mugello 225 port timing help????

[paulski]

i have latest version muggy 225, 60mm mec crank and port timings are ex:182 transfers :127 and inlet:164 and squish 1.2mm. left packer plate out to get squish right. sterling pipe and sx200 box with 15/47 and oko30mm carb.timing set at 19 degrees... had it dyno'd yesterday and showed 15.9 bhp @ 7000rpm.and 16 torque at same time.... which is not too bad but power curve dips a bit just before midrange so makes it a bit peaky, and that shows on the road cos it feels like a headwind would be a struggle.ie not very torque until topend..... wot would be the best approach, to beef up the midrange punch of the motor,should i widen the exhaust port? or pack barrel up and lower head into barrel??? i noted that at b.d.c the piston crown is 1,5mm lower than the exhaust port floor,so if i pack the barrel this will obviously make this worse which i am sure is not good, do i go for a longer conrod than the standard 107 thats in now??? any ideas or expertise please anyone. also carb needle is a jjh on 3rd clip/122 main. is there a better needle that would cure this?? tried a few but this was best i had.

[jonny snatchsniffer]

sx200/tv175 is probably not the best box to use tbh, gears too far apart, tho with yr port timings ive never had a problem with simmiler cast iron tuned barrels but with 15/46, i found it much better with a pacemaker box with 17/46

[paulski]

sx200/tv175 is probably not the best box to use tbh, gears too far apart, tho with yr port timings ive never had a problem with simmiler cast iron tuned barrels but with 15/46, i found it much better with a pacemaker box with 17/46

cheers ive got a pacemaker box,may give it a go but while engine on bench i want to do whatever i can to get it spot on if poss. to measure exhaust port width should i hold a piece of paper down the barrel against the port and take a rubbing and then place paper flattened out on table and use a vernier,is this an accurate way of measuring width???. i think mine is aprox 68% of bore size, how far can it be widened safely??is it a specialist job cos of nicasil or can it be done with a dye grinder.

[drunkmunkey6969]

Depends how far you want to go mate...how long is a piwce of string etc etc? 16ft-lbs is respectable, but 16bhp is a bit low for a 230cc.

Personally, if it were my scoot, i'd run a different pipe, a close ratio gearbox and have the cylinder ported (the 70% will help, but you have more issues than that).

However...if on a budget, get the cylinder done first....and see how you get on, then try a different pipe...and lasty...if still not happy, split the engine and add the close ratio box that you have.

[paulski]

Depends how far you want to go mate...how long is a piwce of string etc etc? 16ft-lbs is respectable, but 16bhp is a bit low for a 230cc.

Personally, if it were my scoot, i'd run a different pipe, a close ratio gearbox and have the cylinder ported (the 70% will help, but you have more issues than that).

However...if on a budget, get the cylinder done first....and see how you get on, then try a different pipe...and lasty...if still not happy, split the engine and add the close ratio box that you have.

when you say ported are we just talking exh port width??? who can you recommend to do any port work on the barrel??? any suggestions for better pipe???. just a thought but if its more rideability im looking for should i just flog the kit and get a rapido225 or is the muggy gonna do the bis???? is the inlet timing too tall on the muggy with 60mm crank???should i change for longer rod????

[joey]

...i'm well pleased with my ancillotti exhaust on my 200 mugello....mate runs 225 19/47 gp ancillotti.....very good mid range and revs on till it sounds like its goin to blow!