Sheradan Posted September 7, 2009 Share #1 Posted September 7, 2009 Just getting this 83 put back together. The carbs were off, cleaned, 1 new diaphram and slide. All carbs look good. The sync looks good although vacuum seems a little low (29-30hg). Idles great, starts great. When I take it up to 4500-5000 rpm (in driveway, not on road) it starts to miss fire. It appears to be on the 3-4 cylinder side. Any ideas? Link to comment Share on other sites More sharing options...
Thom Posted September 7, 2009 Share #2 Posted September 7, 2009 1st thing that comes to mind is spark plugs 2nd is the leads or caps if you have not put new caps on yet try swapping the spark plug caps , they unscrew from the leads . forgot the simple check , make sure that the spark plugs are tite in the cyl. Link to comment Share on other sites More sharing options...
Sheradan Posted September 7, 2009 Author Share #3 Posted September 7, 2009 Plugs are new, but wires are not. That could be an issue. The sensor hooked to carb #2 checks out fine. Where can I get new wires, or test the ones I have? Link to comment Share on other sites More sharing options...
elag Posted September 7, 2009 Share #4 Posted September 7, 2009 I bought a complete new set of aftermarket wire made by NGK from a local Yamaha dealer. 8 feet of wire (had a little left over) and 4 caps for just under $70 tax included. But before spending money on new wire and caps. Try cleaning the contacts on your TCI unit. Link to comment Share on other sites More sharing options...
Thom Posted September 7, 2009 Share #5 Posted September 7, 2009 you can buy the wire at a auto parts it 7mm none res. or ebay has a complete set caps and wire , but 1st unscrew the caps from the wires , cut a little off of each wire than reinstall the caps . Link to comment Share on other sites More sharing options...
bobcat Posted September 9, 2009 Share #6 Posted September 9, 2009 (edited) Just getting this 83 put back together. The carbs were off, cleaned, 1 new diaphram and slide. All carbs look good. The sync looks good although vacuum seems a little low (29-30hg). Idles great, starts great. When I take it up to 4500-5000 rpm (in driveway, not on road) it starts to miss fire. It appears to be on the 3-4 cylinder side. Any ideas? You mentioned you synced the carbs...Double check to make sure you put all those rubber nipples back on the sync ports.. Edited September 9, 2009 by bobcat Link to comment Share on other sites More sharing options...
Yammer Dan Posted September 9, 2009 Share #7 Posted September 9, 2009 Sea-Foam even if you have cleaned. Set of plug wires on E-Bay now. You can get color yuo want ad shows yellow. About 35 bucks with ends on them. I never checked lately but I think they are the right ends. Link to comment Share on other sites More sharing options...
Yammer Dan Posted September 9, 2009 Share #8 Posted September 9, 2009 E-Bay #390091672499 and they are the right ends in black,red or yellow. Link to comment Share on other sites More sharing options...
Sheradan Posted September 9, 2009 Author Share #9 Posted September 9, 2009 E-Bay #390091672499 and they are the right ends in black,red or yellow. Bought them. Thanx. I just hope that's the problem. The wires did need changing anyway. Link to comment Share on other sites More sharing options...
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