Slipping Out of Gear After 3-4K rpms

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Re: Slipping Out of Gear After 3-4K rpms

Postby Fishrider » 28 Mar 2018, 01:09

Yep, before you even replied I pulled the cover and sure enough...the front sprocket is basically round. I am concerned about the amount of crud that was inside the cover. Not sure why my mechanic I had take a look at the bike didn't catch this. My fault as well for not inspecting this earlier. The dirt and grease is infused with metal shavings from the sprocket. I going to clean it up, order a sprocket, and hopefully that will be that. What else should I be looking for considering the damage done here? Either the 3500 miles was extremely abusive or the 3500 isn't true. IIs there anyway to find out if the mileage was tampered with?
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Re: Slipping Out of Gear After 3-4K rpms

Postby DaftRusty » 28 Mar 2018, 01:47

I have never seen a sprocket that worn down!! That is f@%king insane!
There is no way that way that can happen in 3,500 miles unless the chain is massively out of alignment and even then the rear sprocket would show just as much wear. Its like they used a 520 chain on a 525 sprocket and it just ate its way through the sprocket.
No matter what, you will need to buy both front and rear sprockets along with a new chain. They are supposed to be replaced as a unit, If not then the old chain will just chew away at the new sprocket and it will be prematurely worn/damaged.

As for the milage, probably when the bike was dropped it shattered the old gauges (they are all made of notoriously brittle plastic) and they replaced them with a low or zero mileage speedo. Unless it has unworn factory tires with the wiskers still on them, it seems doubtful that is the original milage.
1991 zr550
Factory Pro stage 1 jet kit
zx550 pistons and cams
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Re: Slipping Out of Gear After 3-4K rpms

Postby Freddy » 28 Mar 2018, 03:09

Fishrider wrote:Yep, before you even replied I pulled the cover and sure enough...the front sprocket is basically round. I am concerned about the amount of crud that was inside the cover. Not sure why my mechanic I had take a look at the bike didn't catch this. My fault as well for not inspecting this earlier. The dirt and grease is infused with metal shavings from the sprocket. I going to clean it up, order a sprocket, and hopefully that will be that. What else should I be looking for considering the damage done here? Either the 3500 miles was extremely abusive or the 3500 isn't true. IIs there anyway to find out if the mileage was tampered with?



First thing, get a new mechanic.

As DraftRusty said, no way has the bike only done 3500 miles. You have to assume the speedo was damaged in the crash and replaced with a used unit. Weather or not you want to pursue some legal recourse I'll leave to you. But if you didn't pay much for the bike, and this problem can be easily fixed, weight up the stress and hassle etc.

To replace both sprockets and chain is the correct solution. Now to the problem.

Without some decent tools e.g. an impact gun, decent socket bars and torque wrench , chain tool, etc, the job of getting the front sprocket off, riveting the chain etc. is difficult. It's only about a 1 hour job for someone with the gear v's the cost of perhaps buying the tools (assume something like $300+). So unless you already have a reasonably well setup tool collection, or want to set yourself up to be able to do it in future, it'll be cheaper to just find a new mechanic and get them to fit new front/rear sprockets and chain. Buy quality parts yourself (DID chain and JT sprockets are good options) and just pay to get them fitted.
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Re: Slipping Out of Gear After 3-4K rpms

Postby Freddy » 28 Mar 2018, 03:35

Here's something else to ponder ..... look carefully at the photograph of the sprocket. Am I correct that its stamped on the sprocket (upside down) 'Made in the USA'?

What's the chances Kawasaki Japan sourced the original front sprockets for a Kawasaki Zephyr 750 from a USA supplier rather than a local Japanese one? We have an Australian expression 'Buckley's chance' (I'll let you work out how that expression arose to mean virtually zero).

So considering the front sprocket is unlikely to be original, the chopped up a bit lock tab supports this conclusion, .......... still not sure what it means but something interesting no doubt. Did someone fit a wrong pitch front sprocket?????

A picture of the rear sprocket would be an interesting bit of information for this puzzle if you don't mind.
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Re: Slipping Out of Gear After 3-4K rpms

Postby Swampy » 28 Mar 2018, 08:12

That front sprocket and your so called mechanic are both just unbelievable, replace the lot ASAP :shock:
In my honest opinion I think that the bike has done a wee bit more than 3 1/2k, Any paperwork to support the claim ?
Swamps :)
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Re: Slipping Out of Gear After 3-4K rpms

Postby Freddy » 28 Mar 2018, 09:02

Fishrider wrote:I am concerned about the amount of crud that was inside the cover.


Didn't comment on the above previously. No need to be concerned just give it a good clean. Actually its exceptionally clean. If you lubricate the chain regularly like you should using he best tacky chain lube known to man, pull that cover off and they'll be buildup grease from what flings off the chain everywhere.
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Re: Slipping Out of Gear After 3-4K rpms

Postby Fishrider » 29 Mar 2018, 01:43

Thanks, for the advice everyone. I ordered a set, and I will post the conclusion as well as a pic of the back sprocket. I didn't pay enough for the bike to worry about going after anyone, but maybe a bit too much considering the hassle. I won't be going back to that mechanic. I used to do 90% of my bike work in the old days. I let someone else take point on this project because I just didn't have enough time to deal with it.

-Mike
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Re: Slipping Out of Gear After 3-4K rpms

Postby ZR468 » 29 Mar 2018, 16:49

fishrider, may be my eyes are playing tricks on me. I see the stamping on the wore front sprocket as 18T, the factory OEM specification is 15T. You can up teeth it to 16T and to a maximum 17T. This may be the reason for the extreme wearing, if it was indeed 18 Teeth.
I am too going through replacing the front and rear sprockets and the chain on my ZR750 C2. I am also replacing the damper AKA cush drive. It is a rubber piece that gets hard with age. My favourite repair shop is doing it for me.
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Re: Slipping Out of Gear After 3-4K rpms

Postby Shedman » 29 Mar 2018, 22:43

ZR468 wrote:fishrider, may be my eyes are playing tricks on me. I see the stamping on the wore front sprocket as 18T, the factory OEM specification is 15T. You can up teeth it to 16T and to a maximum 17T. This may be the reason for the extreme wearing, if it was indeed 18 Teeth.
I am too going through replacing the front and rear sprockets and the chain on my ZR750 C2. I am also replacing the damper AKA cush drive. It is a rubber piece that gets hard with age. My favourite repair shop is doing it for me.


Its your eyes playing tricks ZR, if you click on the picture then click on it again it super enlarges and you can clearly see 15T and count the remains of the teeth. I have never seen a sprocket so Donald Ducked either :shock:
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Re: Slipping Out of Gear After 3-4K rpms

Postby Fishrider » 22 May 2018, 00:03

So I finally found the time to get the sprocket all fixed up. I took apart the entire back end and cleaned it up. New front and back sprocket, new chain, and I overhauled the back brake caliper. Got it all buttoned up, and now have a starting problem.

The bike will start at full choke, but then dies after about 3-5 seconds. I have to let it sit for a minute before trying to start the bike again or it won't start at all. What are some of the obvious culprits? Keep in mind that I just had the carbs overhauled, new plugs, new carb boots, new petcock, I think a new fuel filter as well. Air filter looks good.

TIA.
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