172 running in advice

Hi all,

Just fitted a new malossi 172 kit to my T5 classic, also new rear shaft, new cruciform, new crank, new bearings and oil seals.

How many miles should I do running this in and what kind of speeds for first 50 miles / first 100 miles etc.


have a go with a 122 main jet this is what i have in my T5 no problems

me again…

new carb has made absolutely no difference!..

Still struggling to reach anything higher then 3/4 rpm in all gears. Top speed is a max of about 45 mph!.

Someone please help before I am tempted to set fire to the thing!! :

…no it is not normal.

please give me more inf. about your set up, carb, jets,needle and needle clip position, exhaust, timing ecc…

Fuel tank breather hole is definately not blocked… checked that

hi what top speed are you getting

I used to be in ISCA… quite a while ago now though. Is oggy and gilly going to Sandford? Steve as well? Lookin forward to your thing in August down at the double locks… that will be a good weekend.

I might do as you suggest and try a different plug lead tomorrow. There is a new one on there at the moment which I bought about a month ago in an attempt to cure the problem. I’ll try popping the old one back on tomorrow night and see how it goes.

Managed to clock up another 25 miles this evening on the thing though. (numerous laps of Exeter)


if you are sure about your carb set up and timing, you can reach same preatty high rpm on lower speed for the first 50 miles and then you can go 90% of max speed for no more then 5 - 10 sec. for the next 100.
Then it is ok. If something goes wrong is because something it is not well set up in your egine and even if you have driven 500 miles you would have not solved the prob.

Yes… piston is definately around the right way

I know you have tried it before but! if useing the choke(continuasly)it makes it run better in top, not bottom, as it would be rich. would have thougt it was fuel/air.
If no matter what you do to the carb, wont make it rev out, would put down to electrics,can you borrow a running bike to swap parts one at a time? even the spark plug, I have bought brand new plugs, that are shite.
Before you start diconnect the green earth/stop switch wire to the coil(usally the nearst green wire) and if you can, the black and blue wire to the lights(T5 has a connector in the black box on the casing’s)it will basicly eliminate everything apart from the igntion system,then! work your way back plug,cap,lead,coil,stator one at a time.
Or you could just burn it! but save the fourth gear/carb and fly wheel as they will go on the p2!!!

Ermm… yeah… that’s me. [:)] I was there on my dragster… would have been there on Pepsi… if it would have done more than 40!! he he …

Were you there as well? … what were you riding?

Here’s pics of the day if you hadn’t seen them:


Managed to order a new stator from Turners today and it will be here by tomorrow morning… fingers crossed that it will cure the problems.

Not to worry BEERACE! saw you were busy, should see you at newquay!you might be able to relax my then!
matt , That’s me in the action shot!! green gp, last in! you were with terry, Might see you at sanford? hopefully on your T5!!

I think I found the answer to my problems today.

The mixture screw on the carb had actually pushed some of the threads through making it impossible to get a good mixture setting.

Looks like I’m gonna have to buy a new carb. :

Hello again slidingdog.

Yes I am in Devon… Exeter to be precise. I’m going to see if I can borrow a friends stator plate.

It will be about the only part that hasn’t been replaced with new.

If it still doesn’t work after I try a different stator plate… I will be well and truly at my wits end.!!! [:rolleyes:]

Thankyou for the advice so far curare…

I have been out riding it around slowly today, but something doesn’t seem right. It is struggling to go any higher than 60% rpm in all gears.?? I have checked all jets in the carb and all are OK.

Is this normal because the engine is still ‚bedding in‘ as such?


Have you checked the fuel tank breather hole is not blocked also what colour is the plug.

Yep! shhhh, I’m from ISCA!!!
I know it will sound daft, but might be worth going back over the plug/cap/lead and coil,as you might be unluckey enough to have two broken parts!! but does sound like more jetting could resolve it.
mine used a 122 main with modifed head,matched ports, taff pipe and cosa 21 clutch.
At least you haven’t give up!!

Sounds daft but is the piston round the right way?

You must be pepsi matt! were you at the eggesford run?
I’m in Honiton, so if stuck, just ask! but cant do much more than you have tried!!

Hi Slidy, after our intro at Revival I got dragged away to talk about exhausts by Bob. Didnt catch up with myself on the day let alone anyone else, sorry. You should have grabbed me later on. Doing Ozzys 166 at the mo and getting a few dominators packed ready to go, for when the insurances kick in. See you soon, Run From The Scum is next for me. Maxxed out till then!! BRT.