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[SDCVO]

Well, worst case scenario happened last weekend. After running my crate 120r insanely hard (cant get 5000 miles out of a year tire) for 18000 miles, I heard a sound in the rear cylinder. Yep, it was the piston slapping around. Shop will do a complete tear down tomorrow to see if we can salvage anything but its either bad news or really bad news.
My question is since I now have no choice, what would those of you that know a heck of a lot more than me (not hard) recommend I change in the rebuild other than the obvious (Timkin, weld)? Which cam? anything else?

[mike jesse]

I would wait until the engine is down and apart and see what needs to be addressed.
IMO if it's just the top end that needs work/replacement, fine go ahead and perform the necessary parts replacement
and be done. OTOH if you have to split the case I'd be more tempted to just slip the S&S 124 into the frame.
I base this opinion on the fact that I would be doing all of the labor myself.

[HILLSIDECYCLE.COM]

Well, worst case scenario happened last weekend. After running my crate 120r insanely hard (cant get 5000 miles out of a year tire) for 18000 miles, I heard a sound in the rear cylinder. Yep, it was the piston slapping around. Shop will do a complete tear down tomorrow to see if we can salvage anything but its either bad news or really bad news.
My question is since I now have no choice, what would those of you that know a heck of a lot more than me (not hard) recommend I change in the rebuild other than the obvious (Timkin, weld)? Which cam? anything else?

On the re-build, a T-Man 662-2 or Wood 9F and appropiate compression/head work with a 66mm T/Hog would be a viable option.
Scott

[GMR-PERFORMANCE]

Well, worst case scenario happened last weekend. After running my crate 120r insanely hard (cant get 5000 miles out of a year tire) for 18000 miles, I heard a sound in the rear cylinder. Yep, it was the piston slapping around. Shop will do a complete tear down tomorrow to see if we can salvage anything but its either bad news or really bad news.
My question is since I now have no choice, what would those of you that know a heck of a lot more than me (not hard) recommend I change in the rebuild other than the obvious (Timkin, weld)? Which cam? anything else?

Look to see if the cylinder has a crack in the spigot area,  If not and its just a bad piston to wall fitment and the skirt collapsed, We have a piston that will be a nice options, It has a 5.5 cc dome , no need to mill the head effect intake fitment, decrease piston to valve etc. With a bump in compression the stock cam works very well.

Just one sheet we have built at least 100 of these now.. Its a very basic build. The SE 58 t/b vs say others will not yield a ton more power as we have tested it. If you have a SE 58 the cost vs gain is not going to be enough to spend the money on a larger t/b. The 66 is a nice option however it is draw backs in stop and go traffic low speed riding. Even turned all the way down the cross section is massive so minor changes in throttle = air increase.

A timken is not needed 100% if you want to do it go ahead but tons of them out there without a timken running without issue. Have the crank prepped after a failure would be a good idea. Or if that crank has a rod issue S&S has a direct replacement for it. The stock SE crank is a powdered rod and I have seen the rod fail and create issues as well.

Tons of things can happen, some pics and a vid on crank failure.  Overall the engine is a good item but like anything else its not a hand built item but mass produced item and things get over looked and some of the specs are not what we would like to see.  Good luck I hope its a minor deal and bore and hone set of new pistons and you are back up and running




















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[Spiderman]

I'd give Dave Mackie a call at Dave Mackie Engineering (DME)

There are a lot of good vendors and i respect 99% of them but in my opinion and many others on this site he is far and away the best in the business on top ends. His cams produce gobs of real world power and his headwork is incomparable.

You make your own choices but you owe it to yourself to check out DME

B B

[Rooster]

When Jim's was rebuilding my motor they said Mackie does their headwork. Bad news was Jim's blamed their slowness on Mackie saying he is the best at the same time. Mine has been fine since.

[SDCVO]

There was metal shavings all thru the motor so I am going to go all in and try and rebuild it as bulletproof as possible. Spent a couple of hours with the guys at the shop coming up with a plan. Going to drop in a Axtell 124 kit, Dark Horse crank, woods 400 cam, Timken bearing, head work by Doc Jim in Alabama (recommended by Woods and known by my tech as the best as everyone thinks their guy is). Do I need to go larger than my SE 58 throttle body? Am I missing anything?
I of course understand that there is never any guarantees with a big motor like this (especially the way I run it) but I want to try and do this right and try and get as much dependability I can on this build. It would be less money to just buy a new crate motor and drop it in but I feel I would just end up here again

[2k]

It all depends on what you and your pocket book think. I have heard great things about Dark Horse Cranks......but like someone else said, everybody knows the best. If(when) it happens to me, I'm going GMR...........just because.

[ultrarider123]

It all depends on what you and your pocket book think. I have heard great things about Dark Horse Cranks......but like someone else said, everybody knows the best. If(when) it happens to me, I'm going GMR...........just because.

Same here.....

[sadunbar]

There was metal shavings all thru the motor so I am going to go all in and try and rebuild it as bulletproof as possible. Spent a couple of hours with the guys at the shop coming up with a plan. Going to drop in a Axtell 124 kit, Dark Horse crank, woods 400 cam, Timken bearing, head work by Doc Jim in Alabama (recommended by Woods and known by my tech as the best as everyone thinks their guy is). Do I need to go larger than my SE 58 throttle body? Am I missing anything?
I of course understand that there is never any guarantees with a big motor like this (especially the way I run it) but I want to try and do this right and try and get as much dependability I can on this build. It would be less money to just buy a new crate motor and drop it in but I feel I would just end up here again

Definitely not...  58mm or even 55mm will work great with this build...   

Larger throttle bodies will deliver numbers, but smaller throttle bodies enhance drivability, especially at slow and parking lot speeds...

[HILLSIDECYCLE.COM]

Contrary to popular belief, we use 66mm, and 62mm t/body's on even 117" builds, in certain applications.
S&S came out with a 66, for a reason................
Scott

[Mr. Warlock]

Contrary to popular belief, we use 66mm, and 62mm t/body's on even 117" builds, in certain applications.
S&S came out with a 66, for a reason................
Scott

Yup, high horse power / high rpm builds - Not low end power and drivability. OF course this is my opinion based on my experiences.

[JCZ]

Yup, high horse power / high rpm builds - Not low end power and drivability. OF course this is my opinion based on my experiences.

Personal opinion based on personal experiences have carried a lot of weight on this forum for years.    Justsayinzall

[GMR-PERFORMANCE]

I have the 66 on my own 124 I am swapping it for a 58 E from HPI. As I have run both back to back and I pick up[ low end power with the 58 peak numbers stay the same but low speed drivability is vastly improved.

 

[HILLSIDECYCLE.COM]

Low speed does NOT lack, just touchy throttle.........