Cheetah Cub kit - which one?

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LC Cnd
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Cheetah Cub kit - which one?

#1 Post by LC Cnd » Sat Dec 23, 2017 1:01 pm

Doing a bit a reseach on these kits for an Elsie motor (spare) I recently located and thought of the above noted as apposed to an Athena. Like to purchase one in Canada but not aware of who sells. So, I'm asking for wisdom fm those who have 'been there done that' in the realm of street-ablitiy/reliability regarding the 392 vs 421, and maxing out at 443cc. Anything above that is for the track I imagine. The only other possibility is fuel injection but thats considerable R&D and the best bang for the buck literally is a bolt on kit is what I've read so far. Lastly... Merry Christmas to all.

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Re: Cheetah Cub kit - which one?

#2 Post by MK » Sat Dec 23, 2017 1:46 pm

First piece of wisdom is that any of the described won't bolt on your 4L0 cases.
They all require a YPVS or Banshee bottom end where the latter one would be best suited for the 4L0 (different gearing, especially 5 and 6).
Bye
Martin

LC Cnd
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Re: Cheetah Cub kit - which one?

#3 Post by LC Cnd » Sat Dec 23, 2017 2:24 pm

So basically there are no big bore kits that can be applied to a 4LO? I do have access to YPVS cases - that being said which kit works best?

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Re: Cheetah Cub kit - which one?

#4 Post by MK » Sat Dec 23, 2017 3:39 pm

C'mon, you're not telling me you decided spending AT LEAST 1500 $ on any of those kits and try to avoid maybe some 500 for a used Banshee bottom end ?
Bye
Martin

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Re: Cheetah Cub kit - which one?

#5 Post by LC Cnd » Sat Dec 23, 2017 3:55 pm

I'm aware the cost of the kit(s) and have a budget I would like to work/plan within - no harm in that. Xmas cash gifts may help (lol). Found the TSB that describes how to up the HP by porting (not alotta room on a 4L0 barrel it appears) & shaving the head which is also a recipe for possible early grenade-ing or frustating to tune. Read Rory's comments on upgrades mods and that was interesting advise (don't port etc). Also a consideration is a pair of good aftermarket pipes (TSAs) vs a YPVS bottom end etc for better HP investment but interested in the challange of assembling a big bore kit. Jon read your 3 yr labour of love on 421 Athena conversion (well written blog) - ever considered a different size or is 421cc it?

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Re: Cheetah Cub kit - which one?

#6 Post by 2smoke » Sat Dec 23, 2017 6:57 pm

The problem is too much choice.
TZ750 top end
https://www.youtube.com/watch?v=GZ6u8awv5n0

I think the 4L0 would be a good engine for a turbo kit. Maybe one of those affordable Chinese kits and make some custom parts to fit it?
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Re: Cheetah Cub kit - which one?

#7 Post by kenny » Sat Dec 23, 2017 7:59 pm

If you go the YPVS engine route then a Trinity Cheetah would be my choice as you have access to the power valves to help with the power spread.

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Re: Cheetah Cub kit - which one?

#8 Post by JonW » Sat Dec 23, 2017 8:15 pm

LC Cnd wrote: Jon read your 3 yr labour of love on 421 Athena conversion (well written blog) - ever considered a different size or is 421cc it?
Well I started the build before many had even thought about big bores on the bikes (certainly on the UK Bike (like the classic car) forums that was seen as an American thing back then) and my documenting of it was one of (arguably 'the') first of its kind. Yes, and as many of my mates have told me, I could have had this bike on the road years ago... but I always wanted to do something else with or to it. Over the years its been my play thing for new ideas and I never knew if id finish it or not, it runs beautifully and is silly powerful, those whove heard and seen it have always wanted their own so its been great for that, but Its never been run in anger, but it will... And to prove the point its actually on my lift again in a part built state right now for me to rebuild as I convalesce. My plan is that I will finally have it registered this year after the frame swap to a strengthened frame (a great sub project that few had undertaken so I documented it of course) and hopefully sorting out an alignment issue that dogged me for ages. That issue taught me a hell of a lot about hybrids, enough for me to get my XT500's KTM wheels in the bike with almost perfect alignment by eye, which was then backed up with a laser which Id bought to help solution my 421s problem. 'By eye' alignments might seem some feat but really come from understanding and learning and its that learning is what I love with these projects, so my LC421 project was never a huge hurry for me to have on the road, more fun to play and learn. :) Anyway...

With what I'd learnt about big engines I decided to give back (remember few had built or knew about them at the time) I created the 'Big Bore Primer' which was really just to whet people's appetites, its designed for those who are new to it and hence usually at the lower end of the budget, which as we know is still not cheap, just not the silly money needed for the big cc's. In my experience anything above 421 starts to get expensive in even more areas, adding in the costs of primary gears, trenching etc etc so rather than create an impossible article I stuck at the lower end, which is where most seem to start, to get a reliable 421 from proven products. so it advises Athena as there is a lot of them about and you can ask on forums where people who have them can help you, conversely if you need help about pretty much any of the others you will struggle for bike centric advice, drag race ATV advice no problem of course, but a bike on the road is not a sand drag atv... So, while I could make the Primer cover other stuff, I figured if youre going the larger or more esoteric product route that you probably know better whats on the market at the time of reading than I could cover without updating it weekly. Research is king for each build and I say that a lot in the article, much better to understand what youre getting into up front than later etc. Of course, if i was buying again Id buy something other than Athena, but that's mostly cos Im experienced in these motors now and would want to build something different, ie i already have an athena. I do like a number of the other options and PVs would be nice again, but those choices seriously up the budget, and of course Id build one with more power, which of course ups the budget yet again. you can spend what you like on this stuff, but the beauty is that you dont have to and you can start with even OEM cyls and a long stroke crank and have some fun, but be aware that all new parts and having them be 'bigger' will mean costs for new other parts that attach or feed to/from them, its the knock on effect. HTH.

Here is the Primer, if youve never read it. Its not the definitive on this subject but the only place Ive ever seen with this info in it and you should be aware that its written for a target audience; ie perfect for someone with little knowledge of big bores. As you research you'll know more than this article and see its limitations, that's understood.

http://2smoked.com/Yamaha_RD_%26_RZ_upg ... rimer.html" onclick="window.open(this.href);return false;
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Re: Cheetah Cub kit - which one?

#9 Post by hondaror » Sun Dec 24, 2017 1:24 am

Scott, don't do it. Get an RZ to hop up. The LC frame is not a good mix. Like Jon said, beefing up the frame is a big job, and I don't think it's worth it. The LC is an awesome bike, so much fun, but upping the hp and torque is not, what I consider a good idea on that bike. I'm not a fan of porting, due to the losses, that most people miss and the loss of reliability. However, so much more can be squeezed out by blue printing, case hogging and barrel matching. The RZ is a much better platform if you want high hp numbers.
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Re: Cheetah Cub kit - which one?

#10 Post by winner_evo » Sun Dec 24, 2017 8:39 pm

hondaror wrote:Scott, don't do it. Get an RZ to hop up. The LC frame is not a good mix. Like Jon said, beefing up the frame is a big job, and I don't think it's worth it. The LC is an awesome bike, so much fun, but upping the hp and torque is not, what I consider a good idea on that bike. I'm not a fan of porting, due to the losses, that most people miss and the loss of reliability. However, so much more can be squeezed out by blue printing, case hogging and barrel matching. The RZ is a much better platform if you want high hp numbers.

^^^This is my take on mostly stock LC's.

My 350LC is fine with 50 odd hp but I wouldn't want to ride it with a 421 motor in it.

My Hybrid 421LC rides fine but that has much better forks,swinger,wheels,shock & brakes.

A nicely tuned LC motor is a good mix with a largely stock but well fettled LC chassis.

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Re: Cheetah Cub kit - which one?

#11 Post by JonW » Sun Dec 24, 2017 9:35 pm

I agree. My LC421 is far from stock... uprated wheels and suspension (which is then uprated again, ie RGV and fitted with uprated parts) as well as better brakes and a strengthened frame too. This means a longer wheelbase as well, all this helps stability and the quality of the componentry helps too. If you add the cost of doing all that to a bike on top of the motor its probably very scary indeed, but if you love the LCs look, which I know I and a few here (Winner Evo included) then youve 'no choice' if you want to indulge.

To be honest I think sticking 80+ bhp in a standard RZ might not be ideal either. youd need better brakes for a start and uprated suspension too as a start. Some will argue you dont need to but, well, you can stick a 350 ypvs in a FS1E, but would you ride it like you stole it if you did? I dont think i'd feel safe lol.
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Re: Cheetah Cub kit - which one?

#12 Post by hondaror » Mon Dec 25, 2017 2:51 am

Jon is a huge LC fan, as am I. I spent 9 years on mine. I may be buying a hybrid unit in the future. I will heavily beef up the frame to handle better suspension and components, and massage the engine for a natural improvement. (Stuff that is extremely costly unless you can tackle it yourself).
I'm attracted to the RZ, from a racer's standpoint. It's that much better, and much more capable, thus better suited for the bigger bore mods. I tried to race RZs on the track with my LC. Absolutely fruitless.
I do love the LC lines. It has it's place in history as the naked innovator. The 250 was the first to crack the 100 mile an hour barrier, from a stock unit.
Rory
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Re: Cheetah Cub kit - which one?

#13 Post by 2smoke » Mon Dec 25, 2017 11:26 pm

hondaror wrote:Jon is a huge LC fan, as am I. I spent 9 years on mine. I may be buying a hybrid unit in the future. I will heavily beef up the frame to handle better suspension and components, and massage the engine for a natural improvement. (Stuff that is extremely costly unless you can tackle it yourself).
I'm attracted to the RZ, from a racer's standpoint. It's that much better, and much more capable, thus better suited for the bigger bore mods. I tried to race RZs on the track with my LC. Absolutely fruitless.
I do love the LC lines. It has it's place in history as the naked innovator. The 250 was the first to crack the 100 mile an hour barrier, from a stock unit.
I am curious Rory. Did you ever upgrade the 32mm forks on your LC?
My LC has the early RZ350 35mm forks on it with progressive springs and it honestly feels as confident in the corners as my stock 87 RZ350 did. And at top speed.
Best money spent on this bike.
I don't race at the track and push the limits to the max though.
Also I think upgrading the rear shock would make a big difference. The lower eye on the stock shock is thin and weak and worries me a bit. lol.
Colin
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Re: Cheetah Cub kit - which one?

#14 Post by LC Cnd » Tue Dec 26, 2017 12:08 am

So I sence that from a stock prospective, a LC engine upgrade is do-able only if one consider a systems upgrade on braking, suspension and frame mods; ergo, there is no such thing as a stock upgrade on an Elsie that will allow you safe margin of error for more performance grin safely. That leaves one with the following choices: choose from a myrid of hybrid projects and satisfied customers/builders noted under the custom projects/restorations thread, 2) or go with the techincal service bulletin, that came out of Yamaha Holland circa 1982-83(?) on a 5-7 hp upgrade (surely within the safety margin, or is it), lastly purchase a RZ if I can find one meets the current budget (not likely). Kinda leaning towards Rory's logic on this if affordable.

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Re: Cheetah Cub kit - which one?

#15 Post by JonW » Tue Dec 26, 2017 8:09 am

Well you can upgrade the engine if you like and there are options for the LC stud pattern and cyls, people did it back in the day, you just have to understand the limitations of the chassis, of course had we never moved on to the RZ and onwards, no one would have suggested you might need to upgrade.
80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD350LC decapitation project
82 RD250LC JDM '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

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