1979 WR 250

In other words "Be very careful and look at all of the photos when I buy parts"


The head-to-cylinder is flat-to-flat, (as opposed to valves or flywheel where there's a clear inset), so that differs from lapping I've done in the past. A brief search didn't turn up any videos. do you just do small concentric circles to lap it (like if using emery paper on a flat surface to flatten/shave a metal surface)?
Also, do you do that while the engine is fully apart (benefit would be easier to clean, concern would be oxidation, I suppose could coat it in oil while doing remaining engine work...) or wait until you're about to put the head on to lap it (benefit is less concern w/ oxidation, drawback is harder to clean to 100% certainty of no grit in cylinder afterwards)?

Or is this outlined in the engine manual that I probably need to buy from Phil on CD?

Ok the second sparkplug hole was machined for probably a compression release. There are shallow sparkplug threaded adapters for a 10mm compression release on eBay.

Let's clean that carb and see if she fires up?

I have always lapped the head to the cylinder while the cylinder is off the rest of the engine . Don't need a lot of lapping compound as the more you use the more you will have to make sure is cleaned off . I will usually do about 1/4 turn at a time half dozen times . Then turn head by another 1/4 turn ,repeat and continue to make a complete revolution of the head . After cleaning off all the lapping compound , inspect both surfaces to make sure the newly lapped surfaces are uniform in thier appearance . If they look good , put it together and enjoy . What you don't want to see is any indication of unlapped areas .

After reading this, I came down with a serious case of F---it and decided I could put in a couple hours on the bike despite the pile of work stuff.

After about 40 minutes of general tinkering, I was ready to give it some kicks. Spark looks fine.

Once started, the bike revved off on me. I may have managed to stick the throttle 3/4 open (operator error), but I'm not sure. It ran long enough before I got it stopped that I'm pretty sure it was pulling gas through the carb (I did put a couple of drops of gas in the cylinder before screwing in the spark plug, but not enough for as long as it ran).

So, I need to pull everything in-front of the cylinder and go through it in a detailed way to eliminate or rule out any sort of air leaks. It would probably be good to do something from a silencer perspective too.

Anyone have any recommendations on silencer including a spark-arrestor? since I'm missing 2/3 of my silencer anyway, might as well just shop up one that meets all of my needs (and I ride places that need an approved arrestor).

Also, anyone have suggestions on my screw adjustments on the carb? Something tells me someone has made a few changes there, maybe not for the better.

the liner doesnt protrude up at all? no recess on the head? maybe someone with the exact year can verify but the head should center on the sleeve like the 80s air cooled bikes. perhaps someone milled things?

guys, make sure your kill works before starting..... before theres damage to you, property, or the bike itself. even if theres just the kill wire you have to ground would be better than a runaway situation. the throttle returning helps too.
i would go against bigbills advice and not try running it. as he likes to preach over and over about replacing everything in the motor always..
do a compression test or even a leakdown. hard to say where to stop inspecting but the rod could be real loose just waiting to escape. other than seeing if the ignition is capable of making a good blue spark, no reason for it to run.

Your local small engine mower shop should have a suitable decomp valve.twist conrod to see if theres any movement in the big end be hard to check for cheeks spreading with the crank installed but might be able to with some special tools.leak down is the go while youve got the carb off.

Yeah, I know, a bit reckless. Kill seemed functional before the engine was going. The throttle was returning fine, but the throttle tensioner at the handle bar was loose, and the cable sheath came out of the tensioner resulting in some of the length of the cable being taken up, and the throttle not returning to zero.
Looking at ebay photos, it does appear that the sleeve should create a protrusion that the head centers on. The lapping process makes a bit more sense in light of that.

really i didn't know that mine was a later one bought new as a leftover in 1980

got to ensure you get that "clunk" when you shut the carb otherwise much unhappiness

I am familiar with the sound and was getting it. The kick that started the bike was with WOT, I rolled the throttle back too quickly and the cable sheath/cover slid out of the adjuster (it needs lubricating), catching and creating a false bottom, thus the run-off. Before I start it again, I'll be a little more thorough on the carb/throtle side.

Cylinder base gasket was in this morning's mail. Not sure when I'll get to do some Disassembly and Diagnosis, but I'll pull the top and make sure all seems well below. Figure out why compression is low, and then sort my next steps on the engine.

Once I get the frame cleaned off, I'll know more about the appearance and drive-train side of things.

Seems like things are working in a back wards process here ?
acquire bike
admire
tear down
inspect
clean, replace, paint
build
test,inspect
admire new bike

At this point, I've spent more time on this forum than the bike due to lacking a good solid block of time to do anything (also it's rather cold in my garage right now).

Reckless is reckless, I will openly admit that assessing condtion with the kicker is risky. At the same time, my current time and $ investment is relatively small, some risk is acceptable in my book (though the risk of personal or property harm that Justintendo brought up was not well thought through on my part). I realize some may have a more emotional attachment to specific models/years of bikes, and I can respect that. I'm not there though.

My collection of bikes are not museum pieces, and I don't intend to build a showroom for them. The clean-up I do will not be mistaken for a "full restoration". Over the next few months though, I will tear it down, inspect, clean, replace (maybe paint some), and get it back together and running as a trail rider. At that point, I will store it inside, maintain it, periodically ride it in a fashion that is unlikely to cause any serious damage or deterioration to the bike itself, and clean it up afterwards. In other words, keep it in good mechanical condition and prevent unnecessary deterioration.

At some point further into the future, I will very likely repeat those same steps above (maybe even replacing some of the same wear parts for second time), resulting in something similar to a "full restoration".

At some point, I'd really like to do something similar to what Big Bill talks about, and do a ground-up restore, to each of my bikes, one at a time, but I really don't think this is the bike I want to "cut my teeth" on as far as a full cosmetic restoration goes.

Well said.

I agree , we all have different views of how things should be done and I didn't mean to come off in a negative way to you or any other members here. Sometimes when your typing and just can't talk it comes out that way.
But on the other hand "here we go again" as far as BB goes we still have yet to see any pics and after many attempts from the guys on here we still have "None, Notta, Zilch....

Here is one of mine , just for you E.

I've been working on my 400 and I'm close to finishing a rider. I've repainted bits, cleaned fasteners, did the suspension, etc, etc.
I want to ride my bikes so they won't be restored. I hate to worry about scratching a dirt bike up because I know I will fall/crash/centerpunch somehow.

theres no need to tear every bike down to the last nut and bolt, start replating etc...
but after so many old two strokes are torn into, you kinda know that theres probably something wrong in the engine somewhere..and it just waiting to ruin everything. sometimes it pays to get the motor somewhat right or just inspected and go from there. restoration can always come later.
but yeah, no one wants to sound negative, just sometimes you want to save others from making mistakes youve made.

Believe me, I'd love to be disassembling, photographing, bragging about real progress made, etc, just haven't had time. Soon though...

let it sit then. it will be there waiting. the bike is likely just happy to be sitting with other swedes.

let it sit then. it will be there waiting

not like bloody hayburners