Absolute Cheapest 66cc and 49cc Engines I Could Find!

[Frankfort MB's]

I understand, I've heard a 48-54 tooth works well for better hill climbing ablities.... I've always wanted to go faster so idk much about bigger sprockets.

 

[Hello Moto!]

Yeah faster is always better

I would really like to gain a good amount of torque but I also don't want to lose all of my precious 25mph lol!!!

 

[FurryOnTheInside]

Lol I hope you don't change the sprocket, you should not have to.. Should not have a lack of power.. I guess you were unlucky. It is easy to pull the cylinder off anyway, and just measure some things to see if they are indeed off spec.

A super cheap engine would be good for practising dremel work on too. Mine (was not super cheap but) I have to buy it a new cylinder anyway as it has nasty gouges by the transfers so I can practice on that.

 

[Hello Moto!]

I don't know..I've seen in some old gear calculation threads that 26/27mph is a common speed for a 44t rear sprocket. What really throws me off is how the heck was I hittin 35mph with my other bike on the same gear set up

Now I am perfectly ok with buying a bigger sprocket if that IS the problem. Which the more I think of it..the engine pulls good all the way through except from a dead stop. I know that is common for the most part, it's just worse on this new bike than it was on my old one. SO if I have to sacrifice 5mph to be able to pull off with less effort..I would totally do it.

Do you really think there is something else goin on with the motor? It seems sound just not as fast and less torque than my other. What else do you think it could be?

 

[FurryOnTheInside]

I don't know..I've seen in some old gear calculation threads that 26/27mph is a common speed for a 44t rear sprocket. What really throws me off is how the heck was I hittin 35mph with my other bike on the same gear set up

Now I am perfectly ok with buying a bigger sprocket if that IS the problem. Which the more I think of it..the engine pulls good all the way through except from a dead stop. I know that is common for the most part, it's just worse on this new bike than it was on my old one. SO if I have to sacrifice 5mph to be able to pull off with less effort..I would totally do it.

Do you really think there is something else goin on with the motor? It seems sound just not as fast and less torque than my other. What else do you think it could be?

Well yeah, your experience doesn't match others' accounts of their experience with these engines on here.
Well I can speculate blindly or say what I would check first. (Fuel, air, carburetion, compression, spark, exhaust)
Fuel tank strainer blocked.
Fuel line blocked.
Fuel filter blocked.
Carb blocked. With rust, from new gas tank.
Air filter restrictive.
Poor compression (head gasket leak)
Poor spark (bad coil, lead, plug)
Shellac on the four coil whatsit mounting screws that Jaguar's always warning people of.
New EPA compliance exhaust was just a guess really..
All this stuff is free and pretty easy to check even if it is not the likeliest cause. I'm sure in a day or so when a few more experienced builders read this they will have an idea of what is likely.

 

[Hello Moto!]

I can tell you that it is none of those things except maybe the air filter or a head gasket leak. My air filter is kinda jammed in there but I doubt that's it. You can look at that on the 40mm offset intake thread. I guess it could possibly be a head gasket leak but I'm not seeing any residue around the head where I would expect to see something. The engine does get pretty hot though so maybe I'll pull off the head tomorrow and have a look and just replace the head gasket since I have an extra. I didn't think that would be a problem on these. The gasket I have is for my old eBay 66cc. Do these take the same head gasket? Just thought I'd ask before I take the head off.

 

[Frankfort MB's]

Should take the same gasket. You could try a new plug. The plug I got with my kit was a 3 prong POS.... Didn't have very good spark, forgot to tell you about that

 

[Hello Moto!]

Should take the same gasket. You could try a new plug. The plug I got with my kit was a 3 prong POS.... Didn't have very good spark, forgot to tell you about that

Thanks dude. By the way, I thought about the plug too. It's got an NGK B6HS in it. I thought the same thing.

 

[Frankfort MB's]

What do you have it gapped at? Could be part of your problem

 

[Hello Moto!]

Well I popped off the head and everything looked nice. If it was leaking there was absolutely no sign of it. I replaced the gasket and reversed the head just to see if that may have an impact. I'll giver a go tomorrow.

The spark plug is at the factory gap. Is there a proper gap I should use for this engine?