You may or may not remember, about two months ago I bought my first bike, an 88 cane and took her apart for an engine rebuild.

The bike already had an overbore (618) when I got it, but I wasn't aware of it until I got hold of a 'new' cylinder block and my old pistons didn't fit. Luckily, the person who sold me the cylinder block still had the original pistons to go with it and sent them to me as well (thanks cbrhead).

I also changed the cylinder block gasket, head gasket, valve cover gasket, piston rings, various o-rings, all filters (air, fuel, oil), spark plugs. Bought an used oem exhaust header (my old one had the mid-support bracket broken, together with a good chunk of that exhaust section) that came with a D&D pipe. Also took the carbs apart and cleaned them.

Put it all back together, reassembled the bike and filled her with new fluids (including fuel). It took a few cranks but she started and was making a beautiful sound... I could tell there was a major improvement from when I got her. What a satisfactory feeling!

I know there are still a few tweaks to be done, particularly to the carbs as I don't have the tool to sync them and may have to do it the traditional way. But I want to consult with you guys and see if what I need to fix may be related to something else I'm missing. She idles nicely, without variations, and if I open the throttle gradually, there's no issue. But if I open the throttle too fast, she spudders and bogs around 4-5k rpm. Sounds like she's either missing air or fuel or there's too much of either.

I soaked up a lot of knowledge from what's available on this forum and it was immensly usefull to me so far. Any further suggestion would be greatly appreciated.

 

given that the last set of cylinders were over, i'm going to say that the carb jets were changed to compensate for increased bore. with that in mind, the jets are bigger than they need to be if you put theengine back to stock dimensions. thus, when you grab a handful of throttle, too much fuel is getting sent(rich condition)and flooding the engine before the it can be burned off before the next cycle.

this is really not a problem per say, becuase you are usinga more open exhuast that can take advantage of increased jet size. but maybe you may want to go down 1 size and see what happens assuming the carbs are not using stock jets. or you can ride the bike as is being mindful that when you are going to grab a handful of throttleto be in the higher rpm range (6000&ltor lower gear at higher rpm where it will not bog the engine down. or roll on the throttle to gradually send more fuel.

you'll have to actually ride the bike and see if after snapping the throttle back and bogging if the engine will pick pack up and continue normally at that throttle opening.

you may be able to eliminate this issue with a proper carb sync. i would do this first before going any further.

 

There's something I didn't think of... Thanks for the input, michigan. You've no idea (or maybe you do) how anxious I am to give it a test ride but the eastern-canadian weather won't cooperate... been snowing here all day today

 

how would I know which size jets I have now?

 

when you pull the float chamber cap off, the first jet that you see sticking out between the floats will be the main jet. there will be a number stamped into the brass. same with the slow jet just after it.

oem slow jet size for '88 is #35.

oem main jet size for '88 is #105.

 

Thanks for the info!

Wish I knew this when I had them open [:@]