Author Topic: Japanese '91 3XV deresriction  (Read 3860 times)

Steveog

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Re: Japanese '91 3XV deresriction
« Reply #90 on: April 15, 2018, 10:39:27 PM »
Gentlemen -

I've been riding the 3xv in short heating cycles with ever increasing RPM, but did ring its neck once to 12K. Power is smooth from off idle to 5000 which then builds to a nice surge to 8000 at which point it jumps cleanly and enthusiastically to 10,500, then flattens out.From everything I've read here, that sounds about right for an "R" with pipes (Dog Fight) and stock CDI box and jetting that's spot on. At this point, the plan was to take the bike to a DYNO for a benchmark reading. However, our local dyno guy is a four stroke expert, mostly with new R-1's, etc. Mellorp and others have spooked me about dyno runs done by tuners who are not familiar with these 2T's. What's next? My local expert (a retired TZ racer) recommends a "Plug Chop" to see what's going on. I know what to look for, but wondering if there's any other form of VooDoo I'm missing to be sure we're getting all we can in the bike's current form. I have yet to ride any real corners, as the bike is not street legal and the track is about 1.5 hours away. If this seems all good, then some easy track time seems obvious. Opinions?   
Brief, fleeting Glory. Which of itself cannot last, but while it does is the greatest game of all.

Warwick

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Re: Japanese '91 3XV deresriction
« Reply #91 on: April 15, 2018, 11:16:37 PM »
A few plug chop runs would be useful to see how it's fuelling under load. Assuming all looks OK there, I'd be inclined to just take it to the track and get a good feel for it as is, personally. A bone stock 3XV is plenty of fun on the track, and if the track is more curves than long straights, it might even surprise you a bit as a stock 3XV has nce, flexible power and should handle quite nicely if all is well with the chassis and runing gear.

A simple dyno power check run would give you a nice baseline to check against as you develop the motor further, later. If it's running the oil pump, even an operator more used to four strokes is unlikely to cause any damage really. If it's running pre-mix, just let the operator know to not let the drum push the engine on a closed throttle after the run (blip the trottle with the clutch in on the run down etc.) If the operator is the obliging type, maybe ask if you can run the bike on the roller yourself?

In its current guise, the restrictive stock porting and ignition are the factors holding it back above 10.5k, and there's no real voodoo you can perform to get around that I'm afraid. Checking everything is as healthy as possible in terms of the motor, chassis and running gear though will allow you to make the most of it until you get around to de-restricting it fully.

Enjoy!   (-P)
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Steveog

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Re: Japanese '91 3XV deresriction
« Reply #92 on: April 16, 2018, 02:00:26 AM »
Thanks Warrick - The injection pump is still intact and we have no plan to remove it. I've only use "mix" on my ancient RM80. The dyno-op I would be working with owns the biggest bike shop in our area. He also races "Expert Superbike" in the WERA series here in the US. (Second only to Moto-America, which used to be the AMA series seen in "On Any Sunday"). He knows what he's doing. Thanks for talking me down. I believe "Plug Chops" and riding our 3xv with care at the track is the best answer. I posted a diagram of the track earlier in this thread. It has a lot of everything. Long straights, interesting, tricky corners, fast sweepers and one hairpin leading to the grandstand straight. I just need to avoid the temptation to stretch the throttle on an engine that is supposed to be "fresh". Tough to do, but at my age (67) patience "should" be easier than when I was 25. 

The 3XV runs great and I just don't want to "Fook"it up. Steering input is telepathic, without any twitchiness. Of course, as I said, I haven't challenged any real corners, yet. We have a large agricultural park near our shop that we've been using for testing. But, that's nothing like a great back-road, let alone a racetrack.

Any other opinions are welcome. I've got one week from today before we go to the track. If Warrick has offered the final word on how it "should" be, I'm also open to any other thoughts about how to deal with this first track day.
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thump566

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Re: Japanese '91 3XV deresriction
« Reply #93 on: April 22, 2018, 10:26:11 AM »
No, there's no English language manual I'm afraid- the 3XV was only ever sold new in Japan. You'll find links to the Japanese manuals and parts books in the resources section. Main measurments, specs and part numbers etc. are in universal 'English' script so it's fairly easy to work with them really.

Good idea to get a base dyno reading as soon as you can. That way you will be able to clearly measure the effect of any mods as and when you make them  (-P).

Hi Warwick.

Recall a few years back a UK mag featured a nut and bolt restoration of a 3XV done in Marlboro livery with black wheels. Think the guy either worked at / owned a bike dealership in SW England ? Anyhow, recall his other half was Japanese and had translated a fair part of the 3XV to assist with the rebuild so I tried to email him and request a pdf copy emphasising that it was for personal use only to assist with my rebuild and that I would in no circumstances sell "his work" without his permission but received no response to my email.
Quite understand as he didn't know me from Adam but perhaps you may know him from the forum and have better luck than I? :-\
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Steveog

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Re: Japanese '91 3XV deresriction
« Reply #94 on: April 23, 2018, 08:39:06 PM »
First track-day was successful. Partial rain out. But, learned a lot about my 3xv. Naturally, we had to come in as Novices. The Intermediate and Expert classes were full, which meant any late entry Experts were put into Novice. (Maybe, 5-6 guys) For me, I could hang with any bike there (scrubbed the rear tire to the edge), until the two long straights. But, it did seem that extreme closing rates of jacked up R-1's and GSXR's verses novices on anything is an extremely dangerous situation. The sponsoring organization had "Coaches" on the track with us, which acted as traffic cops, but stifled my partner, just as he was getting to know his raced prepped ZX-6R.

How are track days handled where you ride? Similar? We're thinking of writing a complaint to the sponsors concerning filling the novice grid with Experts. They certainly wouldn't let us move up a class.

Also, both front forks and rear shock spring felt soft on the perfectly smooth track.

Any recommendations on front brake pads? I contacted EBC, but got no response. We have braided lines coming, but at track speeds things got spongy at the end of a 20 minute segment. The discs are in good shape. The brakes were never strong enough.

At 8,000rpm in sixth, the speedometer started bouncing wildly when approaching 180kph.

Lots of questions. Perhaps I should start a new thread, but we're still working on deconstriction, its just taking on new dimensions following this first track experience.

Thanks for any input. On any subject mentioned here.
Brief, fleeting Glory. Which of itself cannot last, but while it does is the greatest game of all.

jcsnook

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Re: Japanese '91 3XV deresriction
« Reply #95 on: April 23, 2018, 09:52:13 PM »
First track-day was successful. Partial rain out. But, learned a lot about my 3xv. Naturally, we had to come in as Novices. The Intermediate and Expert classes were full, which meant any late entry Experts were put into Novice. (Maybe, 5-6 guys) For me, I could hang with any bike there (scrubbed the rear tire to the edge), until the two long straights. But, it did seem that extreme closing rates of jacked up R-1's and GSXR's verses novices on anything is an extremely dangerous situation. The sponsoring organization had "Coaches" on the track with us, which acted as traffic cops, but stifled my partner, just as he was getting to know his raced prepped ZX-6R.

How are track days handled where you ride? Similar? We're thinking of writing a complaint to the sponsors concerning filling the novice grid with Experts. They certainly wouldn't let us move up a class.

Also, both front forks and rear shock spring felt soft on the perfectly smooth track.

Any recommendations on front brake pads? I contacted EBC, but got no response. We have braided lines coming, but at track speeds things got spongy at the end of a 20 minute segment. The discs are in good shape. The brakes were never strong enough.

At 8,000rpm in sixth, the speedometer started bouncing wildly when approaching 180kph.

Lots of questions. Perhaps I should start a new thread, but we're still working on deconstriction, its just taking on new dimensions following this first track experience.

Thanks for any input. On any subject mentioned here.

Glad the bike ran well!

The last set of pads I got for mine (rears) were the Gold Fren pads.  I've not had a chance to run them yet, but they came recommended by others here.  Any quality sintered race pads would work tho I would think.  I've not head many complaints about the front brakes on the 3XV's tho.  I think some have swapped out there OEM calipers for Nissen ones, similar to the TZ race ones, but off a Triumph if I not mistaken.  Same caliper, just have to machine off the "Triumph" logo if it bothers you.  Bolt straight up as I'm told, but I've not personally done it.
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Steveog

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Re: Japanese '91 3XV deresriction
« Reply #96 on: April 23, 2018, 11:39:12 PM »
Thank, jcsnook. I was running the bike the way I got it. Rubber lines. Old Brake fluid. I was waiting to install the steel lines for bleeding. The pads aren't used up, but are also stock.

I figured as long as I was into the brakes, new pads would help. I'm also around 190lbs, so I'm sure that adds to load on and performance of the stock brakes.

Love this bike. It was the only 2T on the track across all classes.
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ybk

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Re: Japanese '91 3XV deresriction
« Reply #97 on: April 23, 2018, 11:50:09 PM »
Track day setup sounds rough - surely overfilling the expert/intermediate classes would be better than mixing novices with experts..  ???

3XV's are softly sprung as stock, ie, setup for an average Japanese guy. Rear suspension you can't do much about apart from replace with a SP unit or another brand altogether(ohlins, wilber and maxton do shocks for the 3xv I think). Up front using 10W fork oil makes it better I found.

Brake wise get I would replace the seals and get a set of braided hoses. Then use Motul RBF 600 or 660 brake fluid, it has a really high boiling point (300degrees +). Brake pad wise I use SBS634 HS (Sintered) or SBS634 RS (Racing). I have this on both my track bikes and it's effortless 2 fingered braking. World of difference from my road bike with stock hoses and organic pads.

The speedo is mechanical so it may be worth checking or replacing the cable. Otherwise just put some tape over the speedo glass  ;D ;)

Steveog

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Re: Japanese '91 3XV deresriction
« Reply #98 on: April 24, 2018, 12:14:26 AM »
Appreciate your take on our trackday, YBK. I didn't like the shock of being passed at my speed, plus 50mph. My partner was really unhappy, being held back by their coaches to allow the "fast guys" to pass. I agree, if they want the money (I don't blame them) for this premier track back filling intermediate would be safer. In the US, insurance considerations are always running the show on everything from diving boards to our health care system. I'm guessing the sponsor's policy has maximum bike/session clause.

Good tips on suspension and brakes. Just what I needed.

I'm going to try stiffer springs, then scrape my wallet if a new rear damper is needed.

Seriously considering scrapping the stock dash in favor of fabricating my own from black Lexan (with UV protection formula). No need for the speedo.

Steve
Brief, fleeting Glory. Which of itself cannot last, but while it does is the greatest game of all.