Rebuilding your first engine

[MadMax]

Hey Yall,

1985 Yamaha YTM Tri-Moto 200, 4 stroke

I think ive decided to rebuild my engine rather than replace it. I have never done this crap. My friend matt knows a lot about engines and I think hell help me. But, Im not sure on what all Ill need to rebuild it. I know Ill need a complete gasket set, and maybe a new piston and rings. Since Im going to be going though the entire engine, what could I do to it to give it more power? Ive herd of big bore kits, but I dont know what they are. Can somebody explain this to me? Also, if there is anything else I need to rebuild my engine, please let me know. And please, dont be afraid to talk to me like im about 5 about this, cause I wanna know what in the world I need to be doin, and how to do it the right way.

Id appreciate any help yall!

thanks, MadMax

[GlennMc]

MadMax;
The biggest help that you can do for yourself is to get a manual from Haynes, Clymer or a Yamaha service manual if you can find one. Study the engine section of the manual which will take you through a complete rebuild. Ask yourself these questions;

Do I know what they are talking about? If not post specific questions here for answers.

Do I have the right tools? Buy, beg or borrow what you need before you start, it reduces the temptation to take shortcuts while you are elbow deep inside your engine and find that you don't have the right tool.

Am I in over my head? Don't take this as an insult but there are those who shouldn't tackle a job like this, and there are those who can do it if they are patient. I once spent several weeks fixing a Honda 400 twin that was rebuilt by an impatient amateur and I have also seen first time rebuilds done patiently and very successfully.

The more informed that you are before you start, the more enjoyable and successful the job will be. Good luck and have fun, GlennMc.

[KLT Man]

Well, first off, it is not as difficult as you think, but don't underestimate it.
If you are mechanically inclined and can follow a manual, it just requires a little research, some tips from those experienced, and is quite a learning experience. :-D

Next, ensure that any parts that you may need to replace are available through dealer, aftermarket, EBAY (alot of NOS parts there), and here amongst the 3WW members. :clap

You need engine specifications. Make sure that you have a list, table, or the MFGR service manual with all the correct info. This is critical to ensure that you do the job right the first time and not end up with something expensively worse than what you started with. The manual will also have info on any tool you may need. Some special tools are required, but you will only use once, are expensive, and may be relatively easy to fabricate. :-P

If boring is required, only bore to the next size that you cylinder requires. Boring to the MAX will be the LAST time you bore. :evil:

As far as performance, anytime I do valve work, I include port polishing (removal of the rough texture left by the casting). This improves airflow through the INT and EXH valves.


Just my Nickle and Dime...................

[Falstaff]

I would recommed using or borrowing a digital camera. Take pictures of every little step and take notes to help you put it all back together. DEFINITELY get a service manual, not a universal manual but a specific model manual. Try to find a parts manual as well. You can usually find something online.

I would recommend before buying any replacement parts that you completely disassemble everything first to see what you need. If you don't have the tools, take the cylinder and piston to a shop and have them recommend whether you need to a rebore/hone/new rings. Spend a lot of time cleaning the carb and replacing parts in there.

I think you'll find it a great and fun experience if you take your time. If you get stuck or frustrated, let it cool down and wait a day or two.

Good luck!

[waterfowler]

I just finished my 4th engine rebuild on different Honda machines. Even after being somewhat experienced I still forgot to do things that caused me to disassemble and fix. My advice is in line with others. Patients, Patients, Patients! Do it slow and have fun. Take pics of the disassembly and make sure you have the CORRECT TOOLS. I know with Honda you need a special tool to get the clutch and oil filter nuts off. Do not try to make or jury rig a tool. This will cost you in the end. If you need a special tool, most are made in a generic form and are considerably cheaper than the OEM tool. Remember, if you do it right the first time it will last a long time.
Good Luck,