I've started to build a RS850 replica from a VF750F chassis and using a VFR750 RC24 engine.
I've replaced the front end with one from a Triumph T595, using this one as it's one of the largest right way up fork set up with full suspension adjustment, I had to extend the steering stem but the bearings are the same size, I'm also having a new top yoke made with a step down to give more fork length. Installed CBR600 front wheel, disc's etc and made some brackets to install a set of 4 pot Nissin's, using Brembo master cylinders for both the brake and clutch.
I've installed the RC24 engine (due to the RC15 engine being shot) with a little frame mod, I had to remake some engine mounting bracket and still have to make the rear one, I'll probably wait untill I've sorted the exhaust out. Tack welded some bracing in around the head stock, started to make up some brackets for the the coils , ECU etc. I've cut and welded some brackets for the rearsets.
At the rear I plan to replace the rear shock with a new adjustable one, I've installed the CBR600 rear wheel and have started to make up the bracket to hold the rear Brembo caliper.
I'm hoping to be collecting some copies of genuine RS850 body work over the next few weeks, but have only just started to look out for a fuel tank as I don't like the look of the standard VF one and the VFR one doesn't fit very well.
I will try and post updates if anybody is interested in the build.
Yes I agree about the forks, I'm planning to try and machine the ridges off them and get some Showa stickers, I would have liked some correct forks but those are out of my budget range. Spent a good couple of hours yesterday making the rear caliper bracket out of 10mm thick aluminium plate trying to mill external radius's by hand (not an easy job).
I'm off to Stafford classic bike show this weekend coming up to see what goodies I can get, i'll be looking at petrol tanks mostly.
Todays update, Managed to obtain a VFR400 NC30 fuel tank but not sure about it's use, it looks about 50mm (2") short might have to look into getting it extended or the standard VF tank altered, I will have a chat the a guy I know which he thinks is going to be easier.
Also attached a photo of the rear caliper bracket just needs some modifications to it and the caliper to allow it to clear the wheel
Neither fit with the air box in place I plan to make the whole area above the front cylinder and onto the carb top casting and the underside of the tank a air box, as it's not planed to be used on the road .I'm not too worried about using no airbox
Neither fit with the air box in place I plan to make the whole area above the front cylinder and onto the carb top casting and the underside of the tank a air box, as it's not planed to be used on the road .I'm not too worried about using no airbox
Hi, I've had a busy week at work so not been able to do much to the RS this week and next week will be even worse, but just to give you an update, I've made some progress on the fibre glass front, met a great guy at Stafford show who has a Genuine RS850 and he was very forth coming with info about the genuine bike, he said he may be up for me to get copies of his body work made. Managed to get the rear brake caliper fitted just need to make a mounting arm for the caliper. started work on the exhaust pipe, oh my life the rear isn't going to be easy, I'm going to order some pre-made bends and other parts and try and mock up a system, still on with making small brackets for this and that, going to order a pair of alloy VFR400/NC30 radiators and that will mean more brackets.
Looks like a long night on the internet shopping is in store for me.
Has anybody got any ideas on trackday tyres 120/17/17 front, 160/60/17 rear
It's either a labour of love or the owner need psychiatric help :491:
Not managed to get much done this week, managed to get the rear brake and wheel sorted and all spacers made up.
Started to order exhaust bends to get on with that, made a little headway with the bodywork but nothing definite yet, I will make the rear exhaust as a temporary job and alter it later if needed, I just need to get some stainless wire for my MIG welder, I'm going to tack it together and then get it TIG welded up.
My plan is to get the engine running in this frame by the end of the year, I'll post some more photo's when there is more progress to see
Hi All, I've had a good result today and managed to get hold of a genuine seat for a RS850, collected it today and the same guy says he has a fairing that he would sell as well but he needs to dig it out, I'll try and get some photo's of the seat in a 1st fitting later this week.
I've been really busy with work so not managed to get anything done over the last few week, but hopefully things should start to move a little. Friday I managed to get a start with the rear exhaust, but part way through ran out of gas for the welder, so I spent a good couple of hours sorting that out.
I need to get my finger out and get some work done or this will take me for ever
I think I've been bad, I have just bid and won these on evil bay, it will involve JUST a little more work to swap the complete front end AGAIN
But they will look a lot better and more in keeping with the time line, so all the work to make the longer steering stem and caliper bracket is now not needed and I will have to make the lot again, hopefully the steering stem will be OK but just got to wait until they are shipped from the USA.
I've not had much chance to get anything done for weeks (works keeps getting in the way, oh the joys of being self employed) Just a quick update then, I've managed to get the VF1000R fork and yokes in, along with the wheel and spacers made to get the wheel centered, I need to sort out the clip on's, and make the new brake adaptors.
I've started to try and teach myself TIG welding and have made a start on the rear exhaust, I need the pig tail in it to gain the length, I've just ran out of argon so that's my next job, get more argon. I'll try and get some more done and more posted.
What are you using to cut the tubing, if I may ask? I recently acquired a really cool vertical, metal-cutting bandsaw (two of them, actually, but I'm only keeping one!) because cutting metal has always been a massive headache for my fabrication projects. Very ambitious to start TIGing on a complex exhaust system, but I'm reminded of a van Gogh quote: "I am always doing what I can't do yet, in order to learn how to do it." (I'm of the same view...)
Sorry nothing as high tech as a band saw only an old fashioned hacksaw with a fine toothed blade in it, and a little bit of filing after to get the edges to meet better, I'm off work today, with everybody else at work I can play most of the day so am getting on with the rear exhaust, I'll post a couple of pics later, writing this with a cuppa tea in my hand. who said men can't multi task?
Gotcha, I was just noticing the little gaps, same as I always got from hand-sawing, which in theory make welding more difficult. But it's good to see that you can compensate for this by spending a bit more time on the filing. In any case, you're doing well!
I'm very interesting about your project ! I tried myself to put an RC24 engine into RC15 frame but I found one major problem.
As you can see on this picture in an other thread RC24 engine in RC15 frame the chain sprocket output shaft is much higher than the stock one (approx 5 cm). Without major modification on the RC15 frame to lower the RC24 engine I cannot align it with the swing arm center bolt pattern. The result is that the chain is sliding too much on the swing arm. More RC24 covers are touching the lower square tube of the frame both sides.
Hi I have lowered the engine into the frame as low as possible, by re positioning the lower engine mounts, an other issue is that the output shaft is shorter on the RC24 than the RC15 engines. It's still a bit high but should be ok
Thanks for that info I'll have to have a good look at RC30 sprockets when I'm ready, I've had quite a good but frustrating week with the Tig welding, some of my welds are ok but some will need tidying up, I've been having trouble welding the rear 2 into 1 joint piece so I've given in and it's gone off to the professionals, started on the front now, I've got one side made up with only slight modification from the standard, I will start on the other hopefully tomorrow and try and get them both into the 2 into 1 collector. I'm just ordering more bends now but it looks like they won't be here until mid next week. I've been looking at silencers and have found these on evilbay has anybody had any dealings with them.
Just note that the RC30 sprockets are narrower than the modern VFR sprockets (not sure about your model), for 525 chains rather than 530 (apparently also called "chain 50" sometimes). And there may be other OEM sprockets out there (that's my graphic, btw); those were just the ones I found in the JT sprockets catalog, I think.
Well thank you for your efforts, I saw it after Seb mentioned the RC30 sprocket for my VF project, I always save things of interest and value....brain is not what it used to be....if it ever was.....haha
I've been very pleased with it (put in RaceTech srintgs and emulators upfront).
I dealt with a man who is an highly regarded suspension guru and works as a consultant for YSS too, visiting the factory in Thailand regularly. The OEM unit is thoroughly shagged...
Thx @trooper1999 for the details about your frame modification.
And thx @JZH and @Forbes for the graphic very helpful.
About the rear shock I gone for a wilbers stage 3 fully adjustable and it works like a charm, great improvement compare to the stock one. For the front a VTR1000 SP1 year 2000 ø41 fork with wheel and brakes.
I think I'm starting to make some progress with the exhaust, I've had a good afternoon. the upper one just needs some spring hooks welding on and the lower needs the left header altering and then on to the silencers.
A little look at the new shock with the exhaust wrapped round it[image: IMG_1857.thumb.JPG.1bfd77368b219511b2eaa8ce3248a754.JPG][image: IMG_1856.thumb.JPG.2d8c4fd3b8f0279b76e9d6f4b769adc4.JPG]
Finally managed to get a little work done on the RS today, made a ruff cut out for the lower silencer bracket, seat mount made just got to make a couple of lugs for the front of the seat.
Started on the rear caliper torque arm (more parts ordered). I've attached a couple of photos with and without the seat fitted.
Sorry all, I've not had much chance to get on line for a few weeks, but I've been pottering with the bike!
Started with the fairing bracket/clock mount, managed to get hold of a set of 125 Honda clocks (not sure what from but they look right), so I've swapped the VFR internals for the 125 ones so all should work OK, New caliper brackets made and fitted along with hoses and front brakes bled. Been on with the wiring alterations and sorting out where and how to mount various bits, ie ECU, fuel pump, starter solenoid etc, trying to cut out all the redundant wiring from the loom.
I've made some good progress with a RS850 fairing hopefully should have a answer on it by the end of May (not easy dealing with somebody who doesn't speak great English).
I'll try and get some up to date photo's posted soon.
Hey Troop, what sort of rear master cylinder is that?
Any info would be much appreciated.
Hi VFROZ, Sorry but I'm not sure of the make, I bought it last year at Stafford Classic bike show for £10.00, I think it's a copy of may be Brembo, I just liked the look of it.
Hi VFROZ, Sorry but I'm not sure of the make, I bought it last year at Stafford Classic bike show for £10.00, I think it's a copy of may be Brembo, I just liked the look of it.
Hi all, I think I need help! with the bike not my mental health😀 this I think applies to all the RC24 owners does the fuel pump run all the time when the ignition key is turned on, mine seems a bit intermittent it runs some times and not others when the engine is not running, I've not had a lot of experience with these bikes so am learning on the fly, but my FZ750 pump runs for a few moments and then cuts out until the engine starts.
So I'm not sure if I've got a faulty pump or it's normal.
The "Fuel Cut Relay" should prevent the pump from working unless it is being cranked for starting or running. It would have to be faulty or jumped to allow the pump to operate when just turning the key on and not cranking. But I have never heard of one going bad in that way. They usually just fail and not allow the pump to run. Many people just bypass them, but I wire in a parallel switch so I can control when it pumps (like after storage when the carbs have been drained) or get home when it fails. It was designed as a safety feature so the pump just wouldn't continue to operate when not wanted.
Just a little update, Friday was my day off so had a couple of hours on the RS, after a few false starts ( sorting oil leaks out that the engine didn't have last time it ran) & with a home made fuel tank we had some life, it ran for a while but I couldn't run it too long as I didn't have the radiators fitted, just got them back today from having the mounting brackets altered so just a test fitting. I have been on with altering the wiring loom mounting ECU fuse box, starter solenoid and trying to find where to put the battery etc.
VFR400 (NC30) radiators with mounting brackets altered, one of the next jobs is the oil cooler, either re mount the standard or sort new one, it should look like this though.
The body work is a copy of the original RS850 parts, I managed to get a set from a guy who has 2 RS's and have had a set of moulds made so I'm now the owner of a correct set of body work, all I have to do is get them to fit better.
I have done the seat and opened out the hole for the rear silencer so that's done, been trying to get the fairing to fit this morning, but it's been on and off, cut a little, refit, and then start it all again, it must have been on and off about 10 times today, trying to get it in the correct position before I make the mounting brackets, oh the joys of making a bike.
Hi All, Today's been a good day, had a phone call to pop a couple of towns away to collect a interesting part from a metalworking GOD, just got home and co
uldn't wait to trail fit it, He has cut and welded the VF750 tank removing the mass of pipework that is the standard fuel tap and filled the hole, he then cut off the original filler cap and made a twin filler setup, I got two alloy filler caps (from a Kawasaki I think) for the endurance look, he also fitted a VFR400R tank breather,.What do you all think?
Hi all, I think I need help! with the bike not my mental health😀 this I think applies to all the RC24 owners does the fuel pump run all the time when the ignition key is turned on, mine seems a bit intermittent it runs some times and not others when the engine is not running, I've not had a lot of experience with these bikes so am learning on the fly, but my FZ750 pump runs for a few moments and then cuts out until the engine starts.
So I'm not sure if I've got a faulty pump or it's normal.
The VFR fuel pump is very simply a relay with a capacitor driven off one of the ignition coils (probably a diode also). When the ign coil "fires" it energises the relay and the capacitor then holds it energised until the next coil firing.
So it *only* runs when the ign is sparking (ie turning over or running). You can as others have said bypass it (I do this for the first start after winter etc).
Hi I have lowered the engine into the frame as low as possible, by re positioning the lower engine mounts, an other issue is that the output shaft is shorter on the RC24 than the RC15 engines. It's still a bit high but should be ok
FYI if you are using the late RC24 engine then the RC36 output shaft is ~13mm longer and a direct swap (Unfortunately the US didn't get the later RC24 model)....You do however also need the RC36 sprocket cover and the clutch pushrod (it's longer).
Plus as a bonus all the important parts on the later RC24 *except* the gears themselves (ratios differ) and the output shaft are shared with the RC30.
Note also that the gear change shaft position also differs between the early and late RC24's (and the ign, and the valve size, and the carb size, and the ign timing...! )
Not managing to get much done this week but have a look at what a proper fuel tap looks like, this array of pipe work has been removed from the VF750 fuel tank[image: IMG_2546.thumb.JPG.1e33d8dba7714f8598cbd18875f258ab.JPG][image: IMG_2547.thumb.JPG.52489009b9b04a08efb893c1c8f6cf14.JPG]
But then you place it in the circuit again right? Should you crash and the engine shuts down, you donot want the pump to continue pumping methink...
:beer: free flowing beer is good, petrol is not!
Oh absolutely, just bypass to test and prime. I wouldn't advise anything other than a temporary bypass although if someone is determined I'd advise to bypass it by running a "normal" relay via a bank (tip-over) sensor (as fitted to EFI bikes as they will quite happily run on their side...until they run out of oil).
Oh absolutely, just bypass to test and prime. I wouldn't advise anything other than a temporary bypass although if someone is determined I'd advise to bypass it by running a "normal" relay via a bank (tip-over) sensor (as fitted to EFI bikes as they will quite happily run on their side...until they run out of oil).
I install a toggle switch in parallel on my bikes which allows me to prime after winter storage and get home WHEN the relay fails.
Just a little update, I've been busy with all the little things alterting a bike needs, ie the oil breather catch tank, alter the steering lock to reduce the amount of travel, trying to sort the screen, making the rear engine mount etc etc all little bit that take loads of time.
I've sorted the guy who is going to paint it for me it should be with him in about a month so that's a big step, as soon as I get it back from him I'll get it apart for powder coating and then start its final build.
At the moment work and family are getting in the way but that's life.
Hi Everyone, I've not managed to get into the garage for a few weeks (family issues), I have managed to get some spanner time this bank holiday weekend, again I've been on with all the little jobs piping up the engine breather into the catch tank, making the battery securing strap and brackets. but the main item I've been on with is altering the seat unit where it joins the tank, I'm trying to make a pattern and then cutting the seat up so I can get it remade, it;s hard to cut up a new seat though. I have put off the painting until I get the seat done. ( I have to go over to the painter to collect my DT175MX tank back after being repaired).
I'm still waiting for the screen to arrive but hopefully it will be with me this week and I will get on with fitting it, while I'm waiting for the seat I might strip the bike and get the frame powder coated and then build it before it goes to paint.
I'll try and get some photos posted just to prove I not stalled with this project.
Not much left of my project now, the frame, wheels etc are at the powder coasters, various other bits are being aqua blasted, should be collecting them all on Saturday and then start the final build.
Hi All, I've just about managed to get my little replica project together and finished (well sort of finished, is a project ever finished), i thought I would post some completed photos and give a little run down of whats what.[image: 20191018_154313.thumb.jpg.2f5c74d27a83b46e6d208c156e8bc7cd.jpg][image: 20191018_154359.thumb.jpg.9e1d43e533255bc2cb00817ebd990950.jpg][image: 20191018_154409.thumb.jpg.7954b1baa945eb5e626633e1ea7f4f70.jpg][image: 20191018_154415.thumb.jpg.0e3712d739f223bef845444e5cee8cfd.jpg][image: 20191018_154429.thumb.jpg.7b37c71a91613a2f7f3422b89165bdc1.jpg]
Just a little info about the bike, Honda VF750F RC15 modified frame and swinging arm using a YSS shock, CBR600 wheels front and rear, Honda VFR750 RC24 engine with hand made exhausts, front cylinders under the bike and the rears out of the seat, VF1000R fork lowers and yokes with VTR1000F (Firestorm) uppers and internals with race springs and internal modification. Altered VF750 fuel tank, altered VFR750 wiring loom.
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