Engine's toast

So.....if you saw my other recent topic https://wr250rforum.forumotion.com/t8937-overheating you already know my situation, but since I'm well beyond overheating problems I figured this warrants a new topic. Here's the short version. I screwed up, got sand past the air filter, and now the engine's toast I'm going to have my mechanic tear it apart tomorrow. Today he just verified everything's hooked up, and it's getting fuel, spark and compression, but...compression's low and I can feel it "sucking" from the exhaust. It's at least a valve job, at worst I need a cylinder, piston, and head.

So....I'm over the initial shock of me flushing a couple grand down the drain, and like any Redblooded American I am now ready to throw money at the problem Right now the bike's bone stock, If the piston and cylinder are still good then I'll just get the head work done and reassemble as cheap as possible. More than likely, I need everything. If I have to throw $1500 - $2000 at her I mine as well upgrade. It looks like the Athena big bore kit isn't much more than replacing OEM (looks like maybe $200 more), is it worth it? If I start down that rabbit hole then I'll need to replace the exhaust, and get a fuel programmer as well. I'm a little skeptical on the value of the aftermarket header, I know the pipe is a must, just up in the air on if it's worth it to get the header.

Thoughts, comments suggestions....

You could do a compression test/ leak down test and it could tell you what your looking at but I'd bet your cylinder is scored all to shit and or you head gaskets popped. You could do valve job while your there but i don't think you'll need it. These bikes run a little lean from the factory and your probably topped out chugging down sand highway putting the bike under a serious load.. This causes overheating, detonation BOOM!
If your set on riding at Glamis do your self a favor and get a 450 and dont ever look back!!

Now if your hard headed and you wanna torture the 250 then go bigbore, PCV, mega bomb/q4 and a good FOAM filter. Then make sure you have it tuned and don't sit on the throttle in 6th gear down sand highway..

I'm done with Glamis, at least on this bike. I'm thinking hard about big bore, and full fmf exhaust. Mechanic should have it broken down today and I can see the damage. I'm hoping the head isn't too bad.

Got a good look at the insides today and it wasn't as bad as it could have been. The biggest problem is that one of the rings seized up. The cylinder actually doesn't look bad, and the yamaha dealer recommended to just hone the cylinder, new piston and rings and it should be good. The head also looked pretty good, but the valves are definitely not sealing. I put in some water on top of the valves and all 4 valves leaked. I think it just needs a valve job. I'll go ahead and measure the cylinder to be sure. Anyone know the limits for the cylinder, it doesn't look bad but I just want to be sure.

go with the big bore.. Trust me, you won't regret it! and do the FMF megabomb and q4.. you will love your bike even more than you do now..

Peterbuilt wrote:

go with the big bore.. Trust me, you won't regret it! and do the FMF megabomb and q4.. you will love your bike even more than you do now..

What's the difference between the megabomb and powerbomb? It looks like the powerbomb is about $70 cheaper. Did you use the Athena controller, or are you using an FMF one?

apparently the megabomb is quieter, but i haven't noticed a difference.. They also say that the Megabomb is designed for more low end, this is a confirmed fact(well, I put it on at the same time as the BB kit) It power wheelies in second gear like nothing and i can clutch it up in third pretty easily as well.

I'm not using the Athena programmer, I sent mine FMF programmer back to Dobeck Performance (the ppl who build it for FMF) and they re-mapped it for the big bore..

If you have the cash, go with the BB kit, you won't regret spending the dough on it!

As much as I want the big bore kit, if my cylinder is still good I can't bring myself to throw an extra $700 at it. Does anyone have access to a service manual that could possibly tell me the tolerance for the cylinder. it looks fine, but I want to get it measured to confirm. If its out of tolerance then I'm all in for the Athena kit.

^ When you say it still looks good, then i take it that there are no excessive score / scuff marks, and you can still clearly see the factory hone marks.....

If yes to all above then i'd very much doupt that it's had any decent amount of sand entry, as it should be quite clear to see the damage cause by it's very abrasive properties - without stating the naturally very obvious here ! lol

Anyway by all means get it all properly measured / checked / inspected / tested. Just be sure to seek out & deal with reputable Techs etc. There must be plenty of very good long term Machine Shops around your area that you can just take the cylinder into for a proper measure up & "second opinion".

Cheers.

I have a manual on my computer at home but I'm 15 days from home. I got it on a forum I think. I'll look.

The cylinder bore is 77mm - 77.010mm or 3.031in-3.032in
the limit on the bore is 77.100mm or 3.035in
taper and out of round limit of .05mm

mcdoudlehopper wrote:

The cylinder bore is 77mm - 77.010mm or 3.031in-3.032in
the limit on the bore is 77.100mm or 3.035in
taper and out of round limit of .05mm

Thanks, I dropped off the cylinder and head at a machine shop this afternoon. I got there just before they closed so they are going to check them out tomorrow.

On the valves, the intake are titanium, and the exhaust are steel. That means the exhaust can be lapped, but what has to be done for the intake?

I would have thought that the Titanium intakes can be lapped in as well, but i'm only a Mechanic, not a metallugist or Machine shop specialist.... In any case i'm sure that the guys at that M/Shop shop will be able to give you the full run down once they have the required time to fully / correctly check everything out.


Maybe best to just wait until then to get the correct answer direct from the specialist / horses mouth. Could be as early as tommorow as you said, but i would'nt rush em 1st thing in the morning.



Hope it turns out to be best case senario for you mate.

****** Edit ********

Just did some quick google research about Titanium valve lapping, so the main concern is regarding the possibility about special coatings on the seating surfaces etc. Lots of different debate, but it seems that a light lap in is often carried out & widely accepted by the engine builders etc.

I suppose again it comes down to the inspection report on YOUR actual head in question = as to how good or bad it may be, and also what the recommended course of action is. Then take it from there. You seem to want to "save" some cash, so if they are not too bad then maybe you might get away with a "light" lap-in ?

Potentate wrote:

Peterbuilt wrote:

go with the big bore.. Trust me, you won't regret it! and do the FMF megabomb and q4.. you will love your bike even more than you do now..

What's the difference between the megabomb and powerbomb? It looks like the powerbomb is about $70 cheaper. Did you use the Athena controller, or are you using an FMF one?

I have the power bomb, my buddy has the megabomb. I've ridden both our bikes side by side. The power and sound difference is negligible. The biggest difference is that his header LOOKS much cooler than mine. If I did it over, I'd get the megabomb.

Looks like it'll be Tuesday at earliest to get a shops opinion on my head and cylinder. I dropped it off about closing time yesterday, the guy was a little snooty and he said he'd call once they could get to it, and that'd be $45. I need an opinion and figured he'd be my fastest option because I'm working today and had no time to take it anywhere. I called him up this afternoon and he told me he was too busy to get to it, and it wouldn't be until Tuesday because he's closed sun and mon. seriously, he couldn't find 15 minutes to measure my parts and call me? I am paying for the inspection, and until now was planning on having him do whatever work it needs. Sounds like he doesn't want my business, so I don't mind taking it elsewhere, I just hate that now my parts are locked up in his shop and I'm stuck waiting to even order anything.

Just needed to get that out

Everyone has a bad day.. Call on Tuesday and see how he sounds. If he gives you some chit, get the head and find another shop. That will usually work out best.

japako wrote:

Everyone has a bad day.. Call on Tuesday and see how he sounds. If he gives you some chit, get the head and find another shop. That will usually work out best.

Yeah I know, its just been a bad week for my little r2, and I was hoping to get some news so I could start ordering whatever she needs. I just had to complain a little, we'll see how he is on tuesday.

So on to more options, any opinions on the Thumper Racing big bore kit. http://thumperracing.net/index.php?route=product/product&product_id=97 Its like a 280, and supposedly uses a lighter piston (than Athena) so it doesn't produce the vibes at high rpm that the Athena does, and it's about $300 cheaper. I read somewhere that it has the same number of rings as the stock piston. If it's a good quality product that might be my route. There's just not as much info out there about it. The few reviews I found all sounded positive.

Wait for your engine report, as from your previous info it would seem that the valves not seating in the head is the most likely main problem. Your "very clean looking" cylinder may well be all ok. If you are unable to wait for the diagnosis of exact fault/s, then maybe just price some new valves etc, as you are at least aware of the possibility that the intakes may not be servicable.

Also i'd say it's a safe bet to look into pricing up all the likely service items, such as piston rings / piston, full top end gasket set, etc.

Really a moot point now, but in future maybe before you actually give the parts to the Machine Shop you should get on the same page as the guys, eg = by asking a question similar to this below =

" I need to have these parts fully inspected / measured, and reported on asap, as in with-in 24 hrs... Is this definately possible ?, if not then i will take the job elsewhere "


I think that if you were to ask as above, then you would get a pretty direct & clear answer..... No point in now jumping up & down, pushing the guy etc - as all you will do is rush the guy into putting you even more "off side". I'm sure that they are a very busy shop, so i doupt that they are going to just drop everything else for your "big" $45 job.


Just kick back & relax mate - another day or two to get the correct report is only a minor "set back" in the relative scheme of things.


Cheers.

Potentate wrote:

So on to more options, any opinions on the Thumper Racing big bore kit. http://thumperracing.net/index.php?route=product/product&product_id=97 Its like a 280, and supposedly uses a lighter piston (than Athena) so it doesn't produce the vibes at high rpm that the Athena does, and it's about $300 cheaper. I read somewhere that it has the same number of rings as the stock piston. If it's a good quality product that might be my route. There's just not as much info out there about it. The few reviews I found all sounded positive.

I'm pretty sure you would be pleased with the upgrade. I can confirm the piston is a 3 ring design (same as OEM). I've got one of those pistons in my garage right now, and I have to say it's oh-so-pretty. I'm coupling mine with the stroker crank whenever I'm healed enough to start the project.

If it were me in your shoes, I'd absolutely do the 280 kit. If you're already opening up the engine anyway, and you can stomach spending a few more bucks (vs. not replacing OEM parts) or saving a few bucks (vs. replacing with OEM parts?), I say go for it. The difference between going for it and not is a base gasket. Granted, you'll have to find someone who can swap the cylinder sleeves (as do I).

I got word back from the machine shop, I need 4 new valves, and seats cut, the rest of the head is fine, and I need a new cylinder. If I'm putting this much cash in I mine as well go all out I'll definitely be going big bore, probably the Thumper Racing 280 kit (which is actually slightly cheaper than OEM) I just want to talk to them before I order and apparently they're closed for this entire week. I assume they're out riding, which I respect. I'll also be going full FMF exhaust and FMF FI controller. It looks like Thumper Racing is actually my best deal for FMF gear, according to their website they offer 25% off if you order with a big bore kit. I'm getting excited, she should be significantly better than before. It's going to take a couple weeks to get all the parts in, here's hoping no more surprises

Bummer on the complete valve job. Big bore improvements for the win! I'm itching to start my BB project as well.