DLC coated internals
 

My slow (but impulsive, lol) planning of my forthcoming rebuild continues. An improvement in my finances means I will get the work done late this summer or fall... woohoo!!!!

I had given thought to going with Carrillo rods as RCVTR had given me a lead about a shop that sells them (although they are now a custom order item) for $600. However, further to comments from our esteemed forum admin, I elected to nix that idea as I don't plan to rev the engine to the moon (very rarely go over 7K, usually counting on the mids to pull me along) and doubt I will get track duty in with it (have too much invested in the bike to risk dropping in, will buy a track bike at some point), I will likely stick with the stock rods (as I have found no evidence indicating that the stock rods are weak) and will get the crank balanced (to the new pistons and OEM rods). Based on comments from a VTR1000.org member in the UK, the VTR engine benefits greatly from this.

Also, I have just pulled the trigger on getting new valves and buckets which I am getting coated with DLC (for reduced friction and added longevity). I found a place in MIchigan that can do it quite cheap for me so the ball is in motion. The reduced friction should gain me a bit of power, along with helping it spool up more quickly while also reducing fuel consumption (just a bonus really) and adding longevity (I plan on keeping the bike for a loooooooong time). THe friction reduction should help to reduce the operating temps a bit too, helping to compensate slightly for the added heat from the heightened compression.

My hope is to get up quite close to 130 rwhp with torque numbers in the low to mid-80s. Combined with all the rotating weight reduction I have managed over the years (wheels, flywheel, rear rotor, 520 chain and sprockets, alum. clutch plates), it should make a formidable street ride (it goes VERY well now and still has the stock pistons with over 80K miles on it).

cheers

RE: connecting rods

You may want to consider the old hot rodders trick of polishing the stock rods. In addition to removing possible stress riser points, you will also lighten them a bit.


Rex

thanks for the advice :)

Sounds good.

I was not suggesting Carillo rods for their added strength. You can't spin a stage 1 engine fast enough to need it.

But they are substantially lighter than the stock rods. This means you can take a corresponding weight out of the crank as well. You talk about decreasing the inertia everywhere else, but it will have the most substantial effect at the crankshaft and reciprocating mass. It's not just the weight, it's the inertia, which affects the angular acceleration Parts which accelerate the most, benefit the most from decreased inertia. No other rotating components undego as much rpm range as the crank assembly. Therefore, they also undergo the most acceleration.

Torque = Inertia X angular acceleration.

Torque that is required to accelerate the components is torque that doesn't reach the ground.

but it is another $600...

Actually I'm with RCVTR on this one... it's a substantial amount of reciprocating mass... But yeah, it's not cheap... I have them on my wish list...

you bastiges, lol

Now you have me thinking again!!!!

Ok, so assuming I change my mind on this (which is bound to happen, lol), I need someone in the US to be my shipping intermediary and upon reception (in a month and a half or so, was told that is how long it'll take to get them done as it's a custom order) would forward them to me as a gift (aw shucks, right?). Guess I have to make a few PMs.....

Well if you need a west coast contact, just let me know ;)

You change your mind...? Nah...:rotf:

Here is a question for you guys:

the stock crank is said to be the weak link in the chain for hopped-up VTRs. Is this because of the Stage 2 and above models resorting to higher revs or is the added torque that causes failure?

AS I head further down the path of increased output (albeit through reduced friction and improved efficiency as opposed to spinning the crap out of it), I can't help but wonder if I will run into crank problems.

Same goes for the durability of the cases?

Comments?

I'm no expert, but I'd say it was probably a bit of both... I have increased the torque quite a bit without increasing revs with my somewhat erratic method of engine improvement and so far it seems to like that just fine......

You go off on wild tangents in planning, I try stuff in practice before I give myself too much chance to change my mind... Wonder why... :rolleyes:

Yep, seems I have an affinity for the road less traveled (should have been an engineer but alas, I am a VTR owner, lol)

Maybe I'll e-mail Roger D on this one....

update: just e-mailed The Man....

Seems to me that lighter rods put less stress on the crank.

I don't think crank strength is an issue until >140 HP. But RD will know more.

Got a (quick) reply from Roger in regards to the crank issue:
"There is a weakness in the standard crank but this is evident when VERY radical camshafts are fitted and the bike is a "full on" racing machine with International quality riders.
Higher compression ratio's or increase rev limits up to 11,200rpm are not a factor (10,800 is best)
ST2 Moriwaki camshaft (or equivalent) would require a replacement standard crank after every World Endurance race weekend which culminated in a 6 or 8 hour race. Honda Canada did this with their "factory" team while Honda France used a HRC Billet crank.
ST3 camshafts (or equivalent) CANNOT be used with Std crank
I think that you have nothing to worry about with the level of spec you envisage and the type of riding the engine will be subjected."

So, it seems I am good to go :) Now I just have to decide on the Carrillo rods.....

Of course, I hae to make it look like the smart thing to do, since I have a set on my shelf, for whenever I get to the next build...

It may not have been the best way to spend the money, but since it's done, I HAVE to use them.

If you are referring to Carrillo rods for a VTR, let me know if you want to part with them, no sense in having them collecting dust :)

Don't worry, they're coated in oil, wrapped in plastic and inside two cardboard boxes.

They'll be just fine. Wouldn't fit your bike anyway.

Gotcha, they're for the RC then.

Well, Fate has stepped in and given me a quick little injection of loot sufficient to.... yoiu guessed it.... pay for the Carrillos. That, and the fact that I may as well do the engine right up and then be done with it, means that I have just placed the order for the rods.

:)