Help swapping hpi cdi from points on Minarelli v1

I have a minarelli v1 80cc polini kit with a mikuni vm20. I just swapped out the points for an hpi cdi and have the timing pretty dang close. My issue is that it is rough to start but once warmed up it is ok. I didnt have this issue with points and now with the hpi cdi it runs hotter. I am able to adjust the timing in either direction but it runs more poorly. I have spent many hours searching many forums and cant seem to find an answer. Some say not to use a resistor spark plug wire with the hpi cdi, which i am using a resistor, could this cause poor spark at low rpms? Does anyone have pointers? Rejet maybe?

Re: Help swapping hpi cdi from points on Minarelli v1

There are plenty of ways to check if it is getting that are well documented. However the advancedness or retardedness does effect ease of starting—find the sweet spot

Re: Help swapping hpi cdi from points on Minarelli v1

🇮🇹💦 Of the Loin /

yes, the resistor impedes electrical flow

so you are effectively shifting the timing curve of your CDI by using the resistor plug

Re: Help swapping hpi cdi from points on Minarelli v1

So i swapped out the restor spark plug boot for a non-resistor style but it didnt make any difference. Then i read somewhere that since the hpi mini rotor is so light it doesnt have the rotational inertia of the stock flywheel. I have the fan bracket and added weights to that to a total of 199.2 grams. That made a world of difference as now it has almost enough rotational inertial at idle to power it through the compression cycle. Hpi sells a flywheel weight of 300 grams that i will be ordering. On top of that i will be playing with timing a bit more.

Thanks for the help everyone!

Re: Help swapping hpi cdi from points on Minarelli v1

Good to know! What other modifications have you done to the motor? Stiffer clutch springs, needle bearings in clutch bell/conrod? Is it wired for running lights and brake lights?

I'm contemplating using the HPI CDI as well, but I think I'd rather settle for the Ducati CDI instead.

Re: Help swapping hpi cdi from points on Minarelli v1

Hello Dmitry. I have installed this kit

https://www.treatland.tv/minarelli-v1-80cc-BIG-BORE-performance-pack-p/minarelli-v1-big-bore-tier-two.htm

With the hpi stator I installed The trail tech ac voltage regulator to help with voltage spikes ( no more blown bulbs). I only have running lights, no 2 fillament bulb or wiring for the brake light (maybe someday)

On the hpi flywheel it doesnt come with a keyway for the woodruf key that the stock flywheel has. I am lucky enough to have access to tools and machinery to make my own keyway on the hpi flywheel. This mod to the flywheel makes small changes in timing much easier because now my flywheel goes back onto the shaft exactly the same every time.

I do plan on getting a performance clutch and needle bearing once i do find one but for now my clutch is completely stock.

I also plan on getting this crankshaft.

https://www.treatland.tv/minarelli-V1-super-stuffy-race-crankshaft-p/v1-stuffy-crank.htm

As for the Ducati CDI I know dont know much other than a pic i saw from treats. The flywheel has a keyway which in my opinion could help immensly with timing, and also it is cheaper.

Hope this helps and i may be able to help more with more directed questions.

Re: Help swapping hpi cdi from points on Minarelli v1

🇮🇹💦 Of the Loin /

yeah, thats also true

the HPI Fan adapter + fan actually makes the idle pretty stable on a v1, its definitely suggested (plus you get air cooling back)

Re: Help swapping hpi cdi from points on Minarelli v1

Yeah i have the fan adaptor and the fan but i dont think that those add up to the 300g of weight. On top of that the stock flywheel weighed in at over 600 grams, so even with the hpi weight i wont be near the stock weight. I will update you guys once i get the weight and try it out

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account