Bottom End Clunk When Cold

[Thug]

Hey Oh great ones!

I've noticed over the past several months, and we are coming out of out winter, that when I start my baby ( No! the Bike TWN :aacute: ) from cold I occasionally hear a bottom end clunk...So the engine will run and the vrrooommm...clunk..voorrmm clunk it will do it about 2 or 3 times over 30 to 40 seconds then once it is warm no more clunks and rides flawlessly.

The bike is stored in a closed garage and has done approx 7000k's and I am using a partial sythetic oil CASTROL GPS 10W50 using a Yamaha supplied oil filter.

As I have stated in a previous thread when this oil went in I noticed that the gear shift was a bit stiffer and still is after about 1000k's or so, SO... should I be changing my oil to something else or persist with this oil whcih is supposed to be very good.

Cheers

 

[twowheelnut]

Mine did that, too. Changed the plugs did a TBS and all was good. Leave the babies alone - you trying to upstage Mikey Jackson?

 

[socalrk]

A long while back, this topic was on the 'other board'. The general concensus, though not proven, was that it had to do with the temp rich condition during cold start up(high idle) and the 'clunk' is a small backfire in the cat converter.

Mine did the same thing when cold and it did sound like a 'clunk' from the cat area. I've got 16k on the bike and it only clunks occasionally when cold now.

 

[Howardrg]

Have to agree with TWN, sounds like a mini misfire, clears when warms up a bit. 17,000 kms mine has been doing this. Prob disapear at next plug change.

Howard

 

[Thug]

Thankyou gentlemen....oh and TWN

 

[radman]

There's no flywheel to store inertia and carry the motor through little lean pops as it warms, so any misfire is transferred immediatley to all the spinny stuff. A minor tune up (tbs, plugs, bottle of Chevron Techron) should get 'er to sing again.

The shifter/oil thing is a different animal. One of my more frequent maintainence items is a removal and disassembly of the shifter mount and assembly for cleaning and lubing. As for the oil, one would think it's fine, see how the shifter job works out, and if still a concern, theres no better lube out there than Mobil1 15w50, especially in high heat environments. Frank has the smoothest, quietest, fastest shift action of any scoot I've owned with this plan.

 

[Thug]

Thanks man I'll give it a burl

 

[shuswaper]

hey thug re: oil and stiff shifting...me thinks your 10w50 is too heavy an oil for the fjr, but thats just my opinion. Afterall, the manual calls for 10w40. In any event, I replaced the yammi oil with Castrol Syntec 5w40...it is a full synthetic, approved for use on BMW,Merc. Benz and VW turbo charged diesel engines. This oil is rated for normally aspirated gasoline engines as well. Because it is a full synthetic, it will stand up to any temperature extremes you may encounter and it IS compatible with wet cluches. Also, when I switched, I noticed an immediate improvement in shift lever action...butter smooth and quiet (it does "snick" a bit)! I have been using this oil for 10,000kms now, and I swear by this stuff.I have also read, this type of oil disperses heat quicker so your engine will run a little cooler (which is a good thing, don`t you think?). There is no better oil for your fjr as far as I`m concerned...but that`s just my opinion! Regards... :assasin:

 

[comleader]

I think this is the noise/sound I have heard on my '05 during the initial stages of warm-up. It almost sounds like the ignition stops firing for just a second, the "clunk", and then the bike runs normally again. It only happens during cold start and will happen once, maybe twice, and then things are fine.

It sounds like the general consensus then is this is "normal" and there is no harm being done to the engine internals? Right?

 

[Thug]

Thanks Shuswaper I'll look into it cheers

And Comleader Yes It appears this is normal.

 

[radman]

hey thug re: oil and stiff shifting...me thinks your 10w50 is too heavy an oil for the fjr, but thats just my opinion. Afterall, the manual calls for10w40  . In any event, I replaced the yammi oil with Castrol Syntec 5w40...it is a full synthetic, approved for use on BMW,Merc. Benz and VW turbo charged diesel engines. This oil is rated for normally aspirated gasoline engines as well. Because it is a full synthetic, it will stand up to any temperature extremes you may encounter and it IS compatible with wet cluches. Also, when I switched, I noticed an immediate improvement in shift lever action...butter smooth and quiet (it does "snick" a bit)! I have been using this oil for 10,000kms now, and I swear by this stuff.I have also read, this type of oil disperses heat quicker so your engine will run a little cooler (which is a good thing, don`t you think?). There is no better oil for your fjr as far as I`m concerned...but that`s just my opinion! Regards... :assasin:

Yammi reccomends 20w40 oil for the FJR. Actually, all the diesel lubes work well in this motor. One of the favorites is Rotella T 5w40 Synthetic.

 

[shuswaper]

Thanks for the correction (I guess I didn`t buy into the hype in the owners manual)...I am also of the view that mother Yamaha recomends this highly unusual viscosity rating in order to market their own overpriced brand. Lets face it, go out there and look for a 20w40 on the shelf at your favourite supplier (other than a Yammi dealer) and I doubt you will find it. I sure as hell couldn`t find it! In other words, Yamaha has utilized a very clever marketting scheme to a captive audience to sell it`s own brand oil...a bit of a scam actually...totally unnecessary from the engine mechanicals standpoint, this "20w40"! :assasin: