scrumpyjunior Posted January 2, 2011 Report Share Posted January 2, 2011 (edited) Hi, I was just wondering if anybody could tell me which would 'soften' my gasgas 250 2009 down more; at the moment it can feel as though it wants to rip your arms off, I know there are a few options but I was going to start with either a flywheel weight or a longer magnesium exhaust front pipe? The one which will soften the bike off the most will be the one i'll buy, hope you guys can advise me here! Flywheel weight is around £100 I think, the exhaust pipe around £160, which is why I was only planning on doing one or the other for the time being. Thanks in advance. Steve Edited January 2, 2011 by ScrumpyJunior Quote Link to comment Share on other sites More sharing options...
jse Posted January 2, 2011 Report Share Posted January 2, 2011 Hi, I was just wondering if anybody could tell me which would 'soften' my gasgas 250 2009 down more; at the moment it can feel as though it wants to rip your arms off, I know there are a few options but I was going to start with either a flywheel weight or a longer magnesium exhaust front pipe? The one which will soften the bike off the most will be the one i'll buy, hope you guys can advise me here! Flywheel weight is around Quote Link to comment Share on other sites More sharing options...
7 Posted January 2, 2011 Report Share Posted January 2, 2011 buy a head spacer from gas gas about 14-95,and go for 10t front,42t rear, slow action throttle (black) Quote Link to comment Share on other sites More sharing options...
scrumpyjunior Posted January 2, 2011 Author Report Share Posted January 2, 2011 Steve, A couple of cheaper ways to tone down the Pro is to get a black tube (slow) Domino throttle and try a 10T countershaft sprocket (you probably have the 41T rear sprocket on your bike). Jon Cheers Jon, Already got a black slow throttle on at the moment and I could try the countershaft sprocket... I'm going to add a carb spacer too. However I don't mind paying a fair amount if it's going to dramatically make a difference. Quote Link to comment Share on other sites More sharing options...
mclarke Posted January 2, 2011 Report Share Posted January 2, 2011 Go down the head spacer , flywheel weight ,slow throttle route all good .But the thing i have found made the most difference is a packer between reed block and barrel ,it,s cheap dead easy to fit and a gasgas part and makes a massive difference (credit to lowbrow for this mod). It works by lowering crankcase compression . Try all these and you will have a bike as smooth as silk Quote Link to comment Share on other sites More sharing options...
ormplus Posted January 2, 2011 Report Share Posted January 2, 2011 you think an 09 is wild you should try a 2011. Quote Link to comment Share on other sites More sharing options...
huski Posted January 3, 2011 Report Share Posted January 3, 2011 09 shouldn't be that wild,maybe the exhaust needs repacking?and the mid box washing out Quote Link to comment Share on other sites More sharing options...
sting32 Posted January 4, 2011 Report Share Posted January 4, 2011 09 shouldn't be that wild,maybe the exhaust needs repacking?and the mid box washing out I like pokey 300 engines, that run like old bultaco's compared to your pipey 250... On mine, I do a thick combination of gaskets below cylinder, no head gasket mods, flywheel weight. Here's a Bolt on: S3 makes insert-adjustable volume cylinder heads now, for I think all 3 sizes of bikes (125/250-280/300). Seems they offer a lower compression insert (larger cylinder volume), with that, you would take away a lot of the 'hit' the bike gives you. You should search web for what Gasgas said as to why they lengthend the headpipe, seems it only changes where the gobs of torque (or the "hit") comes in, that is in relation to the RPMs... And not so much about taking it away. So if lengthening it moves that "hit" part to farther up the RPM range, it could be a good thing for you...? Since you would run at bottom end of rpm ranges to keep the bike under you. Lastly, I just thought of as I type.... you could restrict the exhaust slightly, try a spark arrestor screen and modify it with a washer to reduce the final exit hole diameter, then yo can dril out to 'tune'. I suggest the spark arrestor like we have in the states only for a pattern that could be slip on and remove later without ruining the exhaust. Restricting the exhaust has to work, we did it in the 70's and 80's trying to tame the jap bikes. Plus the Montesa's had I think, 3 different baffles in the 4rt stock, that people remove to "unleash" power, so seems it could be something to try to "lame up" the bike a bit. I definitely would make it an easily reversible modification, lol. I'm sure it would be a small project, trying to find that perfect restriction that allows the bike to run OK yet with less power... But would seem easy enough. Quote Link to comment Share on other sites More sharing options...
jse Posted January 4, 2011 Report Share Posted January 4, 2011 So if lengthening it moves that "hit" part to farther up the RPM range, it could be a good thing for you...? Since you would run at bottom end of rpm ranges to keep the bike under you. In my experience, the longer headpipe tends to favor torque production in the lower RPM range, rather than higher. The added length times the pressure/sonic pulses farther apart, which favors cylinder filling in the low/mid range rather than higher RPMs. The S-3 heads are a nice idea as you can change the secondary compression ratio without changing the port timing. Great for us flatlanders who want to ride in Kansas one week and then head up to Colorado for the Ute Cup and a simple change in chambers makes a huge difference. You have to be real careful with exhaust restriction in a two-stroke as you can run into overheating problems very quickly if you go too far and exact placement of the restrictor in the exhaust system is critical. The four-strokes are less prone to these issues. Jon Quote Link to comment Share on other sites More sharing options...
sting32 Posted January 13, 2011 Report Share Posted January 13, 2011 In my experience, the longer headpipe tends to favor torque production in the lower RPM range, rather than higher. The added length times the pressure/sonic pulses farther apart, which favors cylinder filling in the low/mid range rather than higher RPMs. The S-3 heads are a nice idea as you can change the secondary compression ratio without changing the port timing. Great for us flatlanders who want to ride in Kansas one week and then head up to Colorado for the Ute Cup and a simple change in chambers makes a huge difference. You have to be real careful with exhaust restriction in a two-stroke as you can run into overheating problems very quickly if you go too far and exact placement of the restrictor in the exhaust system is critical. The four-strokes are less prone to these issues. Jon Good to know, JSE sir. learning something new every day. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.