Puzzling engine noise

I have a Malossi tuned 210 that has started to make a very distressing noise. It’s been tuned by Taffspeed and has a SIP Performance exhaust, all fed by a 30mm on a Malossi reed block. It’s run fine up to about a month ago, but suddenly started making a noise like there is dirt in the barrel or exhaust at about half throttle. This noise isn’t there either below or above this point and doesn’t seem to affect the performance.

A few people have suggested that it is pinging, but I had the head off last night and can see no sign of this, also the plug is the correct colour.

I’m open to suggestions as it’s stumped me??

If the fly side bearing has gone you normally get a mass of vibration. Get both bearings changed at the same time while you have the casings apart.

I have tried the needle in the position you have suggested, but with no difference. It leads me to believe it’s something else as the engine was running fine for a couple of months. It could be something mechanical, but it’s hard to hear where it’s coming from when in motion. The only other thing I can think it would be, is the slide on my carb. Also recently there seems to be a lot of fuel surrounding it that appears to be coming out of the overflows. My reed block and carb are all sealed ok, so I think it could be the slide vibrating that could be causing both problems.

Just to keep you informed, I think I’ve found the problem! The flywheel seems to have a fair bit of up and down play (more than my brother’s 200) so I’m going to order a new bearing and seal. Hopefully this will sort the problem.

Made an order today, but not sure if the bearings will be any better than the standard ones. I’ll keep you posted when they arrive.

Fitted new flywheel side bearing and both seals now, but with no change to the noise. It’s a bit annoying now as I was up till half two this morning rebuilding the engine. At least it’s one less thing it could be.

It sounds a bit like when you suck dirt up a hoover. It’s also quite loud and seems to come from the engine side just around the start of my power band.

Hope that’s a little clearer?

I think the fly side bearings go more quickly, or at least they have with me. I have never been able to purchase an original one. The drive side bearings are pretty bullet proof, only changed it once after 22000 miles.

Unfortunately it doesn’t make the noise while ticking over as it would be quite easy to hear where it’s coming from. I could do with using a dyno, but there isn’t one over here. I will get to the bottom of this, even if it means taking the whole engine to bits!

If you cant find what is causing it I think it is probably wise to split the casings and check all the bearings.

If it sounds like a can of marbles then its pinking. Can you describe the noise exactly.

Parts still not arrived yet as I wanted genuine Vespa oil seals. Hopefull will arrive on the Island tomorrow.

[:(] Is it piston slap ? because malssi put a bit in i have been told , my T5 rattle a bit on tick over Richard[:bounce:]

I have a selection of needles and jets so I can richen it up mid range to see if that makes a difference. Someone did say that it may be my clutch, but the plates and springs were uprated when I had the engine done.

What does the CO2 meter do by the way and would a local bike shop have one?

Tried the slide from my brothers carb and no difference. I’m pretty stumped now as I had a feeling that was the problem. I’ve also had a play with the needle and with no affect to the noise. If it’s not the clutch, then I think a complete engine rebuild may be required just in case it goes bang!

Did it cure your problems?