The VFR that wasn't but now is.

You make a good case 50.
I don't plan on hacking this bike apart (like my hawk) although I want those F2 wheels on pronto. I will be saving anything removed and placing in storage, just in case....
I like the idea of "more rare then an RC30".
This does mean however, that unless I want to cross-reference every o-ring, nut and bolt I will be ordering from wemoto I supose. Unless I find a better source with an actual listing for an 88/89. Anyone..anyone

 

Here is a parts listing for 1998 model

https://www.fowlersparts.co.uk/brow.../year/1988/country/england/colour/all-colours

For obsolete items CMSNL.com and davidsilverspares.co.uk are good sources.

eBay.co.uk will turn up lots of parts.

 

To fit the original silencers you will need to refit the collector box which sits between down pipes and silencers. Unlike the "straight through" design used on the 86/87 models in the 88/89 bikes the gases effectively do a 90 degree turn in the collector and exit out of the side. Exhausts pipes then turn the gases through 90degrees before they enter the silencers.
So effectively a 4-2-1-2 system.

Now for the catch. Early Motad downpipes were designed for their 2-1 exhaust. Later versions were modified to allow use with collector box and original silencers.

Marvin did a good set of look alike exhausts.
Still available at https://predatormotorsport.co.uk/Honda-VFR750F-88-89-Silencers-Original-Style-Black-and-Aluminium/

 

Pic of collector box

 

I have the official Honda Addendum for the 88/89 model but at 9MB it is too big for forum 4MB limit

 

Please expand a bit on this. I'm not sure how a system that takes two 90 degree turns on each side is considered an improvement. Seems more like a packaging and manufacturing concession.

 

The arguement that replacing a 4 into 2 system used in FG/FH with effectively a 4 into 1 system improved the efficiency of the system by allowing all the pulses from the four cylinders help each other in drawing the gases away from the engine.

4 into 1 was configuration used in RC30 from 87 on and all 750/800 VFRs from Gen 3 onwards.

This was effectively a 4 into 1 but with two silencers, fed from a single collector to keep the twin pipe balanced look which was still the style the time.

 

The Motad system is a complete tuned stainless steel system and produces more power throughout the rev range

 

OK. I still think it wasn't very elegant in execution and the center stand fitted as stock equipment played a role in that particular design. 86 - 87 center stands were a Hondaline accessory, and pretty rare now. Single sided swingarms on subsequent models likely contributed to the single silencer configuration as well.

In any case, it obviously worked pretty damn good, but I wouldn't be tracking down and shipping heavy stock parts from Europe just to go back to it.

Cheers!

 

Interesting

The centre stand was standard fit on all years of VFR750s and VFR800s sold in Europe.

 

I threw the center stand in the trash. Just didn't like the look.


Just kidding. lol

 

The 90 - 93 VFR didn't even get a center stand in the states as new. And the Hondaline kit was an abomination. This huge slab of steel bolted to the frame so the stand could mount to it. They were HEAVY. I installed a few at the dealership.

 

Hold my Euro trash beer and watch this.
Thumbs nailed it " stock bigger main jets, 122 & 125" and a#38 for the pilot.
Pulling carbs apart over the course of 7 hrs. I am so slow and I am paranoid about every little thing. Reading and re-reading V4dreams online instructions. Just now am I actually pulling #4 off the rack. Only smoking gun is iffy mains across the board and a filthy #1 filter (not sure of the component name, pick below). Pulled slides and every other thing I can find except the "choke plunger??" on the carb body. Any reason I can't put the whole carb in the sonic bath with distilled water and dish soap? That combo seems to work well on all the parts I have removed and cleaned so far.
The needle and boot look great and relatively new on #4 carb.

For performance, any reason to change out stuff while I am here? I have read #40 instead of #38 for the pilot and 125 fronts, 127 rears mains.

 

soaking carbs in water can cause throttle shafts to seize up solid when stored for a while, best avoided, and water doesn't properly clean petroleum-based crud.

gasoline on a toothbrush does a better job.

 

Forget the Haynes manual, good but not perfect would be my assessment.

Down load the much more extensive Honda Workshop Manual from Carl Salter (RC24) and read in conjunction for the Addendum ( Section 25) for the 88/89 model.

 

I’ve put #40 pilots in but as the plugs looked perfect I left the main jets alone, unless you’re going to dyno it then leave it alone

 

Naptha/kerosene/mineral spirits good for greasy stuff too...... I usually use 50/50 water and Simple Green in the ultrasonic cleaner, along with a tablespoon or so of Dawn dishwashing soap.

 

I would go up on the pilots. Mains not likely critical, I agree with thumbs, but if it was my carbs with that exhaust (planning on a thru race can) and perhaps going to run a K&N, I would bump each one up a size. Plus if they are staggered sizes, you can just move 2 and only have to buy 2. I think that's a pretty safe move in my experience. .5mm shim under the needles wouldn't hurt either.

I've done more than a few of these, but I also realize every bike and conditions can be different.

Keep being methodical, when you get thru these carbs it is a big sense of accomplishment. And you realize, they're really not that hard.

Good job.

 

The bike already has a KN, that cleaned up real nice with a hand washing.
The pilot screw (long needle tip with small spring, o-ring, and washer) on #4 was also at 4 turns out. We want those at 2-1/2 correct ? O-ring was early flat.

 

If somebody thought that the screw needed to be 4 turns out, I would up the pilot for sure. 1-3/4 to 2-1/2 is the sweet spot. Sometimes when the screws are at 4 turns, there isn't enough spring pressure to keep them from vibrating out and you find them in the V of the motor when it starts running really shitty. Seen it many times.