88cc bore kit tuning... help me out! - FIDDY TECH: Help, How-to, Parts & Mods

skidmark · 03-10-2008, 05:58 PM

K, so me and a buddy just installed our 88cc kits (i did all the work while he drank!).

Bikes run and are f-in hillarious to ride, just pop up on the back wheel all the time.

Only problem is that in any gear, at high RPM/wide-open-throttle the bikes bog/chug a bit. I tried adjusting the air-fuel mix screw, and doing whatever else I can, but nothing helped.

2nd issue, the valves seem to tick when you 1st get on the gas (like if upi blip the throttle at a stop), then it goes away as soon as RPM's go up. I'm gonna check the cam clearance to see if it changed during our breakin ride. Other than that, is it normal cuz of the more agressive grind on the big-bore-cam?

Any ideas to get em running smooth all through the RPM range?

Here's what we're running (both bikes are identical with the usual setup):

88cc bore kit (block/piston)
Stock head (stock valves/intake port size) + big-bore cam.
Large carb with tapered intake adaptor + K&N stype pod filter
BBR non-big-bore exhaust (we had these when our bikes were 49cc)
Stock rev-limit-box

This shit is fun, but it was easier to wheelie forever when it was 49cc, shit is way more choppy (too powerful) now, but we'll learn to live with it

*Tanus* · 03-10-2008, 08:29 PM

the issue with the low rpm ticking is probaby pinging, try 91 or higher octane gas.
Ive never tuned larger carbs, but 88's run pretty good with stock carbs,I'd throw that back on

skidmark · 03-11-2008, 03:44 PM

stock carb with stock air-filter or the pod-filter... what jet size do you use?

03-10-2008, 05:58 PM	#1
skidmark Registered User Join Date: Nov 2002 Location: Vancouver Age: 28 Bike: Превeд Gender: Male Posts: 1,469	88cc bore kit tuning... help me out! K, so me and a buddy just installed our 88cc kits (i did all the work while he drank!). Bikes run and are f-in hillarious to ride, just pop up on the back wheel all the time. Only problem is that in any gear, at high RPM/wide-open-throttle the bikes bog/chug a bit. I tried adjusting the air-fuel mix screw, and doing whatever else I can, but nothing helped. 2nd issue, the valves seem to tick when you 1st get on the gas (like if upi blip the throttle at a stop), then it goes away as soon as RPM's go up. I'm gonna check the cam clearance to see if it changed during our breakin ride. Other than that, is it normal cuz of the more agressive grind on the big-bore-cam? Any ideas to get em running smooth all through the RPM range? Here's what we're running (both bikes are identical with the usual setup): 88cc bore kit (block/piston) Stock head (stock valves/intake port size) + big-bore cam. Large carb with tapered intake adaptor + K&N stype pod filter BBR non-big-bore exhaust (we had these when our bikes were 49cc) Stock rev-limit-box This shit is fun, but it was easier to wheelie forever when it was 49cc, shit is way more choppy (too powerful) now, but we'll learn to live with it __________________ Heads, I win. Tails, you lose.

03-10-2008, 08:29 PM	#2
Tanus Registered User Join Date: Jan 2005 Location: AZ streets Age: Bike: xr72,f4 Gender: Male Posts: 2,545	Re: 88cc bore kit tuning... help me out! the issue with the low rpm ticking is probaby pinging, try 91 or higher octane gas. Ive never tuned larger carbs, but 88's run pretty good with stock carbs,I'd throw that back on

03-11-2008, 03:44 PM	#3
skidmark Registered User Join Date: Nov 2002 Location: Vancouver Age: 28 Bike: Превeд Gender: Male Posts: 1,469	Re: 88cc bore kit tuning... help me out! stock carb with stock air-filter or the pod-filter... what jet size do you use? __________________ Heads, I win. Tails, you lose.