Running In Nicasil Barrels

Technical Big Block Tonti and Loop Frame models
1

Hi All,

I’ve just replaced the Chrome bore barrels on my T3 with new Nicasil bore replacement barrels. Would anybody know the running in procedure for this kind of barrel?

Many thanks

Mark

2

Ive fitted Nikasil barrels to my T3 in summer of 2025 - now a 950

Kept to 4000 rpm for the first 200 miles, then 5000 rpm for the next 800 miles . Had to remove one barrel to replace a cam follower at about 2000 miles and change the oil (should have changed it when I fitted the barrels) The barrel and piston were perfect.

Russell

1 Like
3

Thanks Russell. I knew it was not a lengthy process but wasn’t exactly sure how long. Your method will do for me. I went through the engine when I changed the barrels so it’s nice and clean inside.Mine’s also a 950 now. No harm in a bit of extra grunt.

4

I would use a good quality mineral oil for the first 1500 miles- then change with the filter to semi synthetic and do another change after a further 3k miles!.

5

Have you run in a bike like this? I’m pretty good on the oil and filter changes. It was more the rpm limits and for how many miles I wanted to know. Thankyou for your input. It will be taken into consideration. I’ve only just done the conversion and haven’t had it out on the road yet.

6

I’m sure you already know, but it’s a good idea to re-torque the heads after a short while. Maybe 1000 miles.
Ian

7

Funny you saying that. I fitted the heads and torqued them down then left them a week and re-torqued them. I was quite surprised at how much they needed re-torquing from just being left.

8

Yes

3000rpm for first 1k

4000 next 2k

5000 next 2k then gradually up to max but depends on your actual mileage per year as to how patent you can or want to be!.

9

I would need to look it up, but I think the advice I followed was to retighten after an overnight rest, as you have done. Then again after a few heat cycles, and then again at 1000 miles. Not sure if it was in Guzziology or This Old Tractor website.

10

I’ve just found that in the owners manuals it has the running in procedures. For a Spada it’s total is 2500 miles. These have Nikasil plated barrels.

11

Also dont forget to increase the main jet

From Memory an 850 T3 runs a 120 and a Spada a 125 - after a bit of experimentation mine are now 130 or 135

Russell

12

That’s great. Thankyou for that

13

I cant remember if i ended up with 130 or 135 - I had them in and out so many times ! - A 120 and a 125 was definitely too lean.

Russell

14

I’ve ordered some 130’s so will put them in before I start riding it. I’ve had it running and it runs really nicely as it is but I didn’t check the main jet size. I’ll see how it goes with the 130’s and go from there. Thanks very much for the info. It’s always handy when someone else has done it first.

15

Spada has iron bores, not Nikasil. But I don’t think it makes much difference to running-in requirements.
Ian

16

I think you might find the late ones have Nikasil bores.

17

Also its only running in the barrels and pistons, not a whole new engine - 1000 miles is more than adequate.

Labouring the engine at low revs is as bad as too many revs when running in.

Russell

18

Thanks Russell. I have several other Guzzi’s and know they like to be revved. I never slog them about. The 1000 miles sounds a lot better than 2500 miles. That would take me all year.