# Big Bore & Engine Kits

> This is a plain-text (markdown) copy of a page on tboltusa.com, made for AI assistants. People see the same page at the HTML link below.

- **Breadcrumbs:** [Home](https://tboltusa.com/store/index.md) > [Japanese Mini Bike Parts](https://tboltusa.com/store/japanese-mini-bike-parts-c-100.md) > [CRF70 and XR70](https://tboltusa.com/store/japanese-mini-bike-parts-crf70-and-xr70-c-100_36.md) > Big Bore & Engine Kits
- **Web page:** [this page on tboltusa.com](https://tboltusa.com/store/crf70-and-xr70-big-bore-engine-kits-c-100_36_488.html)
- **Markdown:** [this page as markdown](https://tboltusa.com/store/crf70-and-xr70-big-bore-engine-kits-c-100_36_488.md)
- **Generated:** 2026-11-03 20:53 EST
- **Site guide for AI assistants:** [llms.txt](https://tboltusa.com/llms.txt)
- **Your list:** To list everything you have looked at in one page, with current prices and stock, add ids to this address (comma separated, up to 20 of each): `https://tboltusa.com/store/seen.md?c=488`

All prices are in US dollars (USD). Shipping and any tax are worked out at checkout.

Products are filed in categories. Most top categories split by bike or engine model; a product can be listed in more than one category.

## Next to this category

- [Brake Pads & Pedals](https://tboltusa.com/store/crf70-and-xr70-brake-pads-pedals-c-100_36_489.md)
- [Carb Kits](https://tboltusa.com/store/crf70-and-xr70-carb-kits-c-100_36_490.md)
- [Controls](https://tboltusa.com/store/crf70-and-xr70-controls-c-100_36_491.md)
- [Electrical](https://tboltusa.com/store/crf70-and-xr70-electrical-c-100_36_493.md)
- [Engine Covers & Dress Up Parts](https://tboltusa.com/store/crf70-and-xr70-engine-covers-dress-up-parts-c-100_36_492.md)
- [Exhaust Pipes](https://tboltusa.com/store/crf70-and-xr70-exhaust-pipes-c-100_36_494.md)
- [Frames & Swingarms](https://tboltusa.com/store/crf70-and-xr70-frames-swingarms-c-100_36_495.md)
- [Front Forks](https://tboltusa.com/store/crf70-and-xr70-front-forks-c-100_36_496.md)
- [Pegs & Mounts](https://tboltusa.com/store/crf70-and-xr70-pegs-mounts-c-100_36_497.md)
- [Plastics & Graphics](https://tboltusa.com/store/crf70-and-xr70-plastics-graphics-c-100_36_499.md)
- [Rear Shocks & Skid plates](https://tboltusa.com/store/crf70-and-xr70-rear-shocks-skid-plates-c-100_36_500.md)
- [Seats & Tanks](https://tboltusa.com/store/crf70-and-xr70-seats-tanks-c-100_36_501.md)
- [Sprockets & Chains](https://tboltusa.com/store/crf70-and-xr70-sprockets-chains-c-100_36_498.md)
- [Wheels and Tires](https://tboltusa.com/store/crf70-and-xr70-wheels-and-tires-c-100_36_502.md)

## Products

Showing 1 to 21 of 21 products (page 1 of 1).

- [TBParts - Heavy Duty Clutch Kit for 67T- CRF70 , XR70 , Z50 69-87 ,CT70 K0 and 91-94 Models](https://tboltusa.com/store/tbparts-heavy-duty-clutch-kit-for-67t-crf70-xr70-z50-69-87-ct70-k0-and-91-94-models-p-415.md): part number `TBW0971-KIT`; $99.98 USD; 5 left
- [TBParts - Manual Clutch kit Z50 CRF50/70 XR50/70 & Pit bikes](https://tboltusa.com/store/tbparts-manual-clutch-kit-z50-crf5070-xr5070-pit-bikes-p-273.md): part number `TBW0953`; $189.99 USD; 4 left
- [TBParts - Roller Rocker Race Head V2 108cc Big Bore Kit XR70 & CRF70](https://tboltusa.com/store/tbparts-roller-rocker-race-head-v2-108cc-big-bore-kit-xr70-crf70-p-8608.md): part number `TBW9109-XR70-CRF70`; $729.99 USD; 2 left
- [TBParts - Roller Rocker Race Head V2 88cc Big Bore Kit XR70 & CRF70 w/ Mikuni VM24 Carb](https://tboltusa.com/store/tbparts-roller-rocker-race-head-v2-88cc-big-bore-kit-xr70-crf70-mikuni-vm24-carb-p-8734.md): part number `TBW9115`; $774.99 USD; 2 left
- [TBParts - Roller Rocker Race Head V2 Kit for 88cc XR70 & CRF70](https://tboltusa.com/store/tbparts-roller-rocker-race-head-v2-kit-for-88cc-xr70-crf70-p-8601.md): part number `TBW9102-XR-CRF70`; $549.99 USD; 2 left
- [70cc Rebuild kit with Full Gasket set with TBparts Piston for China 70 Honda XR70 CRF70 CRF50 XR50](https://tboltusa.com/store/70cc-rebuild-kit-with-full-gasket-set-with-tbparts-piston-for-china-70-honda-xr70-crf70-crf50-xr50-p-10084.md): part number `TRC-10084`; $109.00 USD; 1 left
- [70cc Rebuild kit with Gasket set for China 70 Honda XR70 CRF70 CRF50 XR50](https://tboltusa.com/store/70cc-rebuild-kit-with-gasket-set-for-china-70-honda-xr70-crf70-crf50-xr50-p-12656.md): part number `TRC-2681`; $99.00 USD; 1 left
- [BBR - 88cc Big Bore Kit for XR/CRF70 From 1997-2012](https://tboltusa.com/store/bbr-88cc-big-bore-kit-for-xrcrf70-from-1997-2012-p-12096.md): part number `411-HXR-7001`; $165.95 USD; 2 left
- [Honda - OEM Ball Retainer for CRF50 and XR50](https://tboltusa.com/store/honda-oem-ball-retainer-for-crf50-and-xr50-p-9059.md): part number `22860-GEL-A80`; $7.99 USD; out of stock
- [Intake and Exhaust Valve Kit Honda XR70 CRF70F](https://tboltusa.com/store/intake-and-exhaust-valve-kit-honda-xr70-crf70f-p-3174.md): part number `TRC-3174`; $34.95 USD; 2 left
- [Moose Offroad - High Compression Top End Gasket Set for CRF70 and XR70](https://tboltusa.com/store/moose-offroad-high-compression-top-end-gasket-set-for-crf70-and-xr70-p-12576.md): part number `PU-0934-0262`; $30.06 USD; 2 left
- [TBParts - Magnetic Oil Drain Bolt - XR50 CRF50 CRF70 KLX110 & Pit Bikes](https://tboltusa.com/store/tbparts-magnetic-oil-drain-bolt-xr50-crf50-crf70-klx110-pit-bikes-p-271.md): part number `TBW0341`; $6.99 USD; in stock
- [TBParts - Race Head Kit for 88cc For Z50 CRF50 XR50 & Pit bikes](https://tboltusa.com/store/tbparts-race-head-kit-for-88cc-for-z50-crf50-xr50-pit-bikes-p-45.md): part number `TBW0934`; $264.99 USD; in stock
- [TBparts - Replacment Clutch Kit for Honda 50 and 70 Semi-Auto](https://tboltusa.com/store/tbparts-replacment-clutch-kit-for-honda-50-and-70-semi-auto-p-2796.md): part number `TBW1907`; $24.95 USD; 5 left
- [TBParts - Roller Rocker Race Head V2 88cc Big Bore Kit XR70 & CRF70](https://tboltusa.com/store/tbparts-roller-rocker-race-head-v2-88cc-big-bore-kit-xr70-crf70-p-8605.md): part number `TBW9105-XR70-CRF70`; $599.99 USD; 2 left
- [TBParts - Standard Bore Piston Kit for CT70 91-94, All XR/CRF70](https://tboltusa.com/store/tbparts-standard-bore-piston-kit-for-ct70-91-94-all-xrcrf70-p-10654.md): part number `TBW1172`; $23.99 USD; 2 left
- [TBParts - Stock Shift Shaft - Z50 XR50 CRF50 XR70 CRF70 - 1988 - present](https://tboltusa.com/store/tbparts-stock-shift-shaft-z50-xr50-crf50-xr70-crf70-1988-present-p-1780.md): part number `TBW1222`; $24.99 USD; 3 left
- [TBParts - Stroker kit 1 108cc for Z50 CRF50 XR50 CRF70](https://tboltusa.com/store/tbparts-stroker-kit-108cc-for-z50-crf50-xr50-crf70-p-43.md): part number `TBW0966`; $189.99 USD; 4 left
- [TBParts - Stroker kit 2 108cc for Z50 CRF50 XR50 CRF70](https://tboltusa.com/store/tbparts-stroker-kit-108cc-for-z50-crf50-xr50-crf70-p-268.md): part number `TBW0967`; $352.99 USD; 3 left
- [TBParts - Stroker kit 3 108cc with Race Head for Z50 CRF50 XR50 CRF70](https://tboltusa.com/store/tbparts-stroker-kit-108cc-with-race-head-for-z50-crf50-xr50-crf70-p-269.md): part number `TBW0968`; $612.99 USD; 3 left
- [Wiseco Piston Honda XR/CRF70 STANDARD](https://tboltusa.com/store/wiseco-piston-honda-xrcrf70-standard-p-4888.md): part number `W-4880PS`; $160.95 USD; 1 left

Stock: "in stock" = 9 or more, a number = that many left, "out of stock" = cannot be ordered now. "options" = choose options on the product page before it can go in the cart. Product links go to the markdown copy; for the web page change the ending .md to .html.

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