Spoke to MegaCycle and they told me I have to upgrade to an 11:1 piston. I said nah. Won't do it. So it changes the direction of the build, for which I am grateful. Should be getting some money coming in soon. Then I'll rebuild my top end and do a step by step. I'm stoked to put it back together though and not have to wait for money for a new cam, valve assembly and piston!
Project: 1977 Yamaha TT500D
Started by
PudgyOTE
, Mar 08 2012 01:04 PM
121 replies to this topic
Posted 04 April 2012 - 05:07 PM
Why would you HAVE to upgrade to the 11:1 piston? I don't see why they would want you to.
Posted 04 April 2012 - 08:41 PM
That's cool man. Did you post a rebuild with pics?
I hope I finish mine soon too.
Apparently, the valves lift longer with a MegaCycle cam, so they need the piston to have clearance and apparently the 11:1 has more material on top to cut away? So, the piston ... Dude I don't know! I sort of get what they were saying but I'm such a novice and I do NOT need to be building a race engine or semi-race engine lol! So, either way EFF that whole thing. A simple easy stripped down street tracker will suit me just fine.
I hope I finish mine soon too.
Apparently, the valves lift longer with a MegaCycle cam, so they need the piston to have clearance and apparently the 11:1 has more material on top to cut away? So, the piston ... Dude I don't know! I sort of get what they were saying but I'm such a novice and I do NOT need to be building a race engine or semi-race engine lol! So, either way EFF that whole thing. A simple easy stripped down street tracker will suit me just fine.
Posted 05 April 2012 - 08:11 AM
Nope, it was just a simple piston and ring replace. Nothing big.
If that is the reason, then I would just go with the 11:1 piston. The piston will contact the valves if it isn't ground down a bit. That would be a serious backtracking. The 11:1 isn't a really high performance piston, but it will give a power increase. You have to either run the stock cam with the stock piston, or MegaCycle cam and 11:1 piston.
If that is the reason, then I would just go with the 11:1 piston. The piston will contact the valves if it isn't ground down a bit. That would be a serious backtracking. The 11:1 isn't a really high performance piston, but it will give a power increase. You have to either run the stock cam with the stock piston, or MegaCycle cam and 11:1 piston.
Posted 05 April 2012 - 08:16 AM
Plus, because they will be cutting that piston down, it will have lower than 11:1 compression.
Posted 05 April 2012 - 08:42 AM
You asked about the case vents earlier, and I scanned the thread and didn't see that you got an answer.
A vent on a gearbox case is there to allow the pressure in the case to remain constant even though the air & oil inside the case is expanding with heat, and then contracting again once it cools off. When the oil heats up and expands, it displaces the air in the case which is also heating up and expanding. The case vent allows all this to take place without positive pressure building inside the case. The vent on an engine case does this, plus provides an avenue for blow by gasses to escape.
A sealed case will build pressure as the temperature of the oil and mechanical components rise up to operating temperature. The pressure will eventually overcome the case seals and you will see leakage.
The reverse can also happen. Imagine the axle under a pickup truck that is at full operating temperature, then is suddenly submerged in cold water, as in crossing a creek. Being submerged in cold water will cause the temperature of the axle and the oil in it to decrease rapidly from where it was before being submerged. A low pressure will develop inside the axle and if that axle is not vented, it will likely suck water in past the wheel seals.
A vent on a gearbox case is there to allow the pressure in the case to remain constant even though the air & oil inside the case is expanding with heat, and then contracting again once it cools off. When the oil heats up and expands, it displaces the air in the case which is also heating up and expanding. The case vent allows all this to take place without positive pressure building inside the case. The vent on an engine case does this, plus provides an avenue for blow by gasses to escape.
A sealed case will build pressure as the temperature of the oil and mechanical components rise up to operating temperature. The pressure will eventually overcome the case seals and you will see leakage.
The reverse can also happen. Imagine the axle under a pickup truck that is at full operating temperature, then is suddenly submerged in cold water, as in crossing a creek. Being submerged in cold water will cause the temperature of the axle and the oil in it to decrease rapidly from where it was before being submerged. A low pressure will develop inside the axle and if that axle is not vented, it will likely suck water in past the wheel seals.
Edited by zlathim, 11 April 2012 - 01:33 PM.
Posted 05 April 2012 - 05:28 PM
NEAT! Thanks for the engineering 101 on that breather! I'll treat the hole with respect now that I understand it's existence.
I refuse to go to an 11:1 piston and megacycle cam. It will cost me big time, then I'll need a carillo rod, to balance my crank assembly and for what! I'll be selling this bad boy once I complete. I'll keep the engine stock to increase profitability on the build. As for the rest of the beast... I dunno, I'm gonna build the engine up again and sell this thing.
I'm gonna spend a year or so rebuilding engines and simple restores and treasure hunting. The bike I see in my head is disconnected by my lack of skills, my lack of skills are from lack of equipment to hone those skills, my lack of equipment is from lack of funds. A better place, a better time would be the future where I have accumulated all that I need and the skills are honed.
It's good though, I'd rather be rebuilding engines and practicing welding and stuff. I'll do well rebuilding little singles for people for cheap. Would be fun. Plus, nobody is hiring me for any jobs. I don't really care but I need some money! lol.
I refuse to go to an 11:1 piston and megacycle cam. It will cost me big time, then I'll need a carillo rod, to balance my crank assembly and for what! I'll be selling this bad boy once I complete. I'll keep the engine stock to increase profitability on the build. As for the rest of the beast... I dunno, I'm gonna build the engine up again and sell this thing.
I'm gonna spend a year or so rebuilding engines and simple restores and treasure hunting. The bike I see in my head is disconnected by my lack of skills, my lack of skills are from lack of equipment to hone those skills, my lack of equipment is from lack of funds. A better place, a better time would be the future where I have accumulated all that I need and the skills are honed.
It's good though, I'd rather be rebuilding engines and practicing welding and stuff. I'll do well rebuilding little singles for people for cheap. Would be fun. Plus, nobody is hiring me for any jobs. I don't really care but I need some money! lol.
Posted 05 April 2012 - 06:00 PM
PudgyOTE, on 05 April 2012 - 05:28 PM, said:
NEAT! Thanks for the engineering 101 on that breather! I'll treat the hole with respect now that I understand it's existence.
I refuse to go to an 11:1 piston and megacycle cam. It will cost me big time, then I'll need a carillo rod, to balance my crank assembly and for what! I'll be selling this bad boy once I complete. I'll keep the engine stock to increase profitability on the build. As for the rest of the beast... I dunno, I'm gonna build the engine up again and sell this thing.
I'm gonna spend a year or so rebuilding engines and simple restores and treasure hunting. The bike I see in my head is disconnected by my lack of skills, my lack of skills are from lack of equipment to hone those skills, my lack of equipment is from lack of funds. A better place, a better time would be the future where I have accumulated all that I need and the skills are honed.
It's good though, I'd rather be rebuilding engines and practicing welding and stuff. I'll do well rebuilding little singles for people for cheap. Would be fun. Plus, nobody is hiring me for any jobs. I don't really care but I need some money! lol.
I refuse to go to an 11:1 piston and megacycle cam. It will cost me big time, then I'll need a carillo rod, to balance my crank assembly and for what! I'll be selling this bad boy once I complete. I'll keep the engine stock to increase profitability on the build. As for the rest of the beast... I dunno, I'm gonna build the engine up again and sell this thing.
I'm gonna spend a year or so rebuilding engines and simple restores and treasure hunting. The bike I see in my head is disconnected by my lack of skills, my lack of skills are from lack of equipment to hone those skills, my lack of equipment is from lack of funds. A better place, a better time would be the future where I have accumulated all that I need and the skills are honed.
It's good though, I'd rather be rebuilding engines and practicing welding and stuff. I'll do well rebuilding little singles for people for cheap. Would be fun. Plus, nobody is hiring me for any jobs. I don't really care but I need some money! lol.
I understand it. But the two stocker parts will be necessary to be compatible.
Posted 05 April 2012 - 09:11 PM
I might know a guy who will take the TT off of my hands. If he won't I'll finish the engine, and slowly restore it. But, for now I'm gonna start trying to make money in the short term.
Posted 09 April 2012 - 05:04 AM
Picked up a sweet little 125. It'll be a cafe racer and ready for pics by June. My friend is finishing the company logo, going to start a new post and go through step by step and be more informative. I have funding for this one because it is purely for profit and the TT is a little bit over my head for now. I'll pick the TT up once I get the bulk funds back for this cafe racer.
TT500 is on the back burner
BUT it will be a gnarly street tracker one day!
TT500 is on the back burner
BUT it will be a gnarly street tracker one day!
Posted 10 April 2012 - 05:13 PM
PudgyOTE, on 09 April 2012 - 05:04 AM, said:
Picked up a sweet little 125. It'll be a cafe racer and ready for pics by June. My friend is finishing the company logo, going to start a new post and go through step by step and be more informative. I have funding for this one because it is purely for profit and the TT is a little bit over my head for now. I'll pick the TT up once I get the bulk funds back for this cafe racer.
TT500 is on the back burner BUT it will be a gnarly street tracker one day!
TT500 is on the back burner
BUT it will be a gnarly street tracker one day!What brand? Year? Model?
Posted 11 April 2012 - 09:34 AM
1982 Suzuki GN 125 - Boy I hit a fricken wall. Shipping speed!!!!!! It is a solid wall that owned my face. May 2nd my service manual gets here. 
Bah.. I refuse to touch this motor without that service manual. Otherwise it'll cost more than time. Bike's in good condition, got it for 100 bucks. Runs and reg'd barely any surface rust. Some Rusteco gel and a week of painting and it'll look brand new. Pics soon, can;t find camera memory card!!!
Bah.. I refuse to touch this motor without that service manual. Otherwise it'll cost more than time. Bike's in good condition, got it for 100 bucks. Runs and reg'd barely any surface rust. Some Rusteco gel and a week of painting and it'll look brand new. Pics soon, can;t find camera memory card!!!
Posted 11 April 2012 - 03:04 PM
PudgyOTE, on 11 April 2012 - 09:34 AM, said:
1982 Suzuki GN 125 - Boy I hit a fricken wall. Shipping speed!!!!!! It is a solid wall that owned my face. May 2nd my service manual gets here. Bah.. I refuse to touch this motor without that service manual. Otherwise it'll cost more than time. Bike's in good condition, got it for 100 bucks. Runs and reg'd barely any surface rust. Some Rusteco gel and a week of painting and it'll look brand new. Pics soon, can;t find camera memory card!!!
Bah.. I refuse to touch this motor without that service manual. Otherwise it'll cost more than time. Bike's in good condition, got it for 100 bucks. Runs and reg'd barely any surface rust. Some Rusteco gel and a week of painting and it'll look brand new. Pics soon, can;t find camera memory card!!!May second!?!? And that motor isn't nearly as complicated as the TT. If you can take that TT apart without messing up, than you are fine.
Posted 11 April 2012 - 04:13 PM
Oh boy oh boy! The TT community makes me have all kinds of warm and fuzzy! It's like the support I get from my wife except you all love bikes! 
Posted 11 April 2012 - 08:31 PM
The GN motor is simple and stone reliable. I have the DR version out to 190 cc, which was the most costly option available to me (but still cheaper than EO's version!), and have run them in 153, 143, 125 and 100 cc as well. Never had a problem with any of them, even tho I revved the crap out of my 100 with a DR125 head and a custom 13.5:1 piston. They're an awesome motor.
Posted 12 April 2012 - 08:23 AM
500XC, on 11 April 2012 - 08:31 PM, said:
The GN motor is simple and stone reliable. I have the DR version out to 190 cc, which was the most costly option available to me (but still cheaper than EO's version!), and have run them in 153, 143, 125 and 100 cc as well. Never had a problem with any of them, even tho I revved the crap out of my 100 with a DR125 head and a custom 13.5:1 piston. They're an awesome motor.
Where do you go to for most of your hop up parts? I know of suzukipartshouse.com - chaparralracing.com
EO has that sick exhaust system for the DR125.. I want it so bad but I don't want to spend 400 dollars lol!
Posted 12 April 2012 - 08:49 AM
EBay mostly. A good upgrade is either a DR200 or a LT230S, while an LT185/ ALT185 top end makes a low compression 153 kit.
The 190 kit I run is a NOS Wiseco piston that hasn't been available for over 15 years. Powroll does offer some nice stuff, as does Pro Cycle, but if you can get a good Taobao agent, you can get a whole 150 top end cheap.
The 190 kit I run is a NOS Wiseco piston that hasn't been available for over 15 years. Powroll does offer some nice stuff, as does Pro Cycle, but if you can get a good Taobao agent, you can get a whole 150 top end cheap.
