Kawasaki 454 LTD

[jakeman]

Hi all, I haven't been here for a while since I inherited my son's 1986 454 LTD. Inherited in the sense that it's mine until after I've bought all the parts and gotten the bike back in good condition, then he'll want it back again. Hey, what are dad's for?

To date I've replaced the drive belt, both tires, both throttle cables, new rear brake pedal, new turn signals, new seat cover, cleaned and polished all the aluminum covers, etc, etc,. The bike actually looks quite good compared to the poor waif of a bike I picked up from my son's house back in November.

I do have a problem that I can't seem to get past and I'm hoping some of you can help me out. The engine wont rev up like it's supposed to. When you give it the gas it bogs down. If you keep easing the throttle up and down you can get past this sometimes and the engine will rev on up.

Here's what I have done. Adjusted valves, cleaned carbs about 6 times, inspected fuel valve.The carbs and all the jets look perfect and up until now I've always thought it was a carb problem, but not I'm almost convinced it's something else. But what? Even as I write this, I'm thinking, it's got to be the carbs, but I've been inside them so many times I think I could build one from memory.

I've been over on the Great White Knight's site since I've been working on the bike and they have been a BIG help, even helped me out with some parts, but I think I've got them scratching their heads over this one now.

Any ideas, guys? I'm stumped.

Regards,

[randy]

Jake,

Sounds like you've got a big vacuum leak. Maybe at the head/boot junction or at the carb/boot junction.

Are your band clamps loose or do you have any blind plugs/vacuum lines missing or cracked?

[Shawn27530]

Spray some carb cleaner on the intake boots and vacuum fittings if the engine changes pitch, Bingo. Also when you cleaned the carbs did you remove the float needle seat and clean it. I don't know about the Kaw 454 but most bikes have a little screen on the bottom of the float needle seat that gets clogged up and often times it is over looked when carbs are cleaned.

Is there sufficient fuel flow from the petcock?

Is the float height correct?

Is the Airbox sealed up tight, I had a 86 Honda Rebel 450 one time and it would do the same thing until the airbox was put on and sealed/bolted up. It would not rev up with open carbs.

Just a couple idea's off the top of my head.

[prometheus578]

EN 450-A2 (454 LTD)

Sounds like open vacuum or starvin' fer fuel. Make sure there's no holes in the vacuum diaphrams and that all channels are open and carb cleaner sprayed goes somewhere.

[Czekus21]

Have you " read " your spark plugs? Sounds like a fuel problem Or as stated before, A vacume problem. I'll bet on the fuel.

[GNEPIG]

.. sounds like holes in the slider diaphrams or the you didnt aline a diaphram just right in the grooves when putting the caps back on. missalinement is common for one carb but not on both, if this is the case than one carb should work good enough for it to rev up but not very fast.. but if both diaphrams are holed or missalined than your bike wont want to rev, it will eventually but it wont want to
.. also you get this same reaction when the air boxes are removed. it will only run good at idle, it wont rev it up with out the air boxes hooked up. the earlier ltd 440s were just like that too, and also virago's. no air box no revs, it's just the way these carbs are set up
.. hope this helps.. keep us informed

[jakeman]

Thanks for all the suggestions, and most of you agree that the engine is starving for fuel or a vacuum leak. When I got the bike and took off the carbs for the first time one slide diaphram had a bunch of holes in it. I bought a set of later model carbs off ebay that use the same slide. I put these slides in original carbs and put the carbs back on and hooked up to the airbox. Still wouldn't rev up.

The next time I took off the carbs and put them back I left off the airbox because getting these carbs off is a royal pain. I asked the question on the other board about if there was not enough concentrated air flow through the carbs to lift the slides without the airbox installed but no one has replied yet, but some of you think this may be the problem.

The float valve seats are not removable so I'm assuming there is no screen under them like the xs.

I didn't mention this in my first post, but I tested the bike on the road recently and it ran smooth up to about 4k and would then bog down. I applied full choke and it would rev to about 7k before bogging down. No backfiring, just acts like it's running with a governor. Sounds like it's starving for juel, right?

I don't think I have any vacuum leaks but will check to be sure. I will check to be sure the diaphrams are seated under the caps properly. I have checked the petcock and it seems to be working right. It is a vacuum type petcock.

If time allows tomorrow, I will take the carbs off again, reinstall the airbox and carbs and see what happens next. I have done this before and the bike didn't rev up, but I cleaned the carbs about 4 times since then and replaced one suspect looking pilot jet with one from my other carbs.

Thanks guys, I appreciate all your help. I'll keep you posted.

[jakeman]

Czekus21, no, I haven't read the plugs yet, but only because taking out the plugs on this bike is not an easy task like on our xs's.

[prometheus578]

"Feelings... whoa, whoa, whoa... feelings."

Feelers gauges, yeah, that's the ticket!

I will check to be sure the diaphrams are seated under the caps properly

Almost impossable to check if they're seated properly, for when you take the cap off, they can do what they want. Old diaphrams, and you've already stated that one had holes, assume a shape of their own. I rarely find an old diaphram that wants to play nice and lay flat in it's groove. It's always fun putting the cap on... cause you can't really see if it jumped the groove and is pinched.
Lay the diaphram in it's groove as much as possable. Lay two feeler gauges across it to hold it down in place. Place the cap on the feeler gauges. Pressing down on the cap, slowly work the gauges out. Voila! Diaphram stays in place, cap is flat, ready for screws.

[jakeman]

Thanks prometheus578, that's a good idea and I'll check it out.

[strom]

OK, heres what you do... if it gets gas, then its ok...
if it wont rev while in neutral.... not gas... (or gas problem too, but not imediate).
Check the camchain timing.
Re-check valve clearancies, but I kinda doubt thats the problem
Buy new spark plugs, plug caps and cables. Coils would be nice, at least another set to test the bike.
Check ignition timing!!!! Dont remember whether you got points or pick-ups. If you got points, clean them, set them and try again.
If you got CDI.... it may have gone kaka. Happened to a friend on a GPz600R... no power, couldnt get it above 4k rpm.

Good luck!

LP

[Ken Talbot]

Re: "Feelings... whoa, whoa, whoa... feelings."

Originally posted by prometheus578
Almost impossable to check if they're seated properly, for when you take the cap off, they can do what they want.

Check them this way - it's easy. WIth the carb assembled, stick your finger in and lift the slide to the top of its travel. Let it go. If it snaps down, either the diaphragm is not seated properly, or is torn/full of holes. If the diaphragm is seated and in good condition, the slide will come back down slowly.

[jakeman]

Ken, they do come back down slowly. I am going to hook up the airbox again and give it a try. I really think the carbs are ok. Thanks

[prometheus578]

"Oh, don't be such a fuel!"

A properly tuned machine, if you give it choke, will die (flooding) Your bike runs better when you give it choke(means it's starvin')
Need for an airbox: The airbox and filter are a restriction in the airflow available. The carb delivers the right amount of mixture based upon two considerations. The descending piston causes a vacuum. There must be strong enough vacuum to overcome the airfilter restriction to flow, and also must have enough to siphon the fuel up the tubes from the carb bowl. With no filter or air box lid, it's easier for the engine to get air... so the vacuum in the carb required to lift the fuel is diminished.
T'is why... when putting on a freer-flowing airfilter system, the bikes run lean. Easier to get air flow.. than it is to lift fuel. That's why one has to then rejet higher to get better fuel access. some bikes just don't run without a filter. Especially two-strokes.

[jakeman]

GNEPIG and everyone else who said these engines wont run without an airbox was absolutely right. I put them on this morning and fired it up, let it warm up good, and with fear in my heart cranked the throttle. WOOOOOO HOOOOOO!!!! I got revs! It was a little cool today but no way I wasn't going for a ride. About a mile up the road I could no longer feel my face but that sucker was flying!

Thanks all and Merry Christmas!