I'm new! 84 Yamaha 225DX question...

[COhighcountry]

Great site and I've found some solid discussions here. I have an 84 Yamaha 225DX that I rescued from a storage unit. I'd been looking for a three wheeler for a while and found this one which I got for $225...not a bad deal since the owner listed it for $550. I grew up on Honda trikes and have always wondered about this machine since reading Dirt Wheels back in the day. I have been going through it...new plug, cleaned carbs, new air filter, patched exhaust, new oil, adjustments etc. It idles great and seems to be OK at lower rpms but when I am rolling along and give it gas it hesitates really badly and lacks power. It does have a little bit of engine noise but not too bad for a 20+ year old and compression is great. Fuel flow from the tank is clean and good. I took out the jets and ran wire thru them and they seem fine. I also sprayed the carb out even though it seemed pretty clean. It may be running a little rich. She smokes a bit when cold but when warmed up it gets a lot better. Where would u guys begin with this one? Thx.

PS- I'll post a pic of it here in a bit. Still feeling my way around

[COhighcountry]

179204 here she is

[dougspcs]

Since your low/mid speed is good you really have two places to look..

Carb and valve train..

You've been over the carb and if it's thoroughly clean maybe turn your attention to valves.

1st a set of feeler gauges and a simple adjustment..hope this make things better because if not then thing get a bit deeper.

Also while your valve caps are off check the springs carefully..a broken spring might be causing valve float and your power loss.

Next the timing chain..a worn chain might be causing improper valve timing and your power loss!!

Lastly, engine compression..gauge it and check. 20-30 psi low can feel 'good' when pulling the cord, sure will knock the crap out of your top end power.

This noise you talk about may just be more than the engine showing its age..further investigation is required!

[COhighcountry]

I have never done much with valves or timing but am pretty handy. I'm going to pick up a feeler gauge and a few things today and dig into it tomorrow. I'll keep u posted:p

[dougspcs]

A downloadable version of the manual for your machine is available here:

http://www.oscarmayer.net/atc/manuals/

Lots of useful info!

[emmie357]

Grab that manual listed above, check the valve for proper adjustment, and the same with the timing chain tensioner.
Hopefully that gets you sorted...

Does the engine noise go away as it warms? If so it may be the centrifugal clutch... if it does not it may be piston slap, since you said it smokes you may want to tear the top end open and have a look, replace the rings if everything else looks good.

These old Yamahas are fairly bullet proof, so it's probably nothing catastrophic.

[COhighcountry]

Cleaned and soaked carbs well and blew out the little air holes. Confident the carb is decent. I went in and checked valve clearances a few times and fine tuned them. I also tightened my cam chain tensioner a little bit. I seems a little better but still bogs at the higher RPMs. Almost seems like it intermittently lacks air at full throttle or something. The engine noise isn't too bad and when it warms up it is quieter and much less smokey. Any ideas?

[King Trikester]

I would like to add that that noise you are hearing should be investigated, I've got an 83 225 dx that runs super smoth, no engine noise what so ever, so that noise could potentionally be your issue, I wish I could tell you what's making the noise But I'm not an expert and I'm sure someone else will be able to help you out. If it smokes a bit and your vavles are set correctly I would have to agree with emmie357, replace your rings and go from there. These are great machines I love mine and will never part with it.

[czac]

whats the noise sound like? a knocking? or clicking? a whine or something else? i have the same bike... havent ridden it yet cause im still working on it but im sure that if yours is running and you are riding it, its gotta be something that can be fixed pretty easily... have you tried a different gas? maybe your hearing "Detonation" in the cylander? try a higher octane gas.

[dougspcs]

A broken valve spring can cause the valves to 'float' and stay partially open at high RPM..

At low speed normal power, at high speed bogging..

Maybe something to check!