Rebuilding motor what setup should i go with?

[dantheman7502]

Ok i need to rebuild my motor due to a detonation problem that ruined the crank and possibly the jug and head. But i was wondering what brand of crank i should get, either a stock one or a hot rods, hot rods 5mm long rods or a stroker. Im not a seroius rider just want something powerful and reliable, also i need a new head any recomendations there? thanks for any help

[Bansh-eman]

if your not seriouse about riding, then just grab a stock crank and put back in there. theres other mods you can do that will give you more power without spending 500 bucks on a crank.

 

you can probly get a used tock crak in good condition for 75 bucks.

 

as far as your head goes you can either buy another stock one and have it milled or buy a coolhead and get smaller domes.

again you say your not that seriouse, id go with a stocker thats milled its cheaper then a coolhead.

 

buy your self some vf3 reeds and an adjustable timing plate and some pipes like toomey t-6 and you will be set.

[jmd0346]

Id get a wiseco Hotrod crank. Id get it welded and trued. Its not really needed at your power level but if your in there I cant see why you wouldnt do it. Most shops will do it for like 50-75 bux. Seems like cheap insurance. Plus you may decide to go bigger later. Id do the rest like said above. Some sort of cool head. I have the Vitos Hemi head. It works great for me. Some pipes, V-Force reeds, timing plate(run it at 4 degrees). Later if you want to port it you'll already have the other good stuff.

 

 

 

 

 

 

.... Oh and dont forget the boost bottle! LOL

 

 

 

 

 

 

 

 

... Just kidding. Dont get a boost bottle.

[Bansh-eman]

if your not going to build a storker right now dont waste your money on a hotrods crank. you can snag a stock crank for very cheap and have it welded. get the same performance out of it at a much cheaper price

[dantheman7502]

thanks for the input guys, i think ill just go with a hot rods crank seince i do plan on other mods in the future and iv already got fmf pipes, and ill try and pick up a used head for cheap i think mine is scrap its already been milled down once and the one dome is toast i believe, im also bored .020 over, and trust me i know boost bottles are a waste one of my buddies have one and its a waste,

 

but i got one more thing to ask, would a bad fly wheel cause detonation, mine has a little rattle to it, magnets broken off, you know that though.?? thanks again for the advice.

[dajogejr]

thanks for the input guys, i think ill just go with a hot rods crank seince i do plan on other mods in the future and iv already got fmf pipes, and ill try and pick up a used head for cheap i think mine is scrap its already been milled down once and the one dome is toast i believe, im also bored .020 over, and trust me i know boost bottles are a waste one of my buddies have one and its a waste,

 

but i got one more thing to ask, would a bad fly wheel cause detonation, mine has a little rattle to it, magnets broken off, you know that though.?? thanks again for the advice.

 

Let me rephrase above...unless you're gonna build a stroker, get a stocker trued and welded...

If the magnets inside are rattling, get a new flywheel.

It normally won't cause it to detonate, but it'll certainly run like shit.

 

How much compression were you running with the head, how much timing, and what kind of gas (octane?)

[dantheman7502]

Let me rephrase above...unless you're gonna build a stroker, get a stocker trued and welded...

If the magnets inside are rattling, get a new flywheel.

It normally won't cause it to detonate, but it'll certainly run like shit.

 

How much compression were you running with the head, how much timing, and what kind of gas (octane?)

 

compression was around 150 psi when rebuilt the fist time, when the cylinder whent on it, it was around 130 cold by way both, 5 degree timing advance on 93 octane, ran good for 6 months untill i started getting the detonation and couldent figure out why. couldent find any air leaks carbs where clean. leak down test was good. And if a can find a decent stock crank i will get that and get it welded, trust me i need to save the extra money,

[dantheman7502]

and by the way is vitos a good builder,is there stuff really any good, iv heard some mixed thought on him, i live like 45 min from there shop?

[dajogejr]

Deal with Lane at Vitos...and you can't go wrong. He's a good guy!

[dantheman7502]

ya iv talked with him many times hes real knowledgable about that shit, Any thoughts on why i was having detonation?? could a bad crank case it? what are some causes it was just baffling me??

[dajogejr]

Most common causes are not enough octane, (too much compression and/or timing), lean jetting or an air leak...

 

Could be a bad crankcase, but a leak down test done properly will expose that...

[Washburn]

Rite, if you did a leakdown, were jetted properly, and werent sucking air, you probably werent running a high enough octane with the added compresion of the milled head/timing advance would be my guess.

 

 

If I were you Ide get a fresh bore/hone some pro lites, buy a new RS flywheel/pickup, make sure your stator is good, buy a used stock crank get it welded and a used stock head (You can probably find all of the used stuff on here just post in the wanted section) and get it milled. If you want more later then you can go out and spend with the hotrods 4mil longrod crank a port job to match and a coolhead with domes cut for your application.

[dantheman7502]

Rite, if you did a leakdown, were jetted properly, and werent sucking air, you probably werent running a high enough octane with the added compresion of the milled head/timing advance would be my guess.

If I were you Ide get a fresh bore/hone some pro lites, buy a new RS flywheel/pickup, make sure your stator is good, buy a used stock crank get it welded and a used stock head (You can probably find all of the used stuff on here just post in the wanted section) and get it milled. If you want more later then you can go out and spend with the hotrods 4mil longrod crank a port job to match and a coolhead with domes cut for your application.

 

I was thinking the same thing but when it was fresh it ran great and after the detonation started i put the stock key back in and it didnt help at all, unless i missed a leak somewhere or something, i wasent running lean, a little rich acually but not bad, but i definatly know the crank is bad, left piston dosent even go up to top dead center its like 2-3 mm away, but that was after it broke. so the only thing i can think of is maybe the crankshaft seal on that side went and i couldent tell. could float level be a cause? also when i pulled the head the oil in the left cylinder was dark grey and thick covered everything, the dome too, right cylynder was clean