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View Full Version : Will a polini pipe fit in a grc mini gp?



wfo115
04-06-2002, 08:41 PM
Which pipe would fit 910 or 911? Anyone know please help.

GOGGLES
04-06-2002, 08:48 PM
Ring maxat or Alan mcintosh

Jaz
04-06-2002, 09:21 PM
Lee, I know you're trying to be helpful and, no doubt, your recommendations would give some advice. However, wfo115 probably knows how to contact a dealer and may have already done so.

He has asked the question here to get some impartial advice and hopefully from someone who has learnt from experience of trying different exhausts.

His question appears to be about what pipe would fit a GRC out of the two polini options.

WFO, what engine have you got? what are you trying to do?

Give us a bit more info and i'm sure someone will point you in the right direction soon.

trevor sellars
04-06-2002, 10:43 PM
Hi Folks, How strange I was asking the very same question not long ago!

If you buy the MK7 GRC pipe made by Bizeta it fits the Polini 911 a treat. You will need to file away a very small section of the left hand engine mounting bracket only 3 mm or so but otherwise all is o.k. The difference was amazing when compared with the standard Polini race pipe.

The good thing is, that Bizeta sell a range of 3 headers long, short and yes standard. These will enable you to tune the pipe more easily for short or longer tracks. I bought mine from Julian at Wroughton it cost a 140 ish but the extra headers are about 16 each. The engine certainly revs cleaner and harder with it fitted.

I sold my old Polini race pipe to a GRC owner and he has fitted it with no problems. He says his bike goes better than it used to.

Hope this helps

trev

pocketbike
05-06-2002, 12:31 AM
Allow me to clarify, since the gentleman who posted this has been exceptionally vague - given no location in his profile, nor made it terribly clear what exactly he is in need of...but since I directed him to this forum to find his answer, perhaps I can help him get one.

He has a 4.2 GRC GP Mini, and would like to fit a Polini pipe.

I commonly recommend a Polini 911 race pipe to retrofit the rather lousy stock GRC GP Midi pipe (you do need to fabricate some bracketry), but I could not in good conscience recommend the Polini Carena Mini (910) pipe without knowledge of whether it would fit within the chassis or not.

He would also like to install the reed box upgrade, but again, since I do not currently sell GRC bikes, and have very little experience with them, I could not tell him whether it would fit within the chassis.

Any help would [I'm sure] be appreciated...and in fact the gentleman is located in the USA.

-Marcelo

wfo115
05-06-2002, 02:33 AM
Thank you Marcelo for the clarification. Next time I will be much more specific.

Jaz
05-06-2002, 08:32 AM
So wfo, you have a GRC GP mini fitted with a series 1 (4.2) air cooled polini engine, please confirm.

If this is the case, what 910 exhaust were you thinking of fitting, a 4.2, production or race?

I've no experience of this particular situation but would imagine that all of those will fit with some fabrication to their brackets.

Trouble is, your thinking of a fairly unusual modification. You maybe the first to try it! In which case, let us know how you get on. We don't always have all the answers i'm afraid. But there again, someone (hopefully) may respond with the answer.

Marcelo, as far as the reed block (4.2 dual reed conversion) is concerned, that's hardly known about in the UK. We have the part number (courtesy of your web site (www.pocketbike.com)) but enquiries with dealers here have drawn a blank :(. This is probably because it is a modification that would take the bike out of the 4.2 class.

skunk
05-06-2002, 11:48 AM
i do know that some people (i think it was bengaz and scotty) converted a GRC midi super into having a polini pipe,

but if im thinking right andi have understood what you said, you only want to fit the pipe that goes over the engine, not under?

borrow a pipe and try it i say..

wfo115
05-06-2002, 12:57 PM
Thank you all for the prompt replies. I will try to clarify a little better yet. My intrest is to get the most h.p. for around $200.00 u.s. dollars. I am very new to this, but I am not concerned about staying in 4.2 class. My bike right now is completely stock grc mini gp 4.2 hp. I would like to get the stuff from a U.S. Distributer. So thank you very much again for all the posts.

Checker
05-06-2002, 01:23 PM
I pretty sure that the Polini 910 system would be to short and the fixing brackets would be in the wrong place for a GRC GP. The Polini 911 system should work but there would have to be a modification to the rear-mounting bracket and also removal of part of the cooling fins on the air-cooled cylinder. The cost and design of the stock GRC exhaust is similar to the Polini and they are readily available so why mess with it and not use the stock GRC system (I saw prices for this system on www.midsouthminimoto.com). Also if you purchase new stock from a dealer you would have a good chance of getting the Malossi silencer instead of the Polini one now. The design of the stock GRC pipe is the very similar to the Polini because GRC use to use the Polini pipe before making their own. To my knowledge GRC do not make a race exhaust for the 4.2 for the reason below. For extra power you could try and fit a Polini 910 race system (part no. 143.425.013), which would take a lot of work. I think it is better to have one made, which is not to hard to find. Before you do any thing you better check the 4.2 rules of your local club before doing this as well.

The four-petal reed block should fit on the GRC GP with no problem. I believe the four-petal reed block (part no. 143.270.003) for the 4.2 are not popular in the UK because it is not allow in these classes at most race meetings. In fact the FIM have every year tried to reduce the power with restrictors on both the intake and exhaust manifold for 4.2 junior classes in Italy . This year they went further with firm rules on the 4.2 exhaust designs to reduce the power even more. When one watches the Italian junior racers with a restricted 4.2 machine it is amazing how they ride. This is not to say that there are not amazing junior riders in the UK (and the USA I bet) as well.

pocketbike
05-06-2002, 05:38 PM
Actually, the reason he doesn't want to fit the GRC race pipe is simple - we've had quite a bit of experience with the GRC GP pipes, and they aren't great performers. We often put 911 race pipes on GRC GP Midis, and it dramatically improves the performance of the bike over both the GRC GP proddy and race pipes.

Finding someone to make a custom pipe may be easy in your neck of the woods - but not here...probably as hard to find as bangers and mash.

I firmly suspect that the 910 race pipe will fit - yes, he'll have to grind fins, but that's the case with all a/c motors, and nothing that five minutes with a Dremel tool can't fix....but I could not promise him it would for sure, which is why I directed him HERE, thinking someone might have first-hand experience.

I understand that the reed box upgrade would move one out of 4.2 Jr. class, and thus you would probably have limited experience in the UK with it. Actually, class assignments aside; it's a great mod, and takes the motor from 4.2 to 5.5 hp...but again I had concerns about clearance in the chassis on a GRC Mini - for instance, this kit WILL NOT fit on the Polini Scooterino for this reason.

If anyone has first-hand knowledge of these fitment scenarios, it would be appreciated.

-Marcelo

Checker
05-06-2002, 06:21 PM
"Will a Polini pipe fit on a GRC Mini GP" is a little misleading, is the bike a GP Racing midi or a RC40 Mini? I have seen American made pipes in the UK so it should not be that hard to get one made, Having said that it would be some effort where you are

pocketbike
05-06-2002, 06:40 PM
Was I somehow unclear? (Jaz, maybe you can translate...you speak "British", no?)

I know his initial post was a bit vague, but I think I spent enough time clarifying his intent that there should no longer be any confusion...but, WTF, I'll try again:

A GRC GP Mini (aluminum frame) is precisely what the man has.

He would like to fit a Polini 910 Carena race pipe (143.425.013), and perhaps a reed block upgrade (143.270.003).

-Marcelo

Jaz
05-06-2002, 08:17 PM
Was I somehow unclear? (Jaz, maybe you can translate...you speak "British", no?)



I speak English :!: I'll leave it at that as I don't want to get 'off-topic' :mrgreen:

The post is now perfectly clear but, wfo, you may have wait a long time to find someone who has faced this scenario. An unusual set of circumstances, maybe :?:

I think you've got a few good 'pointers' and i'm sure many more will come but you may need to just go for it. Perhaps a friendly dealer will allow you to 'offer up' an exhaust (or two) to your bike. You will be able to see what needs doing and whether you're prepared to take it on.

As for the reed block, for the reasons already given above, I and I guess very few europeans have seen one. I'm curious about this part and will try to get hold of one and test it on my 4.2 910.

curly
06-06-2002, 05:34 PM
hi wfo

bizeta have released a range of exhausts (as trev mentioned earlier) which have blown the socks of all other exhausts weve seen in the uk. as marcelo said the earlier grc pipes weren't exactly brilliant but have got better each year. the current exhaust from grc is the bizeta one which is the identical exhaust currently fitted to the dm. both grc and dm are currently doing exceptoionally well in the uk proving it has to be this exhaust doing the business. bizeta do an exhaust which fits the grc (aluminium frame mini or midi) as well as the polini 910 / 911. this is without a doubt the best exhaust available in the uk and will fit your bike. the only minor setback is they may only do it to fit the watercooled bike which may result in a little bit of angle grinder work to the head fins for the exhaust to clear. they may do an a/c version though.

pocketbike
06-06-2002, 06:27 PM
I had heard that Bi-Zeta was currently making the pipes for GRC (and DM), and am well aware of how lousy GRC's old pipes were/are...thanks for the confirmation on the Bi-Zeta "connection".

We do source Bi-Zeta here, so I can certainly get them...I'm just wondering, since I think both the DM and GRC (GR1/RSR) have Z-pipes (under and over), do they make one for the GRC GP Mini (over-the-top style)?

-Marcelo

vince
06-06-2002, 06:36 PM
if i understand the description correctly, the pipes on the dm are 'over-the-top-style'. like the one on my steel gp, if that helps to clarify...not the original steel. pretty sure its that way on the GR1...not positive about the RSR, but it sounds like they are all the same.

great pipe, btw...excellent form AND function...

vince
mrgreen

curly
06-06-2002, 06:53 PM
dm,rsr,gr1 all run over the top exhausts, the only difference between the gp racing fitmint is the mounting points. the gp racing has a silencer bracket, the rsr has a mounting just before the silencer.

Jaz
06-06-2002, 09:47 PM
Thanks Ian (curly) for helping out on this one. I was beginning to wonder where you were. I knew you would have the answers.

Bengaz
07-06-2002, 09:24 AM
Curly, you tell em how it is.
I tried every exhaust from here to Timbucktoo on every bike there is for the last 4 years.
When Julian gave me the 1st Bizeta pipe in the country at last years SEMRC Whilton Mill meeting I was amazed. My bike was transformed from a proddy to a super. (Just about anyway).
There is no doubt USA chums - the bizeta is the best pipe you can fit on any mini moto and if you do not own one you do not want to win.
By the way curly, loose the SEMRC 4.2 winner signature, come race the big boys puff ;)

Rita
16-06-2002, 12:08 AM
He has a 4.2 GRC GP Mini, and would like to fit a Polini pipe.
First of all, there is no such thing as a GRC GP Mini, there is a GP Racing midi and there is a RC40 mini but there is no GP mini model made by GRC.



We often put 911 race pipes on GRC GP Midis, and it dramatically improves the performance of the bike over both the GRC GP proddy and race pipes.
Not sure how you fit a 911 race pipes on a GRC GP midi's but the amount of grinding and reattaching brackets leads me to believe you full of 'technical ability' (edited by site admin, sorry Rita, there is no need for this kind of abusive remark).


A GRC GP Mini (aluminum frame) is precisely what the man has.
Once again, there is no such thing as a GRC GP Mini, there is a GP Racing midi and there is a RC40 mini but there is no GP mini model made by GRC.


We do source Bi-Zeta here, so I can certainly get them...I'm just wondering, since I think both the DM and GRC (GR1/RSR) have Z-pipes (under and over), do they make one for the GRC GP Mini (over-the-top style)?
Let me clarify for you Mr. Pocketbike pedagogue know it all, GRC's all have over the top exhaust and have never produced any Z pipes for their bikes (GP Racing's, RC40's , GR1's, or the RSR's). Please do some homework on your models before coming onto these message boards and trying to show off your dumbness.

Go back to the American message boards, where you might get away with your ignorance.

pocketbike
16-06-2002, 12:15 AM
Rita honey...it's that time, huh?

I don't sell GRCs sweety cakes, just trying to help the man.

Try some Pamprin. Hope you feel better.

-Marcelo

Beach Racer
16-06-2002, 03:01 AM
Here we go again............. Rita cut the crap. Everyone is getting tired of this stuff. If you don't anything nice to say don't say anything. And i will not reply to any attacks you try and make on me so dont waste your time.

pocketbike
16-06-2002, 03:18 AM
I was asked by Jaz to try to provide some tech assistance posts from time to time. I was also called on the phone by the gentleman with the GRC, and it was *I* who directed him to this forum.

He didn't buy his bike from me. I don't "need" to help him...but I tried to....and when I didn't have an answer for him, I sent him here.

When he started getting directed to call places in the UK, I thought I would help him by trying to clarify his location, as well as his needs, to help the poor guy get some answers.

Is there any reason for this attack? Is Midsouth Minimoto in some financial straits that require you to take drastic measures, and attack the competition to make yourself "look better"? If so, my sweet, it isn't working.

-Marcelo

akatherazor4
16-06-2002, 03:55 AM
Look Rita before you come on here and start flaming the Racers, Promoters, And supporting dealers I suggest you make a contribution to the sport. You have NEVER I repeat NEVER bothered to show up at a race and support anyone. Furthermore you have never raced period. The Mini Pimps were the ones who put the 911 Pipe on the GRC in connection with pocketbike.com. You see Rita we actually race and promote the sport as well as do R&D on parts. The only grinding that had to be done was minimal. I would almost feel safe to say that the Mid-South idiots could even do this with proper instructions and safety gear. :D

I suggest you crawl back in your hole with the rest of your clan. You guy's have already been banned from 2 pocketbike message boards. You trying to make it 3 now?

P.S. If you ever expect to get any respect in this sport you must first show it. Furthermore you should try and support at least the racers who purchased anything from you. We will continue to be at the races and we are awaiting your arrival!!

Razor.

pocketbike
16-06-2002, 07:08 AM
If it makes you happy, Rita, yes; I was referring to the RC40 Mini.

I know GRC used to call their mini the RC40, but I thought they had brought the naming convention into line with the Midi. I stand corrected...but I think eveyone here had already fully understood what kind of bike the man had...the aluminum framed one (not the GR1).

Someone else had also specified that the pipes of even the new GRCs are all of the over-the-top design.

...So perhaps you could explain the reason for your attack on me? What did you actually hope to accomplish? Was there actually a point to your spew? ...or was it just your way of being charming, and ladylike? What's YOUR agenda? Mine was to help someone who came to me for help...


-Marcelo

curly
16-06-2002, 05:46 PM
i thought the uk dealers had it in for each other! not exactly the way to introduce yourself to the forum Rita. lets try and keep it friendly on the site and help the riders, not use it to try and make another dealer look stupid. you just made yourself look small.

Jaz
16-06-2002, 07:07 PM
Welcome Rita. :rolleyes:

Please note my editing of your (first) post. We do have some posting guidance, you'll find some in the 'Minimoto and this web site' forum as well as in the FAQ accessed using the button at the top of the screen.

Please feel free to point out other users' errors (as you see them).

Please refrain from using MiniMotoClub for personal grievances.

Pedagogue? Just looked it up, it's an American word meaning 'a pedantic teacher'. What a great word, i'm adding it to my vocabulary, so watch out trevor :D

Rita, what's your involvment in the sport?

trevor sellars
16-06-2002, 10:07 PM
Hey Jazz, I've never been called a teacher before, wow!!

trev

pocketbike
17-06-2002, 02:15 AM
Pedagogue? Just looked it up, it's an American word meaning 'a pedantic teacher'. What a great word, i'm adding it to my vocabulary, so watch out trevor :D

She's quoting it from my SBN profile. That's what it says under my Avatar... "Pocketbike Pedagogue"

:rolleyes:

-Marcelo

Rita
19-06-2002, 12:00 AM
Sorry to say my piece. But I get sick of watching a someone dog out everybody who makes mistakes. And thought out I'd point out his. :D


I'm not in the sport. I USED to work for Mike Shelly over at Midsouth. So don't let my words and actions be thorwn at him.

So sorry to bring it on your board.

And Razor I'm not sure what Mike and them are doing, but I have never been banned from a site honey. And you are right I have never been to a race it is not worth the travel to me to watch 5 guys. So no as a person who just rides I don't do anything for the sport.

pocketbike
19-06-2002, 01:09 AM
...And you are right I have never been to a race it is not worth the travel to me to watch 5 guys. So no as a person who just rides I don't do anything for the sport.

Here's a picture of the racing in Ohio on 6/8/02 (all 5 of them).

http://pocketbike.com/images/ohio-racing-6-8-02.jpg

The charge is being led by the "Italian Cruise Missle", Marco Rizzo.

...and you don't just have to "watch", as you put it...you can actually race too...or is your "sig" just for show? How exactly do you "win it", if you don't race "in it"?

-Marcelo

vince
19-06-2002, 03:52 AM
cool pic marcelo. that looks like the start of the first open gp race we had out here a couple mos back. it didnt take long b/f the 3 people scoring threw the towel in b/c they couldnt keep track of all the people racin! since then we have had to run multiple heat races b/c there are so many people.

anywho, it doesnt look like marco likes to waste anytime. from the look of the pic, it cant be more than a couple turns into the race and hes already takin off. whats he got, a jet under that plastic? ;)

vince
mrgreen

ps whos the guy in blue (#47?) ?

pocketbike
19-06-2002, 04:14 AM
That's Brian Carpenter (the picture was supplied by Cliff Carpenter).

Marco took Brian under his wing for some one-on-one instruction in Ohio.

Man, those guys were flying!

Brian has been getting consistently faster, and he really caught on fast that weekend, after Marco taught him some clutch tuning and riding tips.

Their dicing was some of the best action yet.

As for Marco, we checked for a Jato under the fairing, but it was all him, dude. He even embarrassed those who complained his bike was "too fast" by soundly trouncing the field in the production race riding his son's Junior A class restricted Scooterino!

...Hence the cruise missle moniker.

-Marcelo

akatherazor4
19-06-2002, 09:21 PM
...And you are right I have never been to a race it is not worth the travel to me to watch 5 guys. So no as a person who just rides I don't do anything for the sport.

Here's a picture of the racing in Ohio on 6/8/02 (all 5 of them).

...and you don't just have to "watch", as you put it...you can actually race too...or is your "sig" just for show? How exactly do you "win it", if you don't race "in it"?

-Marcelo

ROTFLMAO!!!!!! :D :D :D :D :D :D :D :D :D :D