markf

Cheers. The BT021 is probably on the rim now - picking it up this evening, but will bear in mind for when the next pair is required.

ok, no suggestions forthcoming. back tyre is Bridgestone Battlax BT020 and nice man at local dealer says to keep front and rear same type. However, can't get BT020 any more for front, so it's gonna have to be a BT021....

hehe - already has one, it's just the rattle is louder at 30mph. I guess the answer is to either ride at more than 30mph, or always do it in first ...

hmmm, ok, I guess that could be good news....or not. I haven't managed to get hold of a workshop manual yet, so I'm working a bit in the dark. I found a few suggestions about primary chains, and also found one for sale here: motorcycleproducts.co.uk part number 409250. The picture seems to be of a double width chain rather than a normal final drive chain, so putting all that together I assumed there to be a chain internally. However, if that's not the case, guess I need to delve a bit further. Rattle has been greatly reduced by adjusting the final drive chain, but is still there. It seems worst when doing about 30mph in 4th. I think that's because there isn't a huge amount of drive going through the chain, yet it's quiet enough to hear clearly. Any other suggestions anyone? Thanks.

Assume you had the wheels balanced, especially after the new tyre was fitted?

Good luck. Suggest you check the other bits first simply because they're easier- open the tank cap to check there is no vacuum; make sure no fuel line kinks. If you have a vacuum gauge, this will give a clue as it won't be possible to get the affected carb balanced with the others, the symptom is similar to having an air leak in the inlet (which is another possibility, of course....). Make sure the carbs are mounted correctly and the inlet tract all the way from air filter to cyl head is airtight. If it is the diaphragm, I managed to repair mine, at least temporarily, by using a small dab of superglue.

My 1990 fz750 genesis will need a new front tyre soon. Any recommendations? Don't want a real cheapy, but running bike on a budget, so good mid-range tyre would be ideal. Not into cranked over high-speed cornering (too darn old <g>), but need something that'll be secure in the rain. Mixture of motorway cruising and country roads with long straights and 90deg bends. Thanks.

I collected my fx750 Genesis (1990) on Friday, and have now ridden about 500 miles. It seemed a bit rattly when I first got it, but this has gradually got worse. It is speed related, not engine revs related. The drive chain needs tightening slightly, but is basically OK, and I'm happy to do that. However, moving the drive chain slightly generates a small rattle somewhere behind the small sprocket cover. Therefore, based on other reading, I reckon the problem is the primary chain. Unfortunately, the bike didn't come with a manual (have ordered one), and this is my first bike with a primary chain arrangement, so I don't really know where to start. Can someone describe, in simple steps, how to change the oil and adjust the primary chain? How can I tell whether it needs replacing? Thanks.

If the bike starts, idles, and revs then there is prob nothing much wrong with the valve timings. If it refuses to rev above a certain range but only under load, then it sounds more like a fuelling problem. I had similar problem with Suzuki GSX250 - it was a tiny tiny hole in a carb diaphragm. This causes the mixture to become too lean under load. It's less noticeable when cold as the choke compensates. However, can also be caused by lots of other things, such as blocked or kinked fuel pipe, dodgy fuel tap, blocked tank breather, etc.