1988 VFR750FJ back on the road.

[Fastdruid]

I've owned it since 2004, done about 45k on it but mostly due to having children haven't ridden it in the last 11 years. 

 

Not through any kind of "giving up riding", just didn't have the time, then the MOT lapsed and then it needed things doing and whole inertia thing meant it sat. 

 

Anyway, for reasons I decided that I would sort it for an up and coming trackday, even if I only do one session on it (I'm taking my normal track bike as well) it was motivation with a firm goal to get it sorted. 

 

Even if I don't now take it, it's now running, MOTd, insured and fully road legal so (as it stopped raining here for longer than 10 minutes) I took it out for its first shakedown ride yesterday. 

 

 

Wasn't *entirely* successful as I got home just as steam started rising and a massive gush of water from the lower hose...It's properly burst.

 

 

Thankfully I have a spare so swapped that over (plus ordered a new silicone set) and fixed a couple of other niggles too, I plan another short ride out tomorrow then assuming that is fine I'll venture further afield. 

[Fastdruid]

Another short (17miles) ride out today, more successful. No explosions of coolant. 

 

Slightly odd behaviour at one point from the sidestand warning light but apart from that the only issue is that the clutch is slipping under full throttle. 

 

Suspect maybe oil so I'm going to change to another brand and see if that helps. If not then its new clutch time. 

[Captain 80s]

17 minutes ago, Fastdruid said:

Another short (17miles) ride out today, more successful. No explosions of coolant. 

 

Slightly odd behaviour at one point from the sidestand warning light but apart from that the only issue is that the clutch is slipping under full throttle. 

 

Suspect maybe oil so I'm going to change to another brand and see if that helps. If not then its new clutch time. 

 

Unless you recently decided to change to a full synth late in life, I would just do your oil change when you install the clutch.

[Fastdruid]

2 hours ago, Captain 80s said:

 

Unless you recently decided to change to a full synth late in life, I would just do your oil change when you install the clutch.

 

I'm suspecting oil or something really odd going on with the slave. Someone did suggest air in the line and I guess maybe it might prevent it returning as much as it should. I didn't *actually* bleed it after taking the slave piston out and cleaning things up but rather just operated it until it felt right and the bubbles stopped. 

 

Odd thing is that this is the second engine with the *same* issue, we wont go into the sordid details right now but on the original engine...the clutch slipped when *cold* but only once...and then was fine. 

 

So swapped in a new engine, lower mileage from an FK (mine being an FJ should have been the same).  The good news here is that the new engine was *MUCH* healthier than mine had ever been. The only part swapped over from the original bike was the clutch slave...and I used the same oil. 

 

Still did the same, slipped when *cold* for the first full throttle then was fine.  I swapped in a brand new clutch. Still did it. 

 

Roll forward to now and it's worse. Not just slipping when cold but when hot too. Now I did, purposely put in an oil I expected to swap in not very many miles[1] (and I can't even remember if that was the same oil I used to use) so I've just changed that (to Putoline Sport 4R (this stuff https://www.putoline.com/en/catalogue/product/3249/sport-4r-10w-40/6851/ ). I'll test it out tomorrow. 

 

I have also spent some time measuring the old plates I took out from it. They're all *WELL* within tolerance. Standard is 2.92mm-3.08mm and the very worst of them is 3.03mm. Between those and my "for spares" RC35 engine I have a stack that measures 27.7mm (and 9*3.08mm should me 27.72mm). 

 

I have a full set of spare steels, all as far as I can tell flat and ~2mm thick (there is size or wear limit given for the steel plates). 

 

What doesn't measure up however are the springs I've got two spare sets. They're both in spec but should be 44.4mm and they measure ~43mm. Well within the service limit (41.2mm) but not great. 

 

[1] Mostly because I swapped the oil without changing the filter and because while the oil was unopened it was old. I figured ideal to use to flush the engine and then refill with fresh and change the filter.  

 

 

[Captain 80s]

Got it. 

 

You might consider roughing up the metals perpendicular to normal wear with some emery cloth and install some EBC (or equivalent) heavy duty springs.  

 

I've never had a clutch "slip once when cold".   I guess it is time to verify your slave operation too.

 

Good luck! 

[Fastdruid]

So I can't remember exactly what I had in it before. I know it was Motul but which one? I do know that I stuck Motul 5000 in there this time. 

 

Thinking about things though, the springs that I've got spare haven't been in an engine for 16 years but had lost a chunk of length. I can't remember but I suspect I swapped the springs for new ones (on the basis that the DSS Clutch kit includes them), if I did then they're still 16 years old now. If I didn't then they're 34 years old. 

 

On that basis I ordered some new EBC springs. I've already ordered a gasket so I'll swap them out when they turn up and inspect the plates and frictions at the same time. In the mean while I'll bleed the clutch and see if the oil change has helped. It's still ridable... just can't give it full throttle! 

[rc24dk]

Nice bike 😎

[Fastdruid]

17 hours ago, Fastdruid said:

Slightly odd behaviour at one point from the sidestand warning light

 

This issue "went away". When I went back to look at things again it just worked as it should.

On looking at the wiring diagram however it was clear that the warning light and the cut out circuit are two entirely separate things (which is how I could have the warning light on but it didn't cut the ignition). 

 

My suspicion therefore is a dodgy switch. Although I guess I can't entirely rule out a short in the wiring harness.  

 

 

It may be one of those things that clears up with use, the stand has after all barely been used in 11 years!

 

[Captain 80s]

13 hours ago, Fastdruid said:

Its still ridable... just can't give it full throttle! 

 

Very strange definition of "ridable".

 

🙂

[Fastdruid]

2 hours ago, Captain 80s said:

 

Very strange definition of "ridable".

 

🙂

 

Well, to put it another way, I wouldn't do a trackday with it as it stands as it would be massively frustrating but there is a VFR/RVF400 meet up at the weekend that we might go to (with my wife on her RVF400) which is a ~50mile round trip ride.  I'd happily do that on it with the current level of clutch slip. 

 

 

[Thumbs]

Careful with EBC clutch springs, I bought some and they were so heavy duty that I ended up taking them out 

[Fastdruid]

16 minutes ago, Thumbs said:

Careful with EBC clutch springs, I bought some and they were so heavy duty that I ended up taking them out 

 

Right now I'll settle for it not slipping! I can cross the bridge of it being too heavy later as I have a hard limit of a trackday next week! 

 

Either way though I need to check it out, there is no point in taking it apart without the parts to fix it and EBC springs are both cheaper and quicker to arrive. 

[BusyLittleShop]

On 8/10/2023 at 11:24 AM, Fastdruid said:

 

Suspect maybe oil so I'm going to change to another brand and see if that helps. If not then its new clutch time. 

 

The holy trinity of science is 1)Reason 2)Observation 3)Experience...
employing those tools we observe that the primary cause clutch slip
are high mileage... mileage is the constant among all of the clutches
that begin to slip... oil type is not a constant... 

 

If you wish 100,000 mile clutch life then you have to invest is some
good old sweat equity... first Mic them to determine if they are serviceable
within the factory specifications...

 

It's a fact that all motorcycle wet clutches will reach a point in
their life and begin slipping... the first signs happen during WFO
throttle (Wide Fooking Open)... Don't be surprised if you tear a part
the clutch pack and note that the plate thickness is well within
specifications listed in the shop manual... What you will notice is
the glazed appearance on the surface on the friction plates...

 

 

Inspect the friction plates for glazing... make sure you have plenty
of material to work with... your shop manual states clutch thickness
in thousands of an inch or mm...

 

First removed the contaminants with Acetone... pick a hard surface to lay
over a 600 grit black dry emery paper... rotate the clutch plate in a
circle... you're just busting the glaze... don't get carried away
remove too much material... You should end up with a friction plate
looks dull like a new one as opposed to a shinny glazed one... recheck
thickness...

Next check the pressure plates for bluing caused by localized heat...
make sure they are not warped... consult the manual for a thickness
range... now removed the contaminants with Acetone and wire wheeled
them to erased the blue and also to generally scuff up the surface...
you should end up with a dull surface free of Blue marks...

[Fastdruid]

4 hours ago, BusyLittleShop said:

 

The holy trinity of science is 1)Reason 2)Observation 3)Experience...
employing those tools we observe that the primary cause clutch slip
are high mileage... mileage is the constant among all of the clutches
that begin to slip... oil type is not a constant... 

 

If you wish 100,000 mile clutch life then you have to invest is some
good old sweat equity... first Mic them to determine if they are serviceable
within the factory specifications...

 

 

Thing is though.... while the bike has 72k on it the current engine has ~31k (26k when I fitted it) and it had the same "odd" clutch slip in that it would slip when cold but as soon as it warmed up it was fine. I swapped the clutch at that point and that clutch now has only 5k on it. 

 

I kept all the plates because they were all on the upper limits for thickness.

 

The brand new clutch did exactly the same as the previous one *AND* the previous engine. It was never a massive concern however because outside of the depths of winter it was already warm enough by the time I'd got to suitable roads! 

 

There are two constants. 

 

1) The slave cylinder (and the master cylinder etc). 

2) The oil. 

 

Now I did find a suggestion somewhere that the gasket thickness was somewhat critical to the clutch so I refitted the gasket between engine and sprocket cover that was previously missing.

 

Somewhat foolishly I didn't test things *before* replacing it but now it slips all the time even when hot. It is however about 11 years since I've ridden it "in anger" and it hence my suspicion that it's the springs that have relaxed over time.  Now I have no idea what rate the springs are but if for example they are 20N/mm then for each mm they've lost in length the clutch has lost 100N of clamping pressure. The "spare" springs are ~1.5mm shorter than they should be, I suspect the ones in there have lost more. 

 

 

 

[rc24dk]

Speaking of oil - any friction reducing oil additives ?

[Fastdruid]

23 minutes ago, rc24dk said:

Speaking of oil - any friction reducing oil additives ?

 

Nothing added. Only ever used "bike specific" oil. 

[Fastdruid]

So,  I was reading this VFR world thread and it got me thinking. 

 

The common denominator between the old and new engines (which both had the same behaviour) was the clutch hydraulic system. 

 

However when I came to returning it to the road the clutch master cylinder was in need of new seals but while replacing them, on inspection the bore was corroded so I replaced it with an newer "recon" second hand one which was claimed already rebuilt with new seals. 

 

It's possible though that some muck was dislodged and pushed back up which has caused an issue.  

 

I'll think I'll have a mess with the hydraulic system tonight,  double check the return port is clear and flush/bleed it through with more fresh fluid. I've got to see if I've got any more spare slaves (the one I've found is seized so will probably need new piston as well as seal) but I'm sure I've got at least one more somewhere!

 

Maybe later a justification for an oberon slave!  

 

 

 

 

[Fastdruid]

Figured rather than more boring talk of clutches could have some more pictures...

 

So, way back in 2004. About 27k on the clock. Crappy digital camera back then. 

 

A couple of years later from the other side (and a better camera). 

 

 

At this point I was commuting ~60Mi a day on it all year round...

 

A few incidents along the way...such as when my taillight fell off...

 

 

And the time the tank rusted through and started leaking fuel everywhere (this is why the current tank has dents, I didn't cause them!)  

 

Until suddenly in 2007 it sounded rather louder. 

 

 

Thankfully I'd picked up a second hand but never fitted and "as new" set of Motad downpipes for the miserly sum of £37 (when Motad were still going and new they were £330!)

 

The HBoL says that to replace the exhaust you need to remove the engine. Apart from this being wrong it was somewhat of an issue. 

 

 

 

[Fastdruid]

Removing the engine did not entirely go to plan. 

 

Firstly I snapped a number of exhaust studs. Somewhat expected but still annoying and something I'd have to deal with. 

 

Worse however was that the front and rear engine bolts *refused* to come out. The fronts rounded off the internal hex. I ended up drilling the heads off, pulling the frame legs apart slightly and then hacksawing the remnants. The rear is a stupid tiny internal hex for a great big massive bolt. I snapped two tools in it before I gave up and cut that one off too. 

 

At this point I had an engine with two seized bolts and a number of broken studs. Second hand engines being cheap I figured it would be easier to get another one than deal with the issues.

 

In theory it would have been. 

 

New Engine #1 had eaten a clutch. No idea how far and wide the debris had spread.  

 

 

 

Of course I found this out *after* I'd fitted it... That engine went back for a refund. 

 

New Engine #2 turned out to be an RC35/37 VFR750K (my bad in at the time not understanding the difference between a VFR750FK and a VFR750K). 

 

New Engine #3 was the winner. Lower mileage and out of a FK. Fully intact with carbs and all ancillaries 

 

 

 

 

[Fastdruid]

By this point the bike had been stripped down to frame and a few remaining items.

 

 

After 67k of use all year round it was as grotty as you might expect. 

 

 

There were a lot of new bits fitted.

 

 I replaced the rear heatshield 

 

Along with a new Motad silencer. For two reasons. First one was that there was a hole in the previous one (if you look at previous photos you'll see the black bandage round it) but also because whoever had originally fitted it had modified one of the clamps and it didn't fit the Motad downpipes. 

 

Unfortunately it seems like all my photos of that are blurry so I won't bother with them.

 

Also brand new rear disc, with chain and sprockets

 

 

On the subject of chain and sprockets when the exhaust went I also discovered I'd been rather lucky. The chain had broken a side plate (photo btw taken months after the chain came off and left outside in the "take to the tip" pile which is why its so rusty) and undoubtedly would have failed soon. 

 

 

 

 

 

[Fastdruid]

From a rolling chassis

 

 

In went the "new" engine 

 

Subframe on. Exhaust & radiator refitted. 

 

New rear brake line.

 

 

Brakes on, plastics starting to go back on. 

 

 

 

 

[Fastdruid]

And that brings us to 15 years ago and 67k on her.

 

 

By this stage it was no longer my primary transport as I'd bought a car so it was "sunny" commuting instead of all year round. This meant that over the next three years I only racked up ~5k (rather than 14k/year)...and then along came our first born, a move to a new house and a new job. 

 

The new job office was closer but 80% of the time was now working from home and the journey to work both wasn't a fun one by bike and it didn't save any time either. Commuting by bike was effectively at an end. Free time was limited and with my riding partner now looking after our baby our weekend rides stopped. 

 

Still managed a trackday together in 2011 when #1 was 1 year old (and seeing as her bike is also suitable for this forum here she on it)

 

Then came along child #2. Nether of us gave up riding, if we had we'd have sold the bikes....but...we just didn't really have the time and it just fizzled out. 

 

The MOT and then the insurance lapsed on the VFR and the longer it sat the more needed doing to get it back on the road. 

 

Probably the last photo I have from when it was road legal in 2011 (and with my wifes bike already hibernating). 

 

 

 

...and that brings chapter one to a close. 

 

 

 

 

 

[Fastdruid]

6 years later and we managed another trackday. We'll gloss over my trackbike as it's a Suzuki 😬 🤣but I borrowed my wifes RVF again for a session or two...

 

 

Anyway, enough exotica. 😍

 

I dragged the VFR out from the damp shed it had been relegated to and the time it spent in there hadn't been kind to it.

 

But of course it's a Honda VFR so....

 

 

From here we started the long road back to being back on the road. Lots of cleaning but although nothing "wrong" when it was put away, a number of problems had arisen while it was stored. 

 

First problem was electrical. Almost all the connectors needed taking apart and cleaning. One of wires to the the back lights on the dash had corroded off. Clocks however cleaned up nicely and a second hand set donated better condition parts. 

 

 

All the aluminium parts had furred up.

 

 

They were all cleaned up.

 

 

All the brackets were rusty.

 

These cleaned up nicely in Evaporust.

 

 

Then painted them to protect them. I'm not trying for a restoration btw hence not bothering to get them recoated. 
 

 

A far bigger problem was the subframe.

 

 

 

I wasn't happy with that amount of corrosion so found a better condition second hand subframe for it.

 

 

 

 

 

 

 

 

 

[Captain 80s]

Sheds...   damp ones...   where bikes (usually) go to die.

 

Good job, and just in time.

[Fastdruid]

Way back when I was commuting on it, one of the radiator grill mounts had snapped off, the grill had then flapped loose and worn a hole in the radiator. I fixed it with some epoxy but the radiator was now weeping from the fins. Not an easy fix. While I might be able to get it repaired it was looking very corroded, the fan bracket was frilly and generally it was past it.

 

 

 

I'd tried, multiple times to buy "decent" second hand rads but they were all junk. Bent, leaking or in one case both. I curse that many years ago I didn't buy a brand new Honda rad at a bargain price of £140 (which even then was about 1/3 to 1/4 of the "list" price) which DSS had for sale. 

 

So I bought a Chinese rad for it. Some time was spent sorting out which of the fans still worked, cleaning it all up, repainting it and then getting it to fit. 

Pretty much the same issues as documented here: 

 

With the added problem that the top tabs on mine were square so needed filing back as well.