hungrycamel

DR200 Very noisy, low power

26 posts in this topic

So I have this somewhat beat up 1987 DR200 and ever since my friend bought it and I bought it from him, it doesn't seem to have a functional rev limiter or at least one I can distinctly hear or feel, so I decided to try it out a few days ago and just open it up with the clutch pulled - nothing too crazy or anything I haven't done before, but pretty high. I bailed pretty soon because I didn't hear the telltale cutoff of the limiters on my other bikes and didn't want to damage it, but when I backed off and it fell, the bike was VERY loud from the top end. A sort of rattling/ticking noise. I accelerated again before I realized I should stop and noticed the power was about half of what it was, so I killed it and pushed it home.

I looked and the intake valve nut was completely loose and the valve had literally 1/4" clearance :/ Tightened that up to spec and ran again - was a little quieter, but still very loud. Removed the valve covers and head to check the piston and valves; the piston seemed fine, although I'm not sure exactly what to look for, but basically I thought a valve may have floated? but didn't see any signs of damage. This was my first time tearing down a top end with some idea of what I was doing. The valves looked like they sat fine in the head with no obvious damage. I put the bike back together and waited overnight for the gasket maker to cure, adjusted both valve clearances to spec today, and started it up. Fires up fine so I managed to set the timing correctly, but still very loud and rides with about half power. Feels like the beater CB125Ts I took my safety course on lol.

The sound is slightly different than it was before the valve was tightened, more of a slappy tick with less rattle. My conclusion is maybe rings, explaining the poor power and maybe the sound. 90% sure the sound is coming from the top end as well. Does this sound like a likely explanation? Rings for this bike are cheap, but I've never bought them before and my usual part site offers standard, oversize 0.5, and oversize 1.0mm ring sets - which should I buy and how do I know? 

Lastly, from what I've listed, is it safe to ride the bike if I can live with the poor power until I can find a solution...?

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don't ride it like that because it may seize.

probably the rings are stuck in their slots. take it all apart and clean it up.

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Play stupid games - Win stupid prizes.

You should tear the whole top end down and inspect everything now. There are a lot of things that can be damaged by free revving an unloaded engine like that. Even more so on an old worn engine.

Does the cam in this head ride on roller bearings or journals?  Did you rev it high enough to cause the oil pump to cavitate? Did the timing chain jump a tooth? Is the timing chain stretched? How are the chain guides and tensioner?  How are the rocker arms and rocker pivot shafts? Cam lobes? That 1/4 of play came from somewhere. 

Could have damaged a piston rings, or piston skirt, better check the big end rod bearing too. While you looking at the bottom end check that the flywheel woodruff key is in tact.

Good luck .

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The 1/4" of play came from the lock nut becoming loose and the valve clearance increased as a result of vibration... That's what I thought the problem was at first, but even after adjusting and tightening it, it still made the noises. I'll look at the piston soon - I looked at the top end without removing the piston and everything seemed fine, but I will check the rings.

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Update: rebuilt the top with new piston and rings. Fired up third kick with the choke on with basically the same results as before - very "clattery" and noisy from the top. Let it warm up and rode gently in first, still garbage performance. 

My smallest feeler gauge is a .005", and spec for each valve is .003-.005" so I tightened them to that gauge and then gave a little bit more. Fired up first kick again and rode with much less noise, but the power is still terrible. 

Any ideas anyone? Should I get the proper gauges and try tightening the valves further? The noise is coming right from the top, and it's a metallic clatter/clinking noise.

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The only dr200 I ever rode seemed to have far less hp than my xr 200 did.   If you have the right compression, timing and a clean functioning carb,  exhaust free of obstruction,  air tract the same way,  then I would say you got what  you got.   Finding a "normal" one to compare to isnt too easy I know.   What is the rest of the history on the bike?   Maybe see if the cam is still in spec and the camchain adjusted right is the next step.

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1 minute ago, ossagp said:

The only dr200 I ever rode seemed to have far less hp than my xr 200 did.   If you have the right compression, timing and a clean functioning carb,  exhaust free of obstruction,  air tract the same way,  then I would say you got what  you got.   Finding a "normal" one to compare to isnt too easy I know.   What is the rest of the history on the bike?   Maybe see if the cam is still in spec and the camchain adjusted right is the next step.

It very obviously has far less power than before. As for the history, I know very little. It was my friends who i bought it from, he had no title or any maintenance history. It was essentially a learner bike for me and my friends.

As for the cam chain, it has a manual tensioner, and I think I adjusted it well enough. I tightened the adjuster until I got some resistance. I'm very confident in the timing otherwise. The main thing I'm so concerned with is how drastic the power loss is; I feel like it's something bigger I'm missing.

I recently read some similar threads and found something mentioning the decompressor, that would result in very poor power, right? I didn't pay much attention to it on reassembly, so I'll take a look. 

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2 hours ago, hungrycamel said:

It very obviously has far less power than before. As for the history, I know very little. It was my friends who i bought it from, he had no title or any maintenance history. It was essentially a learner bike for me and my friends.

As for the cam chain, it has a manual tensioner, and I think I adjusted it well enough. I tightened the adjuster until I got some resistance. I'm very confident in the timing otherwise. The main thing I'm so concerned with is how drastic the power loss is; I feel like it's something bigger I'm missing.

I recently read some similar threads and found something mentioning the decompressor, that would result in very poor power, right? I didn't pay much attention to it on reassembly, so I'll take a look. 

I am unfamiliar with that engine.  But if the decompressor on any so equipped is out of adjustment or has been played with to eliminate it,  that could be your problem.  they all pretty much work the same,  and yours could be holding the exhaust valve open.  

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So, it may have been the decomp because I spun it around until I felt no pressure on it anymore. Messed with the valve clearance again and started it up - bike still makes a racket but the power is definitely back. I still don't know what's making the chattering noise because those valves are pretty tight...

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There are lots of other things that can be damaged by over revving a motor.  One big issue with ultra high revs is over stressing the con rod bearings, most specifically the little ends or the cross pin that attaches the pistons to the rod.  Its all about piston speed.

Keep in mind that the pistons accelerate to max velocity mid stroke and then have to be slowed down to zero speed before being yanked in the opposite direction.  There is a certain max piston speed, above which the g-forces experienced by the piston and its connecting bits can be damaged.  

A top end rattle could be piston slap, as a result of over stressing the piston, rod and little end bearing.  

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6 minutes ago, CDNSXV said:

There are lots of other things that can be damaged by over revving a motor.  One big issue with ultra high revs is over stressing the con rod bearings, most specifically the little ends or the cross pin that attaches the pistons to the rod.  Its all about piston speed.

Keep in mind that the pistons accelerate to max velocity mid stroke and then have to be slowed down to zero speed before being yanked in the opposite direction.  There is a certain max piston speed, above which the g-forces experienced by the piston and its connecting bits can be damaged.  

A top end rattle could be piston slap, as a result of over stressing the piston, rod and little end bearing.  

Well I messed with it more today and got the main rattles to quiet down substantially by tweaking the valves again. It's running about how it used to now except for a slightly different and quieter noise, not sure how to describe it... What you're talking about, is that tested by grabbing the connecting rod and checking for play? If so, which direction(s) of free play indicate damage?

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I have this same exact situation going on.  1999 dr200se 1100 miles on it.  Over reved it hear a "tink" then tick tick tick tick.  Shut it down pulled the valve adjustment caps and the lock nut was loose on the intake valve exactly as described by the original poster.  

I adjusted intake valve to spec, no change.  I then thought bent valves due to floating into piston.  Disassembled head replaced valves and cam.  Reset timing and assembled all again.  Started it up and no change.  

Was this problem ever solved??

 

I am thinking bent rocker arm gave excessing clearance and backed the tappet nut loose.  Rocker arm didnt look bent but who knows....

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42 minutes ago, jspicy said:

I have this same exact situation going on.  1999 dr200se 1100 miles on it.  Over reved it hear a "tink" then tick tick tick tick.  Shut it down pulled the valve adjustment caps and the lock nut was loose on the intake valve exactly as described by the original poster.  

I adjusted intake valve to spec, no change.  I then thought bent valves due to floating into piston.  Disassembled head replaced valves and cam.  Reset timing and assembled all again.  Started it up and no change.  

Was this problem ever solved??

 

I am thinking bent rocker arm gave excessing clearance and backed the tappet nut loose.  Rocker arm didnt look bent but who knows....

Fix it ASAP.

My bike ran for a few months in snow riding and the issue was always present, then one day my buddy was riding it up a hill and it was stalling when clutch engaged. I started it and revved it up to try and it clunked and shut off.

Turns out the intake valve destroyed the piston; hammered the crap out of it and shattered the rings and piston skirt. Dented cylinder and pieces are now in the case, but the valve itself is fine.

I assume timing jumped due to stretched cam chain, hence the rattling. 

I recommend a new cam chain, I'll be installing one during my complete rebuild.

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Thank you for the quick reply.  I replaced both valves and the cam.  When I tumed it all the chain seemed okay, newer models have an auto tensioner, when installed it the chain was tight but i will inspect again and keep you posted on progress.  Since i am in there i read it may be play in the wrist pin bearings too so ill check for play in those as well.

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1 hour ago, jspicy said:

Thank you for the quick reply.  I replaced both valves and the cam.  When I tumed it all the chain seemed okay, newer models have an auto tensioner, when installed it the chain was tight but i will inspect again and keep you posted on progress.  Since i am in there i read it may be play in the wrist pin bearings too so ill check for play in those as well.

My piston wrist pin has no bearing with the rod - just spins on a film of oil I guess.

I also thought about cam chain guides being worn out, but they didn't look bad as far as I could tell. 

I did notice that tightening the manual chain tensioner made no difference to the sound, which lead me to believe the chain was stretched past the point of help by the tensioner.

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21 minutes ago, dirtjumpordie said:

..Have you done a compression test?

Before it blew up, no. I hadn't noticed any loss however.

I do however have 0 compression now haha.

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Oh I missed the post where you said it blew up. 

Luckily, you can get that bike running again for pretty cheap.  That engine is made in Suzuki's chinese manufacturing facitility in Qingqi, china.  Its the same engine that is in the Q-link 200cc motorcycles.  No.  Its not a "chinese knock off of a dr200 engine".  Qingqi is literally the exact place that the dr200 engine comes from. 

That means you can find replacement parts or entire replacement engines for pretty cheap. I found a pair of valves for $12.  A cylinder for $75.  A piston for $15   https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20180312134314&SearchText=Qingqi+200cc+engine  I'm sure you could find more parts for that engine cheaply through other channels.  Like wherever Qlink owners buy parts.  

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Yall would be SHOCKED to know how many "Expensive" engine parts inside of big-name engines are made in china for like $1.36.  However many you think it is, double that amount.  And that goes for the "made in the U.S.A" bikes/cars as well as the "made in japan" bikes/cars.

All of those "made in _____ country" vehicles are merely assembled there.  And I'd say over half of the parts on those bikes are made in china.  Even if the mfg puts a sticker on the thing that says otherwise. 

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Update: Since new valves and cam setting timing and adjusting valves didnt repair the problem I opened it up again to see if I messed anything up.  The valves didnt hit the piston at all pulled the jug ti check for play in wrist pin and crank connection to rod, all good there (bike only has 1100 miles).   The cam chain looks good and had plenty of adjustment left on auto tensioner.  At this point I am thinking I bent one of the rocker arms or the pins they pivot on.  Everything else is new and set correctly.  One of these being bent would explain the noise, the backed out intake valve adjustment screw and the pitting I saw on the intake cam lobe.

To answer the question about compression I didnt check but pretty sure it is good after new valves and visually seeing rings and bore look perfect.

Let me know what y'all think about this....

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