Exhaust fouling 1999 model?

Hi everyone,

I picked up a 5th gen around 2 months ago, and in general couldn't be happier with it. The bike has 43K miles, is in stock form and good condition with plenty of service history. It rides well (although it's my first VFR so have no basis for comparison), feels fast when up and running and doesn't appear to have any flat spots.

The one thing that slightly concerns me is some fouling to the exhaust, and it is a little smellier than I would expect (even for a bike of this age). There is a brown-ish residue on the tip of the end can, which I would describe as more of an oily rather than a sooty texture. It can be partially cleaned off with soapy water and some elbow grease.

I've not noticed this on other VFRs of a similar age/mileage - wondering if it rings any any alarm bells for 5th gen owners out there - i.e., completely normal, or sign of poor running? The bike has been a little hesitant to start unless the fast idle switched up all the way, although I replaced the battery today and this has now improved. The throttle response feels quite wooly below 3k but I understand this is fairly normal for this model.... the only other thing I can think is that the spark plugs could do with replacing and have been leading to a slightly rich mixture (haven't checked them yet).

Could be nothing, I don't know! If nothing else, the staining on the exhaust is a bit infuriating as otherwise the bike is a stunning standard example. Appreciate any thoughts!

Cheers!

 

check plugs - however I always replace them if I feel I need to check them. I suspect nothing is wrong.

 

Took the bike out last night and it’s running better already on the new battery - stronger initial throttle response and livelier all round. This is a surprise to me as I didn’t realise a dying battery can influence the running condition of the bike - after a bit of reading I wonder if the weak battery was impacting on the fuelling somehow... will probably change plugs regardless but already feeling an improvement. Even happier with the bike now!

 

Hi James

Good to hear your VFR is now running better. So it has done 43K miles but you don't mention whether you have evidence of past service history or indicate whether the bike has been used by the previous owner as a fair weather only garage queen or been used regularly. Obviously you may not have had any input from the previous owner in which case it is sensible to assume regular servicing stuff has not been done - and give it a decent service as soon as time and funds allow.

One obvious question is whether the bike has been parked for ages as the fuel will degrade over time and can result in the sort of lumpy throttle response you describe.

Also during extended storage (many months) if the tank was not left full to the brim when laid up then it leaves scope for rust to develop on the exposed surfaces inside the tank - and rust is great at clogging fuel system components.

A weak battery won't help any fuel injected motorbike, once the volts fall too low the pump won't prime and the bike wont start. Hopefully the new battery sorts things out, but you should be aware that these bikes have massive history of charging system problems - this thread says all you need to know...

https://vfrworld.com/threads/how-to-fix-common-regulator-stator-failures.39277/

If it was my 20+year old bike, before planning any long trips, I would certainly arrange for someone to check the vitals - tyres - especially age!, brake fuids, pads and lines, and especially consider buying/fitting to an ignition on circuit a cheap voltmeter - the sort which shows volts as numbers which you can get on eBay for little money. They are rarely super accurate and will not prevent electrical gremlins but should allow you to quickly get a feel for what is normal, so if you see volts fall or rise alarmingly you still have a chance to head for some place safe before the energy left in the battery is drained and you are left stranded at the roadside.

Take Care - ATGATT


SkiMad

 

Hi, thanks for the advice. The bike has some good service history with it. Looking through the MOT hisotry it has been ridden a little every year, and is not showing any signs of corrosion or maltreatment. I can see it's been ridden and serviced at regular intervals, and has had a stainless exhaust fitted. I am aware of the dreaded r/r issues - I was actually given a spare rectifier by the previous owner (he was given it when he bought the bike but hadn't needed it) - I had no reason to suspect he was hiding anything from me as he was somewhat of a Honda enthusiast and takes care of his bikes (including an SP1 which I ogled jealously). The fluids/consumables e.g. pads on the bike have been recently replaced, so apart from the issues I've outlined I was very satisfiied with it. I suspect the guy knew the battery needed relpacing but wasn't worth it from his pov (I'm not too fussed, if this was a dealer I would feel otherwise). It is certainly good to hear about the pointers outlined your reply, thanks a lot. I still have a lot to learn when it comes to maintenance, but I guess older bikes have more to teach us, right?! I have purchasd some iridium plugs so that is next to do on my list. Cheers!

 

these bikes don't need iridium plugs as the standard plugs do fine. However if you have them its worth fitting.

 

good to know, I bought them as they were on sale

 

Some staining on the end can is pretty normal as is a bit of fuel odour; remember these don't have a cat so some unburnt HCs would be normal in the exhaust. Get some stainless polish (I am a fan of Autosol) and that will probably clean right up (don't forget to add some elbow grease).

 

stuff the elbow grease - use a polisher

 

Give this a look also... might improve things......
https://vfrworld.com/threads/starter-valve-synch-revisited.53524/#post-620387

 

Regular cleaning with Autosol and a soft cloth works for me too.

 

Not to hijack this thread but... when I looked into buying iridium plugs for my '98 (several years ago) I couldn't find them. Checked most of the major plug manufacturers and there wasn't an iridium plug available. Who makes an iridium for the 5th gen?

Sent from my SM-G975U using Tapatalk

 

I just ordered some from amazon: https://www.amazon.com/gp/product/B0038NZ5TW/ref=ox_sc_act_title_2?smid=A2F5NN4BGKFD8K&psc=1

they weren't hardly anymore then normal plugs and I plan on replacing mine so why not...

 

Thanks.

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I'm using these plugs in my '99 and they work just fine.

 

I've ordered CR8EIX (https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/46521)

After checking various sites they are not compatible with the 98 VFR... although CR8EHIX are - can anyone vouch for this? I can't figure out what the difference is between these two plugs