:guns: :guns: Opened up my top end last night to check the valve clearances... there had been a funny ticking sort of noise at idle... open it up to find that the cam chain tensioner is totally busted. The rail (facing intake, rear of engine) was snapped in half. The top was just sitting there getting grinded away by the cam chain... the tension adjuster was all the way out and the end was also being worn away... had a serious grove machined in it from the cam chain.... looked like it was about to really break apart and cause damage....
So what the f$#% do I have to do now?? I've never done any engine work before but I looks like I'm about to learn! :P I couldn't really find anything terribly useful in the clymer manual except how to replace the cam chain (I did the 20-link measurement and found the cam chain is 157mm long, maximum allowable is 157.8mm) So to replace the cam chain tensioner do I need to split the cases and get the whole bottom end out?? Am I basically looking at a total rebuild? Or is there some sneaky way to do it w/o all the work?? I suppose I should replace the cam chain as well, as long as I'm doing things.... so...
anybody have a cam chain, tensioner and rail set the wanna sell??
Any advice is greatly appreciated as I have not much of a clue what I'm doing at this point!
Thank you :cheers:
Tensioner is replaceable as is... just take off the carbs and its easy, the guide that in on the back may also be replaceable as is. Tensioner end having a groove in it, well its going ot be on the back of the guide under normal situation anyway, so not replacing it may be OK.
Cool.
Srinath.
Naw, guide on the back is not replaceable as is... at least not in my situation... Right now, top end is off. Tensioner is out. Front rail is out... but rear rail is in... well at least the part that didnt snap clean off..... It broke right at the point where the tensioner contacts the rail, so I think the tensioner was in contact with the chain, intsead of the rail.... probably not good, eh??
Good thing you caught it when you did. If you'd ignored it, the cam chain may have let go next. That would have really sucked.
I'm afraid you will have to split the cases to get the rear chain guide replaced. Fortunately its not that hard to do on a GS. At least this will allow you to make sure that you've gotten all the bits of metal and plastic that will be laying around at the bottom of your crank case.
How many miles are on that bike/engine?
18000mi. So what else should I do while I'm in there so that my engine can be like new?? new gaskets/seals, new cam chain, new guide, tensioner....
Not much, the GS bottom end is pretty good the way it is. About the only thing you can do is ditch the counterbalancer and have the crank balanced, but that is quite a bit of $$$ and will hurt its street rideablility/reliability.
Top end you could have the cylinders bored and drop in +2mm OEM or aftermarket hi compression pistons, and maybe have the head ported. Again, that will cost you money.
You could turn the motor upside down. Remove the bottom case and put a new chain guide in. It depends on how far you want to go. But this way you could fix the problem without replacing bearings or rings. Just 3 gaskets for the side cases and oil pan.
hmmm... well I was thinking of just tearing it down and building it back up. I was gonna order one of those engine rebuild kits from partsnmore (all the gaskets for ~$60) as the cylinder head was leaking a small amount... left side has been leaking too as well as the cam tensioner gasket... But you say I'll need to replace the bearings and rings if I tear 'er all the way down? K, stupid question :oops: (but please bear w/ me as I've got no engine work experience) by bearings you mean countershaft bearings? And rings, do you mean piston rings? are these definite replacement items whenever the engine is rebuilt?? I'm trying to put together a parts order so I can have everything I need on hand to just have a crazy go at it.... please advise!
Thanks guys :cheers: :cheers:
Do you mean compression leakage?
Sounds like oil leakage.
You'll need to get the crank bearings, counterbalancer bearings and rod bearings. Also new piston rings.
A complete gasket kit is definately the way to go. It should even come with new valve guide seals. That would involve removing the valve springs requiring a special tool. But it would be wise to replace these seals.
when you order the bearings, you'll need twice as many for the crank and counterbalancer. You only get half a bearing in each package. The rods come with both bearings in the box. So only order 2 rod bearings
The counterbalancer bearings are the same as the crank. There are 6 bearing journals (2 counterbalancer, 4 crank) so you'll need 12 bearings total. You can re-use the 2 thrust bearings (horseshoe shaped bearings) that fit on the 2 inner crank journal sides.
There are a few little details to look for when tearing down the motor. But it's a very easy motor to work on. I just tore one down a hour ago.
I'm rebuilding it just like you're going to. :thumb:
Except I'm going 1mm bigger bore and I'll be running race cams in a ported head. Other than that it's stock. :mrgreen:
We'll guide you through things :cheers:
If the bearings are in good shape he can reuse them, right?
Quote from: JamesGDo you mean compression leakage?
Well I meant oil leakage, but haven't tested compression. My bike was running fine before this though... well, fine except for the snapped guide I didn't know about :oops: .
OK, thanks for all the info about what I need to do, but I'm still a little confused about the bearings and rings. Do I need to tear everything down first, then mic things before I proceed with buying replacement parts? Or can I just order stock replacements?? I saw that bike bandit seems to have a "kit" for these bearings, so it seemed to me like it might include everything... ronayers had everything listed seperately.
For piston rings, do I just check that the cylinder diameter is still within spec and then order the stock replacements if it is?
Oh, can can you recommend a good tool for removing the valve springs?? I'd be game to give that a shot...
I'm trying to get as much information as I can so I can gather the necessary parts and tools and give this a shot!!
Thanks so much for your help!
Quote from: JamesGIf the bearings are in good shape he can reuse them, right?
The bearings can be re-used. But with 18k on the motor and having to split the cases. I'd go ahead and put fresh bearings in. Unless you were really tight on funds.
As far as a "kit" goes. Each motor is individual. That's why they stamp the cases and cranks and color code the bearings.
If you wanted to, you could mic. everything or use plastiguage. But using the letter coding and reference chart is the easiest.
I would just hone the cylinders and put a fresh set of standard size rings.
Suzuki only sells the rings in stock sizes. They have piston kits in .5mm over and 1.0mm over with pistons and rings. But they don't sell rings seperate for the oversized pistons.
The valve spring compressor tool is too pricey unless you use it often.
Motion Pro sells one. I would try to borrow one, rent one or maybe find a shop that will help dismantel and reassemble the head.
It's basically a C-clamp type tool.
If all else fails, let me know and I can mail mine to you and you can mail it back when you're done.
Or you can send your head to me and I'll fix it up for you.
Quote from: Bob BroussardIf all else fails, let me know and I can mail mine to you and you can mail it back when you're done.
Or you can send your head to me and I'll fix it up for you.
Wow :o . Thank you. I'll probably send you my head.. Don't really know what I'm doing and rebuilding the bottom end is probably enough work for me. I'd feel bad borrowing your tools cause I don't know how long it'd take me to do... So I'm gonna order the gasket set and once that arrives I can send you the head and the valve guide seals.... (anything else?) does honing the cylinders involve both piston and head? or do you just clean up the head and then install a new ring on the piston?
OK, as for the rest.. so I'll use the letter coding to know which bearings to order.. and I suppose I'll order a set of standard size rings...
Thanks for your help so far Bob
Honing the cylinders doesn't involve the head. You can send the cylinder too.
I have the hone for that. Send the cams to and I'll set the valve clearences.
I'll clean everything up for you and it'll be ready to bolt on when you get it back. It's all pretty simple when you have the tools :)
There will be some minor things to get through as you work on the motor. Since this will the first time. Removing/replacing the circlip that holds the piston wristpin in is a little pain. You have to figure a way to hold the clutch basket from turning while you take off/replace the nut. You'll need a torque wrench too.
Be prepared for more oil to drain out as you dismantel things. There's always some left in the motor after you drain it. So doing it on a catch pan ( like the ones you slide under a car) would be wise.
Thanks Bob. I'm gonna take you up on your offer. I'm gonna try to get things apart this weekend, then maybe I can send out the head cylinders cams and seals next week... in the meantime i've got plenty of stuff to work on... thanks again! :thumb: :thumb:
BTW - are piston rings sold as a set? or do I need to order two?
i made a tool that fits perfect using old clutch plates, this locks the clutch basket and hub, placing a penny between crank gear and clutch gear jams them while you break the nut loose without hurting the gears. If you folks are interested, send me your old plates and 10$ and i will make a rig for you, i already have a trashed clutch basket setup for it. PM me for more info.
Quote from: BadBatzMaruBTW - are piston rings sold as a set? or do I need to order two?
You need 1 set for each piston. So I guess that would be 2 sets :mrgreen:
I used to take a pair of vise grips on the edge of a metal clutch plate.
Slide it in the basket with the pliers in a slot on the basket.
I finally welded some small angle iron pieces on the clutch plate to make my own tool. If the pistons are off the rods, I just put a socket extension through the rod to stop the rotation. The penny idea in the gears sounds good too.
got the engine out today! whew. but couldnt get the oil pump screws out: didnt have an impact wrench handy... but my question is, am I gonna need to get that out before I continue with the cam chain and tensioner replacement??
Thanks
:)
dont even need to remove oil pump. just the triangle brace behind drive chain sproket on left side, and one behind the the clutch basket, then remove the shifter shaft. Impact driver is a must on these(thought i mentioned it, perhaps another posting) Dont forget the one bolt at back of starter in top of case, and the 2 allen bolts under oilfilter , get them through oil pan area, they are tiiiight.
The oil pump does not need to be removed.
However, the pickup screen in the bottom of the motor does.
Harbor Freight Tools has impact driver sets. I've bought them on sale for $3.00 :o You'll need one for a few screws. And a torque wrench that will go down to 9 ft lbs.
Would something like this work: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=46978 ???
That's exactly what I have.