Author Topic: Question for engine builders (Read 3464 times)

ttewejnodnarb · « **on:** October 17, 2006, 01:06:09 PM »

Hi all,

I'm trying to help a friend with a 2004 Yamaha R6 he bought. To make a long story short, he got a great deal but what was not revealed to him was that the bike had been down. The lower crankcase on the side of the oil pump cover has been ground down and will not hold oil in...it's been leaking a little and the bike is dangerous to ride because of oil on the back tire. There is a massive amount of JB weld and liquid gasket in the area...so it looks like we need to replace the lower crankcase.

Here are some initial questions:

I have some mechanical ability. I've put on a new rivet link chain, removed the shock and swing arm for inspection and cleaning, synched the carbs, adjusted the valves, etc. Will I (with the guide of the shop manual) be able to disassemble the engine? I think I should be able to if I label bags to hold fasteners and lay everything out neatly. Any thoughts?

The crankcase assemble for an R6 is sold as one piece but can be cracked to separate upper and lower. I was thinking about trying to find a used lower case (saw one for an 02 for CHEAP on flee-bay

). What should I be aware of with regard to the cases being separated? There is no visible gasket and the tolerance looks really tight. Will I run into problems being able to assemble the upper and lower portion? What type of adhesive or sealant needs to be used?

If I drop the engine, would it be feasable to turn it upside down and pull the oil pan, etc. and work my way up to the lower case or would I need to rip the entire engine apart from the top down?

I've seen entire engines but want to try and save him a bit of $$, they seem to go for about $2200. I'm afraid of getting in over my head so any advise would be appreciated!

Bob Holland · « **Reply #1 on:** October 17, 2006, 01:20:02 PM »

The upper and lower crankcase is machined as a unit, mixing two different ones would not be a good idea.

kedeg_97B12 · « **Reply #2 on:** October 17, 2006, 01:43:05 PM »

And splitting a case is not fun. Doable with a factory manual and patience.

ttewejnodnarb · « **Reply #3 on:** October 17, 2006, 02:13:20 PM »

Then I guess go with a whole assembly and take apart more of the engine to replace it.

Also, that would seem to mean that the disassembly will have to start from the top down. Remove headers, cylinder head cover, cylinder head, (valves and springs can stay in place, right?) then remove the upper crankcase, pistons, crank.

So it's seams as thought I'm going to have to split the cases anyway.

Any more detail?

stormi · « **Reply #4 on:** October 17, 2006, 04:27:47 PM »

Quote

Any more detail?

Take pictures of the process and anything that you think may be "fuzzy" when reassembling. Even when removing the engine from the frame.

We took Dita's engine out in Oct of last year. It went back in in April. My pictures saved my butt, cos there were a few wires that weren't intuitively matched.

The baggies is a good idea. That's what we did. Label the baggies, and label any wires you disconnect.

Most of all, don't rush this process. Take your time. If you get frustrated with something, step back, take a break, and consider starting up again later, or the next day. Same goes if you're tired. Even if you set a goal for the day, and are close to making it, consider that most mistakes are made when you're tired. Nothing worse than getting it buttoned up and finding that you have to go back in.

While you're in there, make sure anything you encounter is within tolerances with a GOOD pair of calipers. We'd measured the camchain with a cheap pair of calipers, found it to be at the very end of the tolerance, and so bought a new one. When it arrived, the new one was the exact same length as the old one. Measured with our newer, better calipers, the old chain was well within tolerance.

I have to ask though.... did your friend not ride the bike, or see it before buying it?? I'd think if it's spilling oil like you said, and the cases are all messed, it should have been obvious the bike was rubber side up at least once...

ttewejnodnarb · « **Reply #5 on:** October 17, 2006, 06:39:45 PM »

Yeah...I told him to wait until I could look at it but, even though he's a bright guy, he is as impulsive as a child and not that mechanically inclined. Plus some of the newly applied liquid gasket held for the test ride.

Anyway...I found a case set in CA. Is there anything else I have to be aware of? Do I need new piston rings? What kind of pre-lube should I put on the cams and crank? Is it just as "easy" as take apart, throw old cases against wall, put back together with new cases? And what should I use to seal the new case set together upon install?

Thanks!!!!

stormi · « **Reply #6 on:** October 17, 2006, 07:15:50 PM »

Quote

Yeah...I told him to wait until I could look at it but, even though he's a bright guy, he is as impulsive as a child and not that mechanically inclined. Plus some of the newly applied liquid gasket held for the test ride.

Anyway...I found a case set in CA. Is there anything else I have to be aware of? Do I need new piston rings? What kind of pre-lube should I put on the cams and crank? Is it just as "easy" as take apart, throw old cases against wall, put back together with new cases? And what should I use to seal the new case set together upon install?

Thanks!!!!

I gotta say, he's not alone in being impulsive.

hmm,.. if he missed that, did he do a title search or anything else before he bought it?

The rings will only need to be replaced if they are not within spec. (your calipers will come in handy here, as I recall) If you want to change them, cos you're in there, then go ahead. Usually you'll know if the rings need to be replaced if you're blowing a little blue out the back. Of course, it could also be the valve seals too. Do you have any concerns about that?

Engine assembly lube can bought at any auto parts place. When you fire it up the first time, it will be stinky and a little smoky as that lube burns off. We didn't have to go all the way into the engine, so for splitting the cases, I hope someone else will come up and help you.

There will likely be a seal that can be bought from BikeBandit or similar, and a little bit of that liquid gasket shouldn't hurt, if used to augmenting a proper seal. Not meant to -be- the seal.

As long as it doesn't interfere with proper sealing of the parts, and proper torque.

ttewejnodnarb · « **Reply #7 on:** October 17, 2006, 07:32:27 PM »

Thanks for the input Stormi...I don't think I'll be too concerned with the valves, in fact I'll probably lean towards pulling the head off without disturbing them if that's possible. It was running OK with the exception of the leak (a little hesitation here and there because it hasn't been mapped for the FMF pipe). He got the title in hand (no leins), but we should probably do a seach. I guess I'm just a little apprehensive about the complexity of the transmission among other things. I guess I'll have to hopw that I can transplant most of the parts without disassembling them. I'll have to see if we are both that confident in me to finish the job.

If anyone else can shed some light, or if you can think of anything else, Stormi, I'm all ears.

gearset01 · « **Reply #8 on:** October 17, 2006, 08:08:12 PM »

Do what you want, I always ask how much time a thing will take and figure that into the total. Not to mention how much for tools and stuff to do the job with. There are alot of bike yards out there and if you look hard you will find a good deal. There is no guarantee that you wont find more surprises when you take the thing apart. The ease of swapping a complete motor would make it a no brainer to me. Just make sure its not another problem child by looking for the tell tale signs. Plus he will have a doner waiting in the wings for later needs.
Just my 2 cents.
Sample here.
http://www.drumhillcycle.com/index.cfm/Engines/fuseaction/ViewProductDetails/ProductID/3,3097246
PIN

r_outsider · « **Reply #9 on:** October 18, 2006, 12:59:46 AM »

Is there any reason you couldn't change out the cases yourself? No. Anyone with a modicum of skill, the right tools, a manual and some time can do it. But if you're looking to avoid headaches, there's a couple of big ones waiting for you in the bottom end and tranny.

I myself would take Gearset's advice. One nice thing about R6's is, being the king of all squid bikes, they're being lawn-darted into all sorts of things constantly. Hence, used engines are plentiful, and good deals are probably out there to be had. And, if you really want to, you can rip apart the old one, fix it(or better yet, mod the hell out of it)and keep it or sell it!