Punsun starter upgrade - Beware!!

[sno-bro]

I'm on the finishing touches of my Punsun V2 Dnepr build, and did some test runs already. Everything was very promising! Everything works close to what I've expected.

Today I run into some serious problems and the bike is now down for some time. This a word of warning for anyone thinking about upgrading the starter!!!

This is what happened:

I have a 2007 model 840cc Punsun V2 engine that had the original non-geared starter. It had some difficulty turning the engine over, so I ordered the improved geared starter from China. It is definitely stronger, and I've had it on for all of the testing so far. All the time there was a bit of a whine from the starter area, but I didn't pay much attention as the short test rides where quite exiting and I had a lot of other things to think about.

Today the bike at speed suddenly seized for an instant, and the noise at the starter got really bad. I stopped the engine and pushed the bike home. Here is what I found:

Teeth missing from the starter ring



and the starter had seized and teeth were badly worn.

After some investigation I quickly noticed that the old and new starters have different dimensions after all, old on the left, new on the right.



Due to the difference the starter gear is engaged with the starter ring all the time, and will turn when the engine is running. There is a one way clutch in the starter which prevents the actual motor from turning, but the one way clutch will heat and seize after a while, which caused the whole catastrophe.

So if you upgrade the starter you'll need to do some kind of a spacer to move the starter back.

As you can imagine I popped my first beer... It'll be a day or two before I start to dismantle the bike, need to order parts... I'm depressed already. Maybe another beer?

sno-bro

[alexanderfoti]

Thats a shame!

I often thought about getting a geared starter, as I often have the wind the starter up with the decomp lever to build enough momentum to turn it over.

Does the geared started retract the gear using a solenoid in the same way that the non geared one does?

[sno-bro]

Yes it does. This is where I messed up as I thought the starter is a constant mesh type. It is not, a solenoid will move the gear forward considerably during a start.

My engine does not have decompression levers, that is why I went the geared starter route. The new style starter is way stronger.

I'll still get a geared starter in the future, I'll just need to adjust it's position further back. I guess by machining a spacer plate or something.

sno-bro

[alexanderfoti]

Ahh Right I see. you could always just put a couple of washers at the bolt whole, with varying thickness to space it out a bit. Where did you get the starter from?

[sno-bro]

yes, you could put a couple of washers, but you'll need about 1cm worth.

I got the starter from sales@vtwinengine.com. He's been on this site also at least on the member introductions. They were very helpful and the prices reasonable.

sno-bro

[alexanderfoti]

Off right I didn't realise it was so far out,a space would be easier thanks for the info

[Rhynri]

I got into the habit of checking old parts to new parts a long time ago when I swapped out a starter on a tractor and had a similar issue. Difference was I was about 12 or so and dropped the starter on my foot doing the second swap. All 85 @#$@#(%*#@$( pounds of it. Lesson learned!

[alexanderfoti]

Hi there

Not sure if you still have the starter, does it have a part number etc? I am finding it impossible to locate one.

[sno-bro]

hi,

You mean the geared starter?

Try sales sales@vtwinengine.com. He was very helpful.

The actual sale was through aliexpress.com, you can see the geared starter for sale there. Don't be shocked with the price, you'll negotiate it separately and it was not as bad as it seemed

sno-bro