SOHC.co.uk Forums > CB500/550

Questions re Yoshi mods

(1/3) > >>

Seamus:
My 500 has had a 605 Yoshi big bore kit fitted and also a cam with a Yoshi grind, it is running standard 4 pipes and airbox. Seems to run well enough, but not had a standard 500 to compare.
Out with some friends and they complain of a smell of petrol when following me, odd because there are no leaks and it runs smoothly and idles well.
Anyone know if the valve clearances change for the Yoshi cam?
Not sure whats in the carbs as I did not do the work, but assume the jets would have to go up a bit.
Ignition is by dyna and is correctly set, but will recheck as I have a new strobe that needs a test.
I know I need to do a plug chop to see how its running, so hopefully this weekend as the weather is supposed to be good.
Anyone with any general knowledge of this conversion as there is not much on the internet.
Thanks in advance

Johnwebley:
I also don't know any information on different jet sizes.
Suggest you check plugs gap etc and  colours. The do runs at 5K.And 7,5K and full throttle.

See what colours you get.
I would think running 600cc on standard carbs would give lots more mid range grunt.But the carbs could strangle it at top end. They would need to pass 25% more air to fill the cylinders.

Sent from my SM-G361F using Tapatalk

K2-K6:
Undoubtedly specific knowledge would help here with straight numbers for jets if anyone has relevant experience.

In the past people have just assumed that things like this "just need jetting up " but the same carbs used for the smaller engine will have a greater volume of air going through them......... Which also takes more fuel from standard jets,  so it's never as big a change as presented or believed.

You can usually smell an old bike or car ahead in a line of traffic currently as most engines don't kick out unburnt fuel,  so it's very noticeable when you follow one that does.

A basic start view could be to get a reading from each pipe on MOT test equipment,  HC (unburnt hydrocarbons) level will tell you straight away if it's really bad.

I know you'd not want to run it lean,  but heading to bore wash levels is just as bad with people not seeing it as much of a risk.

Bryanj:
Depends on the type of cam but i remember the "street" cam needed a lot more advance than a standard cam plus we had to fit a bigger back sprocket as the extra power from the grind only came in at higher revs and low down power vanished

ka-ja:
I don't know about the 500 yohi kit
The 400 to 460 kit would run quite well on standard carb settings, they can then be assessed for final tuning once running, the bigger bore increases power at a lower rev range, the "road and track" cam puts the power band back up the rev. range, it also allowed a one tooth increase in the final drive sprocket to use the extra power.

Navigation

[0] Message Index

[#] Next page