Looking for great performance parts for an Arrow 7hp Big Block

S

Scooterduder

New Member
Hello everyone I'm new to the forum. I'm not mechanically inclined and I'm having the well known KC Vale set up my bike since he's in one of my favorite parts of town and he's so very helpful as well.

Anyways I dropped some huge cash on an Arrow 7hp Big Block and I'm looking for some ideas for an expansion chamber for low and medium range power. I want to accelerate fast from 0-30ish mph. I'm not interested in taking my mountain bike up to 40mph+ at this time. I'd like for the pipe to go downwards so I won't have to worry about burning my leg. I'd also like it to not be too loud and sound nice. I'm looking into a Ghettobike custom exhaust, but I'd rather get a nice premade. Ghettobike is a good company and I have one of their seat post gas tanks.

Also I'm having some customer service issues with Arrow since they sent me a Huafeng carburetor as a late shipment after I received my engine. I was expecting a Keihin 16mm, but it looks like I got a little known Chinese knockoff. I'm thinking screw that I'll just get the best carb I can find on my own. Any suggestions for a carburetor for this thing. Of course a Keihin 16mm would be one suggestion :)..

My bike is a 1999 Trek 930 mountain bike. I'm willing to spend over 200 for the perfect exhaust set up......

I asked Treatland and they were very helpful and sent me these suggestions........hi, we have a few things here that could work if you don't mind a hack and weld pipe. https://www.treatland.tv/proma-grand-prix-ENJOY-POWER-hacker-special-pipe-p/proma-enjoy-power.htm this one looks to have a close angle to the pipes i saw on the arrow site, we also have the motobecane pipes that also have a close angle. https://www.treatland.tv/motobecane-doppler-pipe-av7-av10-p/motobecane-doppler-pipe-av10.htm https://www.treatland.tv/motobecane-giannelli-exhaust-pipe-p/motobecane-giannelli-pipe30917.htm also this mb5 proma looks close too.


The Motobecane Doppler looks awesome, but I don't know how that would work out.

Thanks so much for your suggestions!brnot
 
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You should try and make it to socal MB races on May 6th at Willow Springs. You can see alot of options for your build.
If you wear pants while riding you won't burn your leg.
I think you will find the stock ignition the best for your needs.
Get a bigger expansion chamber like KX 65 or 85 and have it made to fit your MB. The Arrow engines kick a$$.
You will have no problem hitting 30 real quick!
 
Scooterduder..... you should have build your own motor and got a faster motor than that at a fraction of what you paid for. But as with all things, when you're not able to do it yourself, others will charge an arm and a leg for the service. But screw that though, they didn't even send you the right carb and I've read your other thread..... the seller just took your money and ignored your calls. Eff them and their ridiculous over-hyped over-priced motors.
 
I have built a few case inducted motors like the ones arrow builds. I use a Zama 22mm carb. on mine and it work real good one of my bikes goes 45 to 50 mph. The Zama carb. goes on a 98cc chainsaw it is more than enough for this motor. If you want to see my motor go to this web sight and at going case inducted too or ron344 thread.
 
Thanks Potato, it's true about the DIY vs others doing it. I took the easy though expensive way because I don't have the knowledge myself and it seems like only a few places online are known to modify these engines with a few reviews here and there. I think I'll have a fun little ride soon once I get my stuff assembled, but I wouldn't do it again.


Yes Dave Rust has shown himself to me to be a real cheapskate and cruddy businessman that sent a happy meal fuel filter to me with my $700 purchase while he sells nicer $10 metal ones, and then thinks it's also ok to send me a late shipment of a cheap clone (Huafeng) of the Keihin carb that's supposed to come with the engine. I bought my own Keihin on Amazon for 20 bucks, just because. Dave could have done that and I wouldn't have been pissed off.
 
Hey Ron344, Just out of curiousity would that Zama 22mm carb work on my set up? I'm not a mechanic of any kind. I can just do basic basic stuff. I'll probably use the carb I bought on Amazon, but I am curious about all other performance options. Thanks!
 
It would work but you need to make a plate and spacer for carb and air cleaner to get it to work. I'm not sure if you could do that. also there's a pump on the carb that needs vacuum from the case. a hole would be needed in the case. I don't know if you saw the video of mine running? it sounds real wealthy. this carb works great on it.
I think they sell an adapter for these carbs some where on this sight but can't remember where I saw it.
Good luck with your new motor, it should be a lot of fun!
 
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