Conversion of DE/XC250 to DE/XC300
- Thread starter MattR
- Start date
GMP
Active member
Matt,
Since your XC250 is an '01, it likely has the CDI from the 200. Thats one way GGNA got the extra snap out of the XC. I traded my '03 EC CDI for the one that was in my old '00 XC250, it made a difference in more low end but a bit more hit. Point is, if you go with a 300 conversion, it could be a handfull with the CDI you have now.
The 300s also vibrate a little more and pull harder off the bottom. If you race enduros, this could potentially tire you out faster. I was close to buying a 300 in '03, but I'm glad I got another 250. For me the 300 is too much. If you wan't more grunt from the 250 it can be done cheaper than the 300.
Since your XC250 is an '01, it likely has the CDI from the 200. Thats one way GGNA got the extra snap out of the XC. I traded my '03 EC CDI for the one that was in my old '00 XC250, it made a difference in more low end but a bit more hit. Point is, if you go with a 300 conversion, it could be a handfull with the CDI you have now.
The 300s also vibrate a little more and pull harder off the bottom. If you race enduros, this could potentially tire you out faster. I was close to buying a 300 in '03, but I'm glad I got another 250. For me the 300 is too much. If you wan't more grunt from the 250 it can be done cheaper than the 300.
MattR
Super Moderator
Brian, thanks for the ballpark figure. I thought it would be around that and with a new CDI, it will probably be close to $1K.
Glenn, I think you are right about the CDI. I looked through the 2001 parts list and the 200, 250, 300 each got a different CDI. I will look for a part number on mine to compare with to see if mine is 200 or 250... good to know regardless of the conversion.
I also noticed in the parts list that the 300 gets a different reed valve assembly. I think it is just a spacer, gaskets, and mounting bolt. This got me thinking... does the jetting change on the 300 compared to the 250 (with all of these changes)?
Still not sure yet if I will be doing the conversion. Part of me wants to keep my XC250 "as-is" and buy a new EC300. The EC300 would be the "3-stroke" I keep hearing about and I will forgot about buying a 4T bike. If you remember in my other thread about 4T bikes, I just may pick up a EC300 instead and street-legalize it myself. I really love the 2T bikes. Decisions, decisions, decisions...
Glenn, I think you are right about the CDI. I looked through the 2001 parts list and the 200, 250, 300 each got a different CDI. I will look for a part number on mine to compare with to see if mine is 200 or 250... good to know regardless of the conversion.
I also noticed in the parts list that the 300 gets a different reed valve assembly. I think it is just a spacer, gaskets, and mounting bolt. This got me thinking... does the jetting change on the 300 compared to the 250 (with all of these changes)?
Still not sure yet if I will be doing the conversion. Part of me wants to keep my XC250 "as-is" and buy a new EC300. The EC300 would be the "3-stroke" I keep hearing about and I will forgot about buying a 4T bike. If you remember in my other thread about 4T bikes, I just may pick up a EC300 instead and street-legalize it myself. I really love the 2T bikes. Decisions, decisions, decisions...
GMP
Active member
Matt,
What color is the shrink tubing on the CDI harness? I think '01 was the first year they started to color code the CDIs. A 250 EC CDI should be red.
300s come with a reed spacer. Jetting will change, but if you have the LTR needle it will probably work.
If I were going to do a 300 conversion, and intended on keeping the bike for awhile, I'd go the full route and install the counterbalancer. That would kill any vibes and add flywheel effect.
I made the mistake of riding a Yamaha 250F. Now I think I want one. I think I'm faster on it with less effort when conditions are tough. I'm going to get a few more rides on it, rebuild my '03 this winter, and think about it. I think by the time a good GG 250F comes out our bikes will be vintage.
What color is the shrink tubing on the CDI harness? I think '01 was the first year they started to color code the CDIs. A 250 EC CDI should be red.
300s come with a reed spacer. Jetting will change, but if you have the LTR needle it will probably work.
If I were going to do a 300 conversion, and intended on keeping the bike for awhile, I'd go the full route and install the counterbalancer. That would kill any vibes and add flywheel effect.
I made the mistake of riding a Yamaha 250F. Now I think I want one. I think I'm faster on it with less effort when conditions are tough. I'm going to get a few more rides on it, rebuild my '03 this winter, and think about it. I think by the time a good GG 250F comes out our bikes will be vintage.
the cylinder heads are all different as well, you can't use a 250 head on a 300 and vice versa.
MattR
Super Moderator
Just an update...
Thanks Glenn on the color coding. My current CDI has red tubing which means it's a 250 CDI by your description.
I got some part estimates and the amount gets pricey depending upon the extent of the conversion done. Here are some ballpark prices for those of you interested.
Cylinder head = $135
Cylinder = $850
Piston kit with gaskets = $150
CDI = $350
2007 PV assembly = $200
Reed valve spacer and other gaskets = $30
If you do all of the above, it would run about $1700. Any other combination of parts can be determined from above prices.
My plan now is to keep my bike as an XC250. I will redo the topend this winter and stay under $200. I will spend some more money on other common items like bearings, etc. and just get my bike freshened up. IMHO, for $1700, I would search for a used DE300 and have a second bike for slightly more money.
Thanks Glenn on the color coding. My current CDI has red tubing which means it's a 250 CDI by your description.
I got some part estimates and the amount gets pricey depending upon the extent of the conversion done. Here are some ballpark prices for those of you interested.
Cylinder head = $135
Cylinder = $850
Piston kit with gaskets = $150
CDI = $350
2007 PV assembly = $200
Reed valve spacer and other gaskets = $30
If you do all of the above, it would run about $1700. Any other combination of parts can be determined from above prices.
My plan now is to keep my bike as an XC250. I will redo the topend this winter and stay under $200. I will spend some more money on other common items like bearings, etc. and just get my bike freshened up. IMHO, for $1700, I would search for a used DE300 and have a second bike for slightly more money.
Cdi
Just thought I'd add something that may save money to anyone doing this conversion. I've been looking into buying a new CDI and according to part numbers for the 05 and 06 CDI (I didn't check earlier years) the 250 and 300 use the same CDI, so an additional CDI wouldn't be necessary unless you had an older model and wanted the dual map. I don't know if they all hook up the same.
Just thought I'd add something that may save money to anyone doing this conversion. I've been looking into buying a new CDI and according to part numbers for the 05 and 06 CDI (I didn't check earlier years) the 250 and 300 use the same CDI, so an additional CDI wouldn't be necessary unless you had an older model and wanted the dual map. I don't know if they all hook up the same.
GMP
Active member
I know in '03 and '04 they were different, plus, the MC250 CDI was different as well. Before that, no parts manuals were eaisly available so its anyones guess. The CDI from my '00 XC250 made quite a difference in my '03. Cruiser and I both did this mod.
mattmax,
What are you trying to acheive as far as power delivery? Maybe we can help you out.
mattmax,
What are you trying to acheive as far as power delivery? Maybe we can help you out.
I want more MX like power delivery and I believe something is wrong. I have a ton of low end torque, seems 300-ish and seems to fade as RPM increases and it doesn't feel like a jetting issue(I have the LTR kit installed).
I suspect it's my CDI. I was told by Mark at Gofasters that in late 05, Gas Gas ran out of the standard dual map Kokusan CDI used in both the MC and DE, and installed some unknown CDI. I have the unknown CDI-it's installed under the tank rather than in the airbox.
I've talked to someone else with an 05 MC and he has the CDI mounted in the airbox and his CDI has the dual map, confirming that the DE and MC probably share the same CDI. The dual map would be nice, but that's not the issue.
Matt
GMP
Active member
What pipe are you running?
Static timing stock?
Base gasket(s)?
If you have an FMF pipe, it will contribute to the hard low end pull but flatten out early. Try offsetting this by retarding your static timing by one degree. Rotate the stator 1mm counter clockwise and see if it helps a bit. All things being equal, having the head modified will help stretch the power as well. Generally though, any setup that hits hard down low doesn't rev out as well. I assume you want a more mid-top outdoor MX type setup?
Static timing stock?
Base gasket(s)?
If you have an FMF pipe, it will contribute to the hard low end pull but flatten out early. Try offsetting this by retarding your static timing by one degree. Rotate the stator 1mm counter clockwise and see if it helps a bit. All things being equal, having the head modified will help stretch the power as well. Generally though, any setup that hits hard down low doesn't rev out as well. I assume you want a more mid-top outdoor MX type setup?
pipe
I'm running the stock Messico, but I changed the stock silencer to a FMF "Q" that was made for a KTM 300xcw that I modified to fit.The bike is barely broken in and I think the bike ran like it should with the original silencer, but that was before the LTR jet kit and it was rich. I've been trying to get my other bike set up and jetted right, so I haven't put a lot of time in on this one. Nothing else on the motor has been touched.
Do you think the silencer is too long or just too much back pressure and if so, would removing the S/A section help? I've never once seen a two stroke throw out a spark. I could probably even put the Messico guts in the FMF, and I would have the "US Forestry" stamp for riding national forests.
I'm still afraid I might be missing something by not having the proper CDI. Gofasters has them for $300 and that's a lot to find out there's no difference. I guess i could wait until the 07's come out, and see if they change CDI's for the better.
Matt
I'm running the stock Messico, but I changed the stock silencer to a FMF "Q" that was made for a KTM 300xcw that I modified to fit.The bike is barely broken in and I think the bike ran like it should with the original silencer, but that was before the LTR jet kit and it was rich. I've been trying to get my other bike set up and jetted right, so I haven't put a lot of time in on this one. Nothing else on the motor has been touched.
Do you think the silencer is too long or just too much back pressure and if so, would removing the S/A section help? I've never once seen a two stroke throw out a spark. I could probably even put the Messico guts in the FMF, and I would have the "US Forestry" stamp for riding national forests.
I'm still afraid I might be missing something by not having the proper CDI. Gofasters has them for $300 and that's a lot to find out there's no difference. I guess i could wait until the 07's come out, and see if they change CDI's for the better.
Matt
GMP
Active member
Perhaps a member here has a spare they can send you to try. Sorry I don't or I'd help you out. I know the stock '03 CDI was a bit soft on the bottom but had plenty of top. With the Messico the bike should rev better than the FMF, but I never ran a "Q" so I'm not sure how they affect things. The standard Power core and Turbine core work fine, I had one of each and swapped as needed with no difference. Also, be sure your not a bit lean on top causing it to go flat. My '03 prefered jetting that was rich by the numbers.
FWIW, everything I hear about the dual map is its just about worthless on the 250, but makes a much greater difference on the 300.
FWIW, everything I hear about the dual map is its just about worthless on the 250, but makes a much greater difference on the 300.
silencer
I'd stick the old silence back on there, but I cut of the lead pipe to weld to the FMF Q. I didn't think I'd have a use for a silencer without a s/a. I think the stingers on the Messico and FMF are the same length, and I'll drillout the rivots holding the S/A in and try that out.
I'd stick the old silence back on there, but I cut of the lead pipe to weld to the FMF Q. I didn't think I'd have a use for a silencer without a s/a. I think the stingers on the Messico and FMF are the same length, and I'll drillout the rivots holding the S/A in and try that out.
