87 ninja 750 problems

Green024 · 06-24-2008, 2:13 AM

I've had this bike for 4 years now, and since the day I've owned it, every time i go for a ride longer than 30-40 minutes, the thing sounds as if its choking or its clogged. it first becomes noticeable when i'm taking off in 1st gear, if i lightly roll on it, the thing feels like its hesitating, but if i half throttle it or more, the thing will scream, but eventually after that, every rpm will sound the same, clogged to all hell. This bike has been piped, and the previous owner put on 4 K&N air filters. So, 3 years ago i got 2 new floats do to liquid being inside them.the bike ran good for longer now but still same problem. I realized the gas line from the tank to the carbs (i think. the bikes at the shop and i forget :X) was really short and was getting kinked. so i lengthend it and put a fuel filter in their in case of dirt or rust coming from the gas tank. Then i took the carbs completely apart and made sure all of the little holes in my jets were clean as a whistle, and to make sure my floats are working properly. I did notice that on carbs 1 and 2 on the left side of the bike are spitting a wee bit of gas into the filters.

Does anyone have any clues or ideas as to what might be happening?

Currently my bikes carbs are being synchronized and my uncle is looking it over very carefully for any other issues. AND i replaced those K&N's with some UNI air filters.
Also this bike used to have 2 exhausts , but one of the previous owners converted it to a single yoshi exhaust.

Your help is greatly appreciated

lanbrown · 06-24-2008, 2:23 AM

What about a carb rebuild? With different filters and the pipe, the jets should have been changed and now might be the time to do it.

Green024 · 06-24-2008, 2:46 AM

Quote:

Originally Posted by lanbrown

What about a carb rebuild? With different filters and the pipe, the jets should have been changed and now might be the time to do it.

ill order a rebuild kit this week, i all most did when i ordered those UNI's. The rubber seals were looking a little shaggy....
What do you recommend? Stock jets? Stage 1? stage 2? Would a power commander do any good? harm?

Green024 · 06-25-2008, 2:55 PM

So my uncle/mechanic found out that my water pump is toast..... could that be the answer for my bike dieing out after 45 minutes of riding?

i just ordered a pump today, should be in by friday

lanbrown · 06-25-2008, 6:32 PM

The PowerCommander is for FI bikes.

Get a Factory Pro kit, better than the DJ kits.

If the pump wasn't working, it would take a lot less time that 45 minutes beofre it overheated. The way you described the symptoms, it would be a cooling issue.

Green024 · 06-27-2008, 6:51 PM

So all the places i checked locally and online dont have the water pump or cant get it because its been discontinued. On top if that, while my mechanic was working on a chainsaw, he smelt a funny smoke smell coming from my bike. The key was off and all of my lights were on. Some wire was shorting out and my battery was still connected. so now theres a frickin hole in my electric junction case or fuse box. Luckily he was there to witness the event and stop it before it burnt down his garage. SOOO Im going to try and order a new junction box and find a used water pump at a salvage yard or somethin. Possibly sell the bike before i have to put any more cash into it. TIME to Bite the bullet and buy a new bike with a warranty.

lanbrown · 06-27-2008, 7:09 PM

The bike is 21 years old. I buy new but you don't have to. You just need a current model or one or two back. Honda is good about parts past 11 years though.

jj_long · 06-27-2008, 8:18 PM

Quote:

Originally Posted by lanbrown

The PowerCommander is for FI bikes.

Get a Factory Pro kit, better than the DJ kits.

If the pump wasn't working, it would take a lot less time that 45 minutes beofre it overheated. The way you described the symptoms, it would be a cooling issue.

ya, go to factory pros web site and youll find alot of info on carb tuning there. i like your bike im into those 80's bikes. post some pics id like to see it.

jj_long · 06-27-2008, 8:29 PM

also check some specific forums that discuss those bikes. they are becoming collecters bikes. dont sell it, fix it up and be proud to ride a bike that is not not on every corner. ive got an 86 gsxr 1100 and more people talk to me about that bike than my 929 or harley thats for sure. google your bike and youll find lots of info and parts. also try ebay if you havent already and keep current as the auctions change daily. if you rebuild that bike in your spare time as finances allow youll have a sweet ride and no payments or insurance. i may be biased but the first generation sport bikes rock.

Green024 · 06-28-2008, 3:18 PM

DO you really think a carb rebuild will do the trick? could their be a thermostat problem? Ill post some pics soon, havent seen my bike in a month.

lanbrown · 06-28-2008, 3:52 PM

A thermostat is a crude device and when it fails it fails in the open position; spring wears out. The spring keeps it shut and as the temp rises it opens up. The bike is fully capable of warming up in a matter of minutes and 30 to 45 minutes is way too long; so IMO the thermostat is not the issue.

The pump is a possibilty in that it is not circulating enough coolant, but wouldn't produce the choking issue. It is either way too hot or it's not.

You mention that half throttle and it is better for a little while; that sounds like a fueling issue. Half throttle would use a different jet compraed to low speeds.

Green024 · 08-04-2008, 7:57 PM

So I am back, I replaced all of the spark plug caps, which 3 of them were toast. my coils were ok, but i have an extra set with wires hanging around that came with my caps in case i need it. I got the carbs synced and replaced the water pump, which was leaking a little before.

So none of this changed the bogging down at low RPM's problem once its gets a little warm. i did not even get 10 minutes down the road before it started hesitating in FIRST gear, and then once it got a little warmer it kinda started doing it in sencond, but not as much. So all and all its running a little bit worse than before in regards to the hesitation/bogging aspect.

this friggen machine is depressing me.

As for the good news, The response from the throttle is much better . thats about it for good news. It runs great in the higher rpms in all gears, i can feel the difference from the carb sync.

We discovered that it is the alternator making a ticking squeeking noise when i initially twist the throttle ( most obvious when in neutral). So i will go ahead and get a decent used one from the guy i've been getting all of my other parts from.

Could this cause the problem i am having?
Should i just go ahead and replace those coils? My mechanic never tested them when the bike was warm, because we didnt have the plug caps in yet.

Im at my wits end here, im really about ready to sell it as is, and get a new bike with no problems..... thanks again

pillsbery · 08-24-2008, 1:59 PM

sounds like the same problem alot of us are having I'm starting to wonder if it the ethenol they now put in the Gas or something the three of us have fixed the three different systems but still have the same problem.