New Cylinder on an Old Bike

[Millar]

Hi Guys, first post on here, I've been lurking for far too long. I ended up buying a 2006 ec300 about a year ago based on this forum and I've been loving how it feels over the xr600 I was riding before.

I've read that the older bikes were tuned to have more power in the lower rev range, sacrificing the top end compared to the later bikes, which I've noticed. I stupidly had a test ride on a 2013 ec300 and had it doing power wheelies in third gear which mine would never do! I definitely prefer the power delivery of the newer bikes!

Just wondering what it would take for my bike to run like a new one. Has anyone put a new cylinder from a later bike on a older bike and noticed the power characteristics change much? Is it only the cylinder that has changed over the years?

I've spent a lot a of time playing with the jetting and although it runs a lot better than when I bought it, it doesn't have the top end that the new bikes have. The bike is basically stock apart from the jetting. It still has the banana silencer an a uncut head. Machining the head is on my things to do list but I haven't got around to it yet...

I have been considering getting a new 300 and have the funds but if I can get mine to run like a new one it would probably last me another year or more.

[bowhunter007]

My '01 300 would loft the front tire as easily as any new(er) bike. I'd give her a good once over. Compression test, even teardown the top end, and take a peek inside. Do you know how many hours, on the top end? Anyway, that's where I'd start. However, if given the option...I'd have the new bike and pick away at the old one ' till she's right, or just sell outright.

[Cruiser]

And check to see if it has the reed spacer in it,, if so remove it for more power. That was there to tame it out.

[spooly]

Originally Posted by Cruiser

And check to see if it has the reed spacer in it,, if so remove it for more power. That was there to tame it out.

can u explain more about this reed spacer??

[Millar]

Originally Posted by bowhunter007

My '01 300 would loft the front tire as easily as any new(er) bike. I'd give her a good once over. Compression test, even teardown the top end, and take a peek inside. Do you know how many hours, on the top end? Anyway, that's where I'd start. However, if given the option...I'd have the new bike and pick away at the old one ' till she's right, or just sell outright.

Thanks for the reply, I don't have any problem lifting the front wheel when I need to but I do have to put some work into it. My bike pulls really well low in the revs (as well as a new one) but really lacks in the top end. That's why I was thinking it might be due to changes in the cylinder design over the years. I put a new piston in it with a .5mm base gasket not long after I bought the bike and it did run a bit better. I've put about 80 hours on the current top end so it'll be due for another soon.

It's got good compression, PV moves as it should and the reed petals are in good condition. I'm struggling to think of anything else that might be taming the top end so much. The only thing that I haven't really checked is the timing, someone might have played with that I guess.

A new bike is very tempting at the moment but I'm thinking that there might be better things to spent the cash on like travel, I'm only 21.

Originally Posted by Cruiser

And check to see if it has the reed spacer in it,, if so remove it for more power. That was there to tame it out.

I'll do this next I think. I was going take it out a while ago but there seems to be a lot of conflicting opinions on how it affects the power delivery.

[Millar]

Originally Posted by spooly

can u explain more about this reed spacer??

From what I understand the reed spacer was put in the 300s to correct the the crankcase volume vs cylinder displacement ratio. From what I've read it seems that taking the spacer out can give a stronger top end but sacrifices a bit of torque at the bottom. I'll post back here when I take mine out but I won't be able to do it for a few weeks.

[spooly]

Originally Posted by Millar

From what I understand the reed spacer was put in the 300s to correct the the crankcase volume vs cylinder displacement ratio. From what I've read it seems that taking the spacer out can give a stronger top end but sacrifices a bit of torque at the bottom. I'll post back here when I take mine out but I won't be able to do it for a few weeks.

Thanks. .it will be interesting to hear the results... me personally I wouldn't sacrifice bottom pull for top..

Sent from my GT-I9300 using Tapatalk

[Zman]

I would measure your compressoin and then measure your cylinder head squish. I suspect having the head cut will make a world of difference for you. A cheap easy thing you can do right now is advance the ignition timing a few degrees. Be careful to listen for detonation (rattle like a can full of marbles). Depending on your funding for this project you may also want to have the cylinder ported as some of the cylinder castings were kind of rough.

[Neil E.]

The exhaust has to flow well, so make sure the muffler core is positioned correctly and the packing stays where it should.

[gassergrant]

My old GG goes like a stabbed rat, pops the wheel up in theird no problem, I don't know much about it but changing the port timing ie porting and polishing
Try carbon reeds remove the spacer which I did. I've put a full fmf system on too use good hight octain feul , like here in the uk we get 98 Ron use that. It's not as drutall as a Mx bike but has no probs keeping up on track