Strange noise/How is the chain supposed to look?

[manorat]

Ok so I finally got my bike running, register, and insured. Took it out for the first time today. And it seems to run alright. This is my first bike, and first time riding it so I don't really know what it should sound like or feel like but it seemed ok. Here are the things that seem out of place:

The bike seems to vibrate a lot, particularly at high RPM. I rode for maybe 30 minutes and I was shaken to pieces, my hands really hurt. I know these bike are known to vibrate but this seemed way more than normal (although i can't compare)

Second top run of the chain sits on the top of the rear fork. Is that normal, does it just run along that? I check the slack and it was about 42mm of slack. That should be tight enough, right?

Finally my engine has made a weird grinding sound, it sound like something metallic is being thrown around inside the engine (literally). I think it came from the right side of the engine, and it has made the noise while moving and while in neutral at a stand still. What could this be? Is there a way something could break off and get thrown around by the fly wheel?

Thanks everybody!

[alex.s]

Sounds about right... congrats on the bike

[manorat]

If this is how the bike is supposed to be, no one would buy one. What could cause this vibration issue, i've checked the mounts, they seem to be tight enough. What else, could something be out of balance?

[monster250]

wow sounds kinda scary about the grinding noise, maby you should take it down to a shop and get it checkd out, it might be costly but id say its worth it, it could get worse

[dubojr1]

Sounds like something internally is broken for sure. Truck/trailor it to a bike shop for repairs.

[FrugalNinja250]

The noise may be the cam chain tensioner, it's located on the right side of the motor. There are specs for chain looseness, etc. You should check out the maintenance and adjustment faq here: http://faq.ninja250.org/wiki/Main_Page and do all the required maintenance. The vibration in the engine could be as simple as the carbs not being properly synchronized.

General rule of thumb is to assume nothing, and do all the easy and routine stuff first before trying to develop any more complex failure scenarios.

[dubojr1]

Carb syncing is for the lower RPM's of the powerband and would be odd to cause such a vibration he speaks of. No offense to Jeremy but because of his questioning here, I can only assume he is not real familar with the internal parts function or the carbs for that matter. If in fact there is a piece of metal loose internally, it would not only give him the sounds he is concerned about but would also throw the balance of the engine out giving him the vibration he speaks of. Even if carb sync is an issue, you would have to run the engine to determine and adjust. To be on the safe side...it's time to carry it to a professional. Just my

[manorat]

I am mechanically savvy, I know the what's going on inside an engine however I am new to bike engines so yes, I'm not quite sure what would be the thing to point at on an engine like this one. I have taken the carbs off and rebuilt them a couple of times now (just trying to get it to run) now i need to figure out what the next step is.

[dubojr1]

Originally Posted by manorat

I am mechanically savvy, I know the what's going on inside an engine however I am new to bike engines so yes, I'm not quite sure what would be the thing to point at on an engine like this one. I have taken the carbs off and rebuilt them a couple of times now (just trying to get it to run) now i need to figure out what the next step is.

Cool deal. You should be able to help determine the issue. I think I remeber you on another thread with carb issues. To be clear to everyone here can we have some history please. How many miles is on the bike? What has been done to date as far as maintenance/repairs? It came from a bike shop right so we have no idea how long it has set up before you got it correct? Are you sure the carb repair is working? If the carb is sucking air at that tear, it could cause some vibration issues.

I think the first thing I would do would be to drop the oil out into a clean container and examine for any metal particles in it indicating possibly a loose piece inside. Prolly a good idea to remove the filter too so we can make sure nothing falls out. Odd I know but it has happened. While it is out, look for metal in the folds of the filter too.

Good luck!

[manorat]

Ok background info. The bike is a 2007 with 7200 miles on it. The bike was dropped or possibly crashed but other than that I don't have a history on the bike so my ownership = day 1 of my knowledge. So far I haven't done much to it other than pull the carbs a couple of times to get it working. As stated in the last thread i started there is something funny about the carbs, they are out of sync for sure. When i attempt to do the fluid in the hose test just touching the starter causes fluid to be drawn toward the right carb. I was also thinking maybe the starter solenoid is problematic, hitting the fly wheel and making that sound. I took the filter and oil out, as suggested. Here's a picture of what I found, I'm afraid this isn't looking so good for my starter theory. So now that I know something's being ground up, what do I do, where do I look? And can I keep the filter out in the mean time?



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Uploaded with ImageShack.us

[dubojr1]

Well there is only a few options at this point. The bike is no longer any good to you at this point. Do not try to ride the bike as that could potentially be a dangerous situation.

Options:

1. Personally I would return to the bike shop to see if there is ANY assistance they are willing to offer. I have suspicions they knew of some these underlying issues when they sold it.

2. Time to tear down the engine/transmission for inspection. After looking closely at the pics you posted I found one other clue. There is different colored metal chips in there which leads me to believe that the metal is coming from a place in the engine where either heat occurs or is occurring due to the failure. I'm not a specialist by far on these engines but I'm thinking this issue may have originated in the clutch assembly. If in fact this is true, the engine may can be saved.

3. Carry it to a professional if your not sure if want to handle the tear down. This will probably be the most expensive option.

4. Start a search with online sources for a replacement engine. I believe these engine are plentiful and can be had with low mileage for a reasonable cost.

5. These option has the potential to be the most educating if you are interested. Part out this bike with the mind set to purchase another. I have no idea what kind of money you have in this bike now but if you managed to get it at a low cost up front, there would lots of room for financial benefit in parting it out.

Man I sorry to hear of the additional troubles this bike seems to have. In addition I hope I have been of some help to you. Let us know what you decide to do and the progress of your decision.

[manorat]

Well I removed the oil screen this morning and found what's being ground up in there (or what's left of it). It appears to be a shim to the crankshaft (i think). There was also a piece of aluminum that broke off of something in there (any thoughts?) Here are pictures of what I found in there (oil plug used for relative sizing). Does this mean that the engine is done for?

[dubojr1]

That looks like a connecting rod or crankshaft bearing. I believe this would be what some call a "spun bearing". Here is a look at the schematic if you like.

http://www.bikebandit.com/houseofmot...10043sch451959

Here a look at some actual ones. Not from a 250 engine though. Notice the colors.



I believe you will have to hope the crank can be re-ground and then replace all bearings with an oversized set. This make sense?

[Alex]

Spun bearings aren't uncommon on the pre-gen ninjette engines if they go low on oil.

[FrugalNinja250]

Originally Posted by manorat

Does this mean that the engine is done for?

Pretty much, unless you have access to cheap parts and machine labor. It will be very likely that you can get another used motor for a lot less than what it would take to rebuild that one.

[dubojr1]

Originally Posted by FrugalNinja250

Pretty much, unless you have access to cheap parts and machine labor. It will be very likely that you can get another used motor for a lot less than what it would take to rebuild that one.

I agree...

[slowandlow]

Originally Posted by dubojr1

Well there is only a few options at this point. The bike is no longer any good to you at this point. Do not try to ride the bike as that could potentially be a dangerous situation.


4. Start a search with online sources for a replacement engine. I believe these engine are plentiful and can be had with low mileage for a reasonable cost.

Your engine is toast. This is your best option in my opinion.

[bdavison]

Definitely a bearing...the grinding noise you are hearing is likely the engine trying to chew through the crankshaft.

Dont ride it anymore until you get it fixed. That engine can lock up, and its gonna be nasty if it does.

Unfortunately, thats a major rebuild as you will have to pretty much completely tear down the engine to get to it.

[mrlmd]

Did you buy this bike without even hearing it run, or take it for a ride? From a dealer or an independent seller? And without knowing any previous maintenance or other history on it?
You have 2 choices -
1.) Either figure out what another engine/trans will cost (and what kind of warranty or insurance of it being good do you get), the time and energy needed to replace it, or,
2.) Part it out, make what you can back from it, and get a good bike that you thoroughly inspect first or with some kind of warranty.