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Posted (edited)

Picked up another Bravo long track , 93,last winter, it's been somewhat neglected by it's previous owner.

 

On the snow, under load, it would make an ugly clunk sound and it felt like somewhere along the transmission, skip or slip then hook up again.

 

I brought it home from the cottage, so I could look it over in the shelter of my garage. Everything I thought might be the problem looks fine, cogs, track tension, chain tension, chain gears, jack shaft, motor mounts etc.

 

I have an idea, but would like to hear some people chime in.

 

I miss Bernie being on here more often :)

Edited by chris.brock
Posted (edited)

I would look at track tension/drive sprockets condition - sounds like the sprockets maybe slipping. Edit - sorry..didn't fully read the part about you checking this...

 

Earlier post about secondary would be next on the list...

Edited by Kenny
Posted

Jack shaft Bearings. Does the Speedometer still work?

 

I had this problem 2 seasons ago. I was a light clunking as it would start out and then would be fine. Last trip of the season and the speedo stopped working about 20k from the truck. Service for last season was the bearings and shaft.

drive belt, no goughing

 

I'll assume you have checked the belt but could be as simple as this.

Posted

drive belt, no goughing

 

 

 

 

I'll assume you have checked the belt but could be as simple as this.

 

 

I'm hoping u guys r right, because that's what I was thinking. The belt is worn but so was the belt on all my piece of crap sleds in the last 25 years.

 

any other input is appreciated

Posted

Tear down the secondary clean and replace buttons. If I remember they are a bit of a pain to get off on a bravo. Unlike most sleds they require a puller you can rent one at crappy tire for free.

Posted

Id change the belt before tearing apart the clutch.

 

I bet thats what it is. Our VKs at work are the same way when its time for a new belt.

 

A worn out belt can also mess up your clutch.

 

S.

Posted

I had something similar on a Polaris. When I would give it the beans, I would get a clunking/gear grinding sound. Ended up taking it apart - issue was with the bearings on the drive shaft - not that they were bad or anything, but there was a bracket that holds them to the chassis of the sled.

The person who had "worked" on the machine the previous winter, had put the bracket only on one side - so nothing was stopping the bearings from shifting under load. So when the torque hit - the bearings moved - which allowed the drive shaft to the track to move - which allowed the drive wheels on the track to move. By the time I found it - it had actually started to eat a hole in the chassis.

 

Anyway - ended up replacing the bearings (had it apart so why not) - put the holding bracket on properly, with one piece on each side of the chassis to keep the bearings in the center. Replaced the drive wheels (again - why not). When back together it was a rocket, with no slipping.

Posted

Where does the belt sit in the secondary post a pic if you can. Measure belt width for wear andncheck secondary. But usually the problem your describingnis.in the driveshaft. The "speedo" bearing seizes up causing clunking severe slow down off the throttle. Easy enougj to replace and around $50.

Take belt off elevate sled and spin track by handnmake sure its free then work backwords from there

Posted

If anyone could do it...

 

It's not broken, it's only slightly flux'd

 

 

 

 

The speedo doesn't work. Leaf springs, no trailing arm, it's lame 250 so not much torque, everything I checked (original post) looked fine.

 

Thickest belt I have in the secondary.

 

IMG_03251_zpsj710sk7a.jpg

 

IMG_03261_zpslntvvf1h.jpg

Posted

Where does the belt sit in the secondary post a pic if you can. Measure belt width for wear andncheck secondary. But usually the problem your describingnis.in the driveshaft. The "speedo" bearing seizes up causing clunking severe slow down off the throttle. Easy enougj to replace and around $50.

Take belt off elevate sled and spin track by handnmake sure its free then work backwords from there

Here here! right on.That belt looks a little low in the secondary.Hard to tell with the older steel secondaries but I would bet it should be at least level with the circumference of the secondary.Newer ones you will be slightly higher in the secondary.

Kerry

Posted

that belt looks a little low and worn if i remember correctly that belts min width is 26mm new is 31 if iam right that belt is right at the min. also adjust your chaincase-- easy peasy loosen lock nut tighten adjustor by hand till snug hold and tighten lock bolt.

for clutch servicing use a "brown" xtrafine 3 m scotchbrite pad and acetone to clean all th faces.

to check track tenssion use a spring scale with 10 kg of force (22lb) measure sag in middle of skid should be 25-30mm or 1to 1.2 inches

but i change that one driveshaft bearing every 2 seasons as preventative mainteneance n all my yamahas and jackshaft bearing and chaincase every 12000km or so

Posted

If your speedometer isn't working that's a dead give away that the driveshaft bearings are done and ready to grenade themselves. Once the bearings start to fail, the driveshaft does not turn true and snaps the sacrificial drive pin that drives the speedo cable. I would bet the clunking you are hearing is the driveshaft flopping around under load. It is hard to feel play in it by moving it with your hands because track tension holds it in a fairly firm position at rest.

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