Q: I own a Yamaha V-Max from the eighties and it was running a bit rough to say the least. So I decided to check things out and replace the spark plugs, air filter and give it a general clean. I have worked on the bike before so I have good idea on how things work and fit.
But when I took off the air box I noticed two of the rubbers that connect the air box to the carbs’ are stiff and well out of shape causing air leaks. I asked my Yamaha dealer to order new ones but they’re not sure if they can get anymore, and it will take forever if they can.
I’ve heard of different ways of ‘repairing’ them and wondered if you guys knew of anything about this issue, I understand they’re old parts and all of that?
A: We’ve seen this problem many times with old bikes because these items always become brittle and perish with old age. But there is one thing you can try.
Take the rubbers and soak them in thinners until they swell up to about ten times their normal size. It’s a bit scary to see but don’t be worried. Then take them out and leave them overnight and you’ll be surprised in the morning that they’re back to their normal size and soft and supple once more.
It’s certainly worth a try especially seeing as they’re hard to find, have a go you have nothing to lose seeing as they’re in such a state?
If any of you have the same ‘rubber’ problem on any sort of motorbike give it a try as well, no guarantee though folks.
Q: I’ve just bought a Yamaha BWS, 2006 model, with 30,000km on the little clock. I’m very happy with it but recently I decided to clean the air filter because of the mileage.
It was indeed very dirty so I cleaned it, oiled it, and washed out the air box, which is a standard one. But now the scooter has become sluggish and oil is dripping out of the air box! So should I now replace the filter for a new one?
Pierre De Wet
A: The stock filter is a paper element and therefore requires no oil. So if it is you’ll have ruined it and it will certainly need a new genuine Yamaha replacement, which aren’t too expensive. After fitting it the stock performance will return.
Also, screw the airscrew in and back out one complete turn, which seems to give a better pull-off in stock trim. You might have to raise the idle a bit to compensate. Give that a try as well?
Q: Hi guys and I hope you all have a great holiday because I’ve enjoyed your site all year so keep up the good work in 2019, I’m sure you will?
Anyway back to my question. I own one of those Honda FMX 650 Supermoto fun bikes from around 2007, I believe. I’ve owned the bike for many years and it’s never given me any problems. However, it’s covered in a ‘thousand’ pipes surrounding the engine in the name of reducing emissions I suppose, and I like to take them all off.
I’ve been told this will increase power and living in Jo’burg, at altitude, it also needs a jetting change because the plug seems to run ‘black’? So is this correct and what sort of jet sizes should I be running to get a bit more power from this old 644cc single? The bike also runs the stock air box and exhaust (filter is clean), in case you’re wondering.
Thanks for your time and don’t get too ‘hammered’, which I’m sure you will.
A: We’ve taken all this emission pipe work garbage off before and on the dyno it makes no difference at all to improving power output. The only advantage there is it tends to save a few kilograms of weight. So we wouldn’t bother unless you desire a less cluttered engine to look at?
Regarding jet sizes we tend to drop the size by around 7 to 8% for our 1500m altitude. So take out the main jet and see what the size is, it will have it engraved/stamped on it, and drop accordingly. We also recommend some sort of less restrictive exhaust because the stock twin cans are also very restricted for emission control. They could also affect jetting so try to do that first and check the plug colour as this could lean the bike off considerably.
Hope that helps and thanks for the comments and have a superb holiday too.
Q: My girlfriend owns a pristine Kawasaki z800, which I’ve obviously become a full-time mechanic for. But I’m not writing to moan about ‘mechanical’ relationships.
She keeps on complaining, that sometimes, the bike won’t start when she puts it into gear before she pulls off, excuse the terminology. I’ve ridden the bike myself but everything seems to be OK from my side. So before we have another argument I thought I’d ask you guys with your wealth of knowledge first?
Hopefully you know of something that can cause this so I can have a more peaceful life?
A: Well this is an easy fix and it’ll more than likely be the side stand switch, as they do tend to give problems on this model and on the z1000 as well. Make sure the wires are connected properly, and maybe try a spot of lubricant on the plunger/stem that the side stand pushed onto first, as well.
Either buy a new one or join the two wires leading to the switch together and see if that cures the problem first. Then we can guarantee that you’ll have a more peaceful life – maybe?