TC88b rpm limit : V-Twin Forum: Harley Davidson Forums

rat509 · 09-01-2002, 11:29 PM

Curious to know the factory redline on a tc88b motor. Not that I plan on hitting it often, but still like to know where I am at. I have had a stage 1 flash done to the ecm and seen post where others say that raised my limits. Sort of like big block chevys, add a good rod bolt and 6 grand is no problem to live with. Wondering where my weak points are on a tc88b. Is'nt this done by retarding the timeing, causeing it to fall on its face, or is there some time of ignition stutter box. Thanks for the education fellas, I have'nt hammered on the bike hard enough to know what it really does!!

wyodude · 09-02-2002, 08:09 AM

stock tc88b = 5,800 rpm. stage 1 =6,200 rpm.

tsuter · 09-02-2002, 01:59 PM

Did 48 dyno runs on Sep 1 on my 2002FLHTCUI with 1550 Stage 1. Ran 1500 to 6200 on all 4th gear rollons. Used SE EFI tuner and tuned out all spark retards front and rear. Riched it up a bit in some areas and advanced ignition in some areas. stock cam. took eight separate calibration reloads with dyno runs in between.
Peak HP came in at 72.5 at 5472 RPM and Torque at 89.8 at 3048 RPM.
On the road you will hit 117 MPH at 6100 in 4th.
Gotta find a better road for 5th.

JFScheck · 09-02-2002, 10:05 PM

Damn, that's fast enough for me

Kags · 09-02-2002, 10:20 PM

Dont cout on alot more in 5th! The air your moving at that speed makes it hard for 72 HP to get you any faster the around 120. Man thats booking!

The B motor counter balencers bearings can start to fail much over 6200 RPM. In fact at 6200 the Mo Co says sustaned speeds at that RPM ( like anyone would run around Daytona at 6200 rpm) would cause bearing damage to the C/B bearings. On the good side the mains are good for 7500 rpms, but its the same deal at sustaned speeds. In other words that the RPM's they ran around the track with in testing.

For all TC with stock piston & valve springs the rev limmit is 6200. Valve float and piston explosion can happen at higher levels.

rat509 · 09-02-2002, 11:45 PM

So if I keep it under 5500 and never go over 6200 rpm, this would, or should keep a stock 88b motor happy for a long time?

Kags · 09-03-2002, 09:47 PM

Thats true for any TC motor rat.

FXSTBI · 09-11-2002, 02:10 AM

With the factory limiter set at 6200 you dont have to worry about beating it up.When you do hit the limiter YOU WILL KNOW IT. I tagged mine screwing off one day and since then I'm careful to not take it that far.In second gear 60 mph is safe about 62 mph and well you really should try it so you know what to expect.....

rat509 · 09-11-2002, 02:48 AM

Well, hope it aint like the 454 chevy truck, darn near went through the windshield first time I hit factory limiter. What kind of top end have you seen FXSTBI, on your NT?

FXSTBI · 09-11-2002, 11:47 PM

Top-End? like max Mph? I have no trouble cruising at 100 if I want to.I personally am very happy with the performance of my bike.The stage 1 kit and pipes made a huge difference to me.How about yours?The next one is gonna be a ground up custom with a 125 in. EVO motor,with a baker 6 six speed and dont forget the jocky shift..........