Pinittowinit
New member
Lol I always do that. 3.5mm correct. Can someone explain the effects of the post timing being to high or low
300 to a 200
- Thread starter Pinittowinit
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Pinittowinit
New member
I wonder what would happen if you put on a 200 pipe on a 300.
Jakobi
Super Moderator
The ports (timing, position, sizing, angles, etc) are the foundation of how a 2T engine works. You could read for days and still only know the basics. Your best approach would be to take a port map and then use some software to run some simulations and see what you end up with.
Pinittowinit
New member
What do the last letters mean? The previous years are different
Pinittowinit
New member
I'll ask my buddy to run it threw his software. Question... If I simply raise the 200 cylinder that would put the exhaust ports 3.5mm low correct? And what about advancing the timing? In theory would that spark at the proper port timing?
Zman
Platinum Level Site Supporter
You should not need to change the crank. I think the case volumes are different and you will have big voids with the 200 crank in the 300 cases.
Until you mock it up with the 200 cylinder on the 300 bottom end to get some real numbers, you will just be guessing.
To raise the cylinder, you can make a metal plate to sandwich between gaskets or you can make a thicker base gasket from some 1/16" Felpro sheet gasket material. I bought some of this gasket material from Autozone and cut my own to correct the port timing on a 2001 XC250. I never liked the idea of stacking several gaskets.
The 62.5mm bore and 72mm stroke will yield 221cc.
I am not sure how the balance will work out since the 200 piston is likely to be lighter than the 300 piston. It may not be an issue, but if it is I think the Wossner pistons are heavier and maybe you can find a HD pin that will get you closer to the weight of a 300 piston to minimize vibrations.
Until you mock it up with the 200 cylinder on the 300 bottom end to get some real numbers, you will just be guessing.
To raise the cylinder, you can make a metal plate to sandwich between gaskets or you can make a thicker base gasket from some 1/16" Felpro sheet gasket material. I bought some of this gasket material from Autozone and cut my own to correct the port timing on a 2001 XC250. I never liked the idea of stacking several gaskets.
The 62.5mm bore and 72mm stroke will yield 221cc.
I am not sure how the balance will work out since the 200 piston is likely to be lighter than the 300 piston. It may not be an issue, but if it is I think the Wossner pistons are heavier and maybe you can find a HD pin that will get you closer to the weight of a 300 piston to minimize vibrations.
Pinittowinit
New member
I can scan an oem gasket and cut a spacer from a waterjet. Even after that then I have the port timing to deal with correct? As well as the PV rod.
Oh we are getting closer lol
Oh we are getting closer lol
Pinittowinit
New member
What will not work?
noobi
New member
He's saying that putting a 200 top end on a 300 bottom end will not work.
I'm of the opinion that if you try hard enough at anything you can at least make something mostly work.
Now doing a 200 top on a 300 bottom is going to require custom fabricating of spacers, and machining of the head to get a cylinder that is at least lined up correctly, without accounting for the screwed up port timing.
Even then, you still have a 300 bottom end which has an optimal case volume for the 250/300s. So you will need to split the cases and likely fill in some of that excess volume in the cases, it's not impossible, but it is difficult to do in place.
You will need port maps of both the 200 and the 250 or 300, what you end up with will probably be closer to a 250 at a guess. Then you will need to make a custom port map and then cut that into the 200 cylinder. If you are doing a lot of cutting it might need to be re plated. You might find out that the 200 has port where you don't want port, so you will need the old port filled up and then re-cut, which certainly means it will need to be re-plated.
The expansion chambers are also an interesting point, on the older models, the 200 used a different pipe to the 250/300s. It looks like they use the same pipe on the newer models, how they changed the engines to do this, i'm not sure.
What i'm trying to say is that if you end up with a 221 or anything between a 200 and a 250 then it is likely that the pipe is going to be off, and i'm not sure how you account for that.
So basically, it might work it you really really want it to. Its definitely not a straight forward swap though.
Why do you wan't to do it?
Pinittowinit
New member
"It won't work" isn't an answer. It can it depends on the level of effort.
Why do it?? Because my engineering mind never stops ticking lol. In this case it's a ton of work. Prolly the best option would be is to get a 200 rod and install that in the 300 crank. And a 200 top end. Now unless I'm forgetting something that should work.
I have a 2010 ec300 but always loved 2honeys. You can get used 300's until the cows come home but not 200's. I was curious on how difficult it was to make a 300 a 200. Curiosity that's all. I won't be doing it anytime soon as my plans have changed. I'm selling my husqvarna SM and will use my 300 for the rare occasions I get to race Supermoto
Why do it?? Because my engineering mind never stops ticking lol. In this case it's a ton of work. Prolly the best option would be is to get a 200 rod and install that in the 300 crank. And a 200 top end. Now unless I'm forgetting something that should work.
I have a 2010 ec300 but always loved 2honeys. You can get used 300's until the cows come home but not 200's. I was curious on how difficult it was to make a 300 a 200. Curiosity that's all. I won't be doing it anytime soon as my plans have changed. I'm selling my husqvarna SM and will use my 300 for the rare occasions I get to race Supermoto
Jakobi
Super Moderator
Later idea won't work either. The 200, 250 and 300 all share the same rod. Its the crank and offset that is different on the 200.
Noobi summed up what I've been trying to say really well. While externally its probably not that hard to space and bolt a 200 cylinder onto a 250/300 bottom end, the work involved in getting it to run the way it should won't be a cakewalk.
If you want a project and have the time and knowledge (or time to gain the knowledge), it would make for a wicked thread. If you want to make a start do as was suggested and map the ports for a few cylinders and start forming an idea of what would need to change.
Noobi summed up what I've been trying to say really well. While externally its probably not that hard to space and bolt a 200 cylinder onto a 250/300 bottom end, the work involved in getting it to run the way it should won't be a cakewalk.
If you want a project and have the time and knowledge (or time to gain the knowledge), it would make for a wicked thread. If you want to make a start do as was suggested and map the ports for a few cylinders and start forming an idea of what would need to change.
Nope.They already share the same rod.
desertgasser300
Banned
Not worth all the work, but fun to chat about.
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Fred1956
New member
I would think this would be more efficient, there is a video somewhere around of him running his practice loop and it sounded strong. I don't know if it still around though...... http://www.gasgasrider.org/forum/showthread.php?t=15599
