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Engine rebuild and other stuff?

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So I got a 2003 Drz125 SW for $550, it smokes like a freight train and the top end clatters pretty loud. What do I have to replace?:moon: It has a 143 11:1 big bore from Powroll. I'm thinking I need new valves, cam chain, piston, and rings. Do I need to get it re sleeved or should the bore be fine? Also the exhaust, carb, and everything else on the whole bike is stock.:moon: So also what jetting should I run with the stock carb and the stock pipe with the baffle removed? Also the only other things it needs are, rear wheel bearings and grips and levers. The plastic could also be replaced. What else in the top end could make it so loud also? Could the rockers be shot? I got a Suzuki service manual and the title with it.:p Is there anything else I should know about these engines? thanks and its got brand new tires, :ride:

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You can't tell if you need to bore it oversized until you measure the piston and cylinder.

As far as the top end goes, the noise is probably the valves. The were probably adjusted when the 143 kit was put in(if you're lucky) and then they probably weren't ever adjusted again. But if the cylinder is worn you could also be hearing the piston skirt slapping against the cylinder wall.

I would plan on at least this stuff:

Timing chain

Chain guides

Tensioner

Valves

Valve seals

Valve guides

Oversized gasket kit

Then either measure the piston and cylinder yourself or bring it to a machine shop and have them do it for you. That's the only way to find out if the cylinder is out of round or not.

Most companies that I know of run a pretty tight piston to cylinder wall clearance, like .002"(I know it's .002" for the bbr kits) but I'm guessing you'd have to call Powroll to see what they advise for acceptable piston to cylinder wall clearance.

I only mention the timing chain and guides/tensioner because, well you already have it apart and for what it costs, you might as well do it as it could save costly repairs down the road.

Hope some of that helps man.

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I am buying a timing chain for it. Also why do you recommend me buying a tensioner? Mine moves freely and the spring seems fine, I just took it out. Do I need to get new valve guides also? I have a paper from powroll the PO gave me and it says that the kit has 10.5:1 compression ratio and the piston to cylinder clearance is .001" and the ring end gap is .009". Will the engine noise go away with the new valves and other stuff? And how many hours can I expect this engine to run with new parts? Also I took the carb out and it has a 110 main and a clogged stock 17.5 pilot.:p No wonder it didn't idle.:ride: What jet should I start out with. I live at 1500' elevation and temps around 50 F. thanks

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First off, I would set the valves and check that the timing chain is properly tensioned. I know if the tensioner is forgotten, or out of adjustment (I know its automatic, just try setting it again) that little engine will make horrible noises (dont ask me how I know). If you have a local bike shop they will usually check your cylinder for round and not charge you (at least not around here....) Basicly, check those first, since they are free and you dont have to dissasemble. After that basicly do what Chris said.

Tom

Tom

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I did the timing chain and it didn't seem to make a difference. Will I be ok re ring the powroll piston if the bore is ok? Also what are the chances of me having to get new rockers? One more question, how do I rewind the stator to run lights? d_whitmore did it but he hasn't been on here in a while. I figure I might as well re wind it while it is out.

thanks

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The only reason I recommend a new tensioner is so you know what you have. I got in the habit while back of replacing parts just because I had them apart, I figured it was easier to replace it when it was apart then to put it back and and have it fail. It was better to be safe than sorry ya know?

The guides, you can measure them as well as the valve stems. If the clearance is good, no need to replace them, but I'm guessing if it was smoking as bad as you claimed, it definitely warrants a close look because oil was getting into the combustion chamber somehow, either through valve guides and stem seals or worn out rings or a combination of both.

As for the piston/cylinder clearance, that's pretty tight at .001".

As for ring end gap, I usually put the ring down into the cylinder and if you can see light between the ring ends, you're good.

I'm almost be willing to bet the noise will be gone after you fix the valve train problems.

I'll tell you what I had in my bike when I got it. It didn't idle, took forever to warm up and even warm it wouldn't idle.

It had a 107.5 main in it

and I believe a 17.5 pilot. that was with only the baffle remover and NO airbox mods.

I went up to a 20 pilot and it totally cured the hard start/cold start issues.

Keep in mind I'm in Rhode Island and what I run will be different from what you run.

I'm guessing since you're a little bit further above sea level than I am, you're probably going to want to run the jetting leaner.

If it's rich now, go down on the jet sizes one circuit at a time so you can tell if the jetting changes you did made any difference or not.

Start with the pilot. Get the bike idling and get the slow speed dialed in.

After you got that, start on the main circuit.

Also if you're out more than 2 turns on the fuel screw, you should go up to the next size pilot.

Less than one you should go down the next size.

I took the snorkel out of my airbox, also got rid of the airbox side cover and used some .040 steel mesh for a door and use a twin air filter.

I also run a BBR exhaust which was the single best thing I've done to the bike as of right now. way more over rev and it's kind of gets out of it's own way now.

My jetting with the pipe and air box mods are

115 main

20 pilot

Shimmed the needle up 1.0mm

Fuel screw 1 1/2 turns out from a lightly seated position.

As far as longevity, it's all in the maintenance.

Keep up on valve adjustments, oil and oil filter changes, air filter cleanings and oilings etc...

I've been flogging mine for 2 seasons, with just routine manitenance.

As long as things are kept up on, these motors are indestructable. I really beat mine too.

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find stator pats from a dr or sp that have lighting coil already you should be able to find them cheap.

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I adjusted the timing chain and now the valve train sounds normal. I'm going to have the cylinder checked by the shop for excessive wear. If it is worn out where can I get a new sleeve? Also where can I get an oversize top end gasket set? thanks

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Is it still smoking though?

You adjusted the chain but did you adjust the valves?

But I'm almost positive that the 143cc piston kit, the piston measures out at 61mm which is the largest piston anyone sells. So you'd deff have to measure and see if it's within spec. If not a sleeve and then start over at stock bore. I know it sucks to do that but you wouldn't want to re-sleeve something and then right away bore it to the max bore.

LA sleeve could possibly have a sleeve for it. By the time all is said and done, you could probably buy a new cylinder cheaper than it would be to buy a sleeve and have the cylinder re-sleeved and then bored.

If Powroll sells that piston, I'm sure they sell gaskets for it.

I know cometic has oversize gasket kits.

Have you done a compression test on the bike yet?

Have you done a leakdown test on the bike yet?

What does the plug look like? Is it fouled with oil?

I'm also curious as to why then did a 143 kit and didn't do an exhaust?

IMHO, I think that the exhaust would have been a better bang for the buck than and oversized piston and stock exhaust?

If you're gonna do it, do it right dude.

Tear into and and go nuts.

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It still smokes. I'm definitely tearing into it. But if the valves are in spec I'm not going to replace them. I rode it for like 10 minutes today, I didn't adjust the valves because I tore it down to the frame to clean and grease everything. I haven't even looked at the plug, but the rings are definitely shot because when you get on the gas it puffs out smoke. For all I know the Powroll sheet could be fake and it might be stock.:banghead: I'll find out when I tear it down. I emailed Powroll and they said they could sell me the rings and gaskets.:) I'll find out when I tear it down. Best case everything checks out and it just needs rings, worst case new piston + rings, valves + guides, cam, rockers, cylinder, and cam chain. I'm hoping for the best case scenario. :banghead:

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Ok, I pulled the top end and it needs a cam and piston and rings for sure. The cam journals are grooved in the head and in the cam. Can a machine shop clean up the journals or do I need a new cylinder and head and head cover?:) Also the rod has a tiny amount of up and down play but the side clearance in the crank measures .012 and the service limit is .040.:banghead: The piston is scored some but there is no ridge on the bore. I'm going to get the valves checked by the shop and see what I can do about the cam journals. And get the bore measured.

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Well I guess I'm screwed. I did some reading and it seems there should be no up and down rod play.:) Is it harder to split this engine compared to an rm 250?

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Lack of oil on all points . The one on e-bay that says slight wear on journals is probably worse than what you have. the other at $99.99 is way too much $ IMHO. If your a bit patient they do come up now and then cheaply like $25.00.

I have no idea on the stator but you may need the CDI for that stator to match ?? but that's just a guess.

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So $100 for the jug and head is a bad deal? I probably need a new jug because the one I have is bored to 61mm and probably needs a re sleeve. I'll keep my eyes peeled for a good deal though.

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Both for $20-40? Also what are the chances of the oil pump being bad? thanks

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Also what are the chances of the oil pump being bad? thanks

Well let me look into my crystal ball here.

Did the Auto mechanic that installed the 143cc kit use ample as in tones of black,blue,orange or grey silicone/RTV sealant to seal up the rocker cover and the base gasket and or the side cover on the engine ?? If they did this practice is all to common and it ends up with little bits of silicone all through the engine plugging all kinds of small oil passages. If this is in fact what you found when you took the engine apart, you would need to make sure you get "ALL" of that stuff out of the engine.

A new pump is about $67.00 on parts fish you can check yours for scoring before you buy new.

Edit: Oh that's funny I just looked at the photos of your head and answered my own question . This guy liked the Orange silicone. get that stuff all out of the engine and buy your self a tube of 3Bond-1104 or Yamabond (same stuff) for reassembly with your new parts and this will likely never happen again. This stuff will be good for your RM also . Hopefully you've already been using this stuff on your RM case splitting adventures if you haven't you should.

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