LCGB Forums

Running an original carb and casa exhaust set up on my series 2 Tv175. Also an engine rebuild 1500 miles ago. It runs great but I feel the standard set up is holding it back. It runs along at 50-55 mph comfortably on the flat but starts to die on any kind of incline. Looking to invest in another carb and exhaust for that little more pull on the inclines. What would the recommendations be?

I'm no expert and usually the one asking for advice.
But I run a 175, with a sterling exhaust and PWK carb. The exhaust although cheap and cheerful, does help with higher revs and the 26mm PWK is a lot more responsive than the standard.
I think it boils down to what you want it for and after reading up, it seems that standard exhausts including clubmans, are more suited to knocking around town and a steady run around 40-50 mph tops.
But the other options are endless, with bigger carbs and exhausts.But with the increased performance, comes other problems , which I have ran into.
I think if it ain't broke don't fix it.
There are some really experienced guys on this Forum, including JohhnyXS and Coaster, it might be worth asking them for turning options.

Thanks for your comment. Hopefully the more experienced among us may come up with an option or food for thought. I'm still quite a novice on set ups. Cheers

What about your gearing ?

The gearing is standard series 2 tv175. I don't want to mess about with anything bar the carb and exhaust as I'm hoping that will give the scooter a little bit more pick up on the inclines.

Lower your gearing, replace the rear sprocket with a 47=4.9 although you will need a stretched chain, this will keep the motor in the power a little better.

Are you running the carb thru the standard airbox ? What size is the carb ? 18 ?
I've just sorted my mates TV175 series 2 out which had a similar problem. His had a 22mm carb and a 42mm clubman. I realise the carbs are different, but yours still has a larger exhaust than would normally be used with a smaller carb.
My mates was running thru a standard airbox. Look at the air intake under the airscoop. On my mates the hole under the airscoop, into the airbox was tiny. My solution was to drill several holes in the side of the airbox, the difference in performance was amazing.

Thanks for your relies guys.
MAZ,
Yes I am running a standard Series 2 TV carb(MB21 BS) through a standard non drilled air box. I don't really want to start drilling holes so this is why I thought I would go down the carb and exhaust route. As it's completely standard apart from 12v. Cheers

Why not do this?

Scootopia 22mm carb
Scootopia clubman
Get an old air box then drill it and use a bgm high flow filter

Even with that I think scotty's suggestion of lowering your gearing is sound.

Personal question: What do you weigh ?
Your gearbox is probably one of the best boxes produced by Innocenti. If like too many of us the years of good living have added a few inches to the waistline, then the final drive ratio might just be a bridge too far. If you are NOT like too many of us then I would check a few more things alongside the airbox recommdations that really can make a difference.
1. Try it without the air filter installed. Keep hose intact and connected.
2. How is your spark plug colour ? Most important. Apart from your feel of the scoot that is the only "barometer" of what is happening inside.
3. Check your timing. Make sure somebody has not been over caution and overly retarded it. IMHO 19 degrees BTDC is the mark.
4. Check that rear brake is not binding when warmed up.
5. Is exhaust gasket fitted the right way around. Wring way can obstruct.


55 -60 is what you should expect.

Cheers Guys,
Chris, I'm 14st soaking wet so not really that heavy for the scoot.
With regards to the air filter, Would it cause any damage or running problems?
The spark plug is dark black but not oily in any way.
Timing set at 19 degrees Btdc
Rear brake I will have a look at. Seems ok when cold but not tested when warm.
Exhaust gasket ok.

Thanks

Meant to say try without the air filter for a short run as a comparison. Having said that many of us run open mouth carb without any filtering.
Now the dark black plug is interesting.
That indicates far too rich a mixture. By mixture I mean petrol to air NOT the oil. Rich mixture will be caused by restricted air flow (lots of references in this thread to air box) which might be caused by blocked air filter or collapsed air hose or blockage in air box circuit.
If not restricted air flow then fuelling too rich caused by overjetting OR choke mechanism not fully closing.

The dark black plug is definitely not right. Needs to be mid brown or mocha brown.

Sorry for any confusion. My predictive keyboard changed "overjetting" to "overheating". Lol

You haven't got anything stuffed under the seat that might be blocking the airflow? Have you cut out the baffle in the airscoop?

If it helps, I have a brand new MBD fast flow air box and filter that I never used on my S2. You will need to remove the baffle on the air scoop but will increase air flow and still look standard. Including carb rubber.

Cost me around £110. Open to offers if you want it. Never used. Does come with an amended air scoop if you want to keep the TV one in tacked, and the fast flow filter.
Pm me if interested.