Compression expert advice

[jakeesspoo]

I have rode and owned honda three heelers all my life but i have never had to do any "major" engine work before. I have a 200s that has drug more deer out of the woods than i can count on my fingers and toes and is my favorite atc. Anyhow through various dickerings i have piked up a few more three wheelers that ll need work. Top end work i believe. All seem pretty solid otherwise although the 200e is just going to be a parts bike the engine looks solid but may need work. I did a compression test on each engine. I believe i did it correctly. I put compression gage on and pulled on starter 4-5 times till gage stopped climbing. I did this while holding throttle wide open. After that i then put a teaspoon of oil in cylinder and tested compression while "wet". Here is what i got. On the 1982 200e i got about 120psi dry and 135 psi wet. On the 1984 200es i had 135psi dry and 175 wet. The other bike is a 200m but it looks to me to have a engine from a 200s in it. It was really bad i believe with 70psi dry and 90 psi wet. Do all of these need top ends in your opinion? I have the clymer manual for the 200 atc's but have never dissasmbled a engine or rebuilt one. With that being said i am mechanically inclined, have proper tools and gages, and know a good machine shop. I love three wheelers and I'm going to try to start rescuing the ones i can find before they end up at the steel yard. I think if i can figure out the top end replacements i will be in pretty good shape for the future. What i do not own though is a cylinder hone, flywheel puller, or anything to lean or lap the valves once i figure that out. I guess I'm just afraid I'm going to pull a engine out, get it apart, be overwhelmed, and not get it back together. I guess it will be a learning experience i just need a confidence boost from you guys i suppose. Tell me a monkey could do it or something. Im a tinner/hvac tech by trade and professional three wheeler carburetor cleaner. Once i get it apart though. How do i know what size piston is currently in engine? And your thoughts on my compression readings please.....I'm going to learn this one way or another. Unfortunately none of my friends or family are engine mechanics by any means a least no more so then myself so im on my own with Clymer, you guys, and you tube

[Jmoozy27]

IMO, the 200e and 200es models should be good to go another couple of rides. The pressure is slightly below spec but should run w/ minimal smoke. I would personally rebuild the topend from the low pressure motor you mentioned in the 200m. It really isn't hard especially if you have a manual. The honda manuals go into a little more detail and the info is accurate. When you pull the top end you or your machinist can mic it and examine it to decide if it needs to be bored or simply honed and new rings. Of course ideally you would want to tear it down, fix what is wrong, and put it back together. In this case you will probably have a few days of down time. In that time I usually pull the clutch cover and examine everything. A new timing chain may be something you need to replace. Invest In a torque wrench if you don't already own one. You will need a gasket set for the top end and clutch cover if you go that route. Just take your time maybe even take pics of the progress so you have something to reference. Good luck.

[Devilsclaw]

Considering your background I think you'll be fine, heck I'm pretty much just like you and I've done it with good results. As long as you can read the manual and follow directions you shouldn't have any problems that will overwhelm you. The manual should tell you how to measure the piston as well as ring gap and other components. It should also give you the tollerences that indicate either replacement or reuse. A good set of calipers, micrometers, feelers is required of course, but you don't sound like the kind of guy that plans to do the job using only a ballpeen hammer and pair of pliers like some of the jokers I see on YT! I would let your machine shop worry about grinding and lapping the valves. A hone is only about $20- and go easy on that part it's real easy to overdo it. Read read and re-read all the manuals you can find and treat everything like you are doing surgery and you'll be fine. If you know HVAC this should go pretty easy. I can't comment much on the compression thing other than I think some read too much into it. I've seen some engines that would hardly run under 100 and then others (Kawasakis incidentally) that would run good under 50! So I just go more by how they sound and how much oil they burn that what the gauge says.

[jakeesspoo]

Thanks for the replies. Yeah i have torque wrenches, mics, gages, calipers, you name it. I used to do machine setup when i was right out of trade school working for Delphi (was GM owned). I got a lot of my tools when I quit there. The only hing i think i should purchase right away or could need is a cylinder hone (recommendations please) and a flywheel puller although i thought i read in a forum or something that you could use a certain bolt. In response number two it was mentioned a clutch cover? Are you referring to a gasket for clutch cover? Maybe i will try to get the bikes with the higher compression going. How come you never really hear bout bottom ends being rebuilt in these bikes is it rare?

[oscarmayer]

these motors are very simple to work on. do not sweat it. while mentioned those numbers are on the lower side, the trikes will still run for a while. smoke? you live 30 years of pure abuse and see how well you do. if your really interested you could look at a redo, or go to ebay and buy the 200m crate motor for just under $900 right now on there.

[Trike_crazy]

If you get a chance check the valve clearance on the 82 200e. That might help a bit.

[jakeesspoo]

I will check the valve clearance. Can this affect all of the moors compression? Im assuming ifa valve is not fully seated on compression stroke that you would be losing compression correct? I have no interest in a crate motor. I dont even care if it smokes a little. Oils cheap

[Dirtcrasher]

I'd worry more about cam journals than leaky valves and a worn out cylinder....

[jakeesspoo]

Damn Dirtcrasher dint confuse me that bad already:lol: I dont even know what a cam journal is:p

[Trike_crazy]

Yeah, if the valves aren't opening all the way or being held open from being worn or too tight you could get a low reading. Its worth a shot and best of of all its FREE!

[Devilsclaw]

Also sometimes I think valves get gummed up or carbon lodged under them and they don't seal well and cause low compression reading. Sometimes a good healthy dose of Techron can improve the situation but don't expect miracles on 30 yr old engines that were rode hard and put up wet. I'm like you, a little oil burning is ok as long as you don't have to be cleaning the plugs ALL the time. I have a KLT that is very worn but still runs great doesn't burn oil and will put out way more power than my cherry Big Red 250es, so I'm leaving it be.

[jakeesspoo]

so far last night I threw a carb on the 250 es and a temporary tank and I got it to run It ran rough but it ran. Didnt even bother setting the carb or anything yet. When I finished running it I also noticed that I only had the plug in barely finger tight so it was probably leaking there also. Made me nervous at first cause it smoked so bad but forgot that I dumped all that oil in the cylinder to compression test it but most of it I think was the Kroil burning off from everywhere. As soon as I picked these bikes up I dumped kroil on every nut and bolt that I saw in preperation of worst case scenarios. Im still in the habit of using Kroil like I did when I worked for GM and it was "free". I need to lighten up on it a little and start getting it where I need it and not wasting so much because its not cheap. We used to use this stuff by the gallon. I like the way it smells. Going to check the valves next and change the oil and get the original carb back on it. The original carb once apart was not nearly as dirty as I thought it would be. Im not even going to bother with a rebuild kit yet, just clean it. Its soaking now.