Newbie, little rattle, shaft drive?

[zxtrevr]

Hi folks, just bought this little bike recently and i love it, but i'm concerned with a little rattle when slowing down in gear just when the engine starts to get stressed, eg slowing to about 30mph in 5th gear, its prob jus the way of a shaft drive but this is my first shaft drive and not sure. Its not noticable when changing down gear normally. The rest of the bike is mint, original warning stickers still on it an all.
Any help appreciated, thanks folks.

[jaz66]

sorry zx,
I can't help you there mate.

Guess, one of the others, Maybe pops can help.

I'm sure it's nothing to worry about
(fingers, toes etc crossed)

jim

[pops]

Hi zxtrevr
Cant say ive heard of that one before.Have you checked the dif oil is ok?

Cheers

Pops

[derbyshirebill]

zx,

It could possibly be the transfer gears clattering. These gears (that take the power from the engine to the gearbox) are straight cut on NTVs , and don't have any damping device like on some bikes. When the revs drop in gear and the v-twin's uneven pulses show up, the gears can rattle a bit. It's worse when the carbs need balancing and one cylinder is pulling more than the other. It's nothing to worry about (car racing engines are full of straight cut gears and they sound awful). Mine's been making this noise since I've had it and all it means to me if it gets worse is that the motor needs a tune up..

Bill (gradually getting to annoy people as a know-all)

[pops]

Hi ZK
Have to disagree with you on this one. The damper mechanism is as shown below. The whole crossfeed mechanism is oil fed from the main case via ref 3 a small sleeve.



Pops

[derbyshirebill]

Oh alright pops, you know your stuff. I should have used the proper term- primary gears- they don't have a damper like some bikes have double gears and a slipper.

[zxtrevr]

Checked oil there and it seems ok so its prob just normal noises then. Maybe next time some of you guys are out for a spin you could listen at about 2000rpm in 5th rolling on and pff the throttle, maybe the engine's just a bit stressed at revs as low as this, tell me what you think cos i haven't seen another NTV over here in ages. Thanks.

[Ken Corbett]

I have a NTV 1994 with 50,000 on the clock, I experience the same type of rattle when slowing down from around 30 in 4/3rd from the left side gearbox/shaft area.
I do not think its anything to worry about, just mecanical noise.

[zxtrevr]

thanks folks, this is my first shaft drive and just wasn't sure. Going to France in the summer with the future wife on the back, sort of half tempted to go on to Germany (Nurbergring to be precise) "We'll see!!" she says.
Cool forum by the way.

[Jake]

Used to get the same rattle on my bike. Not knowing any better, I assumed it might be the clutch. I'd heard that a similar problem afflicts the Yamaha Diversion 600 which normal suffers from clutch rattle, and that sometimes the NTV clutch fails at around 15000 miles.

Then I read Bob Callan's old Divvy web page (no longer exists now) and he mentions that after he started using Silkolene Pro4, 10w40 fully synthetic oil, that it all but cured the problem. So I started using this oil on my NTV and it seems to have worked.

Trouble is, it costs around £40 for four litres....

[jonsan]

I too have experienced this rattle, and agree that it's a gear rattle somewhere in the drivetrain. I put it down to my abuse, wrong gear at too low rpm. I think its a bit much to expect a 650 V twin to pull hard from 2000rpm in 5th gear using a handfull of throttle with no vibration or strain, although having said that auNTy will do it if treated gently with only a whiff of throttle [like when you're riding carefully cos you switched to reserve 10 miles earlier ]

Although the pic in the post above clearly shows a damper this is a mechanical damper, I'd guess of the spring loaded cam and ramp variety, and would take a substantial load to work (probably just a failsafe device to prevent something shearing) therefore not as plush as systems used in other bikes, the NTV's shaft drive has no rubber cushdrive in the rear wheelhub, however I like the positive feel this transmission gives.

[hovis]

Hello Jonsan,
must agree with your last sentance "Posative feel" for the gear shift,or a less polite word would be "nutsE" !!!!!!!!!!!!!,
Would also agree about the rattle from the shaft if in to higher gear and to lower speed,it seems they "all do that sir" just a quirk of the bike .
My problem is comming from a 1200 cc four to a 600cc twin i'vehad to adjust my style of riding so occasionally get caught out,but hey i'm learning !!!!!!!!!!!

Hovis