XR650R Clicking noise (top end) XR650R

[Graylack]

Hi guys!

I just registered in this forum, which looks like a great place to get some information on off-road bikes, as I recently bought an '01 XR650R. So hello to everyone (from Europe, please have understandig for my incorrect english if so, but don't limit yourself in language, I'm way better in listening/reading than writing :P)!

Unfortunately, the first topic I'm turning towards you with is an issue I got with my XR650R I recently bought in used condition. It has two problems, which may be related to each other and which I absolutely did not notice during purchase negotiation - either the seller was lucky that the issues didn't turn up that time or I was too excited to notice, latter is absolutely possible - having a shamefaced look at my history in motor vehicle purchasings. ? ?

So issue no. 1 is: The engine will start, but it needs a few vigorous kicks regularly. Also the idle is not really stable, it may stall when not giving a little bit of throttle here and then. My guess is this problem to be only an issue with carb adjustment - but I'm willing to admit I'm wrong, if so. The BRP is uncorked and has a Mikuni TM40 and an Akrapovic installed, according to the seller it was adjusted (saw the bills verifying that statement). Only fact worth mentioning here is that 7000 miles have passed since this carb adjustment. The bike ran around 19k miles in total.

Issue no. 2: The bike makes a significant ticking/clicking RPM-related noise obviously coming from top end. A friend of mine said the cause clearly must be the valve clearance. I adjusted it to 0.15mm in and 0.20mm ex according to the workshop manual. Intake was already in spec, exhaust was around 0.25mm, so too much. (Does it normally click when using the spec measurements??) I also noticed that manual decomp was a little bit overtightened, which may have been like that for longer unfortunately. I fixed that as well. (Fun fact: I haven't noticed it beforehand since the compression was too high to push over the TDC without using the handle. After readjusting only the exhaust valves I had no problem to kick over the TDC without pulling the lever - until I fixed the overtightened decomp. Can't really explain that to me.) So now I've run out of ideas where the ticking can still come from. Is engine ticking acceptable for the XR650R when it's cold? I haven't had the chance to take a thorough test ride since I've bought it. This because I first have to get the issues fixed and then register the bike (living in a large town with no "fun space" available for activities like unregistered test driving. :P).

Thank you guys in advance, hopefully some experienced BRP riders or other guys which encountered the same issue will stumble upon this thread! ?

Kind regards,
Graylack.

 

[alteet]

Get the Mikuni tuning guide from Mikuni.com and set the carb up per their recommendations as a starting point. I don’t know the history of the carb but check float height, jets and make sure all the low-speed passages are clear and flowing well. I usually do a quick verification of that by spraying carb cleaner through them. Don’t forget to check the pilot jet too. In general, if all else is good, these only start hard cold when they don’t have enough fuel in the mixture.

 

As far as the ticking goes, it’s hard to judge without hearing it. If valves are adjusted properly the ticking should not be loud and may diminish as the engine warms up.

 

There are spring washers on the rocker shafts that need to be assembled on the correct side of the rocker arm. Omitting them or assembling them incorrectly could be an issue if the ticking is pretty loud.

 

Just thoughts off the top of my head.

 

Good luck with it.

 

But recognize that these are really well built from the factory. If this is your first xrr I’d just ride it and get used to it’s quirks. I had a hard time starting mine when I first got it, not being used to kick start bikes. Now I can start it easily hot or cold but I had to figure out what she likes and give her plenty of it.

 

[Graylack]

Hi alteet,
I really had a big portion of luck - both problems were solved, thank you for your answer nevertheless!

The exhaust valve clearance was way out of spec. Just when I was about to disassemble the cylinder head cover I noticed I have to disassemble the valve covers as well as there are two mounting screws underneath. When I did so, I told myself, f it, I'll give clearance measurement another try. And boy, I was terrified and relieved at the same time, when the 0.20mm feeler gauge (spec is 0.17-0.22mm) fell right through the gap. Even the 0.45mm gauge was more or less easy to slide through on both valves, just the next one in my set (0.60) was not fitting in. But valve clearance was like more than two times (assumed 0.50mm) the spec, which clearly accounted for the horrendous rattling and ticking. After adjusting and reassembling, the ticking was gone, also the second issue regarding the unstable idle was gone.

My guess is I messed up TDC positioning very badly at the first try, since I just measured it by feeling through the kicker (now I did it with a straw through the spark plug hole). Wouldn't have expected the exhaust valves to be getting opened so soon, as I must have rotated the crank to an already significant rotation angle post-TDC. The exhaust valve clearance already being in spec at the first try obviously was plain coincidence - I would have suspected a misadjustment in all other cases.

If someone wants to put in his two cents, I have a follow-up question (but I will bother the forum search as well now): Why is the valve clearance on the XR so large? Do you guys all set it according to the spec or do you ride smaller clearances? All of the big single-cylinders I saw had a valve clearance of 0.05mm or so, so about a third or less of the XR's valve clearance. Is this just for "safety reasons" from Honda or will all of the clearance really vanish at operating temperature?

Thanks!

Edited May 26, 2019 by Graylack

[alteet]

Glad you figured it out.

 

As far as the magnitude of the valve clearance goes, I don’t see the xrr specs as excessive compared to other bikes I’ve owned. At any rate, there is apparently enough expansion due to heat to make that clearance necessary.

 

I would not run tighter clearances than specified. Doing so will just about guarantee burning your valve seats.

 

Looser (as yours were before you found your issue) May accelerate valve train wear as well as contribute to hard starting, but is less destructive in the short run than too tight.

[XRMANU]

On 5/26/2019 at 12:00 PM, Graylack said:

Hi alteet,
I really had a big portion of luck - both problems were solved, thank you for your answer nevertheless!

The exhaust valve clearance was way out of spec. Just when I was about to disassemble the cylinder head cover I noticed I have to disassemble the valve covers as well as there are two mounting screws underneath. When I did so, I told myself, f it, I'll give clearance measurement another try. And boy, I was terrified and relieved at the same time, when the 0.20mm feeler gauge (spec is 0.17-0.22mm) fell right through the gap. Even the 0.45mm gauge was more or less easy to slide through on both valves, just the next one in my set (0.60) was not fitting in. But valve clearance was like more than two times (assumed 0.50mm) the spec, which clearly accounted for the horrendous rattling and ticking. After adjusting and reassembling, the ticking was gone, also the second issue regarding the unstable idle was gone.

My guess is I messed up TDC positioning very badly at the first try, since I just measured it by feeling through the kicker (now I did it with a straw through the spark plug hole). Wouldn't have expected the exhaust valves to be getting opened so soon, as I must have rotated the crank to an already significant rotation angle post-TDC. The exhaust valve clearance already being in spec at the first try obviously was plain coincidence - I would have suspected a misadjustment in all other cases.

If someone wants to put in his two cents, I have a follow-up question (but I will bother the forum search as well now): Why is the valve clearance on the XR so large? Do you guys all set it according to the spec or do you ride smaller clearances? All of the big single-cylinders I saw had a valve clearance of 0.05mm or so, so about a third or less of the XR's valve clearance. Is this just for "safety reasons" from Honda or will all of the clearance really vanish at operating temperature?

Thanks!

Exhaust Valve clearance was prob set with the auto deco on. 

From Europe? I 'm in Belgium and been busy with Xr's the last 30 years ,check 2Motors (2Mmotors) ?

[Graylack]

2 hours ago, XRMANU said:

Exhaust Valve clearance was prob set with the auto deco on. 

From Europe? I 'm in Belgium and been busy with Xr's the last 30 years ,check 2Motors (2Mmotors) ?

Am I wrong in my understanding that the auto deco only affects the right exhaust valve (both had about the same huge clearance)? You can hear the auto deco clicking during kick starting after I adjusted valve clearance btw, this was not the case beforehand.

Yes, I'm from Austria, it's a pretty unpopular bike here. Just seen one driving around in the last ten years or so, and online market also has available probably 5-10 per year at maximum. (Unfortunately they are also pretty expensive because of that - dealed as very rare bikes oftenly, even with high mileage ?) I'll check out your page!