Should add as a disclaimer, lowering the front end wil make the bike twitchy as all hell, I'd try a couple of slow passes to get the feel of it before going full speed

 

i have stock pipes but i drilled 3- 1/2 inch holes in the each of them._.still wandering about the white plastic piece in the airbox above the air cleaner is it a good idea to gut the airbox???? thanks

 

When times are posted, most times it is their BEST time and they admit that not even they can repete it due to air temp, elevation, moisture, rider, setup and so on.

Drilling holes in the pipe and removing restrictions in the air box may require some re-jetting.

Upon reading about my DR Z400, they say I can drill a hole in the top of the air box to let more air in but I MUST re-jet after.

Most of the bikes these days run lean due to emissions requirements. I remember when my brother drilled holes in the box of his 1972 CB750 and he had to re-jet.

 

Hey:

Leave the stock airbox alone, that white plastic piece is the flow control that equalizes the air flow from the airbox to the carbs. If you want to remove the whole box and go to pods you can, but be prepare for alot of trial and testing to get it to run correctly on pods. You will need a Jet kit, shims or Adj needles and new spark plugs, with lots of runs to get it right. Also all vents must be clear in the tank, Carbs should be clean, sync'd and balanced, plus Valves adjusted prior to setting on a rejetting task. By the way what was your 60' time on that run? needs to be 1.30-1.70 range for sub 11 times on that bike. Also the magazine riders are about a 135-160 lbs weight range or less, if you are larger you need more HP to make up that difference, and at sea level or close to it for those times. Lastly where are you located as enviromentals have a big impact as mentioned above on times? Good Luck.

Dub

 

i raced my bike at cedar falls iowa.. im 6 ft at 207 pounds, also i started it up with no aircleaner and the bike wouldnot rev past 5 grand.. so i will leave the air box alone lol .. i do think i need to rejet now after drilling the holes in the damn pipes before the front tire would skim now it seems to come alive on top end and lost down low and som early mid range..that or plug the holes back up or get a after market exhaust... i will dig out my time slip when i get home to give you all the info... that makes sence though me bieng a bigger guy....

 

Just a thought here. For 1/4 mile performance would this be a good time to bypass the fuel pump and go with gravity feed? The fuel pump delivers in pulses. Why not grab all the gas the carbs can suck under vacuum pressure alone. Again, just a thought

 

when i had my carbs off i took the fuel line off and forgot to shut of petcock and fuel ran out so i think it still can run through the pump by gravity..i know im going to change my sprockets for sure... i just wish i could get more out of it,hmmm i wander how much weight i can loose in a week lol...

 

Now you're really getting into the esoteric world of drag racing. Don't forget to drill holes in everything. "Adding lightness" as Colin Chapman used to call it.

 

Surgery??

 

You need this
1987 Honda CBR1000F Hurricane
comes with a wheelie bar