Honda XRV Forum banner

1 - 20 of 24 Posts

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #1
Hello all. I've recently got my RD03 back from some major work (at no cost to me) but although it looks great, I have a few problems with running which I hope someone can advise on before I start spending money I don't need to.

The bike run perfectly with excellent mpg before going off for it's transformation, but since it arrived back, it will run like clockwork at low revs, but will not rev high and starts to misfire/lose power. Messing with the choke at high revs doesn't make any difference to running.

The Bike. AT RD03, which has been fitted with high flow air filter, and open race pipe. No other changes.

I have spoken to a few people who suggest that because of the new air filter and pipe I will need to re-jet the carbs, and I have also spoken to the guys who did the work, who mentioned that the diaphragms didn't look so good.

I've never had any re-jetting done in my life, so have no idea of cost, and a search on the forums suggest that replacing the diaphragms could cost £100 upwards.

So, my questions are...Where to start, or how can I determine if it needs re-jetting.

I guess I only need to look at the diaphragms, but anyone got any good ideas?

Cheers

Bob
 
G

·
Never done it myself, but you need to rejet when replacing the exhaust and airfilter.

Don't know about the diaphragms.

Cheers,
T.
 

·
Complete Member
Joined
·
3,904 Posts
Bob
I have also got an RD03 with a free flow exhaust and cafe racer style mesh air filters direct on the carbs, I don't know if it's been re-jetted, but it runs fine if a litle on the lean side, 60 mpg average and pulls 90mph on the motorway (and a few other places too :twisted: ).
has a huge flat spot if you rev to 70 mph and then drop off the throttle, but picks up again after a few seconds.
Had problems starting it this morning, doesn't seem to like being stood still for more than a day, suspect this may be to do with the charging/ ignition circuit? (and the cold air at 6:30 am)
pops, farts and crackles like crazy at low revs or if I shut the throttle completely (overrun), would be very embarrassing, if I gave a sh*t :lol:
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #4
Dilbert

Thanks. Perhaps I'll start with a visual inspection of the diaphragms, then take it from there.

I'm reluctant to trust any of my bikes to "so called bike mechanics" as I always seem mostly disappointed with their work, or gutted at how much they've charged me. To this end, if I can do it myself, even if it costs the same, I'm much happier.

I have another bike with open pipes, and when it gets it's silenced alternatives fitted each year for the MOT, it runs like a dog, so I guess getting it right with the RD03 will reward me in the end.

Now, where's that hammer?

Thanks again

Bob
 

·
Registered
Joined
·
34 Posts
big jets

Yes you do need to re jet the carbs, i have done the same mods on my bike and it needed a main jet ten sizes bigger than stock, it now runs very god and the fuel mix is perfect (i have had it on a dyno run) the work is not hard to do it just takes a bit of time because you need to take away a lot of things to get to the carbs, but it sure is worth it :D and your engine will live longer to
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #6
xlv

Thanks for the info. Can you give me any more detail, like, did you get the additional parts from Honda or elsewhere, and what were approximate costs?? Obviously I need to go down this route after I've checked the condition of the diaphragms (which I've been told to do) and is it necessary to put it on a dyno?

Cheers

Bob
 

·
Registered
Joined
·
34 Posts
well

Yes you can get jets from a honda dealer but there is aftermarket parts to, since i live in sweden i cant say how much this will cost you, but it should´nt be to bad i think. A dyno run is a god idea but you dont have to do it. when the carbs are rejetted take the bike out for a spin, let it warm up properly then you take it to top speed for a while, if everything is fine the top speed should be a little higher than before the adjustment and you should feel that the engine pulls a little bit stronger throu the whole rev range. hope this explains it some for you it´s a bit hard to get it right for me in another language and all.
I also read a magazine cald streetfighters and at the back of those ther is a lot of companies that deals in engine work for example BIG CC racing, tts-performance and so on, they seem to have a god reputation among streetfighter riders, and for a dyno run have a chat with SUSSEX ROLLING ROAD at 01903531750 or DOCKGATE MOTORCYCLES in southampton at 02380571200 or MB CUSTOMS east sussex at 01323 743733

best regards Micael
 

·
Complete Member
Joined
·
3,904 Posts
Bob
Our Swedish friend has hit the nail on the head, if you want to get the carbs set up properly then a dyno tester is the best way to do it, as the main, idle and needle jets all do different things you may find you just need to change one of them and the others can be adjusted? a dyno run will confirm this (but it won't be cheap!).
K&N advised me to do this if I was going to be stupid enough to ignore their advice and fit the mesh filters, but I'm just too much of a cheapskate to splash out on this just yet.
I've got a 12mm Colortune which I'm going to use to see what the mixture's like across the rev band, My tax runs out end of October so I'll just run it on the weekends till then, I don't do winters anymore so I'll take the opportunity to strip it down re-paint the frame and re-build it a bit differently, maybe as a single seater? because I don't have a lot of money to spend on mine the overall style is going to end up pretty much the same and I'll be leaving stuff off rather than buying lots of new bits.
Speaking of which on your "project" they didn't just bin the plastics and fuel tank and strap on bits from the new FMX did they!?
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #9
Thanks for the replies chaps.

xlv. Thanks for the info and contact information, I shall be giving them a call to get some estimates.

Dilbert. I'm afraid to say that I think they may have binned the bodywork, which is a shame as I had already promised modrover he could have any bits he required which were left over, as he is already in the US and thats where the work was done. Unfortunately, he didn't have any luck when he contacted the chop shop. The work they did is of a very high standard, even though they had many problems, the main one being the RD03 was never imported to the US or UK, so they had a lot of problems sourcing parts and apparently had to get Honda US involved in a biggish way. Everything has been powdercoated, and they have modifed the frame to accept quite a few Honda CRF parts. The show is on in a couple of weeks, so I'll finally get to see what they did in the workshop, even though I'll have to suffer the humiliation of what they did to me at the same time.

Thanks again

Bob
 

·
Registered
Joined
·
34 Posts
hows it going

Just out of quriosity, have you gotten any prices on dyno runs yet? or have you solved the problem allready?

/Mike
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #11
Hello xlv

I've been a bit lazy getting the bike sorted, but have casually been making some enquiries. I exchanged emails with the guys who did the engine work and said the diaphragms were looking bad, and they recommended one of the following options...

1. Fit a stage 3 kit, re-jetting and having it set up properly on a dyno.

2. Fitting some Kehin FCR Flatside carbs, and having them set up properly.

3. Fitting carbs for an NTV 750 Hawk (remember this advice is from the U.S) and having them set up.

So, here's what I've done so far...

1. I contacted a DynoJet dealer who told me that they do not make a stage 3 kit for an RD03 XRV650. HMMmmm!

2. Amazingly, I just happened to check eBay, and there was a UK guy selling a pair of FCR Flatsides for an NTV, which had been set up for a 650. I watched the bidding which ended "Reserve Not Met" at almost £300. A bit too pricey for me, with my current out of work situation.

3. The advice from the US was to fit some (NTV) 750 carbs, so I'm now wondering if fitting a set of RD04 carbs could be fitted and set up OK?

Thats it so far! If anyone wants to comment or add any info or help, it would be much appreciated. I've decided that I AM going to keep the bike (atleast for now) and intend to concentrate on getting the running spot-on. If I can sort that out, I might sort-of reverse the makeover, and try and turn it into a super radical, more updated version of the NXR but with proper Rothmans livery. In my quest for the Desert racer image, and some better instrumentation, I also contacted Trail Tech regarding their new "Lynx" computer. They told me that there is a delay on the release because of a software bug, but unless anyone has other recommendations, I shall probably pre-order one of these units.

http://www.trailtech.net/lynx.htm


Well thats the dream anyway!!


Regards


Bob
 

·
Complete Member
Joined
·
3,904 Posts
Bob
A stage 3 kit is a new main jet, raise the needle valve and putting conical air filters on the carbs, binning all the air filter box and feed pipe gubbins.
This is pretty much what I've done although I haven't done anything to the carbs I suspect it may have already been re-jetted before I got it.
The Dyno run should indicate what needs doing.
the RD04 carbs may fit, but I was advised by Robelst a while ago that these are not the same as the RD03 ones and they may need the same sort of treatment to get them on-song?
Your open pipes may not be giving enough back pressure (causes the valves to stick open at higher revs), mine didn't run very well when I took off the silencer to repair it (well you have to try these things).
 

·
Registered
Joined
·
34 Posts
dynono!

I´ve heard of some of my swedish dudes that the dynojet kit itself is of very poor quality, you´ll be fine with a re jetting of your stock carbs and at a lower cost as well

/Mike
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #14
xlv Mike

I shall take note of the Swedish Dudes comments!

I think as soon as I get some spare time, I'll run the bike to one of the Dyno centres and let them diagnose it. That seems to be the most logical route, and hopefully I can just sort it out first time instead of faffing around!

‘Jag förbliver Eder ödmjukaste tjänare’

Bob
 

·
Registered
Joined
·
199 Posts
Listening to the symptoms you list, it sounds as if replacing the diaphgrams should solve the problem. In any case, if they are holed, its time they were replaced. Many years ago when I had a similr problem with a Kwak GT550, there was a company who sold just the diaphgram rubbers(at a fraction of the cost of the oe part, which would include slides).

Didn't even need to balance the carbs after, and acceleration returned, and fuel was burnt, instead of drunk.

just my .07p(10c)
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #17
Goldie'

Do you remember the name of the company that sold the diaphragms, or where they were?? Or are we talking TOO MANY years ago to be still in existence? ( Those GT550's were around when the dinosaurs roamed the earth weren't they??!!)

I have already email David Silver spares, and am waiting a reply on the price of OEM parts.

Many Thanks for your 0.7p worth!

Cheers

Bob
 

·
Complete Member
Joined
·
3,904 Posts
BobA said:
Do you remember the name of the company that sold the diaphragms, or where they were?? I have already email David Silver spares, and am waiting a reply on the price of OEM parts.
Bob, let us know what you find out, I had mine serviced 'cos it was so far out when I first got it and the diaphragms (?) were apparantly as thin as bat wings!!!!!!!!!
 

·
Complete Member
Joined
·
3,904 Posts
Bob, now everyones stopped taking the piss, here's a reply I got from a local Dyno centre http://www.bikerztyres.co.uk/

we do just a power run for £25.00, this will tell you what power / torque your bike is putting out.
Any tuning work (jetting) is charged at £35.00 / hour, usually you need to budget for at least 3 hours for us to get any significant gain. If the filter which is on now is simply a mesh gauze filter, these are notoriously diffficult to set up on a standard engine (no head work , std cams etc.) A better option would be a K&N style or foam filter.
Regards
Jim.
 

·
Premium Member
Joined
·
7,170 Posts
Discussion Starter #20
OH MY GOD!!!!!!!!

David Silvers just emailed me with the price of the Honda diaphragms, but forgot to ask me to sit down first!

£109.74 EACH! (although this drops to £82 if I'm prepared to wait a few weeks)

I wonder what it would go down to if I patiently waited a few years!!

So, if I need two diaphragms, and possibly re-jetting and a few hours on a dyno, things could start getting a bit expensive.

Hmmmm, I need to get my improvising head on I think!


Bob
 
1 - 20 of 24 Posts
Top