will i have problems with a 686 piston?

[rubnmenon]

hey i need some help, today i wanted to buy a 686 piston 11:1 compression for my 2005 raptor and i mecanic that i know told me that if i put that piston that my crank wouldnt make it and i would have soon have problems with my motor.......

anyone that has a 686 can tell me if that true?

[hskers82]

I have seen some connecting rod failures but I think they were on drag bikes.I have been running a JE 12 to 1 686(102mm) piston for close to 2 years with no problems

[rubnmenon]

where can i find that part (connecting rod failures)?
and do u use ur raptor a lot?

[hskers82]

I have been racing and trail riding mine for almost 2 years on the stock connecting rod/ no problems at all.
Go onto Bluetraxx.com and get on the raptor forum on there.It is mostly a yamaha website so there is alot of knowledge on the problems/engine failures with raptors

[rubnmenon]

thanx for the info...... i`ll go with a 11:1 piston then

[Katz_2003]

I used to have a 11:1 weisco piston in mine with stage 1 hot cams and sparks pipe. I think it was around 48 or so hp to the wheels and my rod broke at the oil hole at the top,rod went through my piston then the rod went down and stuck in the bottom of my cases. So my whole motor was pretty much gone except for the head and the gears. I have seen a few of these online. Once you get so much hp some will pop. Then there are others that have 60hp on stock rod and they work just fine. So its just a chance you take.

[rubnmenon]

HOW LONG DID U USE UR MOTOR WITH THE 11:1 TILL THAT HAPPEND??

[Katz_2003]

I think it was around 6-8 months then boom...

[rubnmenon]

ok then i think i´ll better get a new and better crankshaft, what crankshaft would u recommend me??

[hskers82]

I see alot of guys using Carillo connecting rods.Not sure on the crank

[Katz_2003]

if you are going to go down that far you may also want to think about getting the stroker. The stroker set up from hot rods is a pretty good set up and will make you some excellent power. I have also heard that the carillo rod is suppost to be one of the best rods out there and you should never had problems with it. You wouldnt have to buy a new crank, just have to have the new rod pressed onto your existing crank and prolly buy some new bearings just to be on the safe side. Its up to you but if it were me I would check into the hot rods stroker/piston set up.

[rubnmenon]

hey im sorry but i cant understand so good what u mean about i have not to buy the whole crankshaft, could u search for that part in ebay and send me the item number please??


there where i buy all parts

[250r4life]

any time you increase your power a lot, things are going to wear out sooner than if you hadnt. how soon? nobody knows...

take my R for instance. when i bought it it was 100% original and the engine had never been touched. i threw a pipe, filter, and reeds on it, and it was solid as an ox for several more years- never had a single problem...

then came the summer of 2005. although my bike ran like a champ and the engine was still 100% original, i went and put a big bore top end on it with an aggressive port, and a bigger carb, etc... pretty much doubled the stock HP...

6 months later, i had a wrist pin bearing grenade and chew up my top end. i rebuilt it, had it ported a little more aggresively, and a month later my rod bearings gave out and took my top and bottom end out... then i rebuilt it, and 3 months later while launching for a race, i grenaded 2nd gear...

if i had left my engine stock, i have no doubts that thing woulda been running strong still without a problem...

however, i sure did have a blast and smoked a lot of people when that big bore kit was running!!! :devil:

[250r4life]

ps- the only thing is, my 2 stroke is a lot less expensive to fix then your 4 stroke is, and i dont have a mechanic- i do all my own work... you may be alright, but you may not- and if not its gunna cost ya...

[Katz_2003]

Ebay Item# 260061406327 for example is a connecting rod. That is not a carillo rod but it is a rod, not the whole crank. You can go with a hot rods stroker kit which you would find here....http://www.kenzcycletech.com/ho4mmstcrwro.html

With the stroker kit you would have to get a special CP piston which are awesome pistons. Just an idea....

[rubnmenon]

thanxa lot!!! now i understand what u mean that i havent to buy the whole crankshaft....

its just i think i wount buy a stroker kit cuz i have the piston already, i didnt knew about the strokerkit but anyways i guees this will work to.....

ok now i´ll buy the rod and im wondering: should i change the balancer gears?? cuz if they brake then i would have a big mess with my motor

[Katz_2003]

The gears should be fine, but while you are in there I would check all the bearings in there and make sure they spin freely and have nothing binding them up at all, you may need to replace a couple bearings.

[rubnmenon]

i´ll do that for sure...

so what else is there that i can replace so the motor is safer cuz i really dont want to blow the whole motor after i ride some times...

im thinking on change the cam chain cuz its just 20 dol so i guees that to cheap to let that out

but what else would be good to replace?

[DieselBoy]

Personally I think if you're worried about a potential motor failure or losing reliability you may not want a high compression piston. Many argue it does stress everything alot more, and others argue it doesn't. Some engines will go a long time with it, and others will blow like fireworks on the fourth of july.

If I was to go with a high comp piston setup I would want to know that the bottom end was in perfect shape, and probably put a better crank / rod in it...

[Glenyzracer25]

i have built several raptors now and have not had any problems with the crank. i have a 686 with a wisceo 11:1 and hotcam and it has run great for 2 years. i ride it often and wide open without failure. i built another motor with a 686 JE 12:1 and hotcam. i havent had a problem with the motor other the starter. i would highly recommend staying with the 11:1. The 12:1 motor puts more strain on the crank bearing, starter, and one-way clutch.

[rubnmenon]

that sounds real good..... and yeah i already boght the 11:1 wiseco and now i want to buy a stage 2 camshaft with the spring kit, i send my head away so they are porting it right now i hope i`ll feel a difference with does mods


anyways.. thanx guys

[rubnmenon]

hey im back again.... i cant find bearings for the crankshaft in ebay, do anyone of you know where i can find them?

[MadDog56]

Originally posted by rubnmenon
hey im back again.... i cant find bearings for the crankshaft in ebay, do anyone of you know where i can find them?

Get them from any online OEM parts dealer or your local dealership.

[rubnmenon]

ok i`ll do that

[MXin700R]

Anytime an engine makes more power it puts more strain on the internals, simple physics on that one. Even just doin intake, exhaust and porting and nothing else puts more strain on the engine simply because of the power it gains. The more power you make, the more "fireworks" you have when the engine lets loose. Its like the Ford 289 and Chevy 283 when you hear "Back in the day you couldnt blow em up!", simple- they didnt make enough power to hurt anything lol. The more power you make with the stock bottom end, the less durable the engine becomes.

[rubnmenon]

Hey i have great new!!! my bike is finally done, im still not sure how much power it will have because im using it real slow the first 3 tanks of gas and i just got one empyt, i´ll let u know how it will work

[rubnmenon]

now im done..... and this thing sure is fast, i already raced some raptor 700 and i won but this one guy has a raptor 700 with a full exhaust, programer and another filter, so u think i can win him?