Author Topic: MG M type  (Read 4232 times)

Jimr1999

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Re: MG M type
« Reply #30 on: 01 Apr 23, 07:25 am »
Hi Guys does anyone have any experience with Hyundai engines sold by Gemini karts?
Is it okay to use this engine? 212cc 7HP, also recommended sprocket size for rear axle.
an help or comments would be appreciated

Cheers Nick
... As for the ratios, well it all depends. I did quite a bit of reading about this and still am not sure if I got it right. I will assume firstly that you are running a TAV30 style torque convertor. I will also assume that your rear wheels are 17" pit bike or Honda style wheels as they should be.
If you search this forum, Rhys put up a post where he looked at the ratios the faster guys were running in the states whilst he was over there. IIRC the consensus was that TAV to rear sprocket was a 7:1 ratio (e.g. 10 teeth at the TAV30, 70 teeth on the axle, 420 chain) Some run 60 teeth, some use a jack shaft and take the ratio even higher.
If your gearing is too tall and you run a heavy cyclekart/driver, you may find yourself "bogging down" when exiting corners where the revs are not high enough to supply a reasonable amount of torque to the rear wheels to accelerate you as you might wish. If your ratio is too far the other way you may run out of revs before you reach an ideal top speed - the chances of the latter happening are perhaps smaller than the former on most of the courses we run.
Adding to the complications of gearing is how the variable drive TAV30 performs. You can change springs, weights and spring positions in them to have engagement not until higher revs and/or drive not maxing out as soon. I would start with stock TAV30 and work that out when you know how your machine performs. Last time I looked, Gemini were out of stock of 70T 420 platewheels.
I hope this helps, but I fear that it is just adding to the confusion. I am sure people with more experience than me will chime in, I might learn something so thanks for bringing this subject up.
Jim
... You can lead a horse to water, but a pencil must be lead.

StefanN

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Re: MG M type
« Reply #31 on: 01 Apr 23, 09:17 am »
I agree with Jim.   A 7:1 ratio through a TAV2 (which multiplies by 0.9-2.7) will be a good starting point and going to a lower ratio from there is easy.  Some are experimenting with higher ratios but that almost always requires a layshaft and hence more complexity.  With smaller chain you might squeeze in a higher tooth count sprocket and hence higher ratio, but sourcing the parts can be tricky.

7:1 should give you a nice drivable cyclekart, which will make you grin, which is what it’s about after all!

NewbieNick

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Re: MG M type
« Reply #32 on: 01 Apr 23, 10:25 am »
Thanks for replies guys very helpful .Another question i am going to be using Honda C90 wheels to a Gemini Karts rear axle, i am  assuming i need Gemini Mono Hubs & Cyclekart Adapter plates do i also need the 90 mm square spacer? Please let me know if this is correct

Cheers Nick. 

Ian L

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Re: MG M type
« Reply #33 on: 01 Apr 23, 02:24 pm »
Nick, I think the spacer is for pit build wheels which have a lip, it can be ground off or the spacer added. I would email Gemini they are quick to reply. Cheers. Ian

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Re: MG M type
« Reply #34 on: 01 Apr 23, 05:55 pm »
Thanks Ian,change of plan just ordered 4 17 inch Pitbike wheels.
I understand the bearings in these can be changed to 17X35 can anyone confirm.
Is anyone using the cloned Torque converter being sold by Gemini any comments.
Cheers Nick

Jimr1999

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Re: MG M type
« Reply #35 on: 01 Apr 23, 06:27 pm »
Yes to the bearings, you will also need new anti crush tubes between the bearings Nick. I don't know anyone using the Gemini clone TAV, but Hutt imports do one for about £85 delivered https://huttimports.co.uk/product/torque-converter-to-fit-gx160/


https://www.ebay.co.uk/itm/123871469862?var=424603379536
The tube with care can be cut to length with a plumbers pipe cutter
https://www.ebay.co.uk/itm/113999848637?var=414284778560
Jim
« Last Edit: 01 Apr 23, 06:41 pm by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.

Ian L

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Re: MG M type
« Reply #36 on: 01 Apr 23, 06:44 pm »
Just as Jim says for the front and 25 by 35 oilite bushes for the rear, unless you are boring out to 37mm. Bearing boys are a good supplier.

NewbieNick

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Re: MG M type
« Reply #37 on: 01 Apr 23, 07:02 pm »
Thanks Jim i had not thought of anti crush tubes. Ian i have all ready sourced oilite Bushes. Henderson Bearings Ringwood 10 Minutes from home
Thanks again

NewbieNick

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Re: MG M type
« Reply #38 on: 02 Apr 23, 07:30 am »
Lights & supports fitted,real & fake light support bracket, 

Jimr1999

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Re: MG M type
« Reply #39 on: 02 Apr 23, 07:35 am »
Looking sweet Nick
... You can lead a horse to water, but a pencil must be lead.

Graham Hill

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Re: MG M type
« Reply #40 on: 02 Apr 23, 12:43 pm »
Thanks Ian,change of plan just ordered 4 17 inch Pitbike wheels.
I understand the bearings in these can be changed to 17X35 can anyone confirm.
Is anyone using the cloned Torque converter being sold by Gemini any comments.
Cheers Nick

Hi Nick. I have a genuine Comet, but I would have no reservation in fitting the clone supplied by Gemini. From discussion I know that they spent some time in sourcing one that they were happy to sell themselves. Being the sole distributors of the genuine Comet they do understand the weaknesses of copies. I have handled the clone for inspection and it appears well machined.   Graham

NewbieNick

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Re: MG M type
« Reply #41 on: 02 Apr 23, 04:26 pm »
Than kyou

NewbieNick

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Re: MG M type
« Reply #42 on: 07 Apr 23, 11:15 am »
Hi Guys good day today. big box of stuff from Gemini arrived for the weekend.
Also 4 Pit bike wheels £ 108.00 from Red circles. Question, i have changed the wheel bearings & offered wheel to front axle without oil seals in place, do you fit oil seals back in & have them rubbing against stub axle shoulder & retaining nut or leave them out & fit a spacer/shim?

Cheers Nick

StefanN

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Re: MG M type
« Reply #43 on: 07 Apr 23, 12:49 pm »
I use sealed bearings, no rubber oil seal and no spacer between the bearing and the stub axle shoulder.   I mount the wheels with the 4 bolt holes facing inboard.

I’m sure you’ll have done this, but I do make new compression spacers to go between the bearings.

NewbieNick

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Re: MG M type
« Reply #44 on: 07 Apr 23, 02:53 pm »
Thanks Stefan I have mounted wheel exactly as you have said, with the stub axle nut tightened to end of thread I have quite a lot of end float. Yes a have made new anti crush tubes, Jim got there before you.
Thanks again any advice would be great.
Regards Nick