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GIVE'ER SUM
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Discussion Starter · #1 ·
ok so far got the motor out and got it sittin in a tote waitin for funds. tore the motor out due to loud tappin noise comin from cam gear area. thought it was the decomp fly weights comin apart but they look to be all there so far. im just a trail rider and the 660 has more then enuff sack for me but... since im in there i must make the best of it lol. gonna go mild i do believe. i wanna still run pump gas so im thinkin 686 or 673 with 12.1 comp piston(if i can. some one chime in if thats to much comp to run pump gas) hot rod crank(oem specs) barnette clutch kit and basket, l&a oneway set, wiseco timin chain. think thats it. as for cam not sure if i need it. any thoughts? pix to follow as i progress thru the tear down and rebuild. thanx guys
 

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12:1 should be fine on a 686. You will probably have to run a stage 3 hotcam.

The numbers I have are
12:1 w/ stg 2 = 223psi dynamic or 10.4 DCR
12:1 w/ stg 3 = 198psi dynamic or 9.46 DCR

"91 can handle UP TO 215 do not exceed this not even by a single point so if it comes out to be 216 psi go to 92 octane and 93 handles up to 225"

Hope that helps you. Basically it is saying that if you can get 93 then you should be able to run a 12:1 w/stage 2 hotcam. However I think this is cutting it very close as far as the numbers are concerned. If you can only get 91 octane then you have to put a stage 3 hotcam into the setup. Personally I'd go with a stage 3 just so you have the flexibility in the future. Stage 3 will give you plenty of mid range power still.
 

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Either way, HC2 or 3, need new valve springs, so get the new valves as well, especially if they are still the originals. If you are putting those motor mods in there, I would say it is a crime if you DON'T put a cam in there. You should consider some porting too, you won't be sorry.
 

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I am unique
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ok so far got the motor out and got it sittin in a tote waitin for funds. tore the motor out due to loud tappin noise comin from cam gear area. thought it was the decomp fly weights comin apart but they look to be all there so far. im just a trail rider and the 660 has more then enuff sack for me but... since im in there i must make the best of it lol. gonna go mild i do believe. i wanna still run pump gas so im thinkin 686 or 673 with 12.1 comp piston(if i can. some one chime in if thats to much comp to run pump gas) hot rod crank(oem specs) barnette clutch kit and basket, l&a oneway set, wiseco timin chain. think thats it. as for cam not sure if i need it. any thoughts? pix to follow as i progress thru the tear down and rebuild. thanx guys
Just change the rod, Hot Rod cranks have a bad habit................
 

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GIVE'ER SUM
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Discussion Starter · #5 ·
Ok so i can get 93 without a problem. So hc stage 2 with valves and springs. So whats hotrods cranks bad habit willy? What othe crank/rod setup do you recommend? Thanx for al the input so far fellas
 

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Ok so i can get 93 without a problem. So hc stage 2 with valves and springs.o wShats hotrods cranks bad habit willy? What othe crank/rod setup do you recommend? Thanx for al the input so far fellas
They break.....................The rod is good, but the cranks arent.................
 

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GIVE'ER SUM
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Discussion Starter · #7 ·
what would you recommend for a crank with rod combo willy?
 

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Just dont push it on the compression ratio as heat is a by product . Good port work by a real 660 guru and a cam known to work with your mods and you should be tearing it up..
 

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Yeah. Personally I'd run a stage 3 hotcam. With stage 2 you will see peak power in the middle of the powerband but with a high compression piston you will also see good numbers middle to upper with a stage 3.

I built my raptor for 93 octane but then I moved and found some places are hard to get 93 as their "premium" is 91 octane.
 

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They break.....................The rod is good, but the cranks arent.................
No record of any of the stock stroke HR cranks breaking unless you count the one where the nitro methane hill climbing motorcycle was improperly tuned (by owner admission) and blew up the entire motor. Even then it was a bent rod, no breaks.

The problems have been with the Hotrods +4mm stroker cranks.

My 660 has had the same stock stroke HR crank in it since 05.
 

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I am unique
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No record of any of the stock stroke HR cranks breaking unless you count the one where the nitro methane hill climbing motorcycle was improperly tuned (by owner admission) and blew up the entire motor. Even then it was a bent rod, no breaks.

The problems have been with the Hotrods +4mm stroker cranks.

My 660 has had the same stock stroke HR crank in it since 05.
I saw it on Rhino Forum............stock stroke HR crank broke, the same as the +4s HRs.........
 

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GIVE'ER SUM
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Discussion Starter · #13 ·
Wow! Guess im gonna go stage 3 cam then. Donnt wana ever have any problems when tryin to fuel up lol. As for my crank issue... i didnt know that the crank came apart thats why i wanted to get a crank with rod already together. So whos a good 660 guru for head work and how much does that run on the wallet?
 

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I saw it on Rhino Forum............stock stroke HR crank broke, the same as the +4s HRs.........
I read a bit from that site and there seem to be a rather large number of HR detractors. From what I can tell the most vocal have never used the products or had any personal experience to turn them off, simply going by what other people have told them or assumptions they have made. Some even claiming that they are no better than or possibly worse than stock. (That last bit was paraphrased from a vendor so he may be exaggerating for his own benefit).

I haven't bought or put in any 660 HR stock stroke cranks in the last two years but all the ones I have or have recommended are still running fine since I got mine in 2005 and subsequently put well over 60hp to it. I was told at the time that it was junk and that it wouldn't handle the power.

Your mention of the Rhino breaking one is the first story I've heard of in a 660 engine on the net, aside from the one I alluded to earlier from the nitro motor. Assuming that one was truly the result of a bad part it's still pretty good odds IMO, especially if you don't have a reliable shop nearby to split and install a rod in your stock crank. That said I have every confidence that a Carillo rod in a stock crank is a stronger alternative, albeit a more expensive one if you aren't doing the split yourself.

Wasn't the consensus that the HR +4 cranks were breaking due to the proximity of the bearing? Wouldn't measurement of this clearance before install resolve the concern? Seemed like it was a case of poor tolerances on the production line.
 

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I am unique
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I read a bit from that site and there seem to be a rather large number of HR detractors. From what I can tell the most vocal have never used the products or had any personal experience to turn them off, simply going by what other people have told them or assumptions they have made. Some even claiming that they are no better than or possibly worse than stock. (That last bit was paraphrased from a vendor so he may be exaggerating for his own benefit).

I haven't bought or put in any 660 HR stock stroke cranks in the last two years but all the ones I have or have recommended are still running fine since I got mine in 2005 and subsequently put well over 60hp to it. I was told at the time that it was junk and that it wouldn't handle the power.

Your mention of the Rhino breaking one is the first story I've heard of in a 660 engine on the net, aside from the one I alluded to earlier from the nitro motor. Assuming that one was truly the result of a bad part it's still pretty good odds IMO, especially if you don't have a reliable shop nearby to split and install a rod in your stock crank. That said I have every confidence that a Carillo rod in a stock crank is a stronger alternative, albeit a more expensive one if you aren't doing the split yourself.

Wasn't the consensus that the HR +4 cranks were breaking due to the proximity of the bearing? Wouldn't measurement of this clearance before install resolve the concern? Seemed like it was a case of poor tolerances on the production line.
Any pictures that I saw of broken cranks were at the radius of the crankshaft where it meets the crank web, on the side of the timing gear, I also suggested that it could be because the bearing radius and crank radius were touching, this is a guarantee to the cranks failure, and since when you buy the crank with this bearing already fit to the crank, the onus is on the installer of the bearing to make sure it is installed properly, which must be the manufacturer..........
So if you buy this crank, is the engine builder going to check this crank for proper clearnace between these two parts, I bet most engine builders wouldn't even know to check this important detail. My point is, whether it is a +4, or a stock crank, the problem can still be there with this radius problem........I wouldn't trust it unless I personally checked it and that the crank was new when I checked it for my own use........
 

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I had my stock stroke hot rods for three years and it was making over 60. When I took that engine apart all the bearing were as tight as a new one. I sold that crank to a fellow member. I bet we will see it make nice power again later this year.
 

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GIVE'ER SUM
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Discussion Starter · #17 ·
well sold some stuff and was able to buy a new wiseco timin chain and complete namura gasket kit so far. thinkin bout what i want to do to this thing keeps me up at night lol. plus i got the itch for the 700 now so not sure on how far im gonna go on this machine. whether i sell it, part it out, or keep it and have both. i gots the fever!!! lol
 

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GIVE'ER SUM
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Discussion Starter · #18 ·
well got the new timin chain in and wow is it a lot quieter on that side of the motor now. when i pulled it apart the acct was all the way out and probly has been for awhile now. so no funds to really start my build as of yet so at least i got my wheeler back for the rest of the season. so heres hoping on "dear santa" lol. i do have one question. how do you burp the cooling system? or tell if its circulating thru the whole system?
 

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I am unique
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well got the new timin chain in and wow is it a lot quieter on that side of the motor now. when i pulled it apart the acct was all the way out and probly has been for awhile now. so no funds to really start my build as of yet so at least i got my wheeler back for the rest of the season. so heres hoping on "dear santa" lol. i do have one question. how do you burp the cooling system? or tell if its circulating thru the whole system?
Leave the rad cap off and run the engine until the coolant level stabilizes.
 

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GIVE'ER SUM
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Discussion Starter · #20 ·
thanx willy. i will do just that tomorrow night when i get home
 
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