restoring 81 650 need guidance

Carbs


And spares

Spares

In the picture of the carbs it appears that the carb holder vacuum ports have tubing attached instead of being capped off (see image below). If that is true the bike won't start. Those vacuum ports must be capped so no air can be drawn in through them. Ed

Does the bike have the stock exhaust system or a 4-1?
By any chance diid you check the numbers on the main jets? stock is 92.5. pod filters would require re-jetting, as they flow more air. larger main jets. maybe larger pilot jets. maybe raise the jet needles. air screw adjustment.

Don't overlook the carburetor synchronization. I very precisely mechanically synced mine using a pair of identical drill bits. the bike ran very good, but I vacuum synced them afterwards.

ps. that air filter appears to be in poor condition.

martin_csr wrote: Does the bike have the stock exhaust system or a 4-1?
By any chance diid you check the numbers on the main jets? stock is 92.5. pod filters would require re-jetting, as they flow more air. larger main jets. maybe larger pilot jets. maybe raise the jet needles. air screw adjustment.

Don't overlook the carburetor synchronization. I very precisely mechanically synced mine using a pair of identical drill bits. the bike ran very good, but I vacuum synced them afterwards.

ps. that air filter appears to be in poor condition.

Has 4 to 1 exhaust. Spare carbs had 102.5 jets and the ones on bike had 92.5 so I switched them already. Do need synced though

And ed I did have caps for them then they must have fallen off during a ride. Tried making makeshift ones with tubing and tape .

Bike

By ogowen: Has 4 to 1 exhaust. Spare carbs had 102.5 jets and the ones on bike had 92.5 so I switched them already. Do need synced though

You're probably going to need bigger main jets (maybe 115 to 117.5), 17.5 pilot jets & the jet needles clipped or shimmed to raise them. The stock 81 650-csr jet needles shouldn't have groove, so you'd have to use washers as shims.

Ignition system pickup plate. just an fyi. It looks like a DynaS. hopefully the bike also has new coils as well.

martin_csr wrote:

By ogowen: Has 4 to 1 exhaust. Spare carbs had 102.5 jets and the ones on bike had 92.5 so I switched them already. Do need synced though

You're probably going to need bigger main jets (maybe 115 to 117.5), 17.5 pilot jets & the jet needles clipped or shimmed to raise them. The stock 81 650-csr jet needles shouldn't have groove, so you'd have to use washers as shims.

Ignition system pickup plate. just an fyi. It looks like a DynaS. hopefully the bike also has new coils as well.

That big on the jets? When it was running it didn't seem too starved of gas but like I said I don't know much about it but I had read somewhere basically 1 jet size increase per "change" ie 4-1 exhaust, pods, etc. And 1 piolet size increase per 2 main increases. And yes it has dynacoils I remember him saying that's why it was parked to begin with was bad coils.

I did search the engine numbers kz650de048771 (on bike) which the number given for an 81 csr is de033101 so I'm guessing? And kz650be120257 (spare) closest I found was 81 for series numbers given for it are be124001.

Also the new ignition pickup plate is on the spare not the one on bike but bike does have new coils

By ogowen: I did search the engine numbers kz650de048771 (on bike) which the number given for an 81 csr is de033101 so I'm guessing? And kz650be120257 (spare) closest I found was 81 for series numbers given for it are be124001.

82 engines. KZ650DE046701- -->> 48771 is after 46701 but before 51401 (83), so the one on the bike is an 82.
The 82-83 had larger carburetor holders.

I think the spare engine is from a 77-80 650, possibly from a 79 650-C3. note roller cam chain in pic.
You should also check the frame number. the date of mfg isn't necessarily the model year.

Main jets & air filters. 102.5 are probably too small. If the air filters are old & clogged, that'll affect how it runs, especially cheap pod filters. some have to be tossed after use. others can be cleaned. some may need to be oiled with air filter oil.