Just bought a CR480, and I need help

Hi all,


I just paid 50$ for this ol 83 model CR480, and I'm all pumped up and feel like a kid again! I tore down the top end, cause the cyl ID was .020 past the service limit, and while I'm waiting on the cylinder to be punched out 1mm over, I'd like to order a flat slide Mikuni. I got a pumper TM33 on my DR350, and I love it, but the problem I'm having is on the TM38 Mikuni, the spigot sizes available are 43 and 47, but the factory Kiehn carb measures 2-7/16, or roughly 62mm.


So If I order a TM38, what do I do about the air inlet hose coming off the air box?


I also read the jetting for the TM38 on a 480 is:

320 Main

40   Pilot

Q8 Needle Jet

6FJ40 Needle

4.0 Slide


Not too sure what setting to put the clip on the needle...

Any help would be greatly appreciated. I'm gonna have it running next weekend, but I'd really like to have it breathing through a new Mikuni vs a 30 year old Kiehn


Thanks again!

Get a pwk. Through the tm in the trash

Edited by Kirkes

I have a 38mm flat slide Mikuni  on my '83 CR480 and  have to tell you I am not impressed with it.


As noted by kirkes, I would also suggest getting a PWK in place of a Mikuni flat slide.


Do note that CR480's are a difficult bike to jet, there is a very narrow sweet spot where the jetting is correct. If jetting is a bit off the bike either is pinging or blubbering and running rich. Needle position on a flat slide is very critical.

On the bright side though I am sure there are quite a few people on this board that would sell you a mikuni that they took off their bikes. Heck I'd give you mine, but it is a short body with tps so it probably wouldn't fit. A 38 pwk would be your best bet and you can pick up a brand new one for 225-250. I wouldn't waste my time with a mikuni especially if those bikes are known to be difficult to jet.

I agree with Paul. We have both struggled with jetting on the Mikuni flat slide. A less expensive alternative is a Keihin PJ. Mine ran very well with that one.



I really apprecieate the input. I understand how finiky it can be to get the jetting right, I'm just thankful that at least its easy to R&R the carb. pulling the carb on my DR is a nightmare.


I'm gonna take the advise and buy a 38mm PMK. So can ya'll give me some suggestions as to what # main and pilot jet to start with? And do you think the needle and needle jet will need to be replaced? Maybe I will get lucky, and it will come close already? My buddy works at the Honda house, and I think he might have a jet kit for the Keihin's


Thanks again for the help gentlemen, its greatly apprecieated. I'm gonna post build pics when time allows. Its all stripped down right now. Its a lot of fun, working on this thing. It reminds me of being a kid- good for the soul.

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