cidnitro - Thank you and will do.


UBETRUN - More strain on the rod and piston.

 

Thanks for clarifying that, I thought maybe the rod broke because it had less stress on it. Derrr!:-)

Let me try again, why do you think the FCRs put more strain on the drivetrain? Were you told this by someone? What jetting did you have in the FCRs?

I'm questioning the link between FCRs and stock rods because I used FCRs on the stock rod and I bought them from Sparks, pre-jetted for their 686 build which also uses a stock rod.

 

Sparks thinks it maybe the rod on how it was built because this is the second rod that has failed on his 690 kits which he has done thousands. I have a buddy that has had the first 690 kit and is still running the stock rod and it still is running great!! The reason I say the carbs is because not only more stress but more fuel and air is coming in and causes more HP. Which in my mind is correct, also, a few other people have mentioned that to me before. But, its still maybe the rod, how they treated the metal or it was weak. Who knows. But from now on, I will replace my rod for sure. Just look at my profile and you will see the hole in my piston.

 

too bad it had to happen before you reliezed it..

When are you back up?

I will be back i hope by 4th of july,just an estimate till the dough gets here..she willl be a screamer for sure ...see you at pismo

 

I don't know if the FCRs add HP over a set of modified stock carbs but I'd agree that they add HP to an unmodified set. But then you're back in my belief that it's jetting and/or octane causing detonation and destroying these pistons/rods. Stock carbs won't flow over 180 or so, not enough to feed a built 686. With modified stock carbs and 190/195 jetting, my 12:1 686 Hotcams 2 Craycraft would scream on top. With 35mm FCRs, the bottom end improved a bunch but I'm not convinced the top end pulled as hard. I could hit the rev limiter with either but the modified stockers felt stronger on top. Maybe I didn't have the FCRs dialed in? I was running 142/145 with a Yoshi full exhaust. Sparks pre-jets their FCRs with 142/148 for use in thier 686s running a Sparks X6 pipe.

What was your FCR jetting and what rod did you order? For my new 727, I went with Ti rod and 39mm FCRs:-)

 

I dont know what the jetting was set at because I had sparks dial it in for me when I purchased the carbs from them. They had to jet it to the bike and the pre set jetting is for starting purposes only I believe cuz all bikes are different. I ordered a Carrillo rod for the 690 that I am going to swap into my new bike. I had the stock carbs modified by sparks and when I placed the FCR's in, I did notice a difference and also gained two bike lengths.

 

Back up? Why are you down? What are you doing? PM me if it's a secret. What about Dumont for Pres day?