VFR750FJ '88 Rear Downpipe Removal

Hi all, I've started some winter fettling on my VFR750, as you do.

The stainless Motad collector box is in good condition, but the front and rear down pipes are corroded. The original Honda silencers/cans are in good condition.

I have bought very clean original used front and rear down pipes and a new stainless Motad 4:1 silencer that fits onto the original spec down pipes - it looks like the collector box is made redundant.

Removing the silencers and collector box was the easy part. The studs on the front pipes were easy to remove as well.

Now the hard part...the Haynes manual advises that the engine needs to be removed in order to replace the rear down pipes. I've read in several places, and been told by those 'in the know', that it can be done without removing the engine.

Can anyone advise if it can be done without removing the engine, and if so, how?

Just to confirm, it's a 1988 VFR750FJ model.

Cheers,

Paul.

 

Not too hard IF you have the right tools.

 

I don't think the FJ/FK was sold in the US so I'm guessing your insight is based on the FG/FH? Later models are not RC24.

Anyhow, care to enlighten me further???

 

Ok, i'll admit that European models are strange to me, but i can't imagine your rear header is any different from my '86 700. Any qualified aircraft mechanic has the tools to do the job without pulling the engine, i believe. :loyal:

 

Every part of the 88-89 exhausts are different than the 86-87.

I believe it's best to pull the rear wheel and shock out, then remove the heat shield to get access to the rear mounting bolts. Then with the front and rear exhaust sections removed, the 2 rear tubes can be wiggled and rotated and pulled down and out.

If that still doesn't work, then the engine mounting bolts to the frame can be removed and the engine pried forward just a tiny bit, just enough to give you room to slide the pipes out. No need to disconnect the entire engine.

You might want to get your new rear down pipes ceramic coated before install to help them last longer as they are mild steel in 88-89 and don't last very long. (the 86-87 down pipes are a mix of stainless and last a nice long time)

Have you tried this forum: http://www.bikersoracle.com/vfr/forum/forumdisplay.php?f=53
Here's a similar thread: http://www.bikersoracle.com/vfr/forum/showthread.php?t=125836

 

Sorry i supplied incorrect info !!

 

No problem.

The exhaust change is pretty darn interesting.

The 86/87 connects diagonal cylinders. Front left to right rear and front right to left rear. They are also routed on the outside of the center stand.

The 88/89 connects similar side cylinders. Front left to rear left and front right to rear right. Then they go through the center stand. The 180* bends on the rear pipes are also a lot tighter.

It's an odd change. It doesn't seem to effect the engines powerband. It's also why the abundant 88/89 center stands won't fit our 86/87 bikes. I still haven't figured out why they changed. Maybe to improve emissions?

 

Thanks, Jason i neva knew any of that ! :tongue: Neva saw one ova 'ere. If they cheaped- out with mild steel rather than stainless headers, not good. Makes '86-'87 better imo.

 

Thanks to all for the help/comments.

I finally managed to fit the 'new' down pipes this week.

It's not hard so long as you have a 10mm socket and an extension bar or two so the rear studs can be reached...assuming you've completely taken the rear of the bike apart!

The old down pipes were a complete mess:

View attachment 31175

The 'new' down pipes with exhaust paint almost finished:

View attachment 31176

Front pipes fitted:

View attachment 31177

Rear pipes fitted:

View attachment 31178

I've had the Showa shock rebuilt by Brooks Suspension and given the swing arm a full strip down/clean.

Let's hope I don't have *too* many bits left over!

BTW, for those that subscribe, my VFR750 is pictured in the letters page in this months Practical Sportsbike magazine.

Cheers,

Paul.

 

Saw your letter, nice find. On the VFRD Forum the guys from Practical Sportbikes are
looking for some 1St gen owners to feature in a future issue.

 

I *finally* got the VFR750 back on the road a few weeks ago, with new front & rear down pipes, new rear brake master cylinder, new 4:1 Motad silencer (the last RC24 one they'll ever make apparently), refurbished rear shock and a *lot* of cleaning up at the rear end.

Photos attached...more to follow!

View attachment 33394
View attachment 33395
View attachment 33396

 

Dunno what happened to the photos in this thread, so here's a few of my VFR750FJ: