Dissatisfied with motor rebuild
- Thread starter hargun2
- Start date
BUBBIE
Well-Known Member
That is Why I wanted to know his static compression on cranking speed.. IF too low It would have problems... Yes that Cam is way BIG and I would never of used it. The 570G cams i used were big enough and the next size up for me was 585 then TOO BIG for my 95" build were the 625/645/725/775,, Not only higher lift but the durations increased also.. BIGGER=Needing MORE compression PLUS piston volume to run at lower RPMs
Sock HD TCs are about .474 lift with 40* on 06 year....... Then changed to .484 lift with int.close 30* on 07 and up TCs. (going for more low end torque)
On the TC Big Bikes of today (96") the best cams for Low End Torque have "intake valve close" from 25* to max around 34* to make power and the durations and overlap is closer to the values needed to keep Torque Ban and RPM band Low...
I have seen the 40* used in lighter bikes quite often but the Heavy Baggers can use the early close to show good Low End Torque results...
The higher numbers like 46* close on the intake take at least 10.5/1 compression to get that cam up to the running pressures it takes to have any low end power at start up... and that CAM SIZE is BEST on Larger displacement motors... like 110" to 134"..
Even tho your bike was bored to 95" that is Still a "little small" for All That Head work and large valves and Not being put it to a good FLOW... This is part of the problem with your Little motor with the TOO Big of parts..
I think they experimented on this build at your expense
signed....BUBBIE
Breeze3at
Experienced Member
You have been getting REALLY experienced and good opinions. I'm gonna toss in mine and hope I am wrong, wrong. You have mentioned porting. IMO there are only about a dozen people in the U.S. that have any business with a die grinder and a Harley head. I don't think any of that dozen work at the shop that did your work. I sincerely hope it's that huge cam and not some "sewer pipe" port job that can't be undone.
I agree with Bubbie and really hope that he is wrong. A bad porting job usually can be rewelded and corrected, but it's easier to start with a new set of heads. I am by no means an engine builder, but I have rebuilt a few and like Smitty says an overbuilt street motor is not something most can deal with. Your static compression would help some here determine if there is something there that would give them a clue of which way you need to go. The original builder not wanting to get involved is not a good sign that the shop has a handle on these components. Has any one on the forum in your area suggested a motor builder you might talk to? If not the only place I would suggest is Carls Speed Shop LPGA Blvd, Daytona
Hoople
Account Removed
I think a solution to a problem can not be made until the problem itself is really understood. So far the the only problem that was mentioned with this rebuild is "the engine would sputter/stutter at certain throttle settings".
I am no engine builder but I can come up with a dozen reasons for an engine having a sputter & stutter at certain RPM that is not camshaft related.
I have never come across a complex project of any type that did not need some debugging to get it right. Did the builder tell you that he could build a radical engine that had the drive-ability of a stock motor?
At this point I don't think anyone hearing this story has any clue as to the severity of the "sputter/stutter" or the drive-ability of the engine. But the builder is getting slammed and hung at sunrise which I don't think is fair.
I am no engine builder but I can come up with a dozen reasons for an engine having a sputter & stutter at certain RPM that is not camshaft related.
I have never come across a complex project of any type that did not need some debugging to get it right. Did the builder tell you that he could build a radical engine that had the drive-ability of a stock motor?
At this point I don't think anyone hearing this story has any clue as to the severity of the "sputter/stutter" or the drive-ability of the engine. But the builder is getting slammed and hung at sunrise which I don't think is fair.
BUBBIE
Well-Known Member
Coughing sputtering IS this the only problem???
Does the Bike Have BIG POWER when throttle is twisted???
This type of Modification of your bike should, that is SHOULD yank the rear tire sideways on throttle twist and you should feel REAL Power thru the gears... IF NOT then no matter WHY the stutter, sputter,,,,it is Over built..IMHO
signed....BUBBIE
Does the Bike Have BIG POWER when throttle is twisted???
This type of Modification of your bike should, that is SHOULD yank the rear tire sideways on throttle twist and you should feel REAL Power thru the gears... IF NOT then no matter WHY the stutter, sputter,,,,it is Over built..IMHO
signed....BUBBIE
Hoople you are correct, we need more info before we badmouth the builder.
J
Jack Klarich
Guest
I have not said a word yet, BUT I think Hoople said it all, We do not have all the facts nor do we know what was said between the owner and builder, IE what was he looking for, Big motor with get up and go or big motor with street able power, No need to slam the builder until we have more info JMO
Shared with Hot Shots that I really baby the bike on the front end I don't think I have ever had it over 3500 RPM's and I run the bike between 2200 and 3500 when I ride. To answer your question about big power when I twist the throttle oh yea it throws you back in the seat. The sputtle/stutter is linked to the throttle position, RPM has no effect I can be at 2000 or 3500 and anywhere in between when the throttle is just barely of the idle stop it sputters/stutters. So an example would be coming down a hill or riding through town with the throttle in the above mentioned position she's a sputtering. Hot Shots admiited that there was something going on there and that the engine management system cannot tune out and the purchase of the performance exhaust system was the answer to cure that issue..
Emailed the builder to ask what cams would work with what was done to the heads and this is now the road he wants to travel.........."As I stated before it is not the cams, it is a tuning issue. Before I make any suggestions I need to see a dyno printout done by step testing so I can determine what the issue may be. Until you provide me with this I am not going to make a determination what your problem is. As soon as I receive this I will review and discuss my findings with you." what a nightmare!!!!!!!!!