Shudder during gear change? Also, hard to start?

Christian Baekkelund /

So I finally got my Tomos Bullet running, but I'm not sure _how well_ it's running...I'm honestly not sure given how it sounds if how it sounds is normal, abnormal, or what.

In any case, three quick things:

1) Whenever it shifts up to it's second gear at around 18mph, it gives a very noticeable about 2-second shudder as it switches. I replaced the transmission fluid before I got it running, so I know that's new (used Dexron III)....but what could the problem be? Or is that just normal? It doesn't seem normal..

2) I've noticed it is especially hard to start up cold. I frequently have to kick it a good 5-10 times before it will start and stay running...and I have to let it idle for a good 10seconds before I even think of giving it any gas, or it just dies instantly. I'm not overly worried about this, but should I be? (BTW, the spark plug is new.)

3) Overall, I know it's a 2-stroke engine, but it definitely seems louder and to vibrate a bit more than I'd expect. As this is my first moped, perhaps I'm just not used to what is normal and what is not...but is there anything in particular I should take a look at, or listen for?

Thanks everyone...

Re: Shudder during gear change? Also, hard to star

1) I had a Kreidler that did the same thing. It's like the clutches are trying to grab but are slip/grab/slip/grabbing. It may be a matter of using exactly the right weight of oil in the tranny.. and not necessarily the weight that the manufacturer suggests. I'd call an oil company's customer / technical service line because i'm not shy about going to the source.. A Consumer information 800 number is on the back of this quart of Chevron 10/40..

2) Check/see that the idle fuel circuit is clear and the choke plate is actually closing.. It sounds like too much air and/or not enough fuel flow at idle. in other words, the idle mix is too lean.

As far as warmup, assuming the idle has been adjusted to perfection and the carb is clean, waiting a few seconds for it to warm up a little may be just another fact of life..

3) Check for loose motor mounts and tighten bolts on anything that rotates. Bad tires and weak suspension can do it too. Determine if the vibration frequency seems to follow engine speed or road speed. Not a lot you can do about engine vibration except to replace vibration isolation mounts if there are any.

I picked up a parts bike the other day. The previous owner neglected to clean the carbon out of the exhaust. I suspected this because there were several holes poked into the bottom of the muffler. I know it for sure because i later cut open the muffler and a tube was completely blocked. So, check for cracks and leaks and holes in the exhaust system.

Re: Shudder during gear change? Also, hard to star

Go to type f. It has less friction reducers and will grab better. don-ohio

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