Hi ! VT500 all over the world !

[Dibingo]

Hi every body !

I came from France. I'm the webmaster of www.v2-honda.com.

I was looking for new ideas to improve my VT500 and I saw your modification about the airbox.
This idea come to my mind too.

You know in France, my VT500 is not an Ascott but a VT500E.
It's the same bike but his look seems different.

In my life, 7 motors and 5 VT500.
The newest is this : (I have to restore it)



My hobbies is improving V2 motors.

My best result was on it :



128 mph on GPS, at 9200 tr/min.
Stock airbox but with à homemade filter. (burning the paper and roll Hotte filter from kitchen on)
Stock needles, main jet to 2x125, same short springs, and no other things !

But ! I planed cylinders and polish outs exhausts.
My finals pipes are percing by a long mesh to through the chicanes.

I've got an Deauville 650 too, but the modifications are more difficult to do.

I hope new friends here, and hope see you one day in holidays ?

Note : sorry for my bad language !

[J6G1Z]

Greetings from the USA.

Don't worry about your English speaking skills. You are doing better than most of the current high school graduates.

I'm very interested in your previous performance improvements. I am in the process of jetting my bike correctly. I purchased a DynoJet kit, but between my dual Super-Trapp exhaust & my modified airbox, I'm having trouble dialing in the jetting. The bike starts easily & revs cleanly to about 5.5K to 6K RPM, then it falls on its face after 6K. The kit contains 2 lighter springs, 2 drill bits, 2 needles & 2 sets of main jets. I started with the larger jets, but that wasn't enough. Then they sent me 2 sizes larger & allthough that was an improvement, it wasn't enough. I just got off the Tech Line yesterday & some even larger jets are on the way. Unfortunately the DynoJet main jets use a proprietory numbering or identification system that does not correspond with either the Mikuni or Keihin main jet identification. I'm running an '85-'86 Shadow air cleaner from UNI. It has much more surface area than the Ascot filter. As an experiment, I wrapped about half of the filter with masking tape & rode the bike around the block. That much restriction brought the jetting in line & the bike operated fairly well. That led me to believe that I'm running lean.

Have you ever experimented with performance camshafts and/or cylinder head porting?

J.

[Dibingo]

Greetings from the USA.
Don't worry about your English speaking skills. You are doing better than most of the current high school graduates.

Thanks. 

From my expérience, Dynojet is a commercial joke. All and nothing in their kit.

You seems to have trouble to go at the top of the rev-counter.
If growing the main jets don't take effect, perhaps you've got a breakdown ? like a problem in the ignition Box or wiring ignition ?

I think you've got to return at stock version to start again since the origin.

About your airbox, I'm not sure that remove and cut off the rubber intake snorkle is a good thing.
It helps the Venturi's working.

In my case, I take all the times, main jets from Keihin as ref : KEC. (2 x 125 for me, the others are on 38)

Needles are stock, lighter springs and the second hole of the leaky bushel.
Nothing else about carburation.

Have you ever experimented with performance camshafts and/or cylinder head porting?

Cylinder head porting ? what's this ?

About camshaft, there's no corresponding with others V2 Honda. (in this forum, i've saw possibility with Transalp or NTV. It's wrong.)
The camshafts of the VT500 have no sisters !

They're sharp enough, nothing to improve there. Valves are too small in any case !
On my last VT5, I can through the red zone, but the valves are playing salsa. (And must be more often adjusted.)

On the other hand, this engine V2 Honda likes being more compressed. ( planed cylinders)

Sorry, of all V2 Honda, the VT500 is already the most successful.
To want to go much farther, we risk the breakage.
( I paid the price for it)

The problem of the cooling and the size of valves raises.
It is inescapable.

The first transalp have the same problems.
Production of the VT500 stopped, and the following models have improvements after the first Transalp. (biggest valves, cooling improvement)
But their breech carries less sharp camshafts and restricted exhaust valves in the conduit.

[scottly]

Regarding Dynojet, I have found their documentation for their dynos to be out of date and lacking in several areas. I have done dyno testing of an FT500 with a low restriction filter and posted my results in the FT tech section.

[Dibingo]

We are in the discussion there? 
Hello Scottly ! 

[J6G1Z]

Cylinder Head Porting, is the art of re-shaping/re-contouring the intake & exhaust ports to reduce any restrictions & increase flow.

To perform the job correctly, you need a flow bench so you can measure your results. An average mechanically inclined guy with a few tools can improve upon the stock port contours by simply cleaning up any casting slag & smoothing any angles that might be present. Remember to stay conservative in your efforts.

Porting is both an art & a science that you could spend a lifetime learning.

J.

[Dibingo]

Only there is a theory and a practice!

When I plane cylinders, I confide the whole to a specialist. I do not make it myself.

I have a problem to indicate you reducing how much cylinders.
It because of our differences of measure.

On the VT5, we can content with tightening more hardly the breech or with abolishing the joint of embase. (The water is external)

This engine likes that! No problem of premature wear.

[Joe D.]

I really like that windscreen on that model.

[scottly]

I have a problem to indicate you reducing how much cylinders.
It because of our differences of measure.

Do the French have some odd sort of measurement? I thought you were on the metric system, like most of the civilized world.

[Dibingo]

Ok ! 

My cylinders are reduced of 0,6mm !

We can make more, but I prefer to keep of the margin. This modification really transforms the aggressiveness of this motorcycle ! Nice !

[J6G1Z]

So if I understand you correctly, you have had the cylinders cut shorter to increase the compression.

Is your measurement 6mm or 0.6mm? Does this bring the piston to "zero" deck height?

Can the heads be cut instead of the cylinders?

How high is the octane rating of your pump gasoline?


Thank you
J.

[Dibingo]

They're very good questions! 

So if I understand you correctly, you have had the cylinders cut shorter to increase the compression.

yes ! 

Is your measurement 6mm or 0.6mm?

Like I post it : 0,6mm ! 1mm works too, but the carrier strap of distribution loses there !

Does this bring the piston to "zero" deck height?

No need other modifications ! There is room and no gap either.

Can the heads be cut instead of the cylinders?

You can, but in lesser proportion.

Like I post, you can too :

On the VT5, we can content with tightening more hardly the breech or with abolishing the joint of embase. (The water is external)

How high is the octane rating of your pump gasoline?

Octane is SP95 or SP98. No jingle sounds !

[J6G1Z]

I don't know how your local gasoline compares to ours. Sounds like yours may be better.

We are usually lucky to have "Premium" at 92 octane. Plus that has at least 10% Ethanol. There are a few filling stations where you can purchase Premium that does not have the Ethanol in it, but they are few & far between.

Thanks
J.

[Dibingo]

In france : 95 and 98 octane.

But our 95 is with 5 or 10% Ethanol. And not our 98 !

I use 98, that changes necessarily things! 

[scottly]

Removing .6mm from a 71mm bore cylinder would reduce the combustion chamber volume by 2.374cc. This would increase the stock compression ratio from 10.5:1 to maybe 11.5:1?

[J6G1Z]

11.5:1 would probably work with our 92 octane pump gas & should make the bike a bit crisper.

Hmmm...


J.

[scottly]

Just remember that 10% ethanol runs about 4% leaner, so that also figures into jetting.

[Dibingo]

Removing .6mm from a 71mm bore cylinder would reduce the combustion chamber volume by 2.374cc. This would increase the stock compression ratio from 10.5:1 to maybe 11.5:1?

That's really it! 

Just remember that 10% ethanol runs about 4% leaner, so that also figures into jetting.

I think it could works with your ethanol too !

[J6G1Z]

I'm thinking that increasing the compression by one full point, installing a couple of performance camshafts from MegaCycle Cams: http://www.megacyclecams.com/catalog/catalog.pdf  (Check out page #32 for the heading on the HONDA NT-650 HAWK (1988—1991) 500 ASCOT twin (1983—1984)) and some light porting work would really wake up a VT. Not that a VT is any slouch for a 500cc bike, but I always want more. I don't suspect there is much than can be done with the carbs other than jetting. I don't suppose that there are a pair of larger venturi canted carbs that will fit between the cylinders.

I wonder how much horsepower increase one would experience.

J.

[J6G1Z]

Just for the heck of it, I called MegaCycle Camshafts to see what type of pricing is involved with an Ascot camshaft swap.

You're looking at sending your stock camshafts in along with the payment (they do not accept credit cards or pay-pal yet, but they will accept your personal check, money orders, etc.) it takes approximately 7 to 10 business days for them to hardface & grind the new profile on your camshafts. You also need to purchase their valve spring upgrade kit.

Camshaft work is: $394
Valve Spring kit is: $369

Prior to placing an order. You need to contact them to discuss your bike, modifications, riding style, etc, to make sure that the new camshafts satisfy your goals. It would be real easy to buy yourself too much camshaft & not enjoy the new powerband.

Good luck
J.

PS. MegaCycle can also provide some Wiseco replacement pistons for the VT.

[Dibingo]

You're right for all.

but I always want more.

Like me my friend ! 

However, some precision :

-increasing the compression by one full point

Really very effective. We spoke about it.

I said it, these engines support it very well.
I have to explain knowing quite the range of V2 Honda, that very often from a model to the other one, the manufacturer gives us the solutions.
For example, the first 600 Transalp was more powerful than the following vintage years.
The air inlet is bigger, the regulations of carbus more hardly and the finer cylinder head gasket. (It seems, for a question of error of supplier.)

-performance camshafts from MegaCycle Cams (Thanks for the link, in France we have to make it do by ourselves.)

Detail first: the camshafts of the hawk is different.
Not by the dimension of the heights of cams (10/40/40/10) but by the shape of their tree.
Because of the gearing of the rev-counter of the VT500. On the hawk, it is electronic. (I think you know that)
I say it because MegaCycle does not say it on its document. 
We do not have to think that they are exchangeable ! 

In brief, as I said it to you, my topspeed (128mph) was made without getting new cams.
I often remained red zone there to obtain the speed maxi. (9500 rpm)

It was necessary to me to resume more often the games in the valves.
I think while the mechanics would not support more.
I do not want to weaken more the mechanics.
Hawk with its biggest valves, takes more advantage.

I also had serious difficulties with the fire chamber and cooling.
The hawk makes better ! 

The links of hoarse air valves, carbonized pistons, the support of cracked camshaft, I gave ! 
I saw in other occasions, that 10000 rpm seemed to be a limit.
That is why, I do not advise too strong camshafts on the VT500. So I ignore what makes Megacycle really on it. 
Also a trick: it is easier to obtain the top speed in 5. (without de 6 overdrive.)

I don't suspect there is much than can be done with the carbs other than jetting. I don't suppose that there are a pair of larger venturi canted carbs that will fit between the cylinders.

You're right.
Honda limited voluntarily carbs.
Because of the world pollution !

The carburation is one of my specialities.
For now, I would like to integrate the carbs of the Transalp. (32mm to 34mm)
It puts some concerns of which we shall speak again later... 

About cornets, it also favors the top speed but it's to the detriment of the Strength.

Sorry, don't you think possible that it would maybe be interesting to put our discussion in another thread? 

[Dibingo]

Sorry, you post on 12:53:56 PM ...

I took a long time to write my message.
Cause I'm French !

Camshaft work is: $394
Valve Spring kit is: $369

Good job !

[Dougie]

Which engine had the biggest valve, you mention the Hawk?

Differences in size in mm.?

Are they interchangeable in the Ascot?

[Buddy]

I have a set of jugs and heads from a 600 (shadow I think). The heads might be interchangeable but wouldn't work. The combustion chamber is too large, but they do have larger valves. The 500 has a heart shape and the 600 is open. Would not have any compression. The cylinders are a little taller also and would require more stroke or special pistons and rods. Probable cost prohibitive. Best case would be if a 600 crank would fit and work in the 500 block. Bore out the block to accept the bigger jugs  Use the 600 top end and hope the taller set up would all fit in the Ascot frame. Lots of work and $$.

Buddy 

[Dougie]

I have a set of jugs and heads from a 600 (shadow I think). The heads might be interchangeable but wouldn't work. The combustion chamber is too large, but they do have larger valves. The 500 has a heart shape and the 600 is open. Would not have any compression. The cylinders are a little taller also and would require more stroke or special pistons and rods. Probable cost prohibitive. Best case would be if a 600 crank would fit and work in the 500 block. Bore out the block to accept the bigger jugs  Use the 600 top end and hope the taller set up would all fit in the Ascot frame. Lots of work and $$.

Buddy

What year is the 600 shadow as the newer ones engine is very different.
The same vintage 600 Transalp is the same with the longer stroke with the drive being chain not shaft.
Should be possible to convert to shaft with original gearbox and drive shaft output coupling.