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jersey stew

Beta 80 Carburettor

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Anybody ever tried converting the beta 80 to a flatslide carb I.E Keihin, OKO etc???

I think the bike would run cleaner on a better carb, we bought my son his new 2017, its never run brilliantly, often fuelling up and idle seems to vary.

I know the smaller cc bikes will suffer with pilot jets blocking up because by nature the hole is very small.

However Ive had to clean out the carb much more often than on any other bike and also play with the needle height, mixture screw etc to try and retain a decent smooth running.

Surely the top lads on these bikes cant have these issues? Do the likes of Hemmingways have modified bikes? or did we just get the Friday afternoon bike?

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Isn't a conversion to a flat side like Keihin or OKO, however I did re-jet my daughters Beta 80 and it runs fantastic.  

 

Note: Because many scooters have the same carb, if the dealer can't get the jets (they often don't have the smaller ones) you should be able to get them here.  https://www.treatland.tv/ 

Summary of jetting changes that should really make a Beta 80 run way better...

The 100 main dropped to 98 and suggest having at least 93 and 95 on hand in case its still a bit rich.  Example: 93 should be good from around 7,000 to 10,000 feet best guess.

The stock 38 pilot to a 35 and if it runs lean up that to a 37, but would expect the 35 to be good.

The needle clip stock on mine was in second down of four slots from the factory. I moved it all the way up to the top slot (maximum lean) and the leaner pilot jet should just round it out.  If that proves a little to lean you should only have to bring it up one slot.

 

Got the recommendations from another forum, a post titled "2014 Beta Evo 80 Full Size Adventure" made by motobene.  Was very helpful.   

 

Hope that helps... really helped out our little Beta 80.  Good luck! :thumbup:

Edited by jonnyc21

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Just really an aside my wee boy has   2016 80.  I'm believe it was one of Dougies sons and the carbs stock.

It runs fine but I'm forever cleaning it out . Probably no one on the forum will agree with this but I feel it runs miles better on semi synthetic oil.

Worth a try?

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Oh and I should have noted that I know of more than one newer Beta 80 that needed a fuel filter because of small particles coming from the tank.  

Guessing it is something from the manufacturing process, maybe a missing step to flush/clean post assembly or something.  

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Lots of good info in the motobene thread. I followed his jetting recommendations but my biggest improvement came from adjusting the little brass mixture screw to the left of the big idle speed screw. Mine was two full turns out from the factory but I ended up at 11/12ths of a turn out. It then actually ran/sounded like all the trials bike I have observed on youtube. Before that it was a blubbery mess even with the leaner jets.

Treatlandtv is an awesome site w/fast response. You have to hunt for the Dellorto jets & small parts page but its there.

Based on my experience w/the Beta 80 that I detailed in the motobene thread (& I was sugarcoating it for a family audience) I would argue they are all made on Monday morning or Friday afternoon. One would think a machine produced w/only small changes for 20 years now would be designed/executed flawlessly. One would be wrong.

 

 

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On 6/25/2018 at 7:29 PM, anachronism said:

Lots of good info in the motobene thread. I followed his jetting recommendations but my biggest improvement came from adjusting the little brass mixture screw to the left of the big idle speed screw. Mine was two full turns out from the factory but I ended up at 11/12ths of a turn out. It then actually ran/sounded like all the trials bike I have observed on youtube. Before that it was a blubbery mess even with the leaner jets.

Treatlandtv is an awesome site w/fast response. You have to hunt for the Dellorto jets & small parts page but its there.

Based on my experience w/the Beta 80 that I detailed in the motobene thread (& I was sugarcoating it for a family audience) I would argue they are all made on Monday morning or Friday afternoon. One would think a machine produced w/only small changes for 20 years now would be designed/executed flawlessly. One would be wrong.

 

 

We had many problems with my son's 2014 beta 80 senior. It would just occaisionally run very lean , rpm would increase then it would run out of fuel. First few times I'd have the carb stripped at the trial then it would run ok but I could never find anything wrong with it.

I stopped cleaning the carb when this happened at trials and started just picking up the bike by the rear wheel and letting it fall, I thought the float must be sticking.

A local guy then offered a different carb he had used on his sons bike. It was a massive improvement and we've had no problems since.

The thread I read on another site, probably referred to above , mentioned small particles being found in the fuel but that they were flaking off the actual original carb.

I'll get the reference off the alternative carb.

.

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On 3/13/2020 at 7:07 AM, baldilocks said:

We had many problems with my son's 2014 beta 80 senior. It would just occaisionally run very lean , rpm would increase then it would run out of fuel. First few times I'd have the carb stripped at the trial then it would run ok but I could never find anything wrong with it.

I stopped cleaning the carb when this happened at trials and started just picking up the bike by the rear wheel and letting it fall, I thought the float must be sticking.

A local guy then offered a different carb he had used on his sons bike. It was a massive improvement and we've had no problems since.

The thread I read on another site, probably referred to above , mentioned small particles being found in the fuel but that they were flaking off the actual original carb.

I'll get the reference off the alternative carb.

.

Have you got the model of the replacement carb you fitted please, and the jetting?

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Hi yes it's a Dellorto phbg 21 DS.

Start with the same jets as the standard carb, they fit. This carb has an inlet spigot in front of the slide , presumably for a 2t injection system. Its blanked off on ours.

 

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Thank you but that the standard carb is a Dellorto PHBG 21 BS (or at least that's what's on mine), do you know what the difference is? It looks pretty much identical apart from the oil input feed. I was hoping it was going to a totally different brand, a much better carb.

 I'm totally fed up with this bike (carb). The pilot jet blocks within the first 15-20 minutes on EVERY ride! I've totally stripped and cleaned the carb down at least twice and removed it to unblock the pilot jet on countless occasions. It's got an inline filter fitted, the airbox/filter is totally sealed, I can only assume that the particles are coming from the carb itself, it's utter garbage.

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In desperation, I've purchased one of the cheap Chinese copies of the PHBG, the black 'racing' version (approx £40). It can't possible be worse and, you never know...I'll post back with how it goes.

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Ah now we haven't mentioned colour before, ours is black ! I'd also say its longer as its more difficult to re fit. Having said that I doesnt get re fitted very often, last couple of months I'm just draining the fuel out of the bowl with the drain bolt. Got away with it, never had a problem since we fitted this carb.

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On 7/21/2020 at 7:16 AM, harryharls said:

In desperation, I've purchased one of the cheap Chinese copies of the PHBG, the black 'racing' version (approx £40). It can't possible be worse and, you never know...I'll post back with how it goes.

Right, I finally remembered to get the jet sizes and slide from the improved carb.

Pilot 40

Main 92

Slide 40

Needle w7, lowest groove. 

 

 

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Thanks for the info baldilocks. I previously stated that I'd update on the cheap Chinese carb but I forgot to be honest. I'll do it now...utter crap, as expected really. Couldn't get it to run well at all with all sorts of jetting and tuning, stay away. I suppose we all knew that already really though didn't we? So the issue with the original carb remains for me. I've since replaced the inline fuel filter with a new one and re-checked the air filter sealing. I've checked compression, re=sealed all inlet gaskets etc. I simply don't know what else to do.

The thing is, when it's running well, it's perfect. However, I get this blocked idle circuit issue on EVERY SINGLE RIDE, without exception. If run for long enough with the idle screw turned in (basically running on the needle and main jet) it will eventually clear and run well for a while, but then it will happen again. When the idle circuit is blocked it has no power at low revs (naturally) and stalls/bogs down on the slightest climb. I feel really bad for my son who has to endure this crap while I chug along merrily on my 250 which never misses a beat, ever.

The upshot is; this thing is going, enough's enough. I'm getting rid and getting him a 125. This problem has persisted for so long that he's naturally ready for a 125 anyway. I will never be buying or recommending a Beta 80 to anyone again. It's completely crap. It's a good job that I'm so happy with my own 250 Evo or I'd be off Betas for life after this.

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On 4/1/2021 at 7:46 PM, harryharls said:

Thanks for the info baldilocks. I previously stated that I'd update on the cheap Chinese carb but I forgot to be honest. I'll do it now...utter crap, as expected really. Couldn't get it to run well at all with all sorts of jetting and tuning, stay away. I suppose we all knew that already really though didn't we? So the issue with the original carb remains for me. I've since replaced the inline fuel filter with a new one and re-checked the air filter sealing. I've checked compression, re=sealed all inlet gaskets etc. I simply don't know what else to do.

The thing is, when it's running well, it's perfect. However, I get this blocked idle circuit issue on EVERY SINGLE RIDE, without exception. If run for long enough with the idle screw turned in (basically running on the needle and main jet) it will eventually clear and run well for a while, but then it will happen again. When the idle circuit is blocked it has no power at low revs (naturally) and stalls/bogs down on the slightest climb. I feel really bad for my son who has to endure this crap while I chug along merrily on my 250 which never misses a beat, ever.

The upshot is; this thing is going, enough's enough. I'm getting rid and getting him a 125. This problem has persisted for so long that he's naturally ready for a 125 anyway. I will never be buying or recommending a Beta 80 to anyone again. It's completely crap. It's a good job that I'm so happy with my own 250 Evo or I'd be off Betas for life after this.

We have had some issues with the better carb, not in terms of reliability but I noticed as my son progressed the peaky nature of the power it provides was becoming an issue. I've fitted a richer slide which has helped but it doesn't rev as high as it should in my view. It's a pity about the carb, the rest of the bike is pretty good

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