How many cc's to upgrade?

[duivendyk]

Power output is roughly proportional to displacement,so going from 24 to 31 cc, an increase of 7cc, would represent close a 30%!! increase in torque (and power),assuming they are the same type engines,that is both 2 strokes or 4 strokes.Not to be sneezed at if you have little power to begin with.If the 31 cc engine is a 2 stroke and the original one a 4 stroke the increase could be even higher.If you crave more getup&go ,I'd say: go for it,assuming that making the change is relatively painless.

 

[fetor56]

If u think your getting a better engine then upgrade....after the work is done you'll probably be glad.

 

[Happy Valley]

In my recent experience, meh, not much difference in 7cc's. I swapped a 33cc 4 stoke with a 40cc 2 stroke a number of times this past summer, same bikes, same drive systems.
The smaller 4 stoke still had more torque and the larger 2 stoke, as expected, had a bit more top speed.

 

[duivendyk]

The reality is that engines cannot be compared based strictly on displacement,there are a host of factors that enter into it.For instance the R466 2 stroke with around 50cc can put out around 4 HP (at high rpm) due to superior engine breathing.But to take advantage of this superior high speed performance, the gearing would have to be lower since the low/mid speed torque is not much higher than less highly tuned engines (and may actually lower).The only valid comparison is to look at the HP/rpm chart or max power/rpm info.This is usually not easy to come by.The best thing that can be said is that based simply on displacement 2 strokes can only be compared to other 2 strokes,and the same applies to 4 stroke engines.2 strokes tend to be more peaky,so in the abscense of a multispeed transmission a lower output 4 stroke may well be easier to live with in terms of overall performance.If you are dealing with the same type of engine from he same manufacturer you are an safer ground.It's pretty much guaranteed that the larger engine will outperform the smaller one.

 

[rkbonds]

Initial set-up

Ok, I got around to getting everything hooked up today still have to do a little more work on it but, this gave me a good idea of what to expect. Here's some pics of what I have going now, it's not exactly how it's going to end up but it'll give you a pretty good idea of where I'm heading. No garage and rain made for a short day of playing with my bike.

 

[rkbonds]

I'm liking this new set up a lot! I lowered the triple tree to give it a more level push and that made a huge difference. If I want I can ride without having to pedal at all. I haven't checked top speed yet I've kept it between 10 -15 max during testing and that's not even half throttle. I'm also going to completely box the trailer in with milk crates to hide what's underneath but, also for use when I go to the store. I'll get some more pics up as soon as it decides to quit raining.

 

[rkbonds]

Ok, today I went for a 8 mile ride in 22 degree weather the bike did really well. I need to do some work on my throttle it's not opening completely (easy fix). Other than that I'm very pleased with the new set up. The only other problem I have is it tends to want to bounce, hop, etc... if you don't baby the throttle. Thought about adding some weight or maybe try some kind of spring tensioner? And see if that helps.

 

[5-7HEAVEN]

Dang, rk, looks like you're towing a pocketbike!

Law man might think it looks unsafe traveling at speed. You mentioned dropping the front fork. If you drop the fork all the way down, remove the seat and all the panels it would look better.

JMO

 

[rkbonds]

I plan on doing just that then I'm going to add milk crates to each side to concel and haul stuff in. I'll try and post more updated picks today if I get the chance.

 

[rkbonds]

I've done some more mods and have been able to solve the bouncing problem I was having during take off by using a spring as a tensioner and 7lb worth of weight. This has been the best mod I've done to the bike yet. I am very pleased with how this has turned out. I still have more cosmetic work to do but that's about it.