HONDA HOBBIT PA50II Rebuild advice

Hayden B /

Nov 26, 2020 05:08PM

Hello gentleman, so I have finally lost compression on my stock Hobbit, only getting 25psi on My

cornwell Tools Compression Tester.

So after tearing down the motor, the Piston head is scratched as well as the piston sleeve. While I’m this far in to my rebuild I’ve decided to do a complete overhaul and replace all seals and upgrade my internals to give me a little more Speed.

The bike has a PROMA Performance pipe on it

And a TJT Variator with Treats Rumpus plate

Everything else is Bone stock with Points ignition system

Here is everything I’m looking to get

So far please let me know if I’m missing anything

*The DR 70CC 46MM Kit

https://www.treatland.tv/ProductDetails.asp?ProductCode=HONDA%2DHOBBIT%2DDR%2D70CC%2DKIT&CartID=8

*The vm20 Mikuni Carb Kit

https://www.treatland.tv/ProductDetails.asp?ProductCode=hobbit%2Dcarb%2Dpack%2Dvm20&CartID=2

Comes with 22.5 Idle Screw

&

180 Main Jet

*The Stuffy Race Crank kit with seals and bearing

https://www.treatland.tv/ProductDetails.asp?ProductCode=hobbit%2Dsuper%2Dstuffy%2DPARTY%2DTIME&CartID=11

Here are the questions that I was hoping someone more experienced then me can answer

1) I have seen others recommend to start with a 17.5 Idle screw for the Mikuni Vm20 as the 22.5 that comes stock in the Mikuni Vm20 runs rough AND also to start at a 150 Main jet compared to the 180 the Mikuni comes with stock

I know every carb tubing Is different due to location and temps but the stock jets supposedly don’t cut it, someone correct me if I’m wrong please

2) I will be using the stock head which I have heard is okay for now until I buy a upgraded head for it will this cause any significant problems besides the head running a little more hot? Any head recommendations for the DR kit ?

3) is the stuffy race crank worth the price compared to using the stock crank with all the other upgrades listed? Or is the crank something I MUST Upgrade because the stock crank can not handle the other upgrades?

Any info is greatly appreciated thank you for you time.

Re: HONDA HOBBIT PA50II Rebuild advice

Beach Club Nick /

khool1499

Nov 26, 2020 05:09PM

You have to upgrade the stock crank or else it'll snap. They all snap eventually. You didn't mention a gasket set, which you will need

Re: HONDA HOBBIT PA50II Rebuild advice

Hayden B /

haydenpaul1 OP

Nov 26, 2020 05:34PM

Ahh thank you for the advice on the crank, That avoids a future headache! And your right I’ll need a gasket for the crank case correct as I believe the crank itself comes with the crank seals and the DR kit comes with the other gaskets.

I do have a spare Reed gasket from Trick Metric that I can use when putting the reeds back on but I meant to add,

any recommendations on REEDS?

Do I need to run these since I’m upgrading

https://www.treatland.tv/honda-hobbit-pa50-boyesen-power-reed-p/boyesen-honda-hobbit-reeds-mod.htm

Re: HONDA HOBBIT PA50II Rebuild advice

Graham Motzing /

Go to branch

grahammotzing

Nov 26, 2020 06:15PM

I've run hobbits for years with stock crank and never had one break, but I think the tjt, especially if it's setup wrong, puts extra stress on them. Just make sure that when it's fully variated the belt isn't too tight and putting stress on it.

I like the stock carb/ dr/ proma /notched vari setup, gets you into the 50s no prob and runs for ever. I don't really like junk hanging off the bike so I've always avoided the carbs that stick way out.

Yeah you will want to go to the boyesen reeds.

Re: HONDA HOBBIT PA50II Rebuild advice

Aaron Blair /

aaronb

Nov 26, 2020 06:18PM

I second the stock carb with the Dr and proma. Total blaster.

Re: HONDA HOBBIT PA50II Rebuild advice

Beach Club Nick /

khool1499

Nov 26, 2020 06:48PM

Stock carbs are good. I've seen 2 stock cranks snap in 4 bikes with TJT's.

Re: HONDA HOBBIT PA50II Rebuild advice

Hayden B /

haydenpaul1 OP

Nov 26, 2020 07:10PM

I appreciate the advice Gentleman, when I got the bike it had some Chinese clone and the Carburetor I do have on it was the closet thing I found to stock was a Wabron from Treatland

https://www.treatland.tv/16mm-honda-hobbit-pa50-clone-carb-p/16mm-hobbit-clone-carb.htm

Any Jet Recommendations tho Keihin 92-95 ?

It seems like I’ll get everything except the Mikuni Carb as y’all are recommending to stick with the Stock. Stuffy race crank definitely seems to be the move tho I appreciate the info!

Re: HONDA HOBBIT PA50II Rebuild advice

Stephen Keller /

keller_stephen

Nov 26, 2020 09:25PM

> Graham Motzing Wrote:

> -------------------------------------------------------

> I've run hobbits for years with stock crank and never had one break, but

> I think the tjt, especially if it's setup wrong, puts extra stress on

> them. Just make sure that when it's fully variated the belt isn't too

> tight and putting stress on it.

>

> I like the stock carb/ dr/ proma /notched vari setup, gets you into the

> 50s no prob and runs for ever. I don't really like junk hanging off the

> bike so I've always avoided the carbs that stick way out.

>

> Yeah you will want to go to the boyesen reeds.

What jet do you run in that set-up? What speed would you estimate without notching the vario? Looking for 40ish?

Re: HONDA HOBBIT PA50II Rebuild advice

Beach Club Nick /

khool1499

Nov 27, 2020 12:17AM

> Stephen Keller Wrote:

> -------------------------------------------------------

> > Graham Motzing Wrote:

>

> > -------------------------------------------------------

>

> > I've run hobbits for years with stock crank and never had one break,

> but

>

> > I think the tjt, especially if it's setup wrong, puts extra stress on

>

> > them. Just make sure that when it's fully variated the belt isn't too

>

> > tight and putting stress on it.

>

> >

>

> > I like the stock carb/ dr/ proma /notched vari setup, gets you into

> the

>

> > 50s no prob and runs for ever. I don't really like junk hanging off

> the

>

> > bike so I've always avoided the carbs that stick way out.

>

> >

>

> > Yeah you will want to go to the boyesen reeds.

>

> What jet do you run in that set-up? What speed would you estimate

> without notching the vario? Looking for 40ish?

Proma DR stock pa50ii variator is good for 43ish all day. But 50 is really hard to achieve without changing/modifying the variator.

Re: HONDA HOBBIT PA50II Rebuild advice

Mattman MopedHead /

zofeone

Nov 29, 2020 02:16AM

Don’t skimp on hobbit parts. I’ve had the vario side of a crank snap. Lucky it didn’t hit a car or person, flying down street in busy SF. That setup is gonna run hot. Get a bigger head soon as you can. I run a temp gauge. Start dumping money into a hobbit, you at least should know when you’re about to blow it up. Good luck! Down the hobbit hole you go..

Re: HONDA HOBBIT PA50II Rebuild advice

Hayden B /

haydenpaul1 OP

Nov 29, 2020 04:41PM

Great advice! Is there a head you have had good results with on the 70CC DR kit?

I decided to get the DR kit with the Stuffy Race crank so I don’t have to worry about snapping the crank hopefully to soon!

MOPED ARMY

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