lacking power

[vespasco]

Ive just rebuilt my 225 and have put a few 100 miles on it, running it in again...the only things of note that ive changed are new piston rings.

The problem is I can no longer reach max revs (7300rpm) but only when in 4th.

It revs upto 7300rpm in 2nd n 3rd ok
Is this just lack of power?! Caused by what? How can.I.improve this?

I used same size base gasket, so squish, compression are the same etc. I ve checked the.timing which.im.happy with but may try giving.it a tiny advance to see if theres any.improvement.

Its just not quite as quick an torquey as it was..
After the rebuild ive also had to up my air corrector jet to a 190, which pulls much smoother through the ranges. It used to machine gun /4 stroke its way through the progressional stage and cruising at town speeds of 25/30mph.
I also upped my main jet to a 132 too. Which has proved to be ok after riding wot for 20 minutes.. Wow that drinks some juice then!

Any suggestions as to why it does not seem to have the power to pull me in 4th gear?
(Im already on a diet)!!

[pxguru]

How did the pilot jet work out? What size you end up with?

Can you remind me what gearing you have, or is it all standard 200?

[vespasco]

Stock 200 gearing.
I tried swapping idle jets from 50/120 to 55/160 but I need to get 'in the zone' and concentrate harder when trying to notice the difference as I found it difficult to tell.
I put the 50/120 back in for now. Take off seems pretty clean now I swapped to the 190 air corrector.
I will experiment a little more when I get time and do some more plug chops to make sure.

[partanen]

What if your piston rings still need some pressure to settle properly? Too gentle break-in and piston rings will leak for ever. Just guessing here.

[pxguru]

If it revs as high in 4th as in 3rd it needs up gearing. If you can get 4th gear within 500rpm of the max rpm in 3rd then the gearing is about right.
What are your max revs in 3rd?

[vespasco]

Max revs in 3rd....72/7300rpm
This is true for motor now, and as it used to he..exactly the same in 2nd also... In 1st it would just be crazy!
I think im loosing power somewhere??! But am trying to find exactly where?!
Piston rings maybe. I will look closer.Thanks. Rinning in new rings etc was 1hr @ 40mph, another at 50, another hour at 60, then.open it up. Disappointed. It didnt really.hit 70 which it always used too whenever I wanted
(Maybe a leak in crankcase? Gearbox? Those cases were pretty bashed about when I bought them).
Edit.. Max revs now in 4th gear is 6400rpm, before and in 2nd and 3rd, it reaches 7200/7300rpm

[pxguru]

Nothing wrong with std gearing for a Pinasco, so you just have a few horses loose somewhere. A little leak won't lose this much. What did you set the timing to when you put it back together? The Pinasco kit can run the standard 23 degrees on the 'A' mark without any issue if the carb is set up well. If you are a bit nervous with your jetting, then just adjust back the width of the timing mark (2mm).

[kru251]

I assumed you honed the bore before the fitted the new rings for running in?

Bore Hone

[vespasco]

Thats a good call kru!!
No I didn't.
There was a noticeable glaze too! As I dont own a 'honer' I only thought about.
Ring gap was right on minimal clearance, thats all i measured.
Thats definitely worth a go. Plus I want to weld a cht sensor ring/thread on the head.

As for running 23* on a pinasco 225 without pinging... Possible with the right head...!?
im not so much nervous of the jetting (or timing), just the Pinasco needs a bit of patience when setting it up for all throttle positions in all gears. But yes I do tend to sit more on the bourbon side of the biscuit!
Cheers guys..ill keep ya posted when I get a chance

[pxguru]

Honing Nikasil is a bit of a skilled job A quick go over with some scotchbrite is far safer.

What is your timing at now? I have visions of it being set fully clockwise!

[vespasco]

Thanks
I have loads of wet n dry...what grade would I need? And wet or dry?! ।ैAnd what direction would I sand in?? Up n down the bore??? Or? Im not sure id achieve a 45* cross hatch by hand?
Dont panic! Timing is around 19* but youre right, I do need to finely tune the timing and i do want to advance it a wee bit, until it starts pinging, readjust carb, if still pinging, retard timing 1/2* at a time, readjust carb. Happy daze.
I.just need to check its not leaking anywhere before I start doing it all...and ive had little chance to do that lately.