Jump to content
Sign in to follow this  

Gearbox noise

Recommended Posts

Hi,

I have a CCM 404E with the DRZ400 engine, modified for touring.  The bike has covered around 13000 miles, the last 7000 with me after a full engine strip and examination, which only revealed rough bearings on the balance shaft requiring attention - these I replaced.  At that time the engine had covered just under 6000 miles and was otherwise in excellent condition. all measured components conforming exactly to the limits specified in the Suzuki workshop manual.  During the subsequent rebuild the bike was fitted with new seals and gaskets, and new sprockets and chain.  I use a semisyn. oil.

The problem (if it is a problem.....) is that when the engine is warm, when shifting into top gear, there is a whine.  This noise only lasts a few seconds and then seems to disappear.  I am intending to strip the engine again, but it would be helpful if anyone who might have experienced a similar problem could advise where to look.  The bike runs well apart from this, although the clutch is a little "draggy", making shifting into neutral when at rest a little difficult occasionally.

My initial thought is that the problem might be with a gearbox bearing, but I checked them for smoothness during the engine strip and nothing appeared to be amiss.  Naturally, I will recheck these bearings again, but has anyone out there experienced anything like this problem, and advise on any areas of weakness of which I should be aware?  

Kind regards,

Sigean

CCM 404e.jpg

Share this post


Link to post
Share on other sites

Ahh.... and there's the problem.  The bike (and engine) are exactly as shown in the photo.  I am just concluding my European tour on the CCM (before we Brits will require a visa to enter the wonderful place that is Europe) and am in southern France, temporising before riding north for my ferry crossing next month. 

But perhaps I should have commented that the noise is no worse (or better) now than it was at the beginning of my 5000 mile trip, and I still have another 1000 miles to get home to Devon.  I have been riding in a manner so as not to overly stress the engine, and hope to return without problem.  The point of my post was simply to elicit comments from anyone who might have experienced a similar problem, the better to inform my investigations once I get to my workshop.

But I will post any relevant photos once the engine has been opened up, probably in late September.

Kind regards,

Sigean

Share this post


Link to post
Share on other sites

No metal in the oil? High gear is usually in the middle of the gearset, which would load both bearings. The load is also much less than in any other gear, since the torque is transmitted at the largest radius from the clutch shaft.

 

I wouldn't worry about it. Chances are, you use high gear the most, and the teeth have lost the perfect profile they were machined to. If you see them flaking off into the oil, then you have a problem. 

Only other issue could be a bent or worn shift fork. I'm not sure which gear is shared on the same fork, but it is usually obvious when clutch less shifting. One of the gears will engage with much less throw on the shifter since the fork is already biased.

Edited by plkracer

Share this post


Link to post
Share on other sites

I have ridden a DRZ400 that had a whiney 3rd gear. It never left any deposits in the oil though.  I think I must have put about 20hours on it and did at least 3 oil changes (they were hard rides in dust)  On another note I have a 2001 motor in parts on the bench.  I have replace the gearset with an ACT version.  To my surprise when I opened it up second gear was well pitted and worn.  I can't comment on how this would have been as I never heard the motor running. Picture attached

20190521_084640775_iOS.jpg.ac2c66dfccc67a3f1ba552abc3d64bc5.jpg

Share this post


Link to post
Share on other sites

Perfect example of surface fatigue. Could be a result of many, many hours, poor lubrication/shear strength, or poor metallurgy. 

How did first gear look? Contact pressure is greatest on first, and it usually shows scuffing on the faces of the gear teeth. If first looks good, my bet is that second gear wasn't heat treated properly, or the OEM got a batch of poor material.

 

Share this post


Link to post
Share on other sites
1 hour ago, plkracer said:

Perfect example of surface fatigue. Could be a result of many, many hours, poor lubrication/shear strength, or poor metallurgy. 

How did first gear look? Contact pressure is greatest on first, and it usually shows scuffing on the faces of the gear teeth. If first looks good, my bet is that second gear wasn't heat treated properly, or the OEM got a batch of poor material.

 

First gear was pristine (as were what was left of the gears) - just as well as it's kept as part of the new gears (2nd, 3rd 4th and 5th all replaced with ACT gears) the output shaft also replaced, the later model shaft is quite a bit thicker at the spline end. All of the spacers and circlips also done. I hope that we're good for many more miles.

20190814_011232555_iOS.jpg.edc0dee93155dbdd1218401821259b0b.jpg20190814_011226531_iOS.jpg.5312f8c6f7b157a8f3b4576d8f5649b7.jpg

Edited by roleyrev

Share this post


Link to post
Share on other sites

Many thanks to all the respondents - great thoughts and some ideas I had not considered.

Perhaps I should have mentioned that I gave the bike a service 500 miles ago.  This bike has been set up for the road and, after discussion with the oil manufacturer, I use relatively extended oil-change intervals at around 5000km.  Amongst other things I changed the oil and filter.  The filter was completely clean apart from a few tiny aluminium flakes which I assume came from the clutch basket.   I found the same thing at an oil and filter change immediately before I started my tour.

On the comments received:

  • I had not considered the selector forks and I will check these when I take the engine apart.
  • As for the "I wouldn't worry about it" comment, I agree wholeheartedly!  This is what I have been trying to do for the last 6000 miles...... and with some success.  When I strip the engine I guess I expect to find nothing amiss - this is just how my engine works.  But it would be good to discover the reason for this anomaly.

Finally, I am astonished when I read reports that engine components have worn out is such short times.  I appreciate that machines ridden competitively have a particularly hard life, but 3 oil changes in 20 hours?!!  The pinions in the photos look worse than those in my 70 year-old BSA!

Once again, many thanks for your thoughts and advice, great comments!

Sigean

Share this post


Link to post
Share on other sites
11 hours ago, plkracer said:

Perfect example of surface fatigue. Could be a result of many, many hours, poor lubrication/shear strength, or poor metallurgy. 

How did first gear look? Contact pressure is greatest on first, and it usually shows scuffing on the faces of the gear teeth. If first looks good, my bet is that second gear wasn't heat treated properly, or the OEM got a batch of poor material.

 

Its a known and common issue with the very first few years DRZ motors, all models..Id hazzerd a guess the heat treatment was off, or a source metal issue. It happens even on bikes that had a known, tracked, correct maintenance done

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...