Gidday Guys,

As the title suggests, Im putting a 28 motor in my 21 with my 21 carbs. Am I safe to leave the jetting as it was when the carbs were on the 21 motor, or would I be wise to change it? I see from the specs pages, the 2 models have the same compression ratios. Maybe there's more to it than that.

My intention is to put it on the dyno to get it sorted after I get it going OK. Am I right to use what I have for now?

If you have any other comments/advice regarding this swap, I'd be keen to hear them!

Thanks
Richard

If you're using the airbox and standard pipe setup as the 21, then I'd say yes, you're safe. What jet sizes are they out of interest?
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Thanks for that. Yes, it will be the standard '21 airbox and pipes going back on.

Im in the shed today just prepping the '28 motor to go in now, so will post the jet sizes later after i have a look.

Out of interest, is there a common fix to hold the oil pump crank seal in place to stop the little bastard dropping down and causing this grief all over again?

thanks

Dave, the primary jets are marked 128S and the secondaries are 38S. Both carbs have the same.

On the '21 motor before it let go, the top plug would start to take on a hint of tan after a hard ride with the lower remaining black with few deposits.

128's and 38's are std yes. The power jets are different sizes.
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