.44 / .41 or 1.117mm / 1.041mm
.42 / .43 or 1.067mm / 1.092mm
I'll button it up eventually (it's freakin' hot in my garage).
Rick
I did two measurements using my analog dial calipers not the digital one I used before at the shop.
These are the numbers from both sides of the squish (I don't know if they were left or right).
.44 / .41 or 1.117mm / 1.041mm
.42 / .43 or 1.067mm / 1.092mm
I'll button it up eventually (it's freakin' hot in my garage).
Rick
I bolted it all together and had a failure to start -- sticky float and empty float bowl. I did notice a pronounced resistance to my kick.
Once the float was fixed, it fired on the first kick. Something tells me I'll be blowing a few more db at the next race.
Acceleration was vigorous in the Phoenix heat. Throttle response was quick.
Once the float was fixed, it fired on the first kick. Something tells me I'll be blowing a few more db at the next race.
Acceleration was vigorous in the Phoenix heat. Throttle response was quick.
stay_upright
New member
Did you ever get results from a compression test?
