Well pushing at sand mt one night i put my money where my mouth is and grabed the throttle and let her go in neutrel. I held her until she finaly died from fuel starvation.then cranked her right back up the ds engine if properly put together can sail too the moon and with my stage threes i do this all the time.and as for my 760 it dose not have a tach but i tach her to the moon every time i race its full throttle or why even try??? you will never sell me on the shim under bucket [img]i/expressions/face-icon-small-disgusted.gif[/img]

 

LMFAO! I bet everyone standing around were shaking and scratching their heads after that one! So, did you have stiffer valve springs or were you all stock? (no shim under bucket of course) I would hope you at least had HD valve springs lol.

By the way, that had to be one frickin bullet proof motor to handle that!!![img]i/expressions/face-icon-small-shocked.gif[/img]

 

Jeff was there dunme was there as amatter of fact i think barttlet was there too. Many forum members were there and seen this trick we were all sitting at the hill when i did this because i new my ride back was safe and it was a ron woods stage there with stock valves springs i do not like hd springs they rip valvestems in half when things go wrong???oh she was on alcahol too!!!!

 

That's purty amazing![img]i/expressions/face-icon-small-shocked.gif[/img]

 

Let me just say that, from a performance perspective, you should run the lightest springs available that keep your valves from floating. Lighter springs do equal quicker RPM response. That being said, you can also run a CDI that has a rev limit built in that will limit your valves from floating. For example, if you have a CDI which has a rev limit of 8900 and your valves float at 9300 - you don't need performance springs. But the question remains, what happens if your springs do fail? They can fail even if your valves don't float. What happens then? So, in my opinion, if you are going to get performance valve springs because you want the motor to rev higher, it makes sence to get 'Shim Under Bucket' springs rather than standard performance springs. They work better, are better from a performance standpoint, and will also save your motor when those springs eventually break. Everyone should know that I am on my THIRD full set of performance springs. The greater the cam lift and duration, the harder you are opening and slamming the valves shut. That equals wear and tear on your valve springs. In my opinion, for performance motors, you should replaced the valve springs at least every two years of hard riding. If not, then get the shim under bucket springs and when they do break, you wont harm the motor.

 

I don't get why everybody doesn't just go ahead and install shim under bucket kits when they got there heads off. It only cost me and extra $115 from web. it may not help anything, but it certainly doesn't hurt anything at all either, and in whatever unlikely event something does happen the shims springs and retainers are trapped, whether it be a broken spring or a broken valve from jumped time due to a failed chain tensioner or whatever else you can think of. We all know of many cases where valves were broken from losing cam chain tension and while yes that's a top end rebuild at least with a shim under in that situation you limit how much shrapnel is available to go down in the bottom end.
personally, I have over $10K in my bike, and I'll dump the pidly extra $115 any day for the security. marky may be the only one we've heard of on the forum that has had this issue, but he's not the only one out there in the world.

 

See thats what i don't understand my self why would you put undue pressure on your cams with heavy springs??? And what about spring bind thats the trick everyone has tried to use on me about my tall cams and stock springs wouldn't stock springs have less colaspeing height than heavy duty springs????Which should prevent spring bind???? im only posing these questions because you guy seem to be able to help answer them???

 

I also would like to know what to do or don't! with all the crediable forum members that posted on this topic I'm lost for words. everyone has stated good reasons why to or not. I'm lost for words, or is it a roll of the dice to upgrade or not? Thanks to biggerisbetter for bringing up this topic & everyone that posted there info! I just hope I make the right choice or that luck is on my side.
peace[img]i/expressions/face-icon-small-smile.gif[/img]
Later!
Joe

 

AZ,

Its a matter of opinion on what you consider 'Undue' pressure. There has to be enough pressure to keep the valves from floating. As you know, if the valves float, the valves will not retract in time to get out of the way of the piston. This is especially true with cams that have a .425 lift or even a .450 lift and a long duration. That means the cams are forcing a quick slam on the valves in order to get out of the way of the piston. If they don't, this will cause the piston and the valves to collide. Thats how you bend valves, turn the stock shims into projectiles and set yourself up for serious engine damage. It is true that springs can bind, but if the valves float, that kind if impact has much more serious consequences.

Later ....

Marky

 

It also would make since to buy TI valves, and keep the stock valve springs. This would surely keep the valves from floating, and give you faster revs by using stock springs. HD valve springs WILL eventually "tulip" the valves(especially larger valves) and that is also a dissaster wiating to happen.

I do agree that better safe than sorry. but I am not wanting to "cheap out" here, I have a set of HD spring laying on my work bench. my question was from a PERFORMANCE stand piont are they nessessary?? and I am still leaning towards NO. But if I were to biuld a HUGE cam , 14:1 motor, I would most likely definately install the HD spring, cause the Piston to Valve tolerances would be much to close to not go with a HD valve spring.




Bigger.