421 Carbs, Pipes, and Clutch

[Z400Banshee]

I'm building a 421 and would like to run dual PWK 35's but I'm wouldering if my pipes will fit with them. I have fmf fattys. Second do i have to get a lock up clutch you around 80hp? I really dont want to but i also dont want it to slip

[Finch]

ported? you could get away with prolly 3hd springs or maybe all 6 my 392 cub did just fine with 3 hds no slippage i would get some different pipes for sure your only hurt performance with those on a cub imo

[Z400Banshee]

thanks for the reply and yes its going to be ported. im looking for mid to top but i want to make sure they will fit past my carbs. Im thinking maybe for toomey t5's if they fit? When I bought the bike it came with the fatty pipes but it was bassically a stock motor

[Finch]

id go with shearers or cpis for the cuby i had t5s and just seemed like they were choked down. and you should be alright with yout carbs brandon at wildcard sells a sweet intake i just picked one up that puts your carbs at a angle to miss pipes works good with shearers

[vulvafan537240]

35's will fit but like finch said, shearers or cpi's will work better with a cub.

[Z400Banshee]

thanks for the help.

 

im having it ported at a local shop that builds race quads.

[n2otoofast4u]

thanks for the help.

 

im having it ported at a local shop that builds race quads.

 

Please do tell there name. We are always looking for a good shop.

[majorcr3]

Like said above...shearers are definitely the way to go(thats whats on my 421 with 35pwks also)  Cpis are also great pipes, though i havent ran them on my 421.  Both are topend pipes.  As for the lock up, if you dont want to go all out direct drive(spendy investment) go with a slingshot lock up.  It will fit right under your stock case and there is a guy selling one on the bhq facebook page for like 125 bucks.  Hopefully your shop knows what they are doing with the porting.  There is a local yamaha shop around me that claims to do great porting, but if you dont know what your looking for they will just do a clean up port and charge you for a full on drag port.  Check into some site sponsors on here, they have great reps and have fast turnaround time with excellent prices.  I have personally delt with cameron at redline, and kevin at HJR.  Both are great guys.  If you live in oregon redline also has a dyno the he can dial your bike in on with jetting and gearing so it is perfect for you.

[Z400Banshee]

What are some good brand name clutches for a 421? Are Barnetts any good? 

[bluebanshee98]

i would not give that shop the cylinders to port....... im not saying they dont do good work but you can be assured to get a excellent port job from one of the site sponsors and you will know exactly what your getting.  shearers or cpis will be the pipe you want for your cub. im guessing your going to be running pods for filters. if not then the shearers will not fit with the stock air box unless they are custom made. cpis will work fine with the air box. imo if your gonna have a cub motor you should run pods, drag port it and use shearer pipes for starters

[camatv]

you dont have to have it "drag ported"  ic cna be ported to suite your style of riding also.  

 

the carbs should fit just fine.  might bang into the pipes on the carb tops but that mostly depends on the intakes you use.

 

a lockup is not totally necessary.  check out the HD clutch kit from driveline performance.  it has stiffer springs and if its too stiff  then work out your clutch grabbin arm....   using any stock springs at all will result in mostlikely a slippy and burnt up clutch..   make sure you get a good billet clutch basket and if necessary replace the clutch boss and preessure plate to have nice new surfaces for your better clutch to work with.

[Z400Banshee]

thanks ill give driveline a try 

[dajogejr]

I have to be honest, it's a good idea to get the trans cut (not full on override, but at least dog removed) to get it to shift.

Once you start making that kind of HP...  in my experience, you may find stiff ass springs to hold the power, but it normally will shift like shit.

If you're gonna have it apart that far, address the trans now.

[camatv]

the trans i do shifts fine with a full driveline HD clutch and a 9 plate nmotion basket in the ole wife's 350cc alky bike... its around 90hp no problem..

 

i have seen a LOT of other modified transmission's shift like do do...   

[Z400Banshee]

I'm thinking I might be right around 80-85HP but I have the whole motor apart right now so you got me thinking about getting the trans cut. I probably will because I dont want to fight it shifting and Im not going to want to pull the motor back out to redo the trans lol. My next question, what does the hinson spring tension basket exactly do compared to a regular hinson basket and can you use different  primary gears on the spring tension basket?