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by Volker_P
Wed Apr 24, 2019 1:41 am
Forum: Technical Discussion
Topic: RPM ISSUES
Replies: 6
Views: 112

Re: RPM ISSUES

Possibly it does not run permanently on all four. Do your plugs look equal and are your header pipes equally hot? A CB650 on three cylinders seems not to run that poor up to 60mph if you do not know better how it should be. Might be a fuel issue, too. Something like kinked fuel line, tank not clean,...
by Volker_P
Thu Apr 11, 2019 3:27 am
Forum: Technical Discussion
Topic: Guard on sprocket. What is this?
Replies: 2
Views: 112

Re: Guard on sprocket. What is this?

Welcome here! :D The factory sprockets did have this guard at the outside. Probably it should generate some confidence for cases where the chain jumps off the sprocket but I doubt it would be of any positive effect in such case. The most important issue to avoid such problems is to care for correct ...
by Volker_P
Fri Apr 05, 2019 3:16 am
Forum: Technical Discussion
Topic: Tire Recommendation
Replies: 1
Views: 143

Re: Tire Recommendation

I do not have a special brand recommendation but avoid tires that were available in more or less similar type when the bike was new. In particular the rear tire makes a huge difference when it comes to ride around corners. The stock Dunlops turned the CB650 into a dangerous bike where it just rolls ...
by Volker_P
Fri Apr 05, 2019 3:07 am
Forum: Technical Discussion
Topic: 650 LC few small issues and hi
Replies: 1
Views: 113

Re: 650 LC few small issues and hi

Often the rev counter or speedo start to do this before the spindle will quit. Note that the spindles like a bit of lubrication from time to time, too. :wink: Typically clutch slipping happens at high speed in last gear first. If your clutch adjustment is fine, clutch slipping is probably related to...
by Volker_P
Wed Mar 20, 2019 1:51 am
Forum: Technical Discussion
Topic: cold/ first start for the day and fuse issues
Replies: 6
Views: 272

Re: cold/ first start for the day and fuse issues

The CB650 ignition has two independent identical circuits for cylinders 1+4 and 2+3 with the plugs connected in series to one coil ( 1+4 to left coil, 2+3 to right coil). So in case of an electric issue typically both or none of each pair should fire. Anyway it is a good idea to check the cables and...
by Volker_P
Fri Mar 15, 2019 6:23 am
Forum: Technical Discussion
Topic: cold/ first start for the day and fuse issues
Replies: 6
Views: 272

Re: cold/ first start for the day and fuse issues

Welcome here! :D Poor cold start is quite normal for a CB650. Choke is required quite long compared to most other bikes and it easily dies on the throttle without choke when cold, too. For sure you found out yourself, too... :lol: also the revs don't seem to increased with the choke on- there is no ...
by Volker_P
Wed Mar 13, 2019 2:29 am
Forum: Technical Discussion
Topic: How does the engine perform between rich vs lean?
Replies: 4
Views: 269

Re: How does the engine perform between rich vs lean?

The T-vents are usually connected by a T into a single line that further goes to the airbox. The pressure conditions in the carb bowls (and therefore at the jets) depend on the T-vents and what comes behind. From experience of several people here it makes a difference whether they are just open or c...
by Volker_P
Tue Mar 12, 2019 4:56 am
Forum: Technical Discussion
Topic: How does the engine perform between rich vs lean?
Replies: 4
Views: 269

Re: How does the engine perform between rich vs lean?

K&N's usually shift mixture towards lean but your plugs look really all right. With air filters like that placed on positions shown in your pictures pressure conditions at your carbs might become strange, especially when you operate the throttle. Things may even depend on the positions of your l...
by Volker_P
Tue Mar 05, 2019 6:28 am
Forum: General Discussion
Topic: '82 cb650sc project
Replies: 44
Views: 11771

Re: '82 cb650sc project

kerryb wrote:...I have taken a break to refurbish a house. Learned how to lay vinyl plank floor last week and my knees are complaining that I'm on them too much!

I use skating kneepads for this kind of work. :wink:
Often helpful for working on the bike, too. A clear must-have for me!
by Volker_P
Thu Jan 24, 2019 2:19 am
Forum: Technical Discussion
Topic: Cam Chain Guide 1981 CB650
Replies: 10
Views: 720

Re: Cam Chain Guide 1981 CB650

Getting good replacements for this part seems no new problem.
Someone even designed and made his own.
by Volker_P
Wed Jan 16, 2019 2:32 am
Forum: General Discussion
Topic: '82 cb650sc project
Replies: 44
Views: 11771

Re: '82 cb650sc project

Great progress. Now you have a nice, straight top rear frame. The shock mounts look great and I assume it was tough work to make them fit that way. Do the coils still fit at their original mounts with the lowered tank? The piston carbs will not fit this cylinder head if you have the full array of fo...
by Volker_P
Fri Jan 11, 2019 2:38 am
Forum: Technical Discussion
Topic: When to replace valve cover and adjustment cover gaskets
Replies: 1
Views: 725

Re: When to replace valve cover and adjustment cover gaskets

The center cover (and at Z-model and '79 also side covers) are a bit special. The center cover is fixed with two of what you called "weird looking ufo bolts" some time ago. :lol: If you turn them in, the metal step at their bottom fixes and limits their position in the thread. More torque ...
by Volker_P
Wed Jan 09, 2019 5:11 am
Forum: Technical Discussion
Topic: Should I go up .001" on valve clearances as I've read in a couple threads here?
Replies: 2
Views: 677

Re: Should I go up .001" on valve clearances as I've read in a couple threads here?

There is no need or reason to deviate from book specs unless you really know what you do. Special fuel or special cams might be a reason for things like that. If somebody should run into valve overheat problems with book specs, this is probably due to too lean. And this is most probably due to pod f...
by Volker_P
Tue Dec 04, 2018 3:05 am
Forum: General Discussion
Topic: Cb750 ignition
Replies: 5
Views: 2792

Re: Cb750 ignition

You will need a cam for the circuit breaker, too. So the crankshaft needs a modification, too. I think the mount of the pulser magnet is screwed into the right side of the crankshaft so basically it should be removable. Some people here got it out but I think that was not that easy because the part ...
by Volker_P
Tue Dec 04, 2018 2:57 am
Forum: Technical Discussion
Topic: fuel vacuum valve
Replies: 3
Views: 661

Re: fuel vacuum valve

Tommysparta wrote:.. or can I run the bike without the vacuum valve as long as I remember to shut off the petcock.

Yes, most previous models are just like that.
You should plug the vacuum nipple for this valve at the carbs however.

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