Need help with 85 Honda 250R ATC

[rmcollector]

Morning everyone, this is my first post on here and wanted to see if I can get some help with my 1985 Honda 250R ATC.

Within the last several months I did a fresh top end on it, along with a rebuild of the water pump. I did a rebuilt of the water pump due to the mechanical seal leaking. I have ran a full tank of gas in it (32:1) and have found it is running way too rich and adjusted the carb and float. Got it running very good for 10-15 min and then it started to run too rich again. It sat for several days and I noticed several drops of oil dripping out of the carb overflow hose. I took the carb off and there was alot of oil inside. I cleaned it out really well and started it up and it ran great for about an hour with no problems at all. It then suddenly bogged out on me and I realized it needed gas. After I put a gallon of gas in it will not start. I also noticed it used ALL of the coolant that was in the radiator after riding for an hour! After I discovered this I took the cylinder off and inspected the wall and piston, everything is in great shape just like when I put it back together with no damage. Current compression is 158 psi. I am getting spark when tested. I am running the 86 flat carb, not the 85 carb. This is the first time this trike hasn't started for me since Ive owned it. Any help with this would be greatly appreciated! Thanks, Rick

[yaegerb]

What does your gear oil look like?

[rmcollector]

Doesn't look much different than when I put it in, slightly darker. Running Pro Honda GN4. I did notice when I took the pipe off the head it had a strong smell of gas with alot of oil inside.

[yaegerb]

My opinion but I would be running a different oil than a gn4. The make 80/85 gear case oil that is much better for your 2 stroke. So if it’s not leeching into your crank case you must be either burning it or leaking it from somewhere. Have you noticed white smoke come out of your tail pipe?

[atc007]

Compression is low. Not the problem as you mentioned. But 185-190 is much preferred. Coolant disappeared. Chase that. Sounds like you have at least 2 gremlins fighting you. Head gasket and maybe worn carb. Assuming you are not ingesting tranny fluid,which Brendon mentioned. After all is said and done. it could also be the CDI box. But for right now. We know other places need attention first.

[rmcollector]

Oh ok, no I haven't had any white smoke come from the tail pipe. It ran great for that hour of riding, but like I mentioned in the post it just bogged out and once I put gas back in it will not start. You think it could be a carb issue? I have cleaned it thoroughly, but it has always had that small drip or two coming from the overflow throughout the day. I bought a 38mm knock off carb for $36 bucks that I am waiting on, I am not sure if it will get it started, but if so...then im guessing the carb is the problem. If it works find after that I am going to buy the Genuine Keihin, just want to see first where im at.

[rmcollector]

That's interesting, I had a 86 TRX 250r that had compression of 150 psi and it ran perfect and always started 1-3 kicks.

[rmcollector]

What am I looking for with the head gasket? It is new, oem gasket. No leaks. Sealed tight with copper sealant.

[efhondakid]

32:1 is wayyyyy to rich on oil if you ask me. I run all my 2 strokes 44:1, 50:1 on the race machines. Royal Purple ATF in the cases on them all as well.

Using coolant means you have a leak somewhere, if you have a small leak in the head gasket you won’t see white smoke with such a pig rich oil mixture, but the top of the piston and head will be clean from the coolant cleaning the carbon.

[HondaRidr]

32:1 is fine and so is 158 psi compression. Are you leaking coolant from any of the hoses or somewhere on the radiators?

[rmcollector]

32:1 is fine and so is 158 psi compression. Are you leaking coolant from any of the hoses or somewhere on the radiators?

Yes, there was coolant leaking from a old radiator that was on there, it was replaced and then was running fine for that hour of riding. Not sure where there is a leak but that coolant was all gone after the hour of riding. I rechecked the compression last night and got it up to 167 psi. Just can't seem to get it running again.

[rmcollector]

Meant to send motor pic, let me see if I can find it.

[yaegerb]

Anything below 170 is NOT fine on a 3rd gen 250r. Are you taking compression correctly with the throttle wide open on every kick? Take the compression reading again with the throttle wide open. If you are still below 170, add a teaspoon of premix oil in your spark plug hole then take another reading. I will bet the compression increases+\- 10 psi. If it does increase one of two things is happening. Your “fresh” top end is incorrect or you haven’t put enough time on the cylinder to seal the rings. If you used wiseco they usually take 1.5 tanks of gas to properly seat. Also, your coolant doesn’t just vanish. Refill it and find where your leak is. If it’s not weeping from a line or around the head then you are burning it up in the combustion process from a failed head gasket. If it is not starting endure you are getting good spark by grounding your plug to your head. Spark should be fat and blue in color.

[rmcollector]

Anything below 170 is NOT fine on a 3rd gen 250r. Are you taking compression correctly with the throttle wide open on every kick? Take the compression reading again with the throttle wide open. If you are still below 170, add a teaspoon of premix oil in your spark plug hole then take another reading. I will bet the compression increases+\- 10 psi. If it does increase one of two things is happening. Your “fresh” top end is incorrect or you haven’t put enough time on the cylinder to seal the rings. If you used wiseco they usually take 1.5 tanks of gas to properly seat. Also, your coolant doesn’t just vanish. Refill it and find where your leak is. If it’s not weeping from a line or around the head then you are burning it up in the combustion process from a failed head gasket. If it is not starting endure you are getting good spark by grounding your plug to your head. Spark should be fat and blue in color.

Yes I have been checking compression with the throttle wipe open on every kick. I will check it again in the morning and see what I come up with. Thanks for the reply.

[Doug8765]

I think your crank seals are bad it creates the rich lean condition. You can run that motor at 20:1 like it says in the manual. That is NOT THE problem. If the coolants not a weird color and carb is clean. New spark plug .. check reeds too if that’s all good it the crank seals . Pretty common


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