What the Heck Happend!!! [Archive]

06-30-2002, 10:50 PM

Wow that suks bad, tell us what was done before the valves disintergrated? Any decking? new cam? timing problems?

I know that the valves are not the best quality (crappy 3 piece) but something had to cause them to come apart like that. And what about the exh valves?

If your gonna replace it what you doing with this one?

Looks like the valves were getting pounded a little while after they came apart.

Hope your luck gets better than this.

06-30-2002, 10:52 PM

nah, get some sandpaper and sand that baby to a nice finish, good as new

06-30-2002, 10:52 PM

ouch, looks like u mighta dropped a vavle lol

Evan

06-30-2002, 11:09 PM

440 4 me- The only thing that was done was a Sparks cam, JE12.5 piston 416. Thats it. I did have the guy that did my boring to put new valve seals in. He also cleaned up the seats, reground the valves, lapped them etc. I trust this guy very much, he does alot of heads, valves etc for cars. No timing problems, ran like a top. When it quit I thought the timing chain had broke, but it was fine. I think I will replace everything just to be safe. Where could I get a heavy duty timing chain, larger stronger valves, stiffer springs. I will proably get a head from service honda. What should I do with this one? The valves punched a hole in the piston, and you can tell the intake valves touched the piston in the indentation part. But why intake, its usally exh that come apart first right? Why did they not touch? Could it have jumped time?

Dave400ex

07-01-2002, 09:37 AM

I think Sparks carries most of the Parts you are wanting. You should call them and tell them what happened and ask what you need or should get. Maybe you should send it to Sparks?

cunderwood

07-01-2002, 09:53 AM

Looks to me like a Timing chain broke. Just like on a car, if the timing gets all out of wack then the valves are open when the piston is on Top Dead Center and WHAMO! the valves take a beating!

Just my thoughts...

Chris

oynot400

07-01-2002, 10:40 AM

I have seen alot of that here at work, but they are diesel engines. :( My guess is it either jumped out of time, or a valve keeper let loose resulting in dropping the valve. How long ago it you do the kit? One thing I noticed on mine was when you put in the cam there are two little dowel pins that sit on the outside of the cam bearings. If they are not in then the cam bearings will slide off. Believe me it will, I forgot to put them in mine and it held together for a year and a half! I was lucky when it did fall off and it lost time the piston did not tap a valve.
Good luck...

Evan

07-01-2002, 04:15 PM

I took it to a honda shop today, they told me exactly what happend. Its all my fault, with a hotter cam you should use heavyduty, stiffer valve springs, which I neglected to put in due to the fact that I thougth I wouldnt need them since I didnt have a rev box. Well a spring got weak since they are weak to begin with and it floated a valve and bam, havoc erupted. Well I guess you learn from yours and other peoples mistakes, so heres a lesson for yall, if you get a hot cam you will need stiffer valve springs. Cost of mine and your lesson: around 600 dollar or more. You can thank me later hehe. So its going to be a 426 12.5 JE, with Sparks valve spring kit, Sparks heavy duty timing chain, new head, new valves. I think I will put a clutch kit in it also. I thought it was my fault which it kinda is but the amazing thing is I have a bout 50-100 hrs and 2 hard races on this motor b4 it happend.

Dave400ex

07-01-2002, 04:53 PM

I would call Sparks and tell them what your Honda Dealer said because if it was from your Valve Springs not being Strong enough then Sparks should have to do something. You got their Aggressive Drop-In Cam right? That says you DO NOT need different Valve Springs or Rockers. Well if that`s the case then what happened to yours? Those are just some of the things that I thought about.

400exBro

07-01-2002, 05:41 PM

that s a good point Warriorman!!!!!!
if sparks said not to (instructions) then you need to advise them so it don't happen to other people.
Bro

Red Rooster

07-01-2002, 05:47 PM

As I was reading, I thought, ''With the more aggressive cam, the valves were floating. Intake only because the cam increased the intake more than the exhaust. you hit a higher rpm, and the valves floated slightly, as rpm increased, they floated even lower/longer, then they disintegrated and punched a hole big hole in your new piston." btw, are your springs broken or anything?

OutlawEX

07-01-2002, 06:06 PM

:huh :devil :huh :devil :huh :

J25

07-01-2002, 07:21 PM

did u have a hot cam??? if i get the stgae one will i need new springs or what? how much are they......

07-02-2002, 10:47 AM

are you going to get a new head? if you are, do u want to sell the other one?

07-02-2002, 01:59 PM

So x-rider was it a sparks drop in cam that you used,,cuz I'm thinkin of goin to a sparks drop in cam in the future,,I'd like to know what else I might need. Thanks..

Evan

07-02-2002, 04:57 PM

Well I ordered the parts, had to go with a 416, Curtis didnt recomend a 426, said the walls are too thin to his liking. So I ordered a stock sleeve from them and will get it resleeved to a 416. All new valves, head, gaskets from Service honda. Head was 285. Stiffer springs, haevy duty cam chain, JE 12.5 piston and 8 plate clutch kit from Sparks. Said what the heck went ahead and ordered Holeshot MXs and put on a 16 tooth sprocket, grips and handle bars.

I told Scott at Sparks about what happened. He said it is the first he has heard of. Said Curtis sat down with honda and spec'd everything out and that it would work fine. He asked if my springs were old I said its an 01 I hope they arent old, well maybe it was a weak spring. I told him that in the future he should at least recomend getting stiffer springs to customers that buy the cams, he said they keep a record of it and would put it on file and watch and see if anymore pop up. I wanted to tell him common sense should tell you if you have more lift its gonna put more stress on the springs. Evidently I didnt think about it, buut you learn from your mistakes right. The way I see it, I would glady have payed the extra hundred dollas for the stiffer springs if I new this would happen, hello it cost me over 700 for this mistake of mine(or theirs)not to mention the time it is down and the trouble you have to go through to get it right again. I had a awesome motor, hope the next one is like it.

Reeko- They sell 3 cams
1. Aggresive cam- needs hardfaced rockers stiffer springs etc, with core cost 199
2. Agrresive (drop in)- they say it needs no springs or hardfacing- (this is the one I have) I say you need at least stiffer springs and it wouldnt hurt to have new valves and the heavy duty cam chain. cost 375 no core. sell youre old one on ebay for about 60
3.Mild (drop in)same as above but cost about 200

If I were you I wouldnt buy a cam without getting stiffer valve springs and a heavyduty cam chain and new valves. Or if you wanted to go the cheap way out and proably avoid problems for a while, at least get new valves, new springs, new cam chain. JMO

Should have the EX running by this Sat, got a race in less than 2 weeks, done missed one cant miss another.

Dave400ex

07-02-2002, 05:39 PM

X-Rider I still think that is Crap on their Part. If the Springs are what caused it, then they should tell people they need the Heavy Springs. Heck by time you buy the Aggressive Drop-In Cam and Valve Springs you could of got the Agressive Cam that needs the Valve Springs and Rockers for about the same Price.

Aggressive Drop-In with Valve Springs: $485

Aggressive Cam with Valve Springs and Rockers: $509

You still have a very Aggressive Cam, maybe even more Aggressive then the Drop-In I don`t know, and you also still get new Valve Springs, but for $14 more dollars you now have Harden Rockers. I would get the Cam that isn`t a Drop-In myself. That makes sense to me if you are going to Buy Valve Springs for the Drop-In anyways.

07-02-2002, 10:06 PM

I took it to a honda shop today, they told me exactly what happend. Its all my fault, with a hotter cam you should use heavyduty, stiffer valve springs, which I neglected to put in due to the fact that I thougth I wouldnt need them since I didnt have a rev box.

I know this is very probable but I am just not completely comfortable believing it. I know that the stock valve springs are not the stiffest but anyone who has removed them knows that they are not the weakest either. At fist look it is very easy to come to this conclusion (I mean like duh the valves hit the piston) but if you go look at the pics again its not easy to see(for me at least) that the marks where the valve dented the piston are at the same angle that the valve would be when installed. Maybe I am missing something but the hits just look like they were after the valve heads were banging around inside the cylinder.

BTW I am hoping that the stock valve springs hold up with the hotcams since I am running one now. Not that I would mind having the aftermarket springs but its just that I have had no reason so to change out the stockers so far.

Well I ordered the parts, had to go with a 416, Curtis didnt recomend a 426, said the walls are too thin to his liking. So I ordered a stock sleeve from them and will get it resleeved to a 416.

If your going thru all this work and expense why arent you doing the 440 ? I hope you dont buy into the reliability or fast rev crap. If your dealing with curtis anyway I think we can all agree that he can build a pretty powerfull fast reving 440.

Evan

07-02-2002, 11:12 PM

Well it is hard to see 440 4 me, the place it hit is in the shadow, the indentions at the front are clean as they are for the exhaust valves. In the shadow where the indentation is for the intake, (since its a high compression the indentation is pretty big) you can plainly see where the valve hit the piston at the correct angle bc it just went to far. And another reason that backs up the theory is since a cam is designed to let more air and fuel in, you can plainly see it was the intake valves that broke. This is what I think happened, 1. valve spring got weak on one of the intakes, 2. I reved it to high and it touched the piston, 3. slightly bent the valve makes a racket, 4.eventually breaks off beats the other valves to peices and the head and locks up motor. Well something like that.

Your stock springs will proably be ok as long as you are not reving it really hard, like missing shifts, and when your racing it puts an abuse on it, take it easy for like recreational riding and they might be ok. But for insurance I would get stiffer valve springs just so you dont have to rebuild the whole thing over like me.

No reason why I am not doing a 440, just dont feel like I have the need for it, for a neglible difference. If anything I would leave it at a 416 and stroke it to a 440. i would rather have it stroked to a 440 than have just a 440 piston(bored to a 440)

Warriorman I agree- If I had known this would happen I would have done that. Like I say, you learn from yours and others mistakes.
So everyone take a lesson

Nausty

07-03-2002, 02:04 AM

x rider I think i'm gonna go with about the same setup as you but I have a question... I would think the sparks racing cam which is 200 bucks would put out lots more power than a drop in right? Well if you payed 375 for a aggressive drop in cam wouldn't of been better to just get the sparks non drop in cam and get hard faced rockers and harder springs for a extra $25? I would think there would be a considerable differance in power and I don't think you would lose much in reliability over the aggressive drop in with stock springs and rocker arms and they say you don't need it and they havn't had any other problems. Then i think I will go with a curtis sparks pipe, 10.2 compression je piston or somthing like that so i can run 92 octane in it and bore it to a 416.

Dave400ex

07-03-2002, 09:52 AM

Nausty that is what I said in my Post above. If you are going to build a Motor with Sparks stuff here`s what I would do:

Sparks X-6 Pipe
JE 416 Piston
Sparks Cam
Sparks Heavy Duty Valve Springs
Sparks HardFace Rockers
Sparks Heavy Duty Cam Chain
Sparks 8 Plate Clutch Kit
Hinson Clutch Basket

All you have left after that is:

39 FCR Carb
Port and Flow Head includes 3 Angle Valve Job
Heavy Duty Connecting Rod

Nausty

07-03-2002, 02:49 PM

thanks

Mxbubs

07-04-2002, 08:09 PM

YOUR MOTOR JUMPED TIME. The stock ex timing chain stretches easily. Check out my experience.

http://groups.msn.com/MXBUBS/howsthisforabadday.msnw

Evan

07-05-2002, 06:51 PM

Heres the stuff, 8 plate clutch etc

400exRacerX

07-05-2002, 06:53 PM

Are you running hard faced rockers or just the stiffer valve springs?

Dave400ex

07-05-2002, 06:58 PM

Looks good. I wish I had all of that on my Floor. So what all will be done to your Motor now?

Rastus

07-05-2002, 08:46 PM

Putting hardfaced rockers/ and stiffer springs doesnt effect reliability at all. The most ive noticed is more power, and it runs alittle louder, due to the hardfaced rockers, and stiffer springs.

Mxbubs

07-05-2002, 09:28 PM

Originally posted by '92 : 250X er
Putting hardfaced rockers/ and stiffer springs doesnt effect reliability at all. The most ive noticed is more power, and it runs alittle louder, due to the hardfaced rockers, and stiffer springs.

I had a web cam and didnt hard face my rockers, after six months of weekend riding my rockers and cam where trash.

Here is my TRUE hinson 8 plate clutch kit. This cost me 935$.

Dave400ex

07-05-2002, 09:30 PM

I might have to ask Tom about getting some Springs and Rockers from mine when I get a Cam. Last time I asked he said there was no need for them so I will have to see what he says now.

MXBubs, What all is in that Hinson 8 Plate Setup?

Rastus

07-05-2002, 09:57 PM

Thats what happens when you dont hard-face them.Guess ya learned from the mistak,huh?lol :)

Mxbubs

07-06-2002, 01:15 PM

Originally posted by WarriorMan
I might have to ask Tom about getting some Springs and Rockers from mine when I get a Cam. Last time I asked he said there was no need for them so I will have to see what he says now.

MXBubs, What all is in that Hinson 8 Plate Setup?

Yeah, I was one of Scott's (at profab) first 426cc kits he did, way back when. He also took a guessed and thought I could get a year or 2 without hardening my rockers, we were both wrong. The cam was ate so bad, I couldnt even use it as a core. The rockers were so bad, I had to trash them too.

I say this is a TRUE hinson 8 plate kit because it has everything, not just the basket.

It has the Basket, Inner and Outer Hub, Clutch Springs, Bolts, and Clutch Plates. I ran the stock setup for a few months with the MOBIL ONE, and my basket exploded like glass, and made my motor jump time. Thats when I did the research and found out the MOBIL ONE has some added polymers that make clutches slip and heat up.

Evan

07-06-2002, 01:27 PM

Well this 8 plate setup is pretty cheap, it is not a true 8 plate like hinsons I dont think. Scott@Sparks said it bolts right on no mods, its oem plates I belive, maybe a little thinner but am not sure. They said they run this setup on almost all their quads and havent had any problems. Its only 139 dollas so its just slightly more than new plates and springs I belive. I figured it was worth a try since I didnt have the money for a full setup. Those are stiffer springs also.

If your cam is not a drop in then springs and rockers are a must. No matter the cam I would reccomend springs also unless its fairly mild. I may later on find a spare set or buy some hardend rockers and throw them on just in case.

Warriorman- theres not much done to my motor, I would like to have porting and a lightened flywheel but I just dont wont to have it apart that long. Maybe even a stroker kit to make it a full 440. But as it stands right now, my motor is this, 416 12.5 comp, stiffer valve springs, heavy duty cam chain, new valves, sparks cam, 8 plate clutch and thats it.

Dave400ex

07-06-2002, 07:44 PM

Man I would really like to have that Hinson 8 Plate setup.

I think all I am going to do to my Motor is a 416 Piston and Cam at first. For XC, TC said that is a Good Setup with his Pipe so I guess that`s Cool. He also told me to run the Stock Clutch until it`s gone.

powerslider

07-06-2002, 07:45 PM

Have you thought about damage to the bottom end from this failure? IMO I think the bottom end should be disassembled to clean the debrie out of the motor, I also think the rod should be replaced as it may be bent. Do it now to avoid more problems......

kicken250x

07-06-2002, 11:48 PM

that site makes me get weak in the knees i hate to see something like that!!!:'(

07-06-2002, 11:52 PM

ran the stock setup for a few months with the MOBIL ONE, and my basket exploded like glass, and made my motor jump time. Thats when I did the research and found out the MOBIL ONE has some added polymers that make clutches slip and heat up.

This is what I have heard before also, but I hear just as many people claiming to use the mobil-1 with no problems. Does anyone have any some sort of test results or a tech sheet etc. from moblil addressing this issue????

If your cam is not a drop in then springs and rockers are a must. No matter the cam I would reccomend springs also unless its fairly mild. I may later on find a spare set or buy some hardend rockers and throw them on just in case.

IMHO if you go with the springs you better get those rockers done too. Just in theory alone the added pressure from the stiffer springs is going to do a job on them rockers and then add the extra lift etc from the cam itself and its got too be pushing the limits of the honda chroming on the rockers.

If anyone has a old set of wasted rockers you dont need (or think your gonna sell for a million on e-bay) pm me as I am working on designing a roller rocker set up and need a set of rockers.

Red Rooster

07-07-2002, 06:31 AM

X-Rider,
Did you ever find an oil cooler laying around your place? It doesn't have to be anything great, just send me a pic and I'll see if I can use it! :D Thanks, Nate

Evan

07-07-2002, 12:33 PM

Red- no I didnt I looked but all of my old dirtbikes are 2 strokes. I will keep a watch out for one though.

Anybody know if you can just buy hardened rockers? Or do you have to exchange yours? I cant stand not riding any longer, LOL it hasnt even been 2 weeks.

Dave400ex

07-07-2002, 05:52 PM

Do you have to Exchange for the Sparks?

mikeboone

07-07-2002, 06:02 PM

440ex4me---I am glad you are here! I have been on this board for a little over 1 yr and NO ONE has ever suggested roller rockers. They could be the best idea for preventing disasters in the future. Good luck with your idea!

Evan

07-08-2002, 05:51 PM

Well, change of plans, I was trying to find someone to sleeve and bore the cyl today and the fastest I could find was Legacy. I went took it there and talk to them, they are really nice people. I told the guy what happened and what I wanted. He said he was real good friends with Curtis and that he was the only guy he knew that didnt recommend the 425. He suggested that since I have the sleeve in there I might as well finish it off. He said they have been doing 425s forever and havent had any problems with them being thin. So I bought a 13.0 JE 425 from him and he is just going to bore it for me. So anyone need a 87 mm JE 12.5 piston?

BTW anyone seen this quad? It was built by legacy. It has almost every aftermarket product you can think of, I dont think anything is stock, if it is it has been powdercoated. I think it was built for Nathan Dallas, he rides for Legacy. Anyway my freind has it now and it has a full TC440. I race against him in every race, its a fast 440. All it needs is a good rider, he finshes about 3rd to 5th everytime. He had a 2nd or 3rd going when his lectron fell off, for all of those who remember, this is the quad. Its a pretty sweet quad I think.

Foxrage

07-08-2002, 06:04 PM

X-rider
I was wondering if you got those new rings for your beadlocks? DID you get all new ones? How do they look? Thanks

Evan

07-08-2002, 06:11 PM

nope not yet

Dave400ex

07-08-2002, 08:05 PM

Well I would like to know if there is much of a Gain from the 416 to 425.

07-08-2002, 08:12 PM

I would suspect about 2%.

07-09-2002, 08:25 AM

Originally posted by X-Rider
So I bought a 13.0 JE 425 from him and he is just going to bore it for me. So anyone need a 87 mm JE 12.5 piston?

I'd get back on the horn with legacy or sparks and see what they say about the stock crank and that high of compression piston..talk with screamin shee and I think it was wyndzer about there nightmares with 13.0 pistons and stock cranks..you haven't even seen problems yet till that crank blows out the bottom end..:eek: Not tryin to discourage you but lookin out for your best interest,,you've had enough problems and you don't need anymore once ya get that monster buttoned up..

07-09-2002, 08:55 AM

So I bought a 13.0 JE 425 from him and he is just going to bore it for me. So anyone need a 87 mm JE 12.5 piston?

Could you make that a 89mm :)

BTW I think you are on track but like Rico said be carefull with the 13:1 cause if they set up your cyl volume correctly its gonna put a lot of stress on your motor. I know that even the gasket mfg start making stronger stuff for use with the higher comp pistons etc. I know that the cometic gasket for the hi comp set ups not only adds a steel ring but also raises the amount of cyl volume due to being thicker than the stocker.

Evan

07-09-2002, 01:04 PM

07-09-2002, 01:29 PM

The only horror stories I've heard were 12.5:1 and higher,,I believe you could go with a 12.1 and be OK...sorry ta scare ya but I'd hate ta see ya post more pics like ya did at the beginning of this thread..:( It's not a real common thing I don't think,,but I know your wanting reliablity with your motor and I wouldn't rely on that high of a compression with stock crank. It could last you for years and not give you any problems,,but it also doesn't snow in texas too often but it has before.:eek:

Evan

07-09-2002, 02:02 PM

Haha Good one Reeko
I just got off the phone with Legacy-that guy is nice, I talked to him for about 15 mins about it. He said that he has seen just about as many rod failures from 11:1 as from 13:1 and he has alot of 13:1 out there. He said they even run them in TT motors with stock rods and they are turning a **** of alot more RPM than I am. I told him I wanted to step down to a 11 but he said there is a very noticable difference. "Do ya wanna win?" So I stuck with the 13. I am proably gonna run it the rest of the season and then put a carillo rod in. I didnt know you had to degree the cam when you stroked a motor. TC is the only one that doesnt recomend a Carillo rod.

FYI Legacy builds CRF450s They can get motors for about 4grand. I think he said the rolling chassis is about 4-5 grand.

07-09-2002, 02:35 PM

Well I'd trust his judgement then and go with the 13.1 piston..:D

400exRacerX

07-09-2002, 02:42 PM

You better order that Carillo rod now if you want it for the winter because they are on national back order last time I checked.

Dave400ex

07-09-2002, 09:24 PM

TC doesn`t recomend a Carillo because he makes his own Rods that are suppose to be better. ChadEXer knows more about that then me.

07-09-2002, 09:36 PM

You guys are scaring me!! Legacy said that the only trouble they had out of these pistons is sometimes they blow head gaskets. If that happens you get the larger studs or head bolts from TC. Hmm maybe I oughta step down to a 11:1

No dont do that, if your scared then get a dog, but keep the 13:1. Just make sure its all set up right.

If you like put a call into cometic and talk with their tech guy (cant remember his name but seems to know his stuff) about the special head gasket for the higher comp set ups to compensate for the wide bolt spacing. Just remember that its thicker than std Xr(.025) or ex(.040) and will lower the comp slightly. Talk to your builder also so your on the same page.

But keep the compression up as high as you can afford :D

ChadEXer

07-11-2002, 08:24 AM

Originally posted by WarriorMan
TC doesn`t recomend a Carillo because he makes his own Rods that are suppose to be better. ChadEXer knows more about that then me.
I know TC told me that he will build a rod for me that is far better than Carillo. Its not because its a stronger rod but because with a Carillo rod you have to grind the rod which makes it weak. Im not sure but I would assume this only applies on the larger bores and strokes. He might do that on them all?????:confused:

Dave400ex

07-11-2002, 08:58 AM

Well I don`t know. If he builds a Rod for you I don`t know why he wouldn`t for a 416 like Chris29`s.

07-11-2002, 11:40 AM

i saw that u had the 425 kit.does it really help and if so how much did it cost and where id ya get it?

07-11-2002, 11:46 AM

Originally posted by WarriorMan
Well I don`t know. If he builds a Rod for you I don`t know why he wouldn`t for a 416 like Chris29`s.

I'm almost positive he's still on a stock rod...I do know that after his motor got full of mud from red bud when rocky ridge upped his from a 416 to 425 Ken at rocky ridge dropped his compression from 13.1 to I beleive a 12.1 because he was scared chris's rod wasn't gonna last much longer with the 13.1 compression..:square

ChadEXer

07-11-2002, 04:00 PM

Rico, unless Chris just wanted a different compression Im pretty sure Tom runs a 12.5:1 on the majority of his bikes??
Warriorman, I think Tom only builds rods for the larger bore motors. With a longer stroke it requires for a Carillo to be ground down when his rods are specially made for the longer stroke,,,,I think anyway!!!!

Dave400ex

07-11-2002, 07:18 PM

When I asked Tom about a 440 Kit he said if I wasn`t just Racing then to go with a 10.5:1 Compression if I wanted it to be reliable. So 12.5:1 can`t be to reliable on a HUGE 505, but Tom knows what he is doing.

Oh and my Brother`s 250r should be back together for the third time now after Motor problems. Everything should be new besides the Crank itself.

Mxbubs

07-11-2002, 08:45 PM

I blew a few head gaskets myself, then I found a fix. I pulled the head off and installed ---keylocking inserts-- into the cylinder. This allowed me to get 5 times the amount of torque on the head bolts without stripping then cylinder. I didnt fool with the big 10mm bolts, I just did the few small 6mm bolts, and that was more than enough. Go to this site, and type in find -key locking insert- and you can order them. http://www.mcmaster.com/

Evan

07-12-2002, 10:56 PM

Well it lives, the 425 is alive exactly 2 weeks from destruction. I cant wait to try it out. I got some 18 inch mx's a 16t sprocket, some renthal handybars, new gloves and a race tomorrow:D Im as happy as a bug in a rug. Maybe now I can get around the corners like everyone else instead of on 2 wheels. Now all I need is a seat cover, anybody got any suggestions? I kinda want something that would go with silver, since I plan on getting some Fullbore silver plastic. I had an idea, I am thinking of selling my R when the motor gets back, I am wondering if I should take the spindles and calipers and everything from it and put them on the EX and put the EX's on the R. This way I would have some stopping power. I am pretty sure I am gonna do the same with the rear, including swaping the carrier and axle and all. Has anybody taken a CR front master cylinder and used it for the front on the EX? Would it work, seems like it has more stopping power, has a shorty lever. The only thing would be its more likely to boil the fluid maybe. I am thinking of buying a used XR400 for a trail bike to mess around on and I could have a spare engine then:D

Evan

01-15-2003, 12:51 AM

Its an old thread but alot of useful info in here.

NOTE: this is whats left of the 425

YZROOSTINYA

01-15-2003, 04:23 AM

i have a stage 2 hotcam which is more agressive than your cam and i am running stock valves and springs with no probs. 45 hours and still runnin like a top. stock rev box

i hit the rev limiter here and there.

i think something else did it in to your motor

UglyMotha™

01-15-2003, 07:34 AM

so why did your 425 gernade how many hrs did you have on it

01-15-2003, 07:38 AM

I believe Evan was runnin a sparks aggressive cam which is alot more aggressive than any stage hotcams.

I'd say it grenaded because it was bored .120 over,,which is way to much i think..some say no but I say no thanks..

UglyMotha™

01-15-2003, 07:44 AM

Originally posted by Rico
I'd say it grenaded because it was bored .120 over

i was hoping you wouldn't say that:(

01-15-2003, 08:19 AM

Originally posted by UglyMotha
i was hoping you wouldn't say that:(

Well i'm not tryin to discourage people but the way I look at a 426 kit is like this.

makin a 400ex into a 426 is kinda like having your gas gauge on the red line and seein how far you can drive before ya run outa gas...:eek: Ya really don't know how far you can make it but ya just keep hopin ya do make it...:eek:

UglyMotha™

01-15-2003, 08:27 AM

Originally posted by Rico
Well i'm not tryin to discourage people but the way I look at a 426 kit is like this.

:D hehe i'm looking at it on my office floor right now:eek:

haven't done any boring yet so maybe i'll rethink my plan of attack

beerock

01-15-2003, 10:53 AM

hehe old thread, i read the first couple posts and diagnosed a floating valve.
then i read down and thats exactly what did happen. YAY for me.

After reading what rico said.

I'd say the best way to do a 426 would be, well this is hard to explain but.

use a sleeve like the 440 does, which requires boring of the cylinder, But for a 426 size. I think that would work very well and improve reliability of it.:D
then you can run a 426 piston and stroke it to 440 and have a bullet proof 440.