KX Riders
Maintenance & Technical => KX500 Original => Topic started by: monster malibu on June 25, 2007, 11:30:35 PM
-
Anybody know who makes big bore kits for the KX500? I'm not sure yet if I want one, but would like to know where to get one. My bike has alot of power, but more is always better.
-
There are all kinds of upgrades on here to get power where you need it, but I'm not sure about the big bore kit. You already have a reed spacer, pipe and silencer, and fresh piston? I suppose you can get a new sleeve and bore it to whatever size, but the Kaws have the Electrofuse coating, which I think is an advantage over other mfg's. Stock cylinders are strong and easy to get pistons for. Like I said already, there are options to get more ponies easier. I would refer you to my engine builder @ Thomas Racing Service for a big bore app. I am 100% sure that he can do it in the same turn around as any stock cylinder, but I would not be in a hurry until you get alot of feedback about the pros and cons of the mod. This will be an interesting thread to watch, because I'm sure there are alot of opinions about this topic.
-
i think you can make a lot of power very relieabley with stock bore and stroke
-
i'm not completely sure but i think a big bore kit would involve boring out the cyl. large and sleeving it to whatever the desired size. heres the problem. anyone whos worked on diesel engines alot knows about the problems associated with sleeves. they tend to wear holes in them from internal electrolisis(or harmonic induced cavitation). the wear occurs on the water side of the sleeve due to tiny bubble explosions that are vibration induced. knowing the revs on these k5s are high, in my opinoin, the sleeve wear on a 2 stroke would probably be worse than on a large low rev diesel. however, if a sleeve kit is chosen then change coolant at least 1 or 2 times per riding season. the sleeve wear is excellerated when running out of spec. coolant in the engine. my opinion only, MADDOGGY
-
Pretty sure Kustom Kraft does bigbore kits for the 500. They are a great company and have been into motor building for over 20 years now.
-
Don't know if you have sidecar motocross over there but over here they take KX 500 engines and get a bit silly with them.
One of the lads that used to come on here (Scarykxer) has had his bored out to something like 570 cc
Bored out and I think they use a 2mm oversize CR piston as well which is 91mm in diameter and change the conrods to CR ones that are aparentely stronger.
I am not sure if they also offset the crankpin to increase stroke.
They also use the Maico engines (you lot might know them as the ATK intimidator engine but its a Maico all the same) and they are re badged as Zabel engines.
Think they are something daft like 700cc, don't fancy licking one of those over with my left foot though.
-
i'm not completely sure but i think a big bore kit would involve boring out the cyl. large and sleeving it to whatever the desired size. heres the problem. anyone whos worked on diesel engines alot knows about the problems associated with sleeves. they tend to wear holes in them from internal electrolisis(or harmonic induced cavitation). the wear occurs on the water side of the sleeve due to tiny bubble explosions that are vibration induced. knowing the revs on these k5s are high, in my opinoin, the sleeve wear on a 2 stroke would probably be worse than on a large low rev diesel. however, if a sleeve kit is chosen then change coolant at least 1 or 2 times per riding season. the sleeve wear is excellerated when running out of spec. coolant in the engine. my opinion only, MADDOGGY
When the cylinder is bored it does not get into the water jacket, you shouldn't have to worry about electrolysis. Now you can use a new style cylinder, but if you desire to go more than 88mm you'll need to weld up the upper kips, or use an 86-88 cylinder. You don't have to install a cast iron sleeve, you can have it bored and re-plated. I have one that is 91mm, it works good, but, not sure if it's worth the work. I would have the Mods that Stewart has posted, I did a cylinder with the head, piston and 44mm carb mod, the thing hauls, it pulls a ton more gearing. Wiesco makes a 88mm piston, you could get your cylinder bored and re-plated to 88mm install the new piston and you'd be good to go.
There was a post asking if anyone had tried a PVL ignition with the Mods by
Stewart, I have and didn't like it at all. There is to much compression to spin the motor fast enough to fire, once running no problem, but getting running no way. The PVL works good on a lower compression motor. by my estimation my motor with the Stewart mods has 180ish psi of compression.
-
This is all great info guys, cheers. I have recently taken my cylinder off to port a big bore, but have found it is allready sleeved, so now im thinking a 540 kit. I would like to run the same mods as some of the members here but i dont think it is possible as in Australia we only really have access to 98 octane fuel and would be looking at detonation. Has anyone here got any engine mods for this kind of fuel?
-
Anybody ever dealt with KUSTOM CRAFT? They list a BBK for the KX500, it's a 540. I'm not sure about the BBK yet, but I'm still thinking about it. I like the idea of more power and speed.
-
I can't be the only one that's interested in the big bore kit for the KX500. Somebody's got to have one? :?
-
thers a lot of ways to make more power
-
if you are gonna do the big bore you'll have to get head chamber cut accordingly if you are set at 0 deck and use steel .010 gasket.also ports will have to be redone to compensate for the bore,including exhaust auxillary ports.not to mention powervalve mods to clear piston.LA Sleeve offers the kit also.hope this helps.
-
Hey guys, this is what's done to the bike so far- pump gas porting, Boyesen rad valve with Moose torque spacer, Pro Circuit platinum pipe, racing clutch (brand not sure) 13-47 sprockets. Instead of a big bore kit what else can I add? I was also thinking of a carb over bore. Would I gain anything by switching the pipe out for a gnarly pipe?
-
I can't be the only one that's interested in the big bore kit for the KX500. Somebody's got to have one? :?
I had one on my KX as well as a lot of porting, bored carb. etc. It made so much power that it literally twisted the crank. The crank was balanced and welded too. Nowdays I stick with the stock bore and get my power from the porting and other mods.
-
I have 2 K5's with 3 different motor's, one is a LA sleeve 540 (that is really only a 527) the other is a 560, and the 3rd motor is a stock 86x86 with the head cut and the piston modded. The 540 is on Nitrous so it's really hard to tell just how good it runs in stock trim. The 560 has tons of torque but doesn't rev very fast, and the stocker revs quick and has tons of overrev, it'll pull 15-48 gearing no problems (hillclimbing).
In my quest for power I've tried many combinations, and frankly the cheapest route was as good as any of the others, invest in a lectron.
-
Hey Don46, Where did you get the 560 kit from? I really like the idea of that instead of a 540.
-
i have a exhaust port set up that's crazy. full width main port kips valve and big sub ports. :-D
lucky my welder does all the alum. welding for all big cylinder platers.
-
Hey Don46, Where did you get the 560 kit from? I really like the idea of that instead of a 540.
There is no Kit, it's a do it yourself with the help of JBSracing.com (England) thye used these in sidecar racing, and he did indicate I could go in excess of 600 cc by boring and stroking. I wanted something somewhat dependable so I opted for the 560.
-
Hey Don46, can you tell us what's involved in the 560 do it yourself motor, I'm lost. I checked out the jbsracing.com and found a site about boat racing, I mustv'e done something wrong.
-
Hey Don46, I got the email you sent me. The 560 idea sounds complicated and I'm new to the bike seen. I think I'll just go with the big bore kit for now. Thanks for all the input guys. DECISIONS, DECISIONS :? :?
-
Hell I would like to make my 500 a 350 . I must be getting old :-D
-
Getting good clean jetting will improve the power output greatly and it's cheaper. Do you have the stock carb for an 87 kx500? I am having a hard time finding jets for the VM38 carb. All the info I can get is that the carb and jetting for that year bike was special made and no O.E.M parts available. I'm looking at buying a new VM38 from tuckrocky so I can get the jetting under control on my bike.
-
The jetting seems to be right on, the bike starts good and runs down the trail like a freight train. I just want more power/torque. Pretty much everything I own with a motor on it is not stock in any way(sled,4x4 truck,car,bike). I live in a small town and get some interesting responses when I tell people I just bought a KX500. My brother took my bike for a ride and said he doesn't like it. His exact words were "THAT THING'S TO F#%^*(! FAST, YOUR'E GOING TO KILL YOURSELF ON THAT"
-
Getting good clean jetting will improve the power output greatly and it's cheaper. Do you have the stock carb for an 87 kx500? I am having a hard time finding jets for the VM38 carb. All the info I can get is that the carb and jetting for that year bike was special made and no O.E.M parts available. I'm looking at buying a new VM38 from tuckrocky so I can get the jetting under control on my bike.
I just sold my two season old Mikuni TMX 38mm to a fellow triker. Great carb.
Mikuni VM should take mikuni large hex main jets hey?
-
If you want easiest big bore go with the 540.you can get the piston from la sleeve.
They have a copper head gasket that?s 60 thousands thick, it will smooth out the power.
The head needs to be cut 3mm bigger, and grind the power valve to fit.
Just send the cylinder to get replated to that piston. You don?t want to use the steel sleeve.
As for the carb use a number 8 slide, it will give you a lot better off idle response.
This set up is a lot smoother and way more bottom end than kx 500, been running one like this for 12 years.
If you need to know more about this setup just let me know.
-
Hey kawsf, can la sleeve do all the work I need? I like the idea of sending everything to one place for the work. If they can't handle the whole job, where would you reccommend I send my parts?
-
i had the la sleeve deal for big bore ......but the late cylinder ,89 and newer does not look thick enough to sleeve in my opionion there are some better combos for all out power but i guess we all have to try our own way
-
Hey Stewart, what combos would you recommend? I don't know a whole lot about what can be done to this bike, it's already got a pipe, rad valve with spacer, porting, racing clutch, 13/47 sprockets. These improvements were done to the bike before I got it, that's why I want to go to the 540.
-
what pipe theres a lot of diffrence.. i dont care for rad valve use v force 2 ,, porting can really slow you down if not right or speed you up if right .. and piston mods help so does 44 lectron if right.. and head mods can be help full
-
The bike has a Pro Circuit Platinum pipe on it. Is there any reason you don't like the Boyesen rad valve? The porting was done by the previous owner and I thought about having it checked out, where would you recommend? What are piston mods? Where can I get a Lectron 44 from? I thought about having my carb bored but I like the idea of the 44 instead. What head mods do you recommend? Is there a place I could send my topend or motor out to for the mods that you trust? Don't get me wrong, this bike is fast(to me), I just want more power/torque like everybody else. Thanks guys for all the replys, I need alot of help and ideas with this bike to get it the way I want it.
-
great pipe .. piston mods are on the thread .. run the 44 lectron..i like 4degree squish band 35 cc head redo bottom end at same time to get whole deal right rod striaght ness crank clocking seals etc...
-
Where can I buy a 44mm lectron carb? Where can I have the head work done? My motor was totally gone through last year, the previous owner said he had $2,000 into the motor. I need to talk to him and find out exactly what was done to it.
-
dennis packerd 801- 451-6142
-
If you want easiest big bore go with the 540.you can get the piston from la sleeve.
They have a copper head gasket that?s 60 thousands thick, it will smooth out the power.
The head needs to be cut 3mm bigger, and grind the power valve to fit.
Just send the cylinder to get replated to that piston. You don?t want to use the steel sleeve.
As for the carb use a number 8 slide, it will give you a lot better off idle response.
This set up is a lot smoother and way more bottom end than kx 500, been running one like this for 12 years.
If you need to know more about this setup just let me know.
Just a word of caution, the advertised 540 is really only a 527 not 540, the bore is 88.4 mm. I'm not sure why they call it a 540, unless they have a stroker kit for the crank that makes it a 540.
With all the discussion about HP lately and whether we need more, I've thought about the big bores, and while I do think they have there place, I don't think trail riding is that place. Big bores tend to vibrate more than standard bores, they make loads of troque but lose some of the quickness. For every day riding I would go with modding the stock 86 mm bore. I only use mine for Hillclimbing, they get ridden 8-30 seconds twice and then back in the trailer, for that there fine but I wouldn't want to go trailriding one, my right hand goes to sleep as it is, I can't imagine riding one of those vibrating things for hours.
-
Just a word of caution, the advertised 540 is really only a 527 not 540, the bore is 88.4 mm. I'm not sure why they call it a 540, unless they have a stroker kit for the crank that makes it a 540.
The 540 is probably from the very last bore size of that sleeve like the 330 kits for Honda 250Rs.
With all the discussion about HP lately and whether we need more, I've thought about the big bores, and while I do think they have there place, I don't think trail riding is that place.
Very good point. You would want smooth power so really any mods like higher compression or agressive porting would be a step in the wrong direction for tight technical (read "slow") trail riding.
-
640cc
http://www.kxriders.com/forums/index.php/topic,112.0.html
-
Nice find BigGreenMachine, now I'm REALLY interested in the big bore idea. Do you know if that B&B Racing is still in buisness? I did a google search for that place and had no luck, I must've done something wrong. I haven't tried their phone # yet.
-
I'm confused! I've been told what I need and where to get parts needed to build my 540, then I hear that I'll actually be building a 527. Can someone give me the right answer? If the motor will actually be a 527 that's ok, I just need to know. When I go to place a parts order, I want to have the right info.