James Henry

The pipe running from under the speedo (fuel tank mounted) is a breather pipe. It connects to a tiny cylinder next to the right-hand coil that I assume is a one-way vent. After that it drops down alongside the front frame to the ground. You should be able to blow through it from the top. I had a similar problem with power loss when revved and randomly when riding. After stripping the pet cock and fuel pump I was happy that fuel reached the carb. All vacuum pipes were removed and blown through. I checked the diaphragm on the carb for holes, that was intact. jets cleaned. Next was the rubber intake manifold under the carb. When removed and flexed it showed a large number of tiny cracks, this would easily weaken the mixture. New one purchased for £40 (a copy, the Yamaha part is around £80). Used RTV silicone sealant on the mating surfaces to ensure a perfect gas tight fit. Fitted the carb back on top but used a jubilee clip instead of the original clip to ensure it was a tight fit. Also found that one of the molded rubber tubes from the air filter to the rigid air box under the tank was also cracked on one shoulder. invisible to the naked eye but showed up when flexed. Used the silicon to seal the crack both inside and out and that wrapped self healing tape over that for insurance. The bike ran better but still had the occasional problem. A friend spotted what turned out to be the problem, one of the coils was short circuiting. He could hear the sparking sound which I couldn't when sat on the bike. All told the bike now runs perfectly and I'm sure my extra inspection helped. It may not cure your problem but it might give you a clue.

Might be a problem if you wanted to get the front wheel off the ground.

Hi Finnerz. Not proposing to cut down the main pipe to the same level as the reserve, just enough so that the bottom of the main pipe filter is level with the top of the reserve pipe filter, i.e. still staggered. My previous explanation wasn't the best!

I've just stripped and cleaned my petrol tap, and replaced the gaskets. The main fuel pipe up into the tank is very long reaching possibly halfway up the tank. It occurs to me that when I'm just below half a tank fuel wouldn't be 'going down the tube' so to speak. I've had instances of engine fade before now and swapped to reserve which cures the problem (it would appear). Should I cut it down so the bottom is level with the top of the reserve pipe? The bike is a Yamaha Dragstar 125 xvs.

None taken. Its been over 35 years since I last stripped an engine and I'm learning, or relearning as I go alone. If something strikes me as useful I'll post it knowing that it's probably old hat to many or alternatively someone will guide me in another direction. Its forums like this that pool knowledge and boy was I pleased to find it. All opinions and advice welcome.

Point taken Campaman however . . . . my problem was I didn't know the size of the internal thread but finding a bolt that fitted and measuring its external thread with the gauge gave me the answer. In essence, I used one to find the other.

A big problem for those whose bikes have no center stand is getting the front or back wheel off the ground. I found this solution for about £36 quid.

Forgive me if this post isn't news but its been a while since I tinkered with bikes so I'm posting anything I find useful. Had to hacksaw off four non standard bolts from the rear frame. They were supplied by whatever company sold the back rest they were holding on. I needed to replace them but had no idea of the size or thread pitch, the standard Yamaha bolts would of course be too short - Then I discovered this handy little gauge. I think its self explanatory.

Just cleaning out the fuel pump and discovered just how well these screwdrivers fit. Bet a Philips driver couldn't do this.

I'll have to admit I didn't know this. Not all screws are the same it would appear - as I was to discovered to my cost. Many of the smaller ones, holding the float bowl of the carburetor for instance are JIS, Japanese Industry Standard. At first glance you would swear (I know I did several times) that they were standard Philips. The giveaway is a tiny dimple or punch mark on the screw head. A Philips driver will fit but it is more likely to twist out or mash up the head. The JIS driver is slightly different in profile and less prone to slipping. Just thought I'd pass this on as I learn from my mistakes.http://www.webbikeworld.com/motorcycle-tools/jis-screwdrivers/

Hi all. Not ridden a bike for over 35 years and decided to go back. Very annoyed to find out I couldn't ride anything above 125. Back in the day a provisional licence would cover up to a 250, my last bike, which was a Yamaha XS 250 twin. However having completed the essential basic training without making a fool of myself I'm now on the road with a Dragstar XVS 125. An odd choice perhaps but a bloke of my age looks a little odd on a street racer type and to be honest, I love the cruiser styling, and of course it looks like a 650 even close up. Sadly the bike is partially dissembled as the MOT ran out and I needed new fork seals and got a little carried away. One of my problems was occasional lack of power and needing the choke to start. I discovered the rubber carb manifold was cracked. I followed the forum and found another who had a similar problem. I managed to get round this using a new rubber self bonding tape, wrapping it tightly around. Whilst bu**ering about I though it would be a good idea to clean the carburetor only to find all the screws had other ideas and remained steadfastly movable. Next I was to discover that these were JIS and not Philips as they would first appear. I'm sat here at home waiting for time to pass and the new screwdrivers to be delivered tomorrow. In my youth I used to strip down my second bike, a Yamaha DT 175 with ease but today I find I lack confidence but I'm not letting that stop me. I hope (know) I shall find this forum helpful and perhaps I can contribute in some small way.