Honda cb350 running issues

A

Andyp

Been Around the Block
Hi DTT,
I'm a recent member on here and have recently purchased a Honda cb350 to turn into a cafe racer.
I have an issue with the engine. It only revs to around 4000 rpm and won't rev any harder? Tick over is fine.
The bike is totally standard apart from some pod/cone type air filters. Would it need rejetting to run these type air filters or should it be OK?
It also won't change past 2nd gear?

Any help is greatly appreciated. :(

Kind regards
 
First things to do are to check ignition timing and compression. If you don't have a strobe light or compression tester, you'll want to buy them. They're necessary tools when owning a vintage bike.
 
Thanks Sonreir, good advice.
More issues to report. My wiring loom from the ignition key connector has burnt out. Unsure why this would be. I did instal some lower wattage lamps could this have caused an electrical fault? The new lamps are 12V 21W.
Maybe I'll just remove the indicators all together?
Any thoughts?
 
Usually a cooking of the wires indicates a short of some kind, but fuses will usually blow first. I've seen it a few times.
 
Yes I checked the main fuse and someone had replaced the 15A with a 30A fuse! To hide another issue I would imagine.
The wire became the fuse and protected the er..fuse. :)
 
The other issue with these bikes , if the CV carb diaphragms are ripped or cracked, the needle slide won't rise. It is like the throttle is stuck. they rise around 4-5000 RPM....
 
Yes it's not sticking at 4000 rpm it just won't rev past that.
Fires up fine and on tick over/idle its fine also around 800-1000 rpm.

I've also replaced the controls for new.

I would post some pictures but for some reason it's not letting me at the moment.
 
I think I may start a build thread as I'm going to be asking quite a few Q's I can see about a multitude of things.
 
Ey up matey, cool bike to start with 8) Was it ok before you changed the filter ?
 
This is the problem I never ran it before starting. It fired up fine but never test road it as it was never road legal.
I had to get it registered and MOT'd for UK roads so took it to my local motorbike shop and they said they balanced the carbs, fitted new plug caps to get it to run correct. They then took it to get it MOT'd.
Started a build thread now with loads of picture if your interested on here:http://www.dotheton.com/forum/index.php?topic=58093.new#new
 
Andyp said:
Yes it's not sticking at 4000 rpm it just won't rev past that.
Fires up fine and on tick over/idle its fine also around 800-1000 rpm.

I've also replaced the controls for new.

I would post some pictures but for some reason it's not letting me at the moment.
Click to expand...

The throttle doesn't stick, the round slides that are lifted by the diaphragm don't lift. It effectively is like a stuck throttle. The Diaphragms can be leaking or the slides themselves stuck from gas residue....You can see if the slides are stuck by manually lifting them, but easiest to remove the top cover and inspect the diaphragm and see if the slides move easily.
 
Hi Just seen your post. Sorry been super busy with work.
I had the cone filters to, but I've since learnt that the standard carbs don't work well with these filters as there is an air intake port at the top of the intake port which gets blocked with these filters. I removed mine and up jetted the carbs and it runs fine now.
 
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