Advice on an RD 250 build

[markjenn]

Originally Posted by sp115

A bit more info: I'm pretty set on having an early RD for him (it was my first road bike and I have a real soft spot for them)...

If the bike runs well, I don't understand why it has a bent crank. Without taking the engine apart, I'm not even sure how you diagnose a bent crank.

Are the folks working on your bike old-bike/two-stroke specialists? Do you really think they know what they're doing? My experience is that it is very hard to find mechanics who know their way around old bikes. And if you're really planning on riding a 40-yo antique, you need to ante up the time/effort to do most of the maintenance/repair work yourself. If you don't have the time, you (or in this case your son) would be much better off riding something more current.

Finally, don't take this too harshly, but are you sure you're not letting your nostalgia and desire for an old RD cloud your judgment about a good first bike for you son? Is it HIS dream to ride an old RD? Unless he shares your desire to want to wrench and ride an antique (in that order), I think he'd be much better served with something a little more current that is reliable (and uses a lot less gas). Not to mention has modern suspension and brakes.

Don't take this as a criticism of old RD's. They're ultra cool. But riding one as an every day bike is a labor of love and not terribly practical.

- Mark

[stainlesscycle]

Originally Posted by markjenn

If the bike runs well, I don't understand why it has a bent crank. Without taking the engine apart, I'm not even sure how you diagnose a bent crank.

my guess is the stator end of the crank some wobble. can't be very much or it would be blowing seals and possibly vibrating - this could also be why the stator is not working... or it could be a spun crank, but you'd feel that one too.. it's all speculation without seeing it.

Originally Posted by sp115

Just to be clear: the $2K is for the entire motor rebuild: new crank, rods, bearings, pistons, seals, re-bore, the stator, etc. Also pulling it from the frame and re-installing it.

you can pull that motor in under an hour. remove tank, exhaust, carbs, unplug stator and pull the motor mounts. it's not rocket science.

someone with experience could pull it, rebuild it, and reinstall it in under 4 hours labor. of course there's some time involved redoing the crank and reboring, but those are flat rate jobs. if the motor was running, there's probably nothing wrong with the stator. might need charge coil replaced or maybe some other part of the charging system has an issue? most guys flat rate the whole deal, because they're faster than shop rate at rebuilding, and the uninitiated think it's some massive undertaking that takes serious time (which it doesn't).

[sprouty115]

Actually I'm pretty sure I'm completely letting my nostalgia of old bikes cloud my judgement, but that's a whole different story...

Anyway, I won't know more until I get down there and see for myself. Trying to make that happen today.

[Shocktower]

Originally Posted by sp115

Actually I'm pretty sure I'm completely letting my nostalgia of old bikes cloud my judegment, but that's a whole different story...

Anyway, I won't know more until I get down there and see for myself. Trying to make that happen today.

This happens

[markjenn]

Originally Posted by sp115

Actually I'm pretty sure I'm completely letting my nostalgia of old bikes cloud my judgement, but that's a whole different story...

Then I'd suggest getting the RD for yourself and getting an SV650 for your son.

- Mark

[sprouty115]

OK, so I just got back from the dealer and this is what I found:
- The bike was torn down to the point where the mufflers, cylinder heads, cylinders, pistons, left and right covers, and the clutch were all off.
- The pistons and cylinders both had slight scoring so it definitely could use a top end.
- The stator was still on but I could hear a loud clunk with each revolution of the crank. I'm not sure exactly how they determined it was bad but there is something going on there.
- The "bent crank" was supposedly on the clutch-side, but there was no visible run-out and no indicator to confirm anything.

We discussed the bike, and the gist of the conversation was that they would prefer that I source all the parts and deliver them, then they do the work. Of course the follow-up to that was - "but remember it's a really old bike and anything could go wrong..." It turns out the $2K figure was simply a swag to see if I was really interested in having them work on it. It wasn't based on specific parts or labor. Oh well, live and learn.

I told them to put it all back together and I'd be back to pick the bike up next week. The bottom line is they must have had over 60 bikes lined up for service and this didn't strike me as something they do often or were particularly excited about getting involved with.

So back to the house it goes. I'll take a look at it and sort it out even though I really don't have time to tear it apart unless I get a reprieve on the two projects ahead of it. Definitely too clean to sell and I can't bear to part it out. Might be time to have a discussion with my son.

BTW, thanks for all the advice. I think I was initially expecting feedback that basically said suck it up, that's what it costs. So thanks for the different perspectives, especially the idea that this may not be the right first-bike.

[markjenn]

I think you're doing the right thing. Working on an old bike like this is a very specialized activity and you need to find the right old-timer to assist you. They're out there, but you have to ferret them out.

Take the $2K you were planning on spending to fix it up and find a more modern bike for your son. Put the RD250 in your garage and start working through the problems one-by-one on your own and on a relaxed schedule. Whether you do the work yourself or take assemblies and farm them out, you'll find that there are literally hundreds of folks on the net who know of specialized shops and individuals who will help you through the process, including many right here. It will be fun. The RD250 is a good bike with a lot of interest and none of the systems are complex or intractable. And it will be worth enough when you're done that you're not going to be pouring money down the drain.

- Mark

[stainlesscycle]

Originally Posted by sp115

Of course the follow-up to that was - "but remember it's a really old bike and anything could go wrong..."

that's the line where i would grab my parts and go. sure there could be issues in there, but nothing really that costly....i wouldn't have 'em put it back together though - they've done half the job for you......


you're doing the right thing. take your time, and build the motor, farm out the crank job, hell even farm out everything - you'll see 2k could build you a pretty stellar motor. .there are some very good engine builders around if you want to send it out.

[Moonshiner]

Yep, I don't think they wanted to work very badly on the little RD. They were trying to talk you out of it.

You did the right thing.

Another good forum for 2 stroke support is USA2strokers.com. That's in addition to HERE of course...

[Edmond Dantès]

It would be ace if you and your son worked on the bike together.

[anonny]

I agree with the masses, go and pick it up in the state it's in and make it a project for you and your son. He needs to learn how a motor works and we all need to spend time with our children.

Rebuilding a two stroke is not that big of a task, and I'm not buying the bent crank without putting a dial gauge on it.

[sprouty115]

Yeah that's the plan at this point. Sort of worked it out with my better-half: grab the bike next week and show it to him at Christmas break. If he digs it, and truthfully I bet he will, then we tear it apart together. I'll send whatever needs work out and collect all the rest of the gaskets, bearings, etc. Then plan a weekend or three when he can get back home and we can put it all back together. Then as time permits we can go through the rest of it.

The worst that can happen is that he's not into the idea and commitment of an old bike (and I'm fine with that), so I sort out another option for him and end up with a cool RD.

Also thanks for the links. I've looking around and found this: http://www.aircooledrdclub.com/smf/i...?topic=25398.0

[stainlesscycle]

Originally Posted by sp115

Also thanks for the links. I've looking around and found this: http://www.aircooledrdclub.com/smf/i...?topic=25398.0

there you go. i bet it took longer for him to take pics/set up for pics then the rebuild itself.

[mtothef]

Originally Posted by sp115

Also thanks for the links. I've looking around and found this: http://www.aircooledrdclub.com/smf/i...?topic=25398.0

i could have used this the other day when putting the bottom end of my rd350 project back together, and putting a crank seal in... backwards...

[Shocktower]

Originally Posted by sp115

Yeah that's the plan at this point. Sort of worked it out with my better-half: grab the bike next week and show it to him at Christmas break. If he digs it, and truthfully I bet he will, then we tear it apart together. I'll send whatever needs work out and collect all the rest of the gaskets, bearings, etc. Then plan a weekend or three when he can get back home and we can put it all back together. Then as time permits we can go through the rest of it.

The worst that can happen is that he's not into the idea and commitment of an old bike (and I'm fine with that), so I sort out another option for him and end up with a cool RD.

Also thanks for the links. I've looking around and found this: http://www.aircooledrdclub.com/smf/i...?topic=25398.0

You need to post a video of the ecited boy with the new to him 2 stroke bike, BTW if he's not happy I'll be your son self supporting and we can do the bike together Dad