T5 clutch gear

Ive been running a mal 172 with a mickek (122 jet) and cosa clutch for the last 8 mths and have been experiencing the same old problem - not much go in 4th gear.
I been wondering what to do , i thought about changing the exhaust but although its not a cheap option the mickek isnt a bad exhaust. Ive tryed changing jets with no avail. so im thinking about grinding off the cosa clutch gear and replacing it with the standard gear.
Before i put myself through hell has anyone out there done this before and has it improved much ???

Yes: Well sort of -
From what I have heard/read of the Mickek it is a high end (revving) pipe with a high powerband (so is the Mal 172) - you are not hitting the power band in 4th (not surprising with rotary induction,? standard carb? + up-gear). You can either change as many of the above as you can afford, go back to the standard clutch, or buy a 20tooth for the cosa (40 quid?). I’d imagine you would have to be a pretty excellent welder to align the cog right and get the correct clearance (perhaps you are though)

From experience changing back to the original clutch worked in similar circumstances (until I got the rest sorted) - why don’t you try the original clutch first to see if the grind/weld is worth doing?Let us know how you get on…

The old clutch had split thus the reason for changing it , i dont want to fork out for a complete new standard clutch but if its going to help maybe i’ll have to - thanks for your reply anyway.
" FOR SALE - 8 mth old cosa clutch "

See if you can borrow a 20 tooth clutch from someone to try it 1st.

Much better and cheaper option than buying a whole new clutch is to put a 20 tooth drive gear on the cosa…

You could always get the same approximate down gearing effect by running 3.00 X 10 tyres to see if gearing is your problem/ solution - know someone with a smallframe?