Endurance Racing VF500 build.

[sportstu]

Right. A bit of development on project close ratio gearbox. This gets a bit confusing and I haven't yet found a solution but hopefully I'll have this sorted over the weekend. I have had the output shaft machined, the 2nd gear pinion ground to a taper to clear the crank case casting and built up the shaft again with shims to line the input and output gears. So far so good right?

 

Everything lines up perfectly, uou can see the taper on the 2nd gear, lovely job!

 

 

So, the next job was to fit the lower case and check that it shifts through all the gears, here is where it all went a bit weird. 

Running through the gears using the shift lever. The mechanism was really bad and wouldn't easily shift through the gears. However, if I rotated the shift drum manually, it all engaged perfectly. What was strange was when I compared the NC30 shift drum with the VF500 drum the were completely different in terms of the groove map, however, all the gears are located in the same place and the clearances are the same so I am at a loss to reason that one out. What I planned to do was to replace the VF drum with the NC drum but that is where I hit a snag, the shift mech is completely different. The VF uses two detent wheel, one for gear engagement and one for neutral whereas the NC just has the one. Not sure if I can get around this but watch this space!!

 

This is the end of the shift drum on the VF500. 

This is the NC30 one. You can see that it has a locating dowel in the centre and space for only one detent wheel. 

The bottom line is that I don't think that I can swap one for the other but because all of the gears are located in a common way I should be able to find a way to make it work, just not sure how yet. I'm spending tomorrow with 2 parts lists for reference, 2 workshop manuals and a lot of loose parts. Wish me luck!

 

 

 

 

[squirrelman]

You've done well and covered alot of bases, but i want to know how long it last on track b4 it drops a valve and blows bigtime.

[sportstu]

3 hours ago, squirrelman said:

You've done well and covered alot of bases, but i want to know how long it last on track b4 it drops a valve and blows bigtime.

Sure, I get asked that by a few folk. During the race series back in the day there were anything up to 40 bikes competing at multiple rounds and there wasn't any evidence of engine blow ups or dropped valves. I'm not convinced that these are any more or less reliable than most bikes from that era, it's just that they are tarnished with the reputation by the VF750 issues. I found this quote from a racer back in the day:  "We did a support race at Donington Transatlantic Trophy when it was snowing. All the USA riders were huddled around a couple of space heaters in one of the garages. Then Shwantz & Merkel did their amazing display of riding ! I only raced the VF500 once, at Brands in 87, it was Paul Stows bike from the 86 Cup series, and I think Lee Finney had been using it as a courier bike for quite a few months before we race it. I think it had 30,000 odd miles on it. Still lasted the 6 hours though".

All I can do is try to build it right and hope for the best.

[sportstu]

I woke up in the middle of the night with a brain wave. I am obviously spending too much time on this if I'm thinking about it in my sleep!!

Anyway, it occurred to me that the shift pattern HAD to be the same on both clusters, there is no way that the forks can move the gears to a different position when I know for a fact that the gears are in the same position on the shafts, so 1st on one set is where 1st is on the other and so on. However, what had thrown me was looking at the groove pattern in each shift drum and seeing that they were totally different, it can't work right?

So waking up I realised that, while the shift pattern had to be the same, the drums didn't necessarily have to rotate the same way, one could go clockwise and the other counter. That explains  why they looked different when I rotated them both the same way.

I came into the workshop this morning and BINGO, rotate them opposite ways and they are the same.

So, the issue I had with selection should be down to the shift mechanism, which I hadn't stripped, without that fitted and rotating the drum by hand it's all good so I'm going to re-assemble the shift mechanism properly and hopefully have some good news.

[keny]

Interesting Project! I wish I had time and money for these kind of projects!

[Dutchy]

WAHEY!!!!!!!!!

 

 

 

 

And as for the "dropped valve" mythos....  Yes Yoshi had it happen, but over on the a Dutch forum, a Ducati Diavel rider (he used his bike for commuting!!!) had his engine go booommm. A conrod shouted "FREEEEEEEEEDDOOMMMMM". Now Ducati says "out of warranty, goodbye". So the "ducati sucks, this is your own stupid mistake for buying a ducati" is out in force.......    Such is life.

I will check out an SP2 tomorrow.....  fingers crossed..

 

We will not name names, but there IS this guy who did an epic trip to go get a VF500F2 and then sold it because VF500's cannot be relied on (and ok there was a leak near the front sprocket as well).  

 

[Dutchy]

PS: you are always welcome to stay at our  place if you want to pick up another bike in NL MR "xxx"

[jeremyr62]

If you google dropped valves, you get thousands of hits for a huge variety of engines, so it's not like it is something that only afflicts the VF500.

It does happen but I think it's overstated myself. I used to try keeping the revs down but that misses the point of the VF500 IMO. A well sorted cooling system is key I reckon.

I do admire the skills and resources of the OP. 

[jrodrims27]

12 hours ago, sportstu said:

I woke up in the middle of the night with a brain wave. I am obviously spending too much time on this if I'm thinking about it in my sleep!!

Anyway, it occurred to me that the shift pattern HAD to be the same on both clusters, there is no way that the forks can move the gears to a different position when I know for a fact that the gears are in the same position on the shafts, so 1st on one set is where 1st is on the other and so on. However, what had thrown me was looking at the groove pattern in each shift drum and seeing that they were totally different, it can't work right?

So waking up I realised that, while the shift pattern had to be the same, the drums didn't necessarily have to rotate the same way, one could go clockwise and the other counter. That explains  why they looked different when I rotated them both the same way.

I came into the workshop this morning and BINGO, rotate them opposite ways and they are the same.

So, the issue I had with selection should be down to the shift mechanism, which I hadn't stripped, without that fitted and rotating the drum by hand it's all good so I'm going to re-assemble the shift mechanism properly and hopefully have some good news.

aaaah, simply the shift mechanism.  Great midnight resolution.  I know that exact feeling when I have a hanging problem I need to solve.  I never stop thinking about it until it's done.

 

For us strictly street folk, I assume the NC30 tranny is that much better than the VF's?  Much tighter ratios intended for racing (not street) maybe?  Is it much more durable?  Not that it matters now after you've accomplished so much but isn't a variation of sprockets much easier if all you want is lower/higher gearing?  

[jrodrims27]

10 hours ago, Dutchy said:

WAHEY!!!!!!!!!

 

 

 

 

And as for the "dropped valve" mythos....  Yes Yoshi had it happen, but over on the a Dutch forum, a Ducati Diavel rider (he used his bike for commuting!!!) had his engine go booommm. A conrod shouted "FREEEEEEEEEDDOOMMMMM". Now Ducati says "out of warranty, goodbye". So the "ducati sucks, this is your own stupid mistake for buying a ducati" is out in force.......    Such is life.

I will check out an SP2 tomorrow.....  fingers crossed..

 

We will not name names, but there IS this guy who did an epic trip to go get a VF500F2 and then sold it because VF500's cannot be relied on (and ok there was a leak near the front sprocket as well).  

 

Do you use the oiling mod on your VF500F's?

[Dutchy]

No I don't on mine, but 5-6000km oil change and valve check.

She is due and come spring it is planned for.

[sportstu]

14 hours ago, jrodrims27 said:

aaaah, simply the shift mechanism.  Great midnight resolution.  I know that exact feeling when I have a hanging problem I need to solve.  I never stop thinking about it until it's done.

 

For us strictly street folk, I assume the NC30 tranny is that much better than the VF's?  Much tighter ratios intended for racing (not street) maybe?  Is it much more durable?  Not that it matters now after you've accomplished so much but isn't a variation of sprockets much easier if all you want is lower/higher gearing?  

I don't think it would be worth it for street. The gear clusters are similar build although the NC30 has more splines on the shaft which may be stronger, I'm not sure. The NC30 ratios are taller than the VF in 1st 2nd and 3rd and shorter in all the others. Because in a race situation you don't really need to worry about hill starts, pillion riding, traffic and cruising at constant speed the closer box is more relevant. The idea is that the ratios will keep the motor spinning in it's most efficient zone because it won't be dropping as many revs on each shift. Most of the riding will be between say 50 and 120mph with a following wind so I'll use the external gear ratios to gear that accordingly but the internal ratios will help make the most of the limited power of the bike. There is a great web site called gearingcommander.com. you can work out your top speed at a given rev limit and also change the wheel sizes, sprocket sizes and primary drive ratios. It will also tell you max speed in each gear. It's been a really useful source for me. 

[sportstu]

Great result. I have rebuilt the shift mechanism which was a bit fiddly to do and set up but now that it is working I have a full set of 6 gears shifting nicely, at least as nicely as they can when you are turning the shaft by hand. 

I'm not doing anything else until Monday when I'll re-split the crank cases and start the engine rebuild properly. It's getting near to the fun part now.........

[keny]

On ‎16‎.‎12‎.‎2016 at 0:04 PM, Dutchy said:

We will not name names, but there IS this guy who did an epic trip to go get a VF500F2 and then sold it because VF500's cannot be relied on (and ok there was a leak near the front sprocket as well).  

 

I know this bastard to

 

And then he go and get a CBX750F whit an even worse repurtation.............

[sportstu]

It's been a bit slow this week but I have started the rebuild proper. I had to do one more modification on the gearbox. There was a 0.4mm gap between the inside edge of the input bearing and the crank case so when you tightened up the clamp plate behind the clutch it loaded the bearing which would undoubtedly have failed. There was also a similar discrepancy in the clearance between the left and right dogs when it was in neutral so I had 0.4 machined off the bearing cap on the opposite end of the shaft to move the whole shaft that way. It's bloody perfect now, at last!!

0.4mm, it makes all the difference.

 

I've spent a bit of time cleaning up the crank journals. There was a very small amount of scoring on one of them but it came off with fine scotchbrite and autosol polish. I also cleaned out the oilways with brake cleaner and blasted them through with air, there was a hell of a lot of sludge in there.

 

Fitted the new bearings and span the crank up, no dramas at all

 

Getting the pistons in was a bit of a bitch. Unfortunately once they were in I managed to pop one out again by accident so ended up doing some of it twice. They are lovely and snug in the bores though. I then made a right fool of myself by fitting the crank and lining up the rods before realising that the new cam chains were still in their boxes on the bench. As I lifted the crank out I popped the same piston out again so I have now fitted that one 3 times. Anyway new chains on, new slippers, con rods in place, all looking good. I would have the halves back together but the clutch rod oil seal is stock in the post somewhere due to the postal guys being on strike so I'm as far as I can go until that lands here.

 

 

 

[Dutchy]

I'm in awe...

 

 

[sportstu]

Got to love this. Terrible quality but some proper old school carnage in the VF500 cup on public roads. It's impressive how quick these change direction.

[jeremyr62]

30 years ago. Blimey.

I wonder how much tweaking they could do. 4 into 1 for sure.

I assume your engine is an 84/85? You might be interested in these

http://vfrworld.com/forums/showthread.php/52364-VF500F-Yoshimura-stage-2-cams

 

[sportstu]

14 minutes ago, jeremyr62 said:

30 years ago. Blimey.

I wonder how much tweaking they could do. 4 into 1 for sure.

I assume your engine is an 84/85? You might be interested in these

http://vfrworld.com/forums/showthread.php/52364-VF500F-Yoshimura-stage-2-cams

 

The UK series only allowed minimal mods, just a Motad exhaust I think. Cams are interesting but not for me. Can't imagine there would be a huge market for them anymore though.

[jeremyr62]

Yes, he wants big bucks for them too. I doubt they could make a much of a difference anyway.

Pity there is so little info about that race series. I was actually around the UK then and following GPs at that time, but the UK VF500 series never appeared on my radar as far as I can remember. And I was (very poor) VF400 owner in 1984/5 too, so would have been paying some attention.

 

[flattrack]

was reading this far and saw that jeremyr62 owned a Vf400 so I'm curious to know if you had any valve problems with that bike too.  My '85 VF500F is apart now and so I read everything I find concerning the valve-train.  oh for the chance to talk with someone at Honda who actually tried to solve the problems.   gears fixed it but what else did they discover?  us diehards that want to keep them running would love to hear what they know.   Trial and error with used parts seems too "Burt Munro-ish". ... but it is an interesting puzzle.

[Terry]

I owned two VF400's from new and did 30,000-odd km on each. Never gave me a moments grief, and I don't recall hearing of any failures around then either; I worked part-time at a Honda dealership and kept my ear to the ground. Very different to the VF750F that I owned around the same time which needed new tensioners and camchains in the brief time I owned it. I recall that one of the magic mechanics replaced the camchains in-situ, splitting the links and re-joining the new one like you would a drive chain, using a hammer and punch. Clever chappie.

[sportstu]

Right. I've got the main part of the motor back together and torqued up. Everything is turning nicely so I'm feeling optimistic.

I'm going to use the primary drive gear and clutch from the racier NC30, partly because it is a slightly different ratio but mainly because it is lighter and stronger than the VF one. The NC30 has 10 friction plates to the VF's 8. Because 1st gear is now so tall it's probably a good idea to have a bit more friction area. It does very slightly foul the clutch casing but I can take a little material off the inside with a file and it'll work.

 

Fitted with the NC30 Clutch.

NC30 primary at the top, much lighter

Narrower teeth, may reduce friction??

It's a worthwhile saving.

 

With the flywheel modification that I'm planning on top of this I should save nearly 3kg off the rotating mass of the crank. Hopefully the little motor will spin up really rapidly.

All being well I should have the heads on tomorrow. It's actually starting to look like an engine again.....

[sportstu]

Had a couple of issues so it's gone a bit slower than I intended but I did get the rear head on today. 

 

Everything on the camshaft drive train is new, chains, tensioner spring, slipper and guide. I polished up the cam lobes and bearing surfaces as much as I could which took a lot of time. They do show some wear but I think they are OK.

 

Plain head against black casings...... I think it looks mega!!

[Dutchy]

"Oh man, it is MEGA..."