Replacement Pistons
06-22-2005, 03:04 AM
#1
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Squid
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Posts: 62
Replacement Pistons
Hey guys,
I notice a few of you have thrown in aftermarket pistons, and it seems the JE are the way to go over the Mori.
Im just chasing some info on what was required, ie just a deglaze etc or do they drop straight in?
Rough cost ? and performance gain please
Thx,
VTR_Beefa
I notice a few of you have thrown in aftermarket pistons, and it seems the JE are the way to go over the Mori.
Im just chasing some info on what was required, ie just a deglaze etc or do they drop straight in?
Rough cost ? and performance gain please
Thx,
VTR_Beefa
06-22-2005, 08:40 AM
#2
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Re: Replacement Pistons
I'm always amazed when I see people talking about "throwing a set of pistons in." JEs are about $300. Bores should be measured fore/aft and side/side at top, middle and bottom. The VTR and RC51 are generally .002"-.004" out of round at the top because the cylinders are unsupported. The engines run fine. Mostly you want to check skirt clearance.
Deglazing and crosshatching with 800 grit works fine. Bores should be very thoroughly cleaned and lightly oiled.
At over 12k miles or so, you can expect the exhaust valves and seats to have some pitting. The seats should be recut and valves replaced IMO for the best results.
It's also a good time to inspect the transmission, especially shift dogs.
Deglazing and crosshatching with 800 grit works fine. Bores should be very thoroughly cleaned and lightly oiled.
At over 12k miles or so, you can expect the exhaust valves and seats to have some pitting. The seats should be recut and valves replaced IMO for the best results.
It's also a good time to inspect the transmission, especially shift dogs.
06-22-2005, 08:41 AM
#3
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Squid
Join Date: May 2005
Location: Nashville, TN
Posts: 84
Re: Replacement Pistons
Mine came with the JE pistons already installed...it's a race-built motor. My experience would be that if your motor has less than about 20k miles, a simple ball hone and careful ring gap adjustment would allow standard sized pistons to drop in. Over 20k miles and you're better off doing what rc996 did (do a search for his full teardown and rebuild post, with excellent pics).
You can bolt it all back together with stock cams and heads, but since you've already got it apart you're better off spending the money on the whole package at once. Max out a credit card if you have to, because you won't want to tear down the top end more than once. The Moriwaki Stage 2 cams are excellent. Some careful, conservative Dremel work on the heads, and some oversized valves with the chambers opened up just a little around the valve seats will improve things tremendously. Get all your ports matched up and polished in the right places. Basically just fix what Honda had to compromise on by building on an assembly line, rather than hand-assembling everything.
The pistons alone offer a pretty good improvement. The Stage 2 package makes an ***-kicker. You'll need to run Premium fuel, and you may even need to retard the ignition a little to keep from knocking. Mine runs on 93 octane ok with the ignition set at stock. With VP race fuel I switch it to the +4 slot and the difference is significant.
Of course you'll need to rejet the carbs and you'll definitely need a good free-flowing exhaust. It's all about the combination. Move down a heat range on your spark plugs, and get them properly indexed.
rc996 is definitely your best resource on this one (on this forum). Good luck.
You can bolt it all back together with stock cams and heads, but since you've already got it apart you're better off spending the money on the whole package at once. Max out a credit card if you have to, because you won't want to tear down the top end more than once. The Moriwaki Stage 2 cams are excellent. Some careful, conservative Dremel work on the heads, and some oversized valves with the chambers opened up just a little around the valve seats will improve things tremendously. Get all your ports matched up and polished in the right places. Basically just fix what Honda had to compromise on by building on an assembly line, rather than hand-assembling everything.
The pistons alone offer a pretty good improvement. The Stage 2 package makes an ***-kicker. You'll need to run Premium fuel, and you may even need to retard the ignition a little to keep from knocking. Mine runs on 93 octane ok with the ignition set at stock. With VP race fuel I switch it to the +4 slot and the difference is significant.
Of course you'll need to rejet the carbs and you'll definitely need a good free-flowing exhaust. It's all about the combination. Move down a heat range on your spark plugs, and get them properly indexed.
rc996 is definitely your best resource on this one (on this forum). Good luck.
06-22-2005, 08:55 AM
#4
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That wasn't my build posted on the site. I do have pictures. Mostly of the head work. I actually have better pictures of an RC51 I did, because I didn't have a camera for the VTR. I did get some with a borrowed camera.
I like the Stage 1 cams, because of their excellent midrange. I haven't tried Stage 2 but my understanding is that you need to increase redline to really take advantage of the Stage 2 cams.
I'm using an HRC race ignition with race gas on the track. Pump gas has been fine for street riding, but I live at altitude. I'm riding to Laguna Seca in two weeks so I'll know if I have two much ignition advance at sea level.
I like the Stage 1 cams, because of their excellent midrange. I haven't tried Stage 2 but my understanding is that you need to increase redline to really take advantage of the Stage 2 cams.
I'm using an HRC race ignition with race gas on the track. Pump gas has been fine for street riding, but I live at altitude. I'm riding to Laguna Seca in two weeks so I'll know if I have two much ignition advance at sea level.
06-22-2005, 09:14 AM
#5
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Squid
Join Date: May 2005
Location: Nashville, TN
Posts: 84
Re: Replacement Pistons
Sorry, my mistake. That teardown/rebuild with pics was posted by Gerrit. See it here: https://www.superhawkforum.com/viewt...4f885daee4bd04
Nicely chronicled. Dunno why I thought it was you, Rand...probably because you have the JE pistons listed in your signature, and you're womping on RC51s at the racetrack. 8)
I haven't seen a post from Gerrit in a while. I'd say he's a good resource for this question.
Nicely chronicled. Dunno why I thought it was you, Rand...probably because you have the JE pistons listed in your signature, and you're womping on RC51s at the racetrack. 8)
I haven't seen a post from Gerrit in a while. I'd say he's a good resource for this question.
06-22-2005, 01:13 PM
#6
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My point is similar to Adam's.
The biggest part of doing the engine work is the removal, cleaning, disassembly, more cleaning, reassembly, reinstallation.
While you have it all apart, you have the opportunity to inspect and measure everything, replace main and rod bearings and freshen up the heads. It's also worth it to spend the 10 hours or so on porting. If you take the time and spend the money to do it right, you'll end up with what you're hoping for. If you don't, you'll probably just wish you had and my bike will still be faster!
The biggest part of doing the engine work is the removal, cleaning, disassembly, more cleaning, reassembly, reinstallation.
While you have it all apart, you have the opportunity to inspect and measure everything, replace main and rod bearings and freshen up the heads. It's also worth it to spend the 10 hours or so on porting. If you take the time and spend the money to do it right, you'll end up with what you're hoping for. If you don't, you'll probably just wish you had and my bike will still be faster!
06-23-2005, 12:37 AM
#7
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Squid
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Join Date: Mar 2005
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Re: Replacement Pistons
Thanks for the info guys, much appreciated. 
RC996, "Throwing in a set of pistons" is merely an expression.. dont take it to mean any lesser of the task involved.
I read that thread with pics on the rebuild and it was great stuff.... my bike has just had its 6000K service and i rely on it to get to work and back, so if I did go down this avenue, more than likely I would take it to someone i trust to do the work for me, as time constraints wouldnt allow me the pleasure.
Lol... I have been smoking guys on bikes way faster than mine for a looong time... you guys know well enough the bike is only part of the equation
Thanks again for the info, will give some serious thought to a cams/piston/headwork .. headwork I am happy doing myself though.
Cheers
RC996, "Throwing in a set of pistons" is merely an expression.. dont take it to mean any lesser of the task involved.
I read that thread with pics on the rebuild and it was great stuff.... my bike has just had its 6000K service and i rely on it to get to work and back, so if I did go down this avenue, more than likely I would take it to someone i trust to do the work for me, as time constraints wouldnt allow me the pleasure.
If you don't, you'll probably just wish you had and my bike will still be faster!
Thanks again for the info, will give some serious thought to a cams/piston/headwork .. headwork I am happy doing myself though.
Cheers
06-23-2005, 08:13 AM
#9
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Re: Replacement Pistons
RC996, "Throwing in a set of pistons" is merely an expression.. dont take it to mean any lesser of the task involved.
Lol... I have been smoking guys on bikes way faster than mine for a looong time... you guys know well enough the bike is only part of the equation
Lol... I have been smoking guys on bikes way faster than mine for a looong time... you guys know well enough the bike is only part of the equation
I have learned from my mentor that engine work is about the details. It's the small stuff that makes the difference.
You can buy pistons on line direct from JE. I believe Big Valley Honda in Reno stocks JE and Moriwaki. They just sold the last set of Moriwaki/HRC oversize valves (Damn i knew I should have bought them)So the next valves will be custom. My next build will involve boring the block an installing 0.5mm oversize pistons, replacing cam chains and rebuilding the transmission. Probably winter of '06.
06-23-2005, 05:04 PM
#11
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Squid
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Join Date: Mar 2005
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Re: Replacement Pistons
I would enjoy th opportunity to try and keep up!
to be honest, I dont think my VTR has the goods yet for serious times at the track. I have spent the last 10 years on a ZXR750 that (standard except for pipe and braided lines) was happy to embarass R1's Gixxers Dukes etc.. not all mind you, just the ones who didnt have the confidence in their bike to really ride it smooth and fast The VTR will smoke most of these guys on back roads where low down torque and compliant suspension rules (although the VTR front end is woeful and was the first thing to get turfed on mine)
Would like another 20hp to really turn the bike into what Honda should have made it in the first place... but all that means is we all have the chance to do it ourselves.
Here in Aus i bought my firestorm brand spanking new 2 or 3 months ago and it cost $12,999(AUD) ride away... which is about $9700US.. the 05 (true)-sports bikes are close to double that.
So why did V2Weapon buy the firestorm....if its the same reason i did its cause the cost of the storm and goodies to make it perform as well as the RC, will still cost less than the RC : ) and you have a whole heap of fun on the way.
*Note this is a lame attempt to justify to myself not being able to afford the RC51 and buying the Firestorm instead.
Cyas
06-24-2005, 08:30 AM
#12
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Building the bike that I think Honda should have built has been my goal.
Everybody expects you to be fast if you ride the RC51. I too have smoked at least one of every bike on the track. I eat R1s on a regular basis. Everybody has to have one. Not that many who can really ride one. People are shocked when you do it on a VTR. That's half the fun!
To get +20 HP is not trivial. That's about what you get with a fully detailed stage 1 build.
Everybody expects you to be fast if you ride the RC51. I too have smoked at least one of every bike on the track. I eat R1s on a regular basis. Everybody has to have one. Not that many who can really ride one. People are shocked when you do it on a VTR. That's half the fun!
To get +20 HP is not trivial. That's about what you get with a fully detailed stage 1 build.
06-24-2005, 10:13 AM
#13
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Re: Replacement Pistons
I also dont think the "oversize" will make great HP difference. Just the High comp will do.
I'm not sure if I still want to sell tho two spare pistons, maybe I'll buy a spare engine and work it up completely. (Bigger valves, porting, cams, ... whatever)
But first thinking about rear shock and maybee RC51 forks
So it makes two : "Building the bike that I think Honda should have build it"
Regards Gerrit.
07-11-2005, 09:37 AM
#14
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Re: Replacement Pistons
The JE pistons can be had for $220.00 from S&K racing . Stock Honda rings are used .
To my knowledge the Stage II Moriwaki cams are no longer available .
Very little head flow can be gained by porting the stock heads . The entry to the valve seats in the port are lower than the seats so nothing there to blend in . Add oversize intake valves then some port work will gain some.
For the guy on a budget , cams will produce the most gain and there's a couple ways to go about it seeing the intake cam parameters is way small . The exhaust cam is plenty large but i do agree , a planned package of components is the way to go .... with any engine .
These couple ways of camming the engine on the cheap that I speak of are time consuming . Maybe next weekend when time permits I'll post more about what I have done and or found out since the first Super Hawk engine I built . It hit hard but not like engine 2 through 5 .
Time time time , never enough these days
To my knowledge the Stage II Moriwaki cams are no longer available .
Very little head flow can be gained by porting the stock heads . The entry to the valve seats in the port are lower than the seats so nothing there to blend in . Add oversize intake valves then some port work will gain some.
For the guy on a budget , cams will produce the most gain and there's a couple ways to go about it seeing the intake cam parameters is way small . The exhaust cam is plenty large but i do agree , a planned package of components is the way to go .... with any engine .
These couple ways of camming the engine on the cheap that I speak of are time consuming . Maybe next weekend when time permits I'll post more about what I have done and or found out since the first Super Hawk engine I built . It hit hard but not like engine 2 through 5 .
Time time time , never enough these days
07-13-2005, 09:28 AM
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Re: Replacement Pistons
You could do same on the SH . The SV 650 guys have been doing it for along time but it will only help some and intake and exhaust will need need re-dregreeing for max results .
The stock ex cam is lazy in terms of lobe intensity but will fill the cylinder better than the stock intake does if you open the valve early .
If you were to search my past posts you'll find both stock cam specs and Moriwakis specs . The Moriwakis look smaller, and are numericaly but they have a more intense profile thus make more power by filling the cylinders more efficiently .
The stock ex cam is lazy in terms of lobe intensity but will fill the cylinder better than the stock intake does if you open the valve early .
If you were to search my past posts you'll find both stock cam specs and Moriwakis specs . The Moriwakis look smaller, and are numericaly but they have a more intense profile thus make more power by filling the cylinders more efficiently .
07-20-2005, 07:23 PM
#17
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Re: Replacement Pistons
Hey Rollingalong,
Do you know anything about the Yoshimura cams?
http://store.yoshimura-rd.com/VTR1000
Do you know anything about the Yoshimura cams?
http://store.yoshimura-rd.com/VTR1000
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