Bigger Bore Etc

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Ace VenTRa
Posts: 86
Joined: Sun Feb 23, 2020 8:32 pm

Bigger Bore Etc

Post by Ace VenTRa »

So far...Here's what I've done:

Manual CCT's
Re-ground cams
.50mm bore
TBR High Mount
Jetted
K&N
Valves
Springs
Porting
Secret spice #1
Primary noise gear delete
Lightened flywheel
Lithium Battery
900RR Rims
Pair Delete
Carb Heat Delete
CBR Coils
Rebuilt trans

Ill start with the cams as they were one of the most frustrating things. Web wanted a 1000 bucks for a hard weld cam and Kent want almost the same when you factor in VAT, Shipping, and Exchange Rate. For some unthinkable reason no one will sell their Moriwaki or Yosh cams at any price, apparently it's better to let them sit on a shelf somewhere, and Crower is fairly pricey as well. What I was able to do was spend a few minutes on the phone with Web and get them to come up with a few specs that we could regrind the oem cams to without hard weld. This cut the price in half and while I do not have the specs on hand, it's grind #1490 and it has a .414 lift. They work quite well and improve top end and mid range without really sacrificing bottom end. I do not yet have a dyno sheet for these but, before the cam swap I made 98Hp at the wheel and 65 LbFt with really fat jetting. I suspect it added a few ponies where I wanted them and time will tell.

Unfortunately shortly after installing the cams my rear piston grenaded for some unknown reason and I was forced to rebuild much sooner than I expected or desired. So, my freshly ported heads needed to be completed in a hurry and off to the machine shop they went. They flow about 50 cfm more than stock with a significant gain in velocity. I left the exhaust valves at the stock size though if I had more time and money I would have made them smaller by 2mm. Many people disagree with me on this one but if you give me time you'll see it my way. I enlarged the intake to 39mm and for all four I used Ferrea stainless; I also replaced the guides. The spring are from Kibble white and all the hardware is new and almost everything had been cryogenically treated and or polished to some degree.

I had a spare block on hand which I chose to use rather than my original block and as a result of the taper in the bores I needed to have them enlarged to 98.5mm with bore clearance set to .002". I used Honda cast OS pistons and, again, with more time and money I would have used forged JE pistons. The stock rods, stock wrist pins/clips and stock bearings set to .0015" clearance were used; one important thing to note is that the stock rods were almost 30 grams different from each other. Rather than grind them down I purchased an extra used one which was within 1 gram, this allowed for an almost perfect balance between front and rear cylinders. The head gaskets are stock as are all the bolts. While in there I replaced all of the snap rings in the transmission. I had an extra V trans laying around which had a few gears with better dogs than mine so I swapped them out. I highly recommend replacing the snap rings and any worn gears as it made a tremendous difference in shifting. I feels much better than it did before, hands down.

I removed the primary noise gear on a whim, I have no idea if it made a difference. It's not any noisier I don't think. I used my 5lb flywheel and just so everyone is aware, the RC flywheel is about 5lbs and does fit the V. Also, the RC starter gear is much lighter and may also work, I haven't checked yet. Which brings me to my next subject: There are many parts from the RC that do work in the VTR. I know this because I bought a bunch of used RC engine parts so that I could A.) Understand what Honda does to improve things and B.) Measure and confirm whether or not they share any parts. I can confirm that we have been missing out on some cool stuff as a result of the common wisdom that they are completely different. I will post, at some point, a list that to the best of my knowledge (as a result of real world testing) works well.

The coils are off of a CBR1000, 2006 I think, and they are a bit tall. Next time I'll use coils from a 600 which are supposed to be shorter. My voltage regulator is a spare one I had from my Triumph and it works just fine even with the Lithium battery. Apparently a little British blood goes a long way in a V.

Jetting: I've tried all the settings that everyone posted about on the web and eventually I settled on stock springs, 2 holes in the slides, 5th clip 190/195 jetting and 48s pilots with the screws set at 2 turns out and a K&N. I have no complaints at this time but I have very few miles on this engine. Prior to that (without ported heads etc) I was running essentially the same thing but with 180/185 mains and the needle on the 4th clip and a stock filter. Keep in mind when attending to your jetting that when I made my last dyno run, and it did quite well, it was at 10.8:1! Also bear in mind that on Factory Pro's website they made the same power as I did (almost) with their jetting "perfect" so don't get too caught up in the hype of jetting. Avoid running to lean and you're probably ok. Also worth noting is that for the DJ kit in the EU the instructions do not indicate that the front and rear need to be jetted differently. To further clear up that issue it is not for cooling, it is because the air entering the front cylinder must make a hard turn to to do so inside the airbox. The shorter velocity stack is an attempt at correcting this and I suspect the different jetting is an attempt at improving emissions in the US. Lastly, after some thinking I have come to the conclusion, as have others, that the shorter slide springs are an attempt at easing the installation and the extra lift hole is an attempt to correct the effects of a weaker spring. In other words, leave the stock springs in and use 2 holes. The DJ needle and the stock needle are almost identical other that the DJ is adjustable. In other words, keep the stock needle and use shims instead. You will save time and money if you just purchase a different set of mains from any supplier and a bag of .010" shims from your local hardware.
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Stephan
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Location: Prague, Czech

Re: Bigger Bore Etc

Post by Stephan »

Thats a lot of effort and some serious stuff you handled with, and lot of wisdom gained :)

I would worry about your blown rear piston at first, because if you don´t know what it caused, it can repeat.

The cam grind is this one with 249 deg duration and 0,414 (10,52 mm) for all 4 cams, or there is different grind used for EX cams? I am also curious about cams timing, what are the numbers? These are not mentioned.

If you want to increase CR, I did some calculations in the past how much you need to skim the block. But after skimming it is must to set the cams timing and check valve to piston clearance, which should be at least 1,6 mm if I remember (you can find this info here on forum).

You can see that there is no room for proper CR increase, but I can imagine 10 can be achieved, all depends on piston to valve clearance value ...

CR: block skim (mm)
9,5: 0,09mm
9,6: 0,18mm
9,7: 0,27mm
9,8: 0,36mm
9,9: 0,44mm
10,0: 0,52mm
10,1: 0,6mm
10,2: 0,68mm
10,3: 0,76mm
10,4: 0,84mm
10,5: 0,91mm
10,6: 0,98mm
10,7: 1,05mm
10,8: 1,12mm
10,9: 1,19mm
11,0: 1,26mm
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sirch345
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Re: Bigger Bore Etc

Post by sirch345 »

Good to read what you have done and found out.
Thanks for posting :thumbup:

Chris.
jchesshyre
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Location: Chester, Cheshire

Re: Bigger Bore Etc

Post by jchesshyre »

Very impressed with your dedication and hard work! I'll not have time for stuff like this in the next probably twenty years as we're having our first baby in a few weeks' time, so I read most of your post with impressed interest rather than thinking 'and now I want to do the same' hahaha.

One thing that did interest me in terms of any fiddling I've done or will do with my bike is the stuff about the carb settings. I was under the impression that the two different size velocity stacks are a way of widening the torque curve (roughly speaking, shorter = torque at high revs, longer = torque at lower revs, so having both was an attempt to have the best of both worlds) – do you think this is also true, or just a side-effect of the need to have them different because of the reasons of geometry that you mention?
Ace VenTRa
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Re: Bigger Bore Etc

Post by Ace VenTRa »

RE: Carb Settings: I'm sure the different trumpets are due to the air flow for the front cylinder being different from the rear. Essentially the air for the front cylinder needs to make a sharp bend and almost reverse direction to enter the throat of the front carb. For the rear it continues on merrilly just the same way as it entered the snorkel.

RE: Broken piston: I stated that it broke for unknown reasons but the back story is that I was beating the crap out of it all day when it happened. Also, when I examined the broken piston along it fracture points there was quite a bit of discoloration which suggests to me, based on my extensive destructive and non-destructive testing experience, that what may have happened is that there was a fracture present from some unknown event in the bikes past that I exploited with a good tune and some hard hammering. Essentially, I made a real life example of why forged and or hypereutectic pistons were invented. Remember, this bike had an unknown history and was not stored, or taken out of storage, correctly. It may have been fine forever had I treated it right.

RE: Cams: They are a single pattern setup so the intake and exhaust are the same. I'll have to dig up the specs this weekend when I get home, I can post the timing events etc with better detail at that time. Either way, I installed them straight up with non adjustable sprockets. I am having and extra set of sprockets slotted for the next episode.

****I noticed one fine day while digging through my manual that the section regarding cam timing was a bit unclear (to me) when it came down to the TDC setting for either front or rear. Having a propensity to fiddle about with everything I made a TDC tool for the V and rotated the flywheel by hand until I found TDC and to my surprise the "FT" or "RT" marks are not TDC. The hash mark below "FT" or "RT" is the actual TDC point and I later confirmed this with a dial indicator and the head off the block during re-assembly. I checked many times to confirm that this is true. To further support this, turn to the section of the manual that deals with ignition timing and you will see that when checking timing the manual refers quite clearly to the hash mark and not the letters. I have taken a bit of heat for this radical idea as well but I believe it to be true and correct based on physical testing and it is how my bike is set up now.

That's it for now I think

AV
Ace VenTRa
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Re: Bigger Bore Etc

Post by Ace VenTRa »

I almost forgot:

Regarding piston to valve clearance:

I checked my motor using the clay method to determine PTV and Radial clearance. The V had miles of room and a gigantic quench area. So much so that it is not of any concern whatsoever with a stock piston and valves. I wager that you could run any cam that will fit in the head without worry. I have the clay mold still and I can always remeasure for anyone. My heads were shaved .003" and my intake is a 39mm. My lift is now .414 and I have well over the .040"/.050" Radial minimum and over .075" for PTV min. Sleep easily on that fact--I would wager the cost of a rebuild on that without a second thought.

AV
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Stephan
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Re: Bigger Bore Etc

Post by Stephan »

I found this spec for grind 1490:http://webcamshafts.com/pages_vehicles/ ... 55793.html

Not sure if I understand right, but if you didnt check or adjust timing of the cams, it is quite a lottery ride it like this, and blown piston can be part of that.

Grind from webcam is not vtr specific, they used only shape from this one, therefore timing values in link above are not applicable for vtr cams, and there is even different grind for EX cams.

Maybe I miss something, but when I did my cam regrind to 256 deg and 10.25mm valve lift, I had to choose IN EX timing for opening and closing valves, considering valve overlap as well, and told my engine builder to set this way (my time/cost/damage ratio implied it was better than do it myself). Add the fact that first thing done when tuning race engine by experienced builder is to correct valves timing from factory as precise as possible. In fact there is not more to do on modern superbike engine internals.
Ace VenTRa
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Re: Bigger Bore Etc

Post by Ace VenTRa »

Certainly, there is always more to be done to any cam and we are bound quite tightly by the size of the core we have and the money in our wallet. Web offers an exceptional cam shaft at twice the price and I'm sure it'll work even better. However, I was pretty dang tired of chasing Yosh, Mori and Kent cams and opted to let Web use their knowledge and experience to tell me what my options were with a standard core and no hard weld. A dirt track engine builder I'm close with, who only races Honda, agrees with their choice based on my limiting factors. The coolest part about my choice is that I get to say that beyond a shadow of a doubt that the grind works well because it's in my motor now and doing just that. Further, I am happy with the results. Whether or not the dyno agrees with me I'll find out soon enough but for now.... And this is kind of the point, as a wise man from down under told me once, "Being a pioneer, you'll get an arrow in the ass every now and again." I'm good with that. I remember quite clearly many people telling me that I can't improve the porting on my V and that was a waste of time. In a matter of hours I did just that by a considerable margin and it runs damned good. Quite literally for every mod I made, including a lightened flywheel for some reason, there are many that disagree vehemently with reams of data (or none at all) to support their objections. I know my data will only get me so far and that I eventually need to waste some hared earned cash to prove my idea. I'm good with that too.

AV
Ace VenTRa
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Re: Bigger Bore Etc

Post by Ace VenTRa »

Also, the link above is not for my cams, I'm not sure why but that is not a correct link. And remember, my front cylinder was unharmed as are my two new cylinders with the same cams.

And then of course there's this video where sounds like the best bike ever created:





Valve Lift:

.414" .414"

Duration:

276° 276°

Lobe Center:

102.5° 107.5°
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Stephan
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Re: Bigger Bore Etc

Post by Stephan »

I think it is the same cam spec as I linked above, I just wrote duration at 0,050.

There was no offense in my post, I have full respect to what you´ve done, I am not native speaker and I want to express correctly at first, maybe it sounds more rude than intended.

My main concern was about valve timing, because if you didn´t it via slotted cam sprockets, you took serious risk. It is working so all is good, but something you can think about in the future.
Ace VenTRa
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Re: Bigger Bore Etc

Post by Ace VenTRa »

No offense taken mate, spirited discussions based on data keep this stuff alive and interesting. I'll post the hard data later this week.

Also, I've run my motor "twingled" and runs like a demon with no ill effects. That's 180 out with no issues. This isn't surprising though when you blook at the data for PTV clearance. I'll post a pic of that later too.

AV
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Wicky
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Re: Bigger Bore Etc

Post by Wicky »

"Also, I've run my motor "twingled" and runs like a demon with no ill effects. That's 180 out with no issues."

Likely down significantly on horsies

http://www.vtr1000.org/phpBB3/viewtopic ... c3#p211159

http://www.vtr1000.org/phpBB3/viewtopic ... d9823ce31b
It may be that your whole purpose in life is simply to serve as a warning to others.

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Ace VenTRa
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Re: Bigger Bore Etc

Post by Ace VenTRa »

Oh for sure, without a lot of tuning it will not run right. The biggest thing is having both cylinders draw in at once starves the airbox. Ditch the box when twingled and get the jetting sorted. It'll fly after that. Totally different animal.

AV
jchesshyre
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Re: Bigger Bore Etc

Post by jchesshyre »

Ace VenTRa wrote: Thu Feb 27, 2020 12:19 am RE: Carb Settings: I'm sure the different trumpets are due to the air flow for the front cylinder being different from the rear. Essentially the air for the front cylinder needs to make a sharp bend and almost reverse direction to enter the throat of the front carb. For the rear it continues on merrilly just the same way as it entered the snorkel.
Where is this sharp bend, I don't quite understand? To me both inlets look like a straight-through run looking down each one with the slide up and the throttle open. Do you mean in terms of the airflow from the snorkel maybe? The rear cylinder's inlet is basically pointing towards that whereas the front cylinder's is the opposite and also immediately below. Actually if this is what you mean, which I guess it is, that totally makes sense now as to why you'd run the front cylinder with leaner settings: it runs with a slightly lower air pressure at the intake!
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Stephan
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Re: Bigger Bore Etc

Post by Stephan »

Ace VenTRa wrote: Thu Feb 27, 2020 6:43 pm Oh for sure, without a lot of tuning it will not run right. The biggest thing is having both cylinders draw in at once starves the airbox. Ditch the box when twingled and get the jetting sorted. It'll fly after that. Totally different animal.

AV
Big bang configuration, nice. Is it revving freely to the redline and can you share your airbox and carb setup? I agree your bike sounds good.
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