peter falling off Posted February 5, 2008 Report Share Posted February 5, 2008 hi does anyone know if i can get any more power from my sons sherco 80cc was looking to for a 100cc barrel and piston if theres any out there, ive also fitted big wheels, will i need to make changes to the sprockets? Quote Link to comment Share on other sites More sharing options...
howard wallace Posted February 5, 2008 Report Share Posted February 5, 2008 125cc complete top end fit straight on. Bigger flywheel helps too. Quote Link to comment Share on other sites More sharing options...
peter falling off Posted February 5, 2008 Author Report Share Posted February 5, 2008 125cc complete top end fit straight on. Bigger flywheel helps too. hi thanks for the help, i have a 290 sherco fly wheel, timing plate cdi (etc) , do you think this will fit on ok ... Quote Link to comment Share on other sites More sharing options...
howard wallace Posted February 6, 2008 Report Share Posted February 6, 2008 Yes, it will fit and the motor will run fine. You`ll find it a much easier motor to use compared to the 80 that has virtually no flywheel. The correct 125 flywheel is about 10 mm diameter smaller than the 290. Recommend you run heavy to start, and lighten as the boy develops more clutch , throttle,technique. Quote Link to comment Share on other sites More sharing options...
millsy Posted February 17, 2008 Report Share Posted February 17, 2008 You could talk to some tuners about porting, but be aware that the wrong porting can result in a backwards step and you can loose bottom end power very quickly. I have made some vast imporvements in this area on aircooled TY's and Montesa's. I have had a small play with the 315R montesa too, but to be honest, it's not bad if you run 100octane fuel and increas the compression ratio and advance the ignitian. I'd like to try a vortex 10 setting ignition modual as well. To be honest, I did have to start over with my first aircooled TY250 port job. I made it a little too agressive and lost all the bottom end power....was like an early YZ250 to ride...lol. Don't fit a larger Carb as this will result in reduced bottom end power too. Expansion chambers are probably best kept away from unless you have a good understanding of how they work. Again you can loose bottom end power. Keep us posted how you go and what direction you decide to take. Quote Link to comment Share on other sites More sharing options...
peter falling off Posted February 18, 2008 Author Report Share Posted February 18, 2008 hi found myself a 100cc barrel and piston, was gonna fit that today is it worth putting the flywheel and electrics from a 290 on thanks for the advice .. Quote Link to comment Share on other sites More sharing options...
bikespace Posted February 18, 2008 Report Share Posted February 18, 2008 by electrics, do you mean stator? Didn't think they were different under the tank? Quote Link to comment Share on other sites More sharing options...
howard wallace Posted February 18, 2008 Report Share Posted February 18, 2008 Not sure what barrell you have ?. Sherco didn`t make a 100cc. 80cc is 44.5mm bore, 125cc is 56mm, measure what you have before jumpin in. Quote Link to comment Share on other sites More sharing options...
bikespace Posted February 18, 2008 Report Share Posted February 18, 2008 Not sure what barrell you have ?. Sherco didn`t make a 100cc. 80cc is 44.5mm bore, 125cc is 56mm, measure what you have before jumpin in. The early 80's were 100cc (strange as it sounds). They probably realised that it didn't fit in any particular class and changed it to a real 80cc. Quote Link to comment Share on other sites More sharing options...
deandev Posted March 2, 2008 Report Share Posted March 2, 2008 (edited) 125cc complete top end fit straight on. Bigger flywheel helps too. My lads are just about to start riding this year for the 1st time. I have aquired a ty80 and a ty80 whitehawk for this year to learn on. Not going to do any trials as yet just practice. The question is. Next year the 10 year old who is a big tall lump will need a modern bit of kit so i was thinking about a sherco 80, but reading this post would it be better to buy a 125 and then a new 80 head and barrel and down size it? this way he gains experience on a full size bike which he can compete on in the c class. the following year when he moves up to the b class i can switch back to the 125 top end. Am i way of the mark here? as anyone done this?Any opinions would be appreciated Cheers Dean Edited March 2, 2008 by deandev Quote Link to comment Share on other sites More sharing options...
bikespace Posted March 3, 2008 Report Share Posted March 3, 2008 My lads are just about to start riding this year for the 1st time. I have aquired a ty80 and a ty80 whitehawk for this year to learn on. Not going to do any trials as yet just practice. The question is. Next year the 10 year old who is a big tall lump will need a modern bit of kit so i was thinking about a sherco 80, but reading this post would it be better to buy a 125 and then a new 80 head and barrel and down size it? this way he gains experience on a full size bike which he can compete on in the c class. the following year when he moves up to the b class i can switch back to the 125 top end. Am i way of the mark here? as anyone done this?Any opinions would be appreciated Cheers Dean Just in case you're not already aware: The Sherco 80 is a full size bike. My lad has one at the moment. He has a 2005 version. It does have smaller (thinner/lighter) forks on it, but other than that, it's the full 21" front wheel and 18" back wheel, full size tyres the same as my 290. I don't know of any other difference between the bikes (in fact half of my bike's been on his from time to time. That was just in case you were going to go to expense of creating a scaled down 125 for no great benefit. My lad is 11 and the bike would (if not run in to the ground) certainly see him a few years yet. I ride his 80 now and then and the forks feel lighter, but still very rideable, and I'm a VERY big lump. I would get the 80 now, and then sell it on as an 80 in a couple of years, or go for the 125 barrel in a couple of years. Could I suppose upgrade the forks as well if absolutely necessary. Quote Link to comment Share on other sites More sharing options...
copemech Posted March 3, 2008 Report Share Posted March 3, 2008 The 80's I seen had the 17 and 19 inch wheels along with the smaller forks. Not good tires on them either unless you gan get the Vee Rubbers like the small Gasser bike! Ck to be sure what you are getting! Quote Link to comment Share on other sites More sharing options...
deandev Posted March 3, 2008 Report Share Posted March 3, 2008 Cheers for that fellas, just a thought but i guess the 80's hold there money so thats probs the way to go. Regards Dean Quote Link to comment Share on other sites More sharing options...
brian r Posted March 3, 2008 Report Share Posted March 3, 2008 Yes, it seems like the early ones were 99cc or so. You could swap wheels, tires, forks ......... I think the big wheels go on without much problem, maybe the fender stay is different. Al B would know if he'd get over here and post. Quote Link to comment Share on other sites More sharing options...
alan bechard Posted March 4, 2008 Report Share Posted March 4, 2008 I am here, had a version or two, and maybe a hybrid or three Short version is that a "sherco 80" is actually several different bikes depending on the year and what they were doing. My experience was (and my reccomendation would still be) that go ahead and buy the appropriate bike, then resell it and buy the next bike in the line as appropriate. That said, those that know me know my kids rode bikes with lots of various pieces and upgraded and changed bits and that I made and fabricated some, and I also had considerable and much appreciated support from RYP. As too the "more power" I personally have always felt the Sherco's had plenty of power, and it was not something we ever worked to improve. I always used my Jonny Anderson training with my kids and said "much this!!!!" and made the throttle motion with my hand (I think that was about all Jonny ever stressed too me ) Even when I felt the need to demo something on the later 80's (true 80cc bikes) I would slide my svelte self (quit laughing those that know me) onto whoevers 80 was there and could do the level of section those riders were riding. All that said, I am pretty sure that RYP did weight all the flywheels of the bikes coming into the US (not positive, but I believe it too be true, a call to Ryan will get a 100% accurate answer) and I believe Dean and Ryan did some testing with various weights etc on his bike. If I remember correctly (I have slept since then) it was more a smoothing and making it more difficult to stall then to give it more power. Good luck. Quote Link to comment Share on other sites More sharing options...
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