Has anyone tuned this combination before ?
I know the 103 likes it but have seen nothing on the 107
Thanks
Dave
So are you going to lower the compression? The added swept area puts the build in the high zone for potential PMS
I was more curious because the 48s seem to do very well in the 96 to 103 Cu in but 107 seems to be a no-no
I guess there is a line drawn for everything and the limit is 103
Thanks
Dave
I considered this on my 96" bagger. Talked to a guy that ran it successfully at 107". 3rd gear rolling burnouts were his favorite, but above 4500rpms fell straight off. If it's a budget thing it has/can be done, if budget is not a part of the decision there might be a reason this is not on the list of "repeatable" builds.
Crevice volume helps a little, 88cc is not a stock head chamber
The only time my bike see's 4500 is if I miss a shift I ride 3000 rpm as that seems to be what it likes
When I bought the bike in 2015 I was the second owner and told the bike was stock and never been opened up
added 48H cams two years and 20,000 miles ago . Now its starting to use a little to much oil and the throttle body is
oily so i figured breathers and since I was tearing it down I would go from 96 to 103 and stay with the cams I have .
But as Im tearing it apart I found two of the intake bolts stripped one cross threaded and one missing , So someone
has been in there , I wont have time to pull the heads for a couple of days but if its already 103 is it ok to go 107
with my cams Its a 2009 FLHTCU with 90,000 on the clock , and yes money is a problem
I'll let you know in a couple of days when the heads are off so I can measure
Dave
One more add on that may help the more knowledgeable , The Cold cranking compression is 194 front and rear as it sits
Dave
If it not 103, consider including compression releases in your budget.
Thanks they are already priced and included in the budjet
Dave
If cylinder head work is in the mix, the chamber volume is usually more, vs an OEM 85cc chamber, and can be easily custom tailored to the cams compression needs.
There's always the overbore 103" as an option. You will have more meat on the spigots too..
Quote from: Barrett on December 31, 2020, 06:07:17 AM
There's always the overbore 103" as an option. You will have more meat on the spigots too..
The 90% solution for 50% the cost based on what the OP states he wants. Agreed.
Add manual releases to the heads and a retune.
Look at HD +.010" 103 pistons- cheaper than the 107 stuff, less drama with tuning. I find a lot of cams become finicky above 9 1/2 corrected. What's the tuning plan?
Edit- Barrett & Don type faster than I...
Quote from: Big Dave on December 30, 2020, 05:58:11 PM
One more add on that may help the more knowledgeable , The Cold cranking compression is 194 front and rear as it sits
Dave
If you keep the R's low like 4,500 there's a good chance you have some carbon buildup.
I run mine hard and play in the rain with an open filter and still had plenty.
Thanks for the info
The heads will getting cleaned up , valve grind minor porting and manual releases
Plan was to bore my cylinders from 96 to 103 as I have new 103 take off pistons ,
Shop doing the heads etc will be putting It on the dyno using my PV
Will know more when the heads are off , probabley Saturday
Dave
Da
Quote from: Big Dave on December 31, 2020, 08:03:36 AM
Thanks for the info
The heads will getting cleaned up , valve grind minor porting and manual releases
Plan was to bore my cylinders from 96 to 103 as I have new 103 take off pistons ,
Shop doing the heads etc will be putting It on the dyno using my PV
Will know more when the heads are off , probabley Saturday
Dave
Da
If you want to use those pistons and are already at 103". Send me a PM, I have a set of 96" jugs sitting on the shelf I will never use. You can have them, you would just need to pay the shipping to get them to Canada 👍
Quote from: 838 on December 31, 2020, 08:38:09 AM
Quote from: Big Dave on December 31, 2020, 08:03:36 AM
Thanks for the info
The heads will getting cleaned up , valve grind minor porting and manual releases
Plan was to bore my cylinders from 96 to 103 as I have new 103 take off pistons ,
Shop doing the heads etc will be putting It on the dyno using my PV
Will know more when the heads are off , probabley Saturday
Dave
Da
If you want to use those pistons and are already at 103". Send me a PM, I have a set of 96" jugs sitting on the shelf I will never use. You can have them, you would just need to pay the shipping to get them to Canada 👍
Thanks will let you know
Dave
Crisis over , stock 96 bore so 103 it shall be
Thanks for the help/info
Dave
Good decision.
Going 107 (and headwork) with a 48h cam in a bike that doesn't go over 4,500 rpm would be a waste of money.
Quote from: Arseclown on January 02, 2021, 03:34:24 PM
Good decision.
Going 107 (and headwork) with a 48h cam in a bike that doesn't go over 4,500 rpm would be a waste of money.
Truth
Dave
Durwood did a 2011 FLHTK with an AP-48 cam in a 107...105hp @5.71/122 tq @3.56, crosses 100 ft/lbs @ 2400, still 115 ft/lbs @ 4500, completely rideable below 4500. Waste of money is in the eye of the beholder... I have a sheet by Durwood I had found posted, I saved when I was looking to do one myself, since it isn't mine I can't show it without getting my patty slapped.
I'd definitely give Durwood a shout if you still want to go this route and at least ask him if the build was worth it...
I have the 48's in my 103 bagger, using a big valve head CNC'd by Rick Ward. Its a touring monster, huge TQ curve and lots of HP.
The dyno sheet is posted in the Dyno section. 110HP and 119TQ. Excellent combination.
It would do even better on a 107. Using a ported large valve head is the key to this combo.
EDIT- The above results are with a stock-type muffler, non-straight through (SE touring mufflers). On a 103/7 with a performance muffler your numbers are going to be even better.
A 3.910" MLS head gasket on a 3.937" bore is a recipe for detonation. :angry:
John
Quote from: Big Dave on December 30, 2020, 12:41:44 PM
Has anyone tuned this combination before ?
I know the 103 likes it but have seen nothing on the 107
Thanks
Dave
A flatop piston, even with a .040" head gasket will be at 10.0cr.
Unless you increase the combustion chamber volume, that short intake closing of the non-emmissions version of the S/E 255 school-bus cam will create unwanted, uncontrolled spark knock, regardless of how large the ports are created/manipulated.
We would not suggest that as a rule here.
Better ways to manufacture much more power.
Quote from: HD Street Performance on December 31, 2020, 06:14:48 AM
Quote from: Barrett on December 31, 2020, 06:07:17 AM
There's always the overbore 103" as an option. You will have more meat on the spigots too..
The 90% solution for 50% the cost based on what the OP states he wants. Agreed.
Add manual releases to the heads and a retune.
HD, can you please tell me what the 103" over bore is? Is it 103" flat top pistons .10" or .20" oversize?
Thanks