 Posted: Mon Aug 15, 2011 11:34 pm Subject: Won't go over 8k rpms?? |
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| OK so this "smoking good deal" of a bike I thought I got, is turning into a bit of a project...
Got some things sorted out, chain adjusted, spacer installed on rear axle, new front brakes pads, new rear tire, and went for a ride tonight. Realized- I think the cause of the pulsing is that rear rotor being warped. Though I don't get a vib in the brakes like you do in a car? guesses? Anyways, what I really am worried about is when I got on the throttle tonight, it felt like there was a rev limiter at about 8000 rpms! Not sure what causes that with these bikes, any help would be nice...I'm wondering if maybe it desperately needs a valve adjustment or a carb sync, idk just throwing out ideas. BTW, bike is '08, has 13k miles THANKS! |
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| Posted: Tue Aug 16, 2011 4:53 am Subject: After a Day of Research |
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| What I've determined:
Forgot to mention the bike has a Two Brothers slip on, looks like i need a jet kit (crap). Pretty sure that is why it craps out, its lean and choking for fuel...hopefully hasn't burnt anything up. Looks like I'll be buying a factory pro kit and spending a couple more nights reading and reading how to "perfect" the jets so I can knock it out when it comes! Also am starting to think that the pulsing is coming from my chain. Looks like I'll be doing a major clean/re greasing before I go out and buy a new one... And hopefully doing all this before school starts back up in two days wooo! |
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| Posted: Tue Aug 16, 2011 7:21 am Subject: Jetting |
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| While it's true that adding exhaust/intake mods will make it run lean, just a slip-on shouldn't be enough to stop it from revving. Were these carbs ever removed? I wonder if one of the boots isn't connected right.
When you do rejet (cause these bikes can really benefit from it) you don't absolutely need a "jet kit". You can can individual keihin jets from http://jetsrus.com for cheap. The only thing you won't get is new needles with a new profile an clip positions. You can accomplish the same as the clip positions by adding small washers. If you're getting pulsing/whining, I would suspect chain tension and/or wheel alignment. Check those first. Lube if it's time. |
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| Posted: Tue Aug 16, 2011 1:19 pm Subject: hmm |
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| I have no idea about the condition of the carbs, if they were ever removed by the previous owners or cleaned or anything. I've only had the bike a couple of weeks, about a week of that with it on stands. I'm going to pull the fairings today and check out the spark plugs and look for any obvious things.
What needle would I need to get from jetsrus.com though? From what I've been reading online it's almost like you need 4 or 5 different needles to find the right by via trial and error... I'm a car mechanic, but only really work on injected engines, jetting is a new concept for me. I adjusted the chain last night but did notice that a link was stiffer than the rest, does that mean it just needs to be cleaned or does it need replaced? Again, no idea when it was last maintained. |
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| Posted: Tue Aug 16, 2011 2:20 pm Subject: Part numbers |
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| Reference this to find the part numbers of what's used in the different keihin carbs.
http://www.keihin-us.com/am/_media/pdf/jetlist.pdf You can change the slow jet and main jet. The base slow jet part number is N424-25B. Stock is N424-25B-038. The base main jet part number is 99101-393. Stock is 99101-393-98. My experience that may be helpful to you. I jetted with no mods though so your results will be different. http://forums.ninja250.org/viewtopic.php?t=73184 Not sure about the chain. It may need replacing if it wasn't maintained though. |
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| Posted: Tue Aug 16, 2011 3:55 pm Subject: When to replace chain |
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| http://faq.ninja250.org/wiki/When_does_the_chain_need_replacement%3F
And info on jetting and general carb stuff: http://faq.ninja250.org/wiki/I_want_to_improve_my_carburetor_jetting http://faq.ninja250.org/wiki/How_do_I_work_on_the_carbs%3F And at 13,000 miles, you are due for a valve adjust, although that likely isn't your problem. http://faq.ninja250.org/wiki/J_Valve_adjustment |
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| Posted: Tue Aug 16, 2011 5:41 pm Subject: OK |
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| THANKS
I've been reading those faq's and tips/tricks about the carbs...probably going to tackle that soon, maybe after school gets under way. So spark plugs actually look ok imo. I'll try to post a picture. Chain- so when spinning the wheel the chain deflection will go from about 1 inch to 2 inch. It seems impossible to adjust since it will either be super tight (causing the surging pretty sure) or super loose... I think the surging was because I had adjusted it at the loose point to about 1 inch, causing it to be really tight, less than .5 inch, at the tight spot. Time for a new chain?  |
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| Posted: Tue Aug 16, 2011 5:42 pm Subject: Yup, time for a new chain |
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| Posted: Wed Aug 17, 2011 5:24 pm Subject: Cleaned Chain |
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| Cleaned the chain, made a huge difference in rolling resistance, that thing was nasty...still looking into replacing it though.
Went to a local shop and after he stuck a finger down the exhaust pipe and looked at my spark plugs, he determined it was running rich. Odd, but makes sense- cutting out in the higher rpms. With that I jumped on the freeway for the first time since buying it just for fun, maxed out at 75mph (cruising with traffic) but couldn't hack it going up the slightest incline. Throttle position didn't matter, from 1/2 throttle to WOT it went the same speed except at WOT it almost felt like it was missing...probably just ridiculously rich I assume. |
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| Posted: Thu Aug 18, 2011 7:39 am Subject: Kinda stumped |
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| The only real reason I can think of for it being rich is that a jet kit is already installed and was not tuned properly. Maybe the previous owner just put in the biggest jet it came with. If they spent the money on an exhaust, they might've sprung for the jet kit also.
These bikes tend to be on the rich side at high rpms. Adding an exhaust causes the mixture to get lean but should still run. So reasons for it not revving to redline that I can think of: - a jet kit is already installed - something is disconnected in the intake - the main jets are clogged - fuel flow to the bowls is restricted at the petcock or inline filter. Either way, you've got a carb removal and cleaning in your future. |
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| Posted: Thu Aug 18, 2011 12:48 pm Subject: I think you are right |
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| Last night I was going to pull the carbs but realized I just filled the tank, so I'll wait till it's a little lighter and easier to manage. But I decided while I was that far to check the idle mixture screws for fun. Guess what, they'd already been adjusted. Pretty sure sign those carbs have been off and likely "tuned".
So I'll be ordering some jets and maybe next weekend I'll have time to dig in...thanks everyone for the help! On a side note, anybody know where to get a chain for a good price? |
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| Posted: Thu Aug 18, 2011 1:26 pm Subject: I just bought this chain on amazon |
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| http://www.amazon.com/gp/product/B000GRXTUK
Though it was $65 when I got it and the shipping was cheaper to. Probably not the best deal anymore. |
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| Posted: Thu Aug 18, 2011 1:38 pm Subject: Chain choices |
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| Would these work too? Obviously making sure to use a riveting master link. Just not wanting to spend any more money than I need to...money that I don't have haha
http://www.mfgsupply.com/m/c/520O-RING-106..html?mv_pc=Froogle http://www.amazon.com/gp/aw/d/B0039K2FVA/ref=aw_d_var_2nd_sporting-goods_txt?qid=1313688634&vs=1&sr=8-39 http://www.powersportsuperstore.com/ProductDetails.asp?ProductCode=4127301&Click=35177 |
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| Posted: Thu Aug 18, 2011 2:45 pm Subject: aha! that's a darn good sign. |
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| Posted: Thu Aug 18, 2011 4:52 pm Subject: Random thought: Does the J still use a 520-106 chain? |
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| Posted: Thu Aug 18, 2011 7:13 pm Subject: Chain |
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| Thats what it looks like if you google it. Looked up 92057-0019 (courtesy of ronayers) which is the part # and it's a ek520sr-o2x106l....translated I'm getting 520-106 lol | |