Having problems with pod.. (1100, -92, 1216cc)

[str33t]

Hi, few years ago i had my motor built, bored to 81mm, 13:1 comp 1216cc, yoshi exhaust, otherwise stock. Bike was first tuned/jetted at dyno with K&N pod filters (ru-2922) at it ran great on dyno, on the street not so much. Wind whirls messed up the airflow and covering filter with hand helped..

At that point i converted back to stock airbox. Now, due to new ideas stock airbox just wont fit, what would be the solution to this? Dynojet stage 3? Velocity stacks inside pods to help with wind whirls? 

Help with this would be much appreciated, im bad with carbs.

 

 

[Blubber]

Hi, welcome to OSS. 

 

A grown up will hopefully get you some answers... Soon

[Gixer1460]

I had a DJ stage 3 kit in my 36mm CV's with dual pods and never had a problem with wind - went like a cat with Acme rocket up its arse! 13:1 CR is brave on a road bike, mine was about 12.5 ish and pinked like a bastard up hills in the summer! Some dynos tend to tune too lean and so will run rubbish on the road. DJ needles on the richer side of middle groove and DJ 136's in 1 & 4 and 138's in 2 & 3 - mainly due to hotter centre cylinders...... carbs, DIY exhaust 1186 kit = 144hp which was a result as far as I was concerned.

[banoffee]

42 minutes ago, Blubber said:

Hi, welcome to OSS. 

 

A grown up will hopefully get you some answers... Soon

You haven’t stopped growing yet? 

[str33t]

33 minutes ago, Gixer1460 said:

I had a DJ stage 3 kit in my 36mm CV's with dual pods and never had a problem with wind - went like a cat with Acme rocket up its arse! 13:1 CR is brave on a road bike, mine was about 12.5 ish and pinked like a bastard up hills in the summer! Some dynos tend to tune too lean and so will run rubbish on the road. DJ needles on the richer side of middle groove and DJ 136's in 1 & 4 and 138's in 2 & 3 - mainly due to hotter centre cylinders...... carbs, DIY exhaust 1186 kit = 144hp which was a result as far as I was concerned.

mm.. i have to check the comp ratio, you made me doubt my memory. anyways, it worked like s*it on the road, all above 3-4krpm was unusable unless you covered filter with hand. Reading this guide: http://www.factorypro.com/tech/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

And for midrange adjusting i should play with need height, could it be just that ? If i recall right mainjet was up at the 150-160 range with pods. Damn winter, kinda prevents testing it.

[no class]

...sounds like you are running cv carbs . Your problems with slide lift are common ...... don't waste anymore money on jet kits and other trinkets.....sell off the cv's..... invest in a set of smooth bore carbs ..... you will not regret it !

[str33t]

2 hours ago, no class said:

...sounds like you are running cv carbs . Your problems with slide lift are common ...... don't waste anymore money on jet kits and other trinkets.....sell off the cv's..... invest in a set of smooth bore carbs ..... you will not regret it !

do you mean rs40's etc? and yeah i have cv40, could have mentioned that earlier. Would RS40's solve the problems with airflows etc and then it would be just matter of jetting 'em correctly?

Edited December 16, 2017 by str33t

[dupersunc]

Plenty of people run cv carb and pods with big bore motors. You will end up with a flatspot around 4-5000 rpm but the motor should pull through it. I try to keep the rpm above 5500rpm.

Sounds like you need to find a new dyno man.

 

[Gixer1460]

CV40's have rep for poor tunability and IMO are too big for even 1216 kitted motors unless for outright power / racing although cv's aren't great in racing applications. 36 / 38mm carbs whether cv or RS flatslides work soooo much better on the road. I have FCR41's on a 1460 GSXR and they are borderline ok with that capacity, tried RS40's but they are a bit 'agricultural' in comparison but a rack of TMR40's would be nice for xmas!

[Oilyspanner]

The 40mm cv carbs work well - with the airbox still fitted.  I fitted a Pipercross filter, which is large and very free flowing - I had to use a FactoryPro config 3.0 jet kit to get the needle rich enough to run properly in that area - it gave a big boost over the k and n fitted before the piperx. The 40mm cv carbs take more time and effort to set-up compared to most other carbs, I like them cos - they can give smooth bottom end, strong mid and upper power, plus fairly decent mpg - many times I didn't like them though !  You might be able to get them to work with velocity stacks and socks, but they might take a while to dial in. I found that the carb bowl vent hose length/size has a big effect on the big cvs too.

The GSXR750Rk used 40mm cvs. The GSXR750WR SP used 40mm TMR carbs, which I had on a 907cc special - they were the best flat slide carbs I've ever used

[nlovien]

the original query is ripe for a bit of head scratching - worth stepping back from thinking "carb" and apply a bit of logic

so you got the comparison between with and without the airbox - leads to the presumption about the effects of side winds etc.. - never trust presumptions unless you can rule out all other posiblilites

there's more to the airbox than where the filters are

1) yi got venturi's connecting the carb to the box - you ain't got venturi's with pod filters - so replicate the venturi's - length

2) yi got all them carb breather tubes - where do they go with or without airbox ? - they establish the pressure signals ( differentials) that make the carb work - maybe try running these hoses to different places, different lengths / bores to try and match the effect of signalling from the airbox

3) yi got the plenum chamber effect of the airbox - not so easy to replicate without fitting an air box - but a partial shield around the filter socks - and positioning  the socks away from the venturi inlets are things to play with ( fitting pod filters = you have no effective stand off )

4) yi got the airbox inlet - is it a negative or positive pressure spot - again not so easy to replicate without making some sort airbox

thing is - you know they can work, you have them working - just need to  find the "magic" thats missing when you take away the airbox - and probably go full circle to find that the (or a type off) airbox - is the magic

[str33t]

Yes, i have original airbox still, but upcoming rear-end and seat modifications wont work with "oem airbox look", maybe it really is time for RS40's, quite hefty price for new ones... but this is not atm my riding bike, i have even considered going to EFI someday, but that would require my own garage. I have spare frame im making mods into, and "just swapping" the parts in when rdy, projects.......

 

edit: and good points to think about up there^, i really have to consider about the final solution(s). I know it could be done somehow with CV's, but do i really want to use that time and effort and maybe wrong investments (dj kits, venturi/velocity stacks..) its hard

Edited December 17, 2017 by str33t

[no class]

Dump the cv's and all the related tunning bs / airbox / fucking hoses ..... tmr's are for the rich....but come with the "ooohhh ahhhh" factor ...... rs's are ok but lack the roller slides which make them a bit sloppy.... 36 or 38's are where the fun is......fcr's will get you where you need to be ....37 or 39's.... unless you live at 10k and only ride wot..... go bigger

[jan800x]

I want to use this thread for a question about my 40mm carbs. When everthing is in stock condotion, how long are the breather tubes of this carbs? On my bike are two tubes with different lenghts. I'm not sure if this are the right tubes.

 

Jan