2 stroke rebuild different from 4????

[outcrydrummer]

Hey guys.

So I picked up a 84 250r yesterday. Runs good but I can hear a little, what sounds like anyways, crank bearing play. It doesn't affect the riding its just there.

So anyways, I'm getting a little bit of extra fluff in the budget end of the month and I'd like to rebuild the engine............... well all the shops close to me , fayetteville nc, are way way way way overpriced on this.

So my question is........

Am I going to run into any issues trying to rebuild the 2 stroke myself?

I have tools, I'm a mechanic in the Army but I don't ever mess with 2 strokes. I've rebuilt a few top ends before on some 4 stroke trikes I've owned but never gone down to the crank or bearings.
I'm pretty good with mechanical stuff, obviously lol, I just want to get some suggestions before I go ripping it to pieces.

I have a torque wrench, ring compressor, honing wand, and general tools....................anything else I will need?
Whats the best rebuild kit for the 250r?
I seriously doubt it needs to be bored as the compression is pretty awesome........to the point it will almost hurt me when kick starting it lol.

Any tips or suggestions are most welcome.

Thanks guys

Josh

[RIDE-RED 250r]

You might not need a rebuild at all. I have noticed that on air cooled 2-strokes, the cooling fins tend to amplify the noises associated with the engine running as it should...

But, if you decide to pull it apart and check things over anyway (and nobody would scorn you if you did) they are alot simpler than a 4-stroke.. especially an air cooled 2-stroke since you don't have to deal with coolant... Once you get the engine accessible or out of the chassis, you will have the topend off in minutes.

As to what you need to go deeper to replace the crank bearings and check the condition of the crank and lower rod bearing.... The main thing you will need is a proper flywheel puller and a tool to hold the clutch while you break loose and re-torque the clutch hub nut. That's about all you will need in the way of special tools... And please, get a proper fylwheel puller at least. Generally all that is accomplished by trying to remove the flywheel without the proper puller is a ruined crankshaft and/or flywheel, and/or crankcase half...

Just take your time and pay attention when you plit the case as you will now be disassembling the transmission as well. MonroeMike usually is pretty handy about posting links to downloadable service manuals. I would highly recommend at least downloading a service manual. The information inside will prove invaluable when you begine to pice the bottom end (mainly the transmission section) back together....

Also, feel free to ask questions here. Although I have no experience with the older air cooled R's, the basic principle is the same. Plus there are lots of folks in here that know those air foolers backwards, forwards, inside and out, 6 ways from Sunday...

Welcome aboard and keep us posted on your progress!

[TecateDan]

piston slap is normal in two stroke Imo... do trailprotrailpro self a favor and get a case splitter for a c note and like he said just be careful to keep every thing in order . I usually take a Tom of pics on disassembly just in case

[outcrydrummer]

Ok thanks guys :D

Yeah this engine sounds really no different then any other old air cooled 2 stroke I had ( honda odysseys ). I usually just overthink things and make things worse then what they should be.

I do have a question though.
On a take off the trike likes to bog. Like If I'm trying to run someone and I give it gas out of the hole it bogs out and then finally catches back up. It only does it from a stop...... No hesitations anywhere else in the rpm's and plug readings look good ( plug chop ).

Any ideas???? Too rich on the idle circuit perhaps?

[RIDE-RED 250r]

Could be a bit off on the idle or pilot circuit. Is it a burbling rich bog or a smooth lean bog?

[outcrydrummer]

It's a smooth bog that takes a few quips of the throttle to recover from.

Also I think the carb on it is not the original carb.

It's flat on both the left and right side with stampings keihn. I'm familiar with there carbs and was thinking that someone put this on.......is this the keihn flat side carb I hear so much about?

I'm gonna mess with the idle circuit today when riding.

[RIDE-RED 250r]

Yep, sounds like someone definitely upgraded the carb at some point. And yes, it sounds like a flatslide. But there are several different Keihin flatslide models... You can narrow it down by measuring the inside diameter of the venturi on the intake side. Also, post a couple pics and maybe we can help identify it...

By the sound of it, you may need to step up the pilot jet a size or 2.

[outcrydrummer]

Dug in the carb today. Gonna post a pic of it in a sec.
Jets were a 135 main and a 48 pilot. It was fairly dirty so glad I got in there and cleaned it up. I knew it was a little dirty cause it would drain fuel out the bowl when the fuel was on so a little bit of carb cleaner fixed that sticky float right up.

[outcrydrummer]

http://i299.photobucket.com/albums/mm295/outcrydrummer/images.jpg

It looks exactly like that carb right there. Took me forever to realize the choke knob was the idle adjustment as well.........................haha

[outcrydrummer]

hmm. really? how does that work?

Not following you just ben? On my carb it has wording on the choke to pull up for choke and rotate it left and right to adjust idle..... no idle adjustment screw and I set my idle with it that way.
So not sure if your saying my pic is not the correct carb I'm describing........ because thats possible

or

If your saying that I'm imagining things by saying that I adjusted my idle with the choke piece........ either way I'm new to this carb so your sarcasm isn't needed or wanted. :D Thanks

[just ben]

sarcasm? I was asking how it works. I have had alot of machines and have never heard of such a thing. I figured being an army mechanic you could explain how it works. whatever piss off then:D thanks

[outcrydrummer]

lol sorry. you get a lot of the internet sarcastic a holes these days.......

I actually have never seen it before this. Took me a good 10 mins to find how to adjust the idle with it though lmao

[RIDE-RED 250r]

Ben: That is a stock carb from an '86-'87. Not sure if it's the same on the '88-'89 though. I have had recent experience with the stock carb on an '87 TRX and that is exactly how the choke/idle speed knob works... I had a heck of a time with it and didn't like it one bit. I would sooner run the old roundslide than one of those if I didn't have my PWK A/S.

Have a little patience with the guy. The way you worded your reply, it could have been taken negatively very easily. Not saying that was your intent, just sayin. It's easy to misunderstand someone's tone with written text.

Drummer: As I was saying above, I have had recent experience with that same carb on my cousin's '87 TRX. I couldn't seem to get that thing to dial in and did not like it one bit. Now there could be other issues at work on that quad, I don't know. Maybe his slide/slide housing was shot. But, if you end up having alot of trouble dialing that thing in and you find everything else with the engine is in good shape, then ditch that carb and get one that has a normal/separate choke and idle speed adjustment.

Again, this is just my experience with one of these carbs. For all I know it may be a great carb. But the one I was playing with didn't want to cooperate with me at all....