chug chug noise!
 

hola,

down in the tierra del fuego and my XT is running well, but when i have it in 1st or second gear below 2500rpms it makes a loud pop/chug noise, especially when climbing. It sounds as if the bike is struggling/going to stall, but it doesn't. a problem combusting the gas? I don't really know, but don't like the noise! Any ideas as to what could be making the bike do this? thanks in advance for any advice!

ben

[This message has been edited by ben_travel (edited 05 October 2002).]

We are not supposed to let this engine get below 3000 rpm !

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Fred, XTZ660, Holland.

thanks for the advice. But riding in uphill in mud and through it on the "highways" of these parts requires the bike to go below 3000rpms...maybe you have a riding technique for mud that allows one to keep the bike over 3000rpms, but for me it is too dangerous. if you do have riding advice to keep her above 3000rpms at all times, please help. if not, i must admit the bike will be well below 3000rpms at times and will make this pop/chug noise. any advice on that would also be great. thanks

Hello Ben, just shift down in gears to keep revs up.
Is the noise appearing when riding through deep mud? Then there's nothing you can do, it's the chain that's full of dirt. It'll go over once out of the shit. Just don't tighten the chain too much or it will jump over the sprocket.

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Fred, XTZ660, Holland.

why do you say you shouldn't go below 3000rpm? a well set up XT will lug up hills at 1200rpm and low speed and steady throttle. must be something wrong if you need such high rpm. can you record a sound-bite of the chug-chug? ;-)
Rich

I know that the engine pulls like a tractor at low rpm [I have a 660], and especially in rough terrain it comes in handy, but it's not good for the system. On the 660, the crankshaft pulley bolt can loosen, and because the oil pump runs slow too, lubrication of the engine and gearbox is not optimal. I think that on-road it's wise to keep rpm over at least 3000. See all stories about 5th gear.


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Fred, XTZ660, Holland.

Hi
Pop/chug noise is a bit of a vague description really.
Unevenly worn chain - ignition problem - carburation problem - loose engine mounts - almost any of the common XT problems.
As regards running below 3000rpm - no problem really ( the only reason the primary nut comes undone is because yamaha never tighten it to the correct torque setting)
As long as the revs are high enough to avoid transmission chatter you wont have any problems.(this will vary from bike to bike)
Let me know when you solve this problem.
David Lambeth.

thanks to all the replies. It is/was a problem with the chain. i am now just working on finding the correct tension. The chain slipped off the sprocket three times yesterday on some Chilean back trails in heavy rain. i couldn't adjust the tension with my tools (the bolt was too tight!) and had a terrible (but laughable today) day in the muddy, rainy hills. not sure about any of the 3000rpm ideas, but i hope that the chain problem will be solved this afternoon!

thanks!